Edible Polysaccharide Films and Coatings [1 ed.] 9781616684938, 9781616681913

Citation preview

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved. Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved. Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

BIOTECHNOLOGY IN AGRICULTURE, INDUSTRY AND MEDICINE SERIES

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

EDIBLE POLYSACCHARIDE FILMS AND COATINGS

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

BIOTECHNOLOGY IN AGRICULTURE, INDUSTRY AND MEDICINE SERIES Agricultural Biotechnology: An Economic Perspective Margriet F. Caswell, Keith O. Fuglie, and Cassandra A. Klotz 2003. ISBN: 1-59033-624-0 Biotechnology in Agriculture and the Food Industry G.E. Zaikov (Editor) 2004. ISBN: 1-59454-119-1

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

Biotechnology and Industry G.E. Zaikov (Editor) 2007. ISBN: 1-59454-116-7 Governing Risk in the 21st Century: Lessons from the World of Biotechnology Peter W.B. Phillips (Editor) 2006. ISBN: 1-59454-818-8 Research Progress in Biotechnology G.E. Zaikov (Editor) 2008. ISBN: 978-1-60456-000-8 Biotechnology and Bioengineering William G. Flynne (Editor) 2008. ISBN: 978-1-60456-067-1 Biotechnology: Research, Technology and Applications Felix W. Richter (Editor) 2008. ISBN: 978-1-60456-901-8 Biotechnology: Research, Technology and Applications Felix W. Richter (Editor) 2008. ISBN: 978-1-60876-369-6 (Online Book)

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Biotechnology, Biodegradation, Water and Foodstuffs G.E. Zaikov and Larisa Petrivna Krylova (Editors) 2009. ISBN: 978-1-60692-097-8 Industrial Biotechnology Shara L. Aranoff, Daniel R. Pearson, Deanna Tanner Okun, Irving A. Williamson, Dean A. Pinkert, Robert A. Rogowsky, and Karen Laney-Cummings 2009. ISBN: 978-1-60692-256-9 Industrial Biotechnology and the U.S. Chemical and Biofuel Industries James R. Thomas 2009. ISBN: 978-1-60741-899-3

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

Biosensors: Properties, Materials and Applications Rafael Comeaux and Pablo Novotny (Editors) 2009. ISBN: 978-1-60741-617-3 Biosensors: Properties, Materials and Applications Rafael Comeaux and Pablo Novotny (Editors) 2009. ISBN: 978-1-61668-181-4 (Online Book) Industrial Biotechnology: Patenting Trends and Innovation Katherine Linton, Philip Stone, Jeremy Wise, Alexander Bamiagis, Shannon Gaffney, Elizabeth Nesbitt, Matthew Potts, Robert Feinberg, Laura Polly, Sharon Greenfield, Monica Reed, Wanda Tolson, and Karen Laney-Cummings 2009. ISBN: 978-1-60741-032-4 Biochemical Engineering Fabian E. Dumont and Jack A. Sacco (Editors) 2009. ISBN: 978-1-60741-257-1 Biometals: Molecular Structures, Binding Properties and Applications Gaillard Blanc and Damien Moreau (Editors) 2010. ISBN: 978-1-60876-852-3

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Medicinal Plants: Classification, Biosynthesis and Pharmacology Alejandro Varela and Jasiah Ibañez (Editors) 2009. ISBN: 978-1-60876-027-5 Perspectives on Lipase Enzyme Technology J. Geraldine Sandana Mala and Satoru Takeuchi 2009. ISBN: 978-1-61741-977-8 Technologies and Management for Sustainable Biosystems Jaya Nair, Christine Furedy; Chanakya Hoysala and Horst Doelle (Editors) 2009. ISBN: 978-1-60876-104-3 Cellulose: Structure and Properties, Derivatives and Industrial Uses Arnaud Lejeune and Thibaut Deprez (Editors) 2010. ISBN: 978-1-60876-388-7

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

Synthetic and Integrative Biology: Parts and Systems, Design Theory and Applications James T. Gevona (Editor) 2010. ISBN: 978-1-60876-678-9 Synthetic and Integrative Biology: Parts and Systems, Design Theory and Applications James T. Gevona (Editor) 2010. ISBN: 978-1-61668-347-4 (Online Book) Carbohydrate Binding Modules: Functions and Applications Susana Moreira and Miguel Gama 2010. ISBN: 978-1-60876-979-7 Bioengineering: Principles, Methodologies and Applications Audric Garcia and Ciel Durand (Editors) 2010. ISBN: 978-1-60741-762-0 Biotechnology in Medicine, Foodstuffs, Biocatalysis, Environment and Biogeotechnology Sergey D. Varfolomeev, Gennady E. Zaikov and Larisa P. Krylova (Editors) 2010. ISBN: 978-1-60876-902-5

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Strategic Alliances in Biotechnology and Pharmaceuticals Hans Gottinger and Celia Umali 2010. ISBN: 978-1-60876-997-1 Use of Organosilanes in Biosensors V. Dugas, C. Demesmay, Y. Chevolot and E. Souteyrand 2010. ISBN: 978-1-61668-029-9 Use of Organosilanes in Biosensors V. Dugas, C. Demesmay, Y. Chevolot and E. Souteyrand 2010. ISBN: 978-1-61668-073-3 (Online Book) Edible Polysaccharide Films and Coatings Pau Talens, María José Fabra and Amparo Chiralt 2010. ISBN: 978-1-61668-191-3

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

Edible Polysaccharide Films and Coatings Pau Talens, María José Fabra and Amparo Chiralt 2010. ISBN: 978-1-61668-493-8 (Online Book) Bioactive Oligosaccharides: Production, Biological Functions and Potential Commercial Applications Aneli M. Barbosa, Robert F. H. Dekker and Ellen C. Giese 2010. ISBN: 978-1-61668-149-4 Pathogen Detection Methods: Biosensor Development Eva Baldrich and Cristina Garcia-Aljaro 2010. ISBN: 978-1-61668-298-9 Pathogen Detection Methods: Biosensor Development Eva Baldrich and Cristina Garcia-Aljaro 2010. ISBN: 978-1-61668-699-4 (Online Book)

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved. Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

BIOTECHNOLOGY IN AGRICULTURE, INDUSTRY AND MEDICINE SERIES

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

EDIBLE POLYSACCHARIDE FILMS AND COATINGS

PAU TALENS, MARÍA JOSÉ FABRA AND

AMPARO CHIRALT

Nova Science Publishers, Inc. New York

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010 by Nova Science Publishers, Inc. All rights reserved. No part of this book may be reproduced, stored in a retrieval system or transmitted in any form or by any means: electronic, electrostatic, magnetic, tape, mechanical photocopying, recording or otherwise without the written permission of the Publisher. For permission to use material from this book please contact us: Telephone 631-231-7269; Fax 631-231-8175 Web Site: http://www.novapublishers.com

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

NOTICE TO THE READER The Publisher has taken reasonable care in the preparation of this book, but makes no expressed or implied warranty of any kind and assumes no responsibility for any errors or omissions. No liability is assumed for incidental or consequential damages in connection with or arising out of information contained in this book. The Publisher shall not be liable for any special, consequential, or exemplary damages resulting, in whole or in part, from the readers’ use of, or reliance upon, this material. Independent verification should be sought for any data, advice or recommendations contained in this book. In addition, no responsibility is assumed by the publisher for any injury and/or damage to persons or property arising from any methods, products, instructions, ideas or otherwise contained in this publication. This publication is designed to provide accurate and authoritative information with regard to the subject matter covered herein. It is sold with the clear understanding that the Publisher is not engaged in rendering legal or any other professional services. If legal or any other expert assistance is required, the services of a competent person should be sought. FROM A DECLARATION OF PARTICIPANTS JOINTLY ADOPTED BY A COMMITTEE OF THE AMERICAN BAR ASSOCIATION AND A COMMITTEE OF PUBLISHERS. LIBRARY OF CONGRESS CATALOGING-IN-PUBLICATION DATA Available upon reques. ISBN: H%RRN

Published by Nova Science Publishers, Inc. † New York

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

CONTENTS Preface

vii

Introduction

1

Chapter 1

Polysaccharides Used for Edible Films and Coatings

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

Chapter 2

3

Polysaccharide Film Formation and Film Characteristics

17

Chapter 3

Polysaccharide Film Properties

23

Chapter 4

Applications of Polysaccharide-Based

Chapter 5

Films in Food Products

29

Conclusions

37

References

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

39

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved. Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

PREFACE Moisture, oxygen, carbon dioxide, lipid, flavor and/or aroma transfer between food components or between foods and their surrounding environment can provoke deterioration of food texture, flavour, color, aroma or nutritional values which results in food quality loss. Regulating the mass transfer in food systems by edible films and coatings can increase foodproduct shelf life and food quality. Besides their barrier properties, edible films and coatings can act as carriers for functional food additives, antioxidants, antimicrobial agents and nutrients; and due to their biodegradability nature, could have an impact on overall packaging requirements. Edible films and coatings are produced from edible biopolymers and foodgrade additives. Film-forming biopolymers can be proteins, polysaccharides (carbohydrates and gums) or lipids. Plasticizers and other additives are combined with the film-forming biopolymers to modify the physical properties or functionality of films. The composition of the film must be chosen according to specific food applications, the type of food products and the major mechanisms of quality deterioration. Polysaccharide films and coatings are used to extend the shelf life of fruits, vegetables, seafood, meats and confectionary products by preventing dehydration, oxidation rancidity, surface browning and oil diffusion; and in some specific cases can improve the physicochemical, nutritional and sensorial properties of the products. The common polysaccharides used for edible films are: starches and their derivatives; cellulose and its derivatives; seaweed extracts; gums; pectins and chitosan. The objectives of this chapter are to (a) review research on polysaccharide film-formation and characteristics, (b) analyze mechanical and barrier

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

xii

Preface

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

properties (water vapour permeability, gas permeabilities and volatile permeability) of polysaccharide-based films, (c) summarize applications of polysaccharide films in food products, and (d) make conclusions as to the status of polysaccharide films and their future developmental direction.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

INTRODUCTION In the last recent years, impressive advances have been made in the production of synthetic polymer films designed to protect foods. Nowadays, food companies and researchers are looking to edible films and coatings to add value to food products, increase shelf-life and/or reduce packaging. Edible films can be used for: coating fresh whole and pre-cut fruits and vegetables to reduce moisture loss, respiration and color change; coating frozen foods to prevent oxidation, as well as prevent moisture, aroma or color migration; coating nuts to prevent oil migration into surrounding food components; coating fragile foods such as breakfast cereals and freeze-dried foods to improve integrity and reduce loss due to damage; or for coating candies, cookies and/or nuts in ice cream to provide a moisture barrier and keep inclusions crisper. Edible films can also stabilize water activity gradients and preserve different textural properties possessed by different food components. For example, an edible film could be used to separate the crisp component of a pizza from the moist semi-solid component. The protective function of edible films and coatings may be enhanced with addition of antioxidants or antimicrobials to the films or coating. Depending on the nature of the food, food additives, such as, flavors, nutrients or colors can be incorporated into edible films and used to control location or rate of release of these additives in a food. A specific film-coating composition is selected as a function of the desired application for the edible food film to be produced. For example, when the purpose is to provide an individual barrier protection in opposition to moisture and oxygen in fresh fish, cheese, meat products or intermediate moisture foods, a film with low water and oxygen permeabilities is required; whereas, when the purpose is to control the moisture balance within heterogeneous foods such as pizzas, sandwiches or cakes, hydrophobic materials are required to make a film with good water barrier properties.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

2

Pau Talens, María José Fabra and Amparo Chiralt

Materials available for forming edible films and coatings fall generally into the categories of lipids, proteins or polysaccharides. The functional properties of edible films and coatings are greatly influenced by the physical and chemical characteristics of the materials used (Sothornvit and Krochta, 2000). Biopolymers can be used independently or in combinations. Films prepared by polysaccharides or proteins generally have excellent oxygen, carbon dioxide, aroma and lipid barrier properties; particularly at low relative humidity levels. They have desirable mechanical properties, making them constructive for improving the structural integrity of fragile products; but inaptly, their predominantly hydrophilic character results in them having poor water barrier characteristics. Due to their hydrophobicity, lipid compounds have been used as protective barrier layers to prevent moisture exchange between the food product and the surrounding medium, or between adjacent components within heterogeneous foods. Proteins and polysaccharides can be combined with lipids, as emulsion particles or multi-layered coatings in order to increase the resistance to water penetration (Pérez-Gago and Krochta, 2001; Morillon et al., 2002, Karbowiak, Debeaufort and Voilley, 2007, Hambleton et al., 2008) The use of polysaccharides as coating materials for food protection has long been recognized and grown extensively in recent years (Cuq et al., 1994, Nisperos-Carriedo, 1994, Phan The et al., 2002, Lacroix and Le Tien, 2005, Phan et al., 2009a,b). Polysaccharides film-forming materials include starches and their derivatives, cellulose and its derivatives, seaweed extracts, gums, pectins and chitosan. The use of polysaccharides presents advantages due to their availability, low cost and biodegradability. Furthermore, polysaccharides can be easily modified in order to improve their physicochemical properties. The sequence of polysaccharides is simple compared to proteins, which have 20 common amino acids. However, the conformation of polysaccharide structures is more complicated and unpredictable, resulting in much longer molecular weights than proteins. Most carbohydrates are neutral, while some gums are mostly negatively charged. Although this electrostatic neutrality of carbohydrates may not significantly affect the properties of formed films and coatings, the occurrence of relatively large numbers of hydroxyl groups or other hydrophilic molecules in the structure indicate that hydrogen bonds may play significant roles in film formation and characteristics. Some negatively charged gums, such as alginate, pectin and carboxymethylcellulose, show significantly different rheological properties in acidic than in neutral or alkaline conditions (Han and Gennadios, 2005)

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Chapter 1

POLYSACCHARIDES USED FOR EDIBLE FILMS AND COATINGS

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

Polysaccharides are obtained from a variety of sources. Common polysaccharides used for edible films and coatings (Table I.1) include starches and their derivatives, cellulose and its derivatives, seaweed extracts, gums, pectins and chitosan.

STARCHES AND DERIVATIVES Starch is one of the most abundant natural polysaccharide, principally derived from tubers or cereals, consisting of a large number of glucose monosaccharide units joined together by glycosidic bonds. It is constituted by two types of molecules: the linear amylase and the branched amylopectin. The content of amylase in starch varies from 0 to 100%, depending on the botanic origins. Most starches, such as those from wheat, corn and potato, contain 20 to 25 percent of amylose and 75 to 80 percent of amylopectin. However, for amylomaizes, the amylose content can be higher than 50 percent and for 'waxy' maize it can be less than 5 percent (Li and Yeh, 2001; Singh et al., 2003). In unmodified forms, starches have very limited use in the food industry, but modified starches by disruption of hydrogen bonding or by chemical substitution, have significantly been playing important roles in the food industry.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

4

Pau Talens, María José Fabra and Amparo Chiralt TabIe.I.1. Common polysaccharides used for edible films and coatings. Structure, formula, properties and films characteristics Polysacc Structure and Polysaccharide Film characteristics haride Formula Properties Odorless, no taste. Modify physical Odorless, tasteless, and properties of food colorless. Low products, permeability to oxygen. contributing Low cost of mainly to texture, production. Starches viscosity, gel Physical formation, characteristics, adhesion, binding, chemical resistance and (C6H10O5)n moisture retention, mechanical properties product similar to those of homogeneity and plastic films. film formation Insoluble in water Transparent, flexible, and most organic odorless, tasteless, Cellulose solvents, water-soluble, and odourless, no taste, resistant to oils and fats (C6H1202)n biodegradable. Insoluble in hot water and soluble No good moisture in cold water and barriers. Excellent Methyl organic solvents. barrier against cellulose The solubilization migration of fats and of MC in organic oils. It can be used to solvents depends reduce oil absorption in of the degree of fried products. substitution.

Hydroxy propyl cellulose

Insoluble in hot water and soluble in cold water and organic solvents.

Thermoplastic and capable of injection molding and extrusion. It can retard spoilage and moisture absorption in coated nuts and candies.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Polysaccharides Used for Edible Films and Coatings Polysacc haride hydroxyp ropyl methylcel lulose

Structure and Formula

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

Carboxy methyl cellulose

Sodium alginate (C6H7NaO6)n Alginate

Calcium alginate (C6H7Ca1/2O6)n

5

Polysaccharide Properties

Film characteristics

Insoluble in hot water and soluble in cold water and organic solvents.

Effective film that can reduce oil absorption in certain reformed products.

Soluble in hot and cold water but insoluble in organic solvents. It basic function is to bind water or impart viscosity to the aqueous phase thereby stabilizing the other ingredients or preventing synerersis.

Forms a complex in the presence of casein, increasing the coatings formulation viscosity. It retains the firmeness of fruits and vegetables, preserves important flavor components of some fresh commodities, reduces oxygen uptake without causing carbon dioxide increase in internal fruits and vegetables, and improves the puncture strength of films based on caseinate

Thickening, stabilizing, suspending, film forming, gel producing and emulsion stabilizes properties.

Uniform, transparent and water-soluble films. Poor moisture barriers Good oxygen barriers. Can retard lipid oxidation in foods, and can improve flavor, texture and batter adhesion. The treatment of alginate films with divalent cation (i.e. calcium) solutions converts these into insoluble films.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

6

Pau Talens, María José Fabra and Amparo Chiralt

Polysacc haride

Carrageenan

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

KapaCarregee nan

IotaCarregee nan

TabIe.I.1. (Continued) Structure and Polysaccharide Formula Properties

Film characteristics

Water soluble galactose polymers. Extensively used as gelling and stabilizing agents in food industries.

Uniform, transparent and water soluble films with good mechanical properties.

Soluble in hot water. Form strong, rigid gels, some syneresis. Insoluble in most organic solvents Slightly opaque gel. Become clear with sugar.

Form excellent gel and film forming properties. Exhibits the highest tensile strength when compared with that of - and -carrageenan films. -carrageenan film containing potassium sorbate had great potential for antimicrobial food packaging, valued properties for extending shelflife or increasing the safety of foods.

Soluble in hot water. The addition of calcium ions ill induces the formation of a durable, elastic gel and increase gelling and melting temperature. Insoluble in most organic solvents.

Good mechanical characteristics. Are emulsion stabilizers, and decrease oxygen transfer.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Polysaccharides Used for Edible Films and Coatings Polysacc haride

Structure and Formula

Polysaccharide Properties

Film characteristics

Partially soluble in cold water, fully soluble in hot water. No gel, random distribution of polymer chains. Range from low to high viscosity. Insoluble in most organic solvents. Compatible with water organic solvents.

Transparent and water soluble films with good mechanical properties.

Agar

Agar produces perceptible gelation at concentrations as low as 0.04%. It forms strong gels characterized by melting points far above the initial gelation temperature.

Clear, transparent, strong and flexible films even at low moisture content levels. Similar water vapor permeability to starch films, arabinoxylan films or cellulose derivative films.

Pulullan gum

Water soluble, insoluble in organic solvents and nonhygroscopic in nature. Its aqueous solutions are stable and show a relatively low viscosity as compared to other polysaccharides. It decomposes at 250– 280 ºC.

Clear, odorless and tasteless. Good oxygen barriers. Generally, pullulan films are commonly combined with other polysaccharides or proteins to improve functional properties of edible films

lamdaCarragee nan

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

7

[-D-Glcp-(1_4)--DGlcp-(1→4)--D-Glcp(1→6)]n (C6H10O5)n

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

8

Pau Talens, María José Fabra and Amparo Chiralt

Polysacc haride

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

Gellan gum

Pectin

TabIe.I.1. (Continued) Structure and Polysaccharide Formula Properties Gels are formed by dispersing the gellan gum in water, heating, adding cations, and then cooling to set. Gel texture can be modified by blending with other gums. It has good stability over a wide pH range (3.5-8.0)

Food additive which is mainly used for its gelling and stabilizing abilities. Very complex structure which depends on both its source and the extraction process. It forms gels in aqueous media containing sugar and acid.

Film characteristics

Transparent, stronger and more brittle films than alginate or carrageenan films.

Can control water activity, preventing moisture loss from food by acting as a sacrificial agent. It can potentially limit fat migration, provide a barrier to gas, help to trap flavor and aroma, and carry and present antioxidants or antimicrobials. High-methoxy pectin forms excellent films Low-methoxyl pectin forms gels in the presence of calcium ions and can also be used for developing edible films.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Polysaccharides Used for Edible Films and Coatings Polysacc haride

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

Chitosan

Structure and Formula

Polysaccharide Properties

Film characteristics

Purified qualities of chitosans are available for biomedical applications. It is nontoxic, biodegradable, and biocompatible. Antimicrobial and antifungal activities

Highly permeable to water vapor. Excellent oxygen barrier properties. Good mechanical properties. Good antimicrobial activity.

9

They have been used to modify physical properties of food products such as soups, sauces, snacks, batters and meat products; contributing mainly to texture, viscosity, gel formation, adhesion, binding, moisture retention, product homogeneity and film formation (Liu, 2005). For applications where viscosity, stability and thickening strength are desired, starches with a high content of amylopectin are required; whereas, for film-forming purposes and for the preparation of strong gels, starches with a high content of amylase are required (Nisperos-Carriedo, 1994).

CELLULOSE AND DERIVATIVES Cellulose, a structural component of the primary cell wall of green plants, many forms of algar and the oomycetes, is a polysaccharide consisting of a linear chain of several hundred to over ten thousand β(1→4) linked D-glucose units. Chemically, cellulose can be broken down into smaller polysaccharides called cellodextrins, or completely into glucose units, by treating it with concentrated acids at high temperature; however, hydrolysis of cellulose is relatively difficult compared to the breakdown of other polysaccharides. Many properties of cellulose depend on its degree of polymerization, or chain length; the numbers of glucose units that make up one polymer molecule (i.e.;

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

10

Pau Talens, María José Fabra and Amparo Chiralt

cellodextrins), in contrast to long-chain cellulose, are typically soluble in water and organic solvents. Due to the high level of intramolecular hydrogen bonding, cellulose is insoluble in water and most organic solvents, but is odorless, biodegradable and has no taste. Compared to starch, cellulose is also much more crystalline. Whereas, starch undergoes a crystalline to amorphous transition when heated beyond 60-70 °C in water (as in cooking), cellulose requires a temperature of 320 °C and pressure of 25 MPa to become amorphous in water. Cellulose is the most abundantly occurring natural polymer on earth and is a cheap raw material. For film production, cellulose is dissolved in an aggressively toxic mixture of sodium hydroxide and carbon disulfide and then recast into sulfuric acid to produce cellophane films (Petersen et al., 1999). However, the usefulness of cellulose as a starting material for edible films and coatings can be extended by chemical modification to cellulose derivatives. The hydroxyl groups of cellulose can be partially or fully reacted with various reagents to afford derivatives with useful properties. Cellulose esters and cellulose ethers are the most important commercial materials. Generally, ether derivatives, like Methylcellulose (MC), Hydroxypropylcellulose (HPC), Hydroxypropylmethylcellulose (HPMC), Carboxymethylcellulose (CMC) or microcrystalline cellulose (MCC) have excellent film-forming properties and are used as raw material for edible films and coatings. Under controlled temperatures and pressures, alkali cellulose is allowed to react with methyl chloride to form MC; with propylene oxide to form HPC; with methyl chloride and propylene oxide to form HPMC and with sodium monochloroacetate to form CMC. MCC is formed by controlled acid hydrolysis of native cellulose. The level quantity of methoxyl, hydroxypropyl or carboxymethyl substitution affects the physical and chemical properties of the material. The number of substituted hydroxyl groups per monomeric units is known as the degree of substitution (DS). MC, HPC and HPMC, nonionic cellulose ethers, are commercially available in powder or granular form, and in varying molecular weights and DS. They are insoluble in hot water but are soluble in cold water and organic solvents (solubilitacion of MC in organic solvents depends of the degree of substitution, under 2.6 DS is partially soluble and upper 2.6 DS is complete soluble). CMC, anionic cellulose ether, is available in a variety of types based on particle size, DS, viscosity and hydration characteristics for different food applications. It is soluble in hot and cold water but insoluble in organic

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Polysaccharides Used for Edible Films and Coatings

11

solvents. It basic function is to bind water or impart viscosity to the aqueous phase thereby stabilizing the other ingredients or preventing syneresis. MCC, is used to gel a variety of sugar-based products, to stabilized a number of low-calorie foods, to replace oil in emulsions, to control ice crystal growth, and for suspension of particulates such as chocolate in sterilized chocolate drinks (Dziezak, 1991)

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

SEAWEED EXTRACTS There are many different types of seaweed extracts used in the food industry. Generally, alginate, carrageenan, agar and furcellan are used for edible films and coatings. Alginates are known as potential biopolymer films or coating components, due to their unique and well-studied colloidal properties; which include, thickening, stabilizing, suspending, film forming, gel producing and emulsion stabilizes properties (Moe et al., 1995; Rhim, 2004). The component with these properties in consideration is a hydrophilic colloidal carbohydrate extracted with dilute alkali from various species of brown seaweeds (Phaeophyceae). Alginates are composed of 1–4 -D-mannuronic acid (M) and -L-guluronicacid (G). In the polymer chain, the monomers are arranged alternately in GG and MM blocks, together with MG blocks. The chemical composition and sequence of the M and G blocks are conditioned by the biological source and growth, and by the seasonal environment (Smidsrød, 1974). While the M-block segments develop in linear and flexible structures, the G-block residues give rise to fold and rigid structures and are responsible for the pronounced stiffness in the molecular chains. The ability of alginates to react with di- and trivalent cations is being exploited in the formation of alginate films. Carrageenans are water soluble galactose polymers extracted from red seaweed (Rhodophyceae), which are extensively used, as gelling and stabilizing agents, in food and pharmaceutical industries. The three main carrageenans, kappa, iota and lambda, differ only in the number of sulphate groups, 20, 33 and 41% (w/w) respectively. They are widely used in the food industry to improve thickening and texture qualities and to stabilize food products. Moreover, they are a renewable resource and commercially available at a reasonable cost. -carrageenan is the most sulphated of the three main carrageenans mentioned, and adopts a coil conformation under all ionic and

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

12

Pau Talens, María José Fabra and Amparo Chiralt

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

temperature conditions. While kappa and iota carrageenans form gels, lambda is unable to do it and is used as a pure thickener (Langendorff et al., 2000; Lizarraga et al., 2006). Iota-carrageenan is composed of altering α(1,3)Dgalactose-4-sulphated and β(1,4)-3,6-anhydro-D-galactose-2-sulphate. In aqueous solutions, -carrageenans produce thermoreversible gels once cooling below the critical temperature; from that point on, the conformation changes from a random coil of single chains, to the formation of double helices of carrageenan chains, and consequently to gels (Yuguchi et al., 2002). Agar is a gum that is derived from a variety of red seaweeds, and, like carrageenan, it is a galactose polymer (Sanderson, 1981). Agar produces perceptible gelation at concentrations as low as 0.04%; and it forms strong gels characterized by melting points far above the initial gelation temperature (Whistler and Daniel, 1985). It is best known as a culture medium and is not used to great extent in foods. Agar based films have recently been tested for edible films (Phan et al., 2008, Phan et al., 2009). Furcellaran is extracted from seaweed Furcellaria fastigiata which is found in the waters surrounding Denmark. It is mainly used in Europe in producing jams and jellies, fruit juices, confectionery, milk puddings, chocolate milk and beer.

GUMS Different varieties of exudates gums, seed gums and microbial fermentation gums are used for edible films and coatings. As described Nispero-Carriedo, 1994, exudate gums are structurally complex heteropolysaccharides obtained from natural exudates of different tree species. Gum Arabic; the dried gummy exudate from the stems or branches of Acacia Senegal and related species of Acacia; gum tragacanth; the dried gum exuded by the steams of Astragalus gummifer and other Asiatic species of Astragalus; gum ghatti; exudate of the Anogeissus latifolia tree and gum karaya; and the dried gummy exudate of the Sterculia tree are all examples of exudate gums that can be used for edible films and coatings. The uses of gum Arabic are based upon its action as a protective colloid or stabilizer and the adhesiveness of its water solutions. It has been used in confections and as a foam stabilizer and agent to promote adhesion of foams to glass. As coating has been used as a protective film on oily foods for eliminate moist, oily appearance and provide a low-calorie product. The gum tragacanth is mainly used as a thickener and stabilizer in salad dressings, sauces, bakery emulsion, toppings,

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

Polysaccharides Used for Edible Films and Coatings

13

ice cream, and confectionery. Its film-forming properties are useful in nonfood systems such as hair lotions, hand lotions and creams. Gum ghatti has been used effectively in food systems as an emulsifier and stabilizers, but films formed form ghatti dispersions are relatively soluble, brittle, and are not considered very useful. Gum karaya has been used as an emulsifier, stabilizer, or binder in the frozen desserts, dairy products, salad dressings, or meat products, but today it has been replaced by better stabilizers. Examples of seed gums that can be used for edible films and coatings are locust bean gum and guar gum. Both are soluble in water (locust bean gum must be heated to be dissolved) and have high viscosity. Though they are insoluble in organic solutions, they are compatible with other polysaccharides and proteins (Nispero-Carriedo, 1994). Locust bean gum generally is used as a thickener or viscosity modifier, binder of free water, suspending agent or stabilizer in chesses, frozen confections, bakery products, pie fillings, meats, sauces and salad dressings. Guar gum is used for controlling the mobility of dispersed or solubilized materials in water. It is used in dairy, bakery and meat products; as well as in beverages and salad dressings. Pullulan, xanthan and gellam gums are microbial polysaccharides that are edible and biodegradable. Pullulan is one of those commercially emerging biopolymers, synthesized by a yeast-like fungus known as Aureobasidium pullulans. It is a water soluble, random coil glucan gum that serves as a paradigm for the behavioral aspects of aqueous polysaccharides (Yalpani, 1988, Morris, 1995; Tsujisaka and Mitsuhashi, 1993, Singh, Saini and Kennedy, 2008). It is a regularly repeating copolymer, with the chemical structure { 6)-a-D-glucopyranosyl-(1  4)-a-D-glucopyranosyl-(1  4)-aD-glucopyranosyl- (1}n. Thus, the polysaccharide is viewed as a succession of a-(1  6)-linked (1 4)-a-D-triglucosides i.e. maltotriose (G3). Pullulan’s solubility can be controlled, or provided with reactive groups, by chemical derivatization. Consequently, pullulan (and its derivatives) has wide potential for food, pharmaceutical and other industrial applications. Pullulan is water soluble, insoluble in organic solvents and non-hygroscopic in nature. Its aqueous solutions are stable and show a relatively low viscosity as compared to other polysaccharides. It decomposes at 250–280 ºC. It is moldable and spinnable, being a good adhesive and binder. It is also non-toxic, edible, and biodegradable (Singh, Saini and Kennedy, 2008). Pullulan membranes/films are being used as coating and packaging materials for foods such as instant food seasonings, powdered tea and coffee. Pullulan-coated paper also decomposes easily and does not contaminate the environment (Doman - Pytka and Bardowski, 2004).

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

14

Pau Talens, María José Fabra and Amparo Chiralt

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

Xanthan gum is produced by fermentation from the organism Xanthomonas campestris. It contains five sugar residues: two β-Dglucopyranosyl, two β-D-mannopyranosyl, and one β- glucopyranosyluronic acid residue (Jansson et al., 1975; Melton et al., 1976). Xanthan gum is soluble in both cold and hot water and has a high viscosity. It is used for its thickening, suspending and stabilizing effects in salad dressings, dry mix products, icings and frostings, confectionery, dairy products, fruit gels, sauces, syrups and baked goods. It can be used to provide uniform coating, good clinging qualities, improved adhesion in wet batters, and to prevent moisture migration during frying (Nisperos-Carriedo, 1994). Gellan gum is produced by the fermentation of a pure culture of Pseudomonas elodea. The gum has a linear tetrasaccharide as a repeating unit, consisting of (13)-β-D-glucopyranosyl, (14)- β-D- glucopyranosyluronic, (14) )-β-D-glucopyranosyl, and (14)-α-L-rhamnopyranosyl units. Gels are formed by dispersing the gellan gum in water, heating, adding cations, and then cooling to set. Gel texture can be modified by blending with other gums, especially the gelling gums. It has good stability over a wide pH range (3.58.0) (Nisperos-Carriedo, 1994).

PECTINS Pectin is a family of heterogeneous branched polysaccharides consisting mostly of variably methylated galacturonan segments separated by rhamnose residues, some of which may be linked to short neutral sugar side chains. The rhamnose residues redirect the orientation of galacturonan segments to produce kinks, which upon aggregation, ensure open structures favorable for gel formation. Isolation of pectin from plant cell walls is achieved by breaking up the gel structure, usually stabilized by calcium cations, to solubilize large aggregates of pectin. Various grades of pectin are commercially available in different degrees of methyl esterification and in different ranges of molecular weights, or more accurately, different degrees of disaggregation (Hoagland and Parris, 1996).

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Polysaccharides Used for Edible Films and Coatings

15

CHITOSAN

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

Chitosan is derived from chitin by deacetylation in the presence of alkali. Therefore, chitosan is a copolymer consisting of -(1-4)-2-acetamido-glucose and -(1-4)-2-amino--glucose units with the latter usually exceeding 80%. Chitosans are described in terms of the degree of deacetylation and average molecular weight; and, their importance resides in their antimicrobial properties in conjunction with their cationicity and their film-forming properties (Muzzarelli, 1996). This is the second most abundant polysaccharide on Earth, after cellulose, (Lezica and Quesada-Allue, 1990) and is commercially available from a stable, renewable source; that is, waste from the shellfish industry (Andrady and Xu, 1997).

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved. Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Chapter 2

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

POLYSACCHARIDE FILM FORMATION AND FILM CHARACTERISTICS Polysaccharide film formation and film characteristics depend of the type of polysaccharides used. Table I.1 summarize structure, formula and polysaccharide properties and Film characteristics For edible starch films, it is important to prepare a clear starch solution with proper solid concentration, in order to insure both the continuity of films and the ease of casting. A solid concentration of 10-15% is suggested for casting conventional starch films (Liu, 2005). With high concentrations, the solution is too viscous to be cast; and with low concentrations, the solution of completely solubilized starch polymers has low level gelling results, causing problems for the process of forming a continuous film of sufficient thickness (Protzman et al., 1967). To prevent the hydrolysis or oxidation of starch, the formation process of edible starch films must ensure that the starch polymers are completely gelatinized, disintegrated and solubilized (Lourdin et al., 1997). Complete solubilization of starches in water required high temperatures and can be facilitated using amylase-complexing agents like butanol. Aqueous starch solutions are normally unstable, and in this sense, it is necessary to keep the starch solution at a temperature above their gelation temperature prior casting. When the solid concentration is 10-15%, the gelation temperature is 60-74 ºC (Muetgeert et al., 1962). Generally, films produced from edible starches are odorless, tasteless, and colorless and exhibit physical characteristics, chemical resistance and mechanical properties similar to those of plastic films (Wolff et al., 1951). They have been utilized in the packaging and coating of food products because of their edibility, low permeability to oxygen and their low cost of production. The overall performance of starch

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

18

Pau Talens, María José Fabra and Amparo Chiralt

films and coatings is highly likely to be customizable, because of the availability of a wide variety of starches and their capacity for physical and/or chemical modifications (Liu, 2002). They are commonly used in bakery, confectionery, batters and meat products (Thomas and Atwell, 1997). MC, HPC and HPMC are water soluble ethers with good film-forming properties. In order to avoid the formation of agglomerates the dissolution of these nonionic cellulose ethers must be done in two steps: dispersion and hydration. Wherever possible, they should be put into solution before other soluble ingredients are added or should be dispersed in water miscible nonsolvent such as glycerol, ethanol or propylene glycol and then add the slurry to water. The solutions of these cellulose ethers are stable at pH 2-11 and are compatible with surfactants, other water-soluble polysaccharides, and with salts. The procedure for the preparation of clear CMC solutions follows that of the nonionic cellulose ethers, except for pH conditions. CMC solutions are only stable at pH 7-9. CMC is compatible with a wide range of other food ingredients including protein, sugar, starches and others hydrocolloids. Edible coatings including MC, HPC, HPMC or CMC have been applied to a variety of foods to provide moisture, oxygen or oil barriers, and to improve batter adhesion. These cellulose ether films are generally transparent, flexible, odorless, tasteless, water-soluble, and resistant to oils and fats (NisperoCarriedo, 1994; Lacroix and Le Tien, 2005). MC films do not have good moisture barriers, but do provide an excellent barrier against migration of fats and oils and it can be used to reduce oil absorption in fried products. HPC is thermoplastic and capable of injection molding and extrusion. It can retard spoilage and moisture absorption in coated nuts and candies. The film-forming characteristics of HPMC upon heating provide an effective film that can reduce oil absorption in certain reformed products. CMC forms a complex in the presence of casein, increasing the coatings formulation viscosity. It retains the firmeness of fruits and vegetables, preserves important flavor components of some fresh commodities, reduces oxygen uptake without causing carbon dioxide increase in internal fruits and vegetables, and improves the puncture strength of films based on caseinate (Lacroix and Le Tien, 2005). Alginates produce uniform, transparent and water-soluble films. Divalent cations are used as gelling agents (to induce ionic interactions, followed by hydrogen bonding) in the formation of alginate films (Kester and Fennema, 1986). Films and coatings can be made from a sodium alginate solution; these films and coatings can be produced by means of a rapid reaction with a cold application of calcium, forming intermolecular associations involving the G-

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

Polysaccharide Film Formation and Film Characteristics

19

blocks regions (Nisperos-Carriedo, 1994). The treatment of alginate films with divalent cation (i.e. calcium) solutions converts these into insoluble films (Pavlath et al., 1999). Alginates films are quite brittle; nonetheless, they may be further plasticized with glycerol (Nussinovitch and Hershko, 1996, Cha et al., 2002, Rhim, 2004, Immirzi et al., 2009). Alginate coatings are good oxygen barriers, can retard lipid oxidation in foods, and can improve flavor, texture and batter adhesion. Due to it high hydrophilic nature, alginate based films are poor moisture barriers; although alginate gel coatings can significantly reduce moisture loss from foods, because moisture is lost from the coating before the food dehydrates (Conca and Yang, 1993). Fabra et al., 2008 evaluated the effect of adding alginates to sodium caseinate-lipid films. In lipid free films, alginates improved the tensile properties of films, although water vapor permeability values increased. However, in sodium caseinate-lipid films, the addition of alginates to protein matrices produced less flexible, less stretchable and more permeable films. Carrageenan-based coatings have been applied to a variety of foods for a long time, they have been applied to incorporate antimicrobials or antioxidants, and to reduce moisture loss, oxidation, or disintegration (Lacroix and Le Tien, 2005). -carrageenan has one negative charge per disaccharide, with a tendency to form excellent gel and film forming properties, and exhibits the highest tensile strength when compared with that of - and -carrageenan films (Park, 1996). Choi et al., 2005 reported that the studied -carrageenan film containing potassium sorbate had great potential for antimicrobial food packaging, valued properties for extending shelf-life or increasing the safety of foods, when it is used as packaging or coating material. -carrageenan-based edible films have good mechanical characteristics, are emulsion stabilizers, and decrease oxygen transfer. The addition of lipids to form emulsified films decreases the water vapor transfer and could be used to encapsulate active molecules or aroma compounds (Hambleton et al., 2008, Fabra et al., 2009). Fabra et al., 2008 reported that -carrageenan improves tensile and water vapor permeability of sodium caseinate-oleic acid-beeswax films, though barrier properties of lipid-free films decreased with -carrageenan. The films made of agar are clear, transparent, strong and flexible even at low moisture content levels. Their water vapor permeability quality did not appreciably differ in comparison to starch films, arabinoxylan films or cellulose derivative films. Moreover, agar based films were found to be heatsealable. Like with other polysaccaharides; antioxidants, antimicrobials, bacteriocins or antibiotics can be incorporated in agar based films to improve

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

20

Pau Talens, María José Fabra and Amparo Chiralt

shelf life of foods. Phan et al., 2009b studied edible films based on the binary combination of agar, cassava starch and arabinoxylan; the study was conducted with investigative emphasis on their microstructure, moisture barrier and mechanical properties. They observed that mechanical properties of agar based films are degraded when cassava or arabinoxylan were added. The results suggest that agar can potentially provide a very good cohesive matrix, which contributes towards enhancing the mechanical properties of other polysaccharide based films. Pullulan films cast from aqueous solutions are clear, odorless and tasteless and have good oxygen barriers (Yuen, 1974, Conca and Yang, 1993). Pullulan films are commonly combined with other polysaccharides (alginate, carboxymethylcellulose) or proteins (whey protein, sodium caseinate) to improve functional properties of edible films (Tong, Xiao, and Lim, 2008; Gounga, Xu, and Wang, 2007; Kristo and Biliaderis, 2006; Kristo, Biliaderis and Zampraka, 2007). Tong, Xiao, and Lim, (2008) reported that pullulan films had lower water vapor permeability than alginate and carboxymethylcellulose (CMC) films (4.4 × 10−7, 9.7 × 10−7, and 1.3 × 10−6 g m/Pa h m2, respectively), but dissolved in water quicker than alginate and CMC films. By incorporating alginate and CMC into pullulan, water barrier and mechanical properties were weakened significantly. Blending pullulan with alginate or CMC up to about 17–33% (w/w total polymer) reduced film solubilization time in water. FTIR results indicated that blending pullulan with alginate and CMC resulted in weaker hydrogen bonds acting on –OH groups, compared to those of pure pullulan. The addition of pullulan (at low concentrations) to whey protein isolate films exhibited acceptable results that significantly modified oxygen permeability, water vapor permeability, moisture content and film solubility (FS); hence improving the potential characteristics of WPI-based films for food applications (Gounga, Xu, and Wang, 2007) Gellan gum films are transparent, stronger and more brittle than alginate or carrageenan (Nussinovitch and Hershko, 1996). Gellan films can also be used as a carrier of antimicrobials or antioxidants. In this sense, León and Rojas, 2007 evaluated edible gellan films as carriers for stabilizing l-(+)ascorbic acid (AA) for nutritional purposes and its antioxidant effect on foods. Moreover, antimicrobial films incorporating nisin were found to have antimicrobial activity against Staphylococcus aureus, particularly those with higher contents of gellan gum. Studies showed that as the gellan gum content increased, so did the enhancements of the antimicrobial effects. These results suggest that films with a 70% blend of konjac glucomannan could be applied

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

.

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

Polysaccharide Film Formation and Film Characteristics

21

as a potential food package material for releasing active agents such as nisin (Xu et al., 2007). Pectin coatings have been investigated for their ability to retard moisture loss and lipid migration, and improve handling and appearance of foods. Generally, high-methoxy pectin forms excellent films and low-methoxyl pectin, derived by controlling esterification, forms gels in the presence of calcium ions and can also be used for developing edible films. Despite their hydrophilic character, pectinate coatings can control water activity, preventing moisture loss from food by acting as a sacrificial agent. It can potentially limit fat migration, provide a barrier to gas, help to trap flavor and aroma, and carry and present antioxidants or antimicrobials (Maftoonazad, Ramaswamy, and Marcotte, 2007). Addition of lipids may increase their resistance to water vapor transmission. Plasticized blends of citrus pectin give strong, flexible films; which are thermally stable up to 180ºC (Tharanthan and Kittur, 2003). Maftoonazad, Ramaswamy, and Marcotte, 2007 evaluated the moisture sorption behavior of pectin films formulated with different sorbitol contents. Based on changes observed in moisture sorption isotherms, they concluded that sorbitol strongly interacts with pectin polymers. Incorporation of sorbitol in pectin films resulted in lower equilibrium moisture contents at low to intermediate water activities (aw), but much higher moisture contents at aw > 0.53. Increasing moisture or addition of sorbitol to pectin films increased the elongation at break, but decreased the tensile strength, modulus of elasticity and Tg; even so, increasing the water vapor permeability of the films. Chitosan is of interest as a potential edible film component because of its excellent oxygen barrier properties (Hosokawa et al., 1990, Conca and Yang, 1993; Nisperos-Carriedo, 1994; Anker, 1996) and its good mechanical properties. However, the fact that it is highly permeable to water vapor limits its use (Butler, Vergano, Testin, Bunn, and Wiles 1996; Caner, Vergano, and Wiles, 1998), which is an important drawback since an effective control of moisture transfer is a desirable property for most foods. Acetic acid has often been the solvent for the production of chitosan films. Inherent antibacterial properties and the film-forming ability of chitosan make it an ideal choice for use as a biodegradable antimicrobial packaging material that can be used to improve the storability of perishable foods. It has been confirmed that chitosan films exhibit good antimicrobial activity, which can help extend the food shelf life (Kendra et al., 1989; Muzzarelli et al., 1990; El Ghaouth et al., 1991, 1994; Fang et al., 1994; Chen et al., 1996; Tsai et al., 2000, Coma et al., 2002, Dutta, Triphatti, Mehrotra and Dutta, 2009). In this sense, chitosan has exhibited high antimicrobial activity against a wide variety of pathogenic and

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

22

Pau Talens, María José Fabra and Amparo Chiralt

spoilage microorganisms, including fungi, and Gram-positive and Gramnegative bacteria, especially in limiting the development of bacteria such as Listeria monocytogenes, which are unacceptable in foodstuffs because of their pathogenicity (Dutta et al., 2009). Due to the antimicrobial properties of these films, some research is based on the use of chitosan in developing “active” packaging systems (Brody, 2001). Active packaging is a type of packaging that changes the condition of the packaging to extend shelf-life or improve safety or sensory properties while maintaining the quality of the food. Thus, it is the packaging system possessing attributes beyond basic barrier properties, special attributes that are achieved by adding active ingredients in the packaging system and/or using functionally active polymers. The binding of antimicrobial to polymeric surfaces such as polyethylene (PE), polyvinyl chloride (PVC), polylactic acid (PLA), nylon and others has been achieved by different means; means ranging from simply spreading antimicrobial solutions onto the polymer surface, or by more sophisticated means such as combining the antimicrobials with binders. These binders can be of a cellulosic, or an acrylic co-polymer nature. Sometimes the antimicrobials have been covalently attached, with natural and synthetic cross-linkers like genipine, glutaraldehyde, formaldehyde etc. (Sebastien et al., 2006; Dutta et al., 2009). For instance, Sebastien et al. 2006 proposed a chitosan-loaded PLA film, consisting of high inhibitory properties, for usage against mycotoxinogen fungal strains.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Chapter 3

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

POLYSACCHARIDE FILM PROPERTIES The main properties of edible films and coatings are their mechanical and barrier properties. Both properties are generally related to the physical and chemical nature of the polymers. Generally, polysaccharide-based films are very sensitive to humidity changes. At low relative humidities these films tend to crack. At high relative humidities these films swell and their barrier characteristics are markedly degraded. Mechanical properties reflect the durability of films and the ability of a coating to enhance the mechanical integrity of foods. Polysaccharide films are relatively stiff, and therefore plasticizers are needed to facilitate handling to achieve the desirable mechanical properties. As polysaccharide-based films are generally water-based, the most effective plasticizers are similar to the polysaccharide structure; therefore, hydrophilic plasticizers containing hydroxyl groups are best suited to this use. The plasticizers commonly used for polysaccharide-based films are glycerol, sorbitol, xylitol, mannitol, propylene glycol, polyethylene glycol and ethylene glycol (Sothornvit and Krochta, 2005). The effect of various plasticizers have been explored for films made from MC, HPC (Ayranci and Tunc, 2001), HPMC (Ayranci et al., 1997), locust bean gum (Aydinli and Tutas, 2000), gellan (Yang and Paulson, 2000), starches (Kim et al., 2002; Ryu et al., 2002) or pullulan (Kim et al., 2002). Barrier properties are important to separate food components or foods from the environment, which causes food deterioration. The most common barriers of interest include water, oxygen, carbon dioxide, aroma and oil barriers.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

24

Pau Talens, María José Fabra and Amparo Chiralt

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

Table I.2. Water vapor permeability (WVP) and tensile parameters of different polysaccharide based films Film composition

Test conditions

WVP (g mm/m2 d kPa)

TS (MPa)

E (%)

Agar+15% glycerol

25ºC/22-99%

11.2 ± 0.9

42.11 ± 3.27

6.51 ± 0.96

Cassava+15% glycerol

25ºC/22-99%

9.7 ± 0.9

35.17 ± 4.60

2.64 ± 0.73

Arabinoxylan+1 5% glycerol

25ºC/22-99%

11.7 ± 0.8

22.30 ± 2.97

5.46 ± 1.89

iotacarragenan+ glycerol (1:0.3)

25ºC/30100%

8.4 ± 0.9

HPMC

25ºC/22-84%

8.6 ± 0.8

HPMC +15 % Gly

25ºC/22-84%

17.3 ± 0.5

Alginateglycerol (1:0.5)

25ºC / 50100%

12.3 ± 0.1

33.6 ± 3.1

14.0 ± 2.9

Chitosan

5ºC/58-100%

12 ± 8

17 ± 8

Chitosan + 2% OA

5ºC/58-100%

7±2

11 ± 7

9.5 ± 0.6

14.1 ± 0.59

Chitosan + whey protein Cellulose+PEG (1:0.4)

25ºC/0-84% 25ºC/0-84%

MC (4%)

25ºC/0-52%

MC (3%) +PEG

21ºC/0-85%

HPC (3%) +PEG

21ºC/0-85%

Corn starch

20ºC/33-98%

Amylomaize starch PVC

20ºC/33-98% 28ºC/0-100%

0.00324 ± 0.0001 0.002983 ± 0.0021 4.27 ± 0.15 7.950 ± 0.003 9.504 ± 0.004 3.17 ± 2.24 2.26 ± 1.39 0.62

23 ± 3

11 ± 1

Reference Phan The, Debeaufort, Voilley and Luu, 2009 Phan The, Debeaufort, Voilley and Luu, 2009 Phan The, Debeaufort, Voilley and Luu, 2009 Fabra, Hambleton, Talens, Debeaufort, Chiralt and Voilley, 2009 Phan The, Peroval, Debeaufort, Despré, Courthaudon and Voilley, 2002 Phan The, Peroval, Debeaufort, Despré, Courthaudon and Voilley, 2002 Rhim 2004 Vargas, Albors, Chiralt and GonzálezMartínez, 2009 Vargas, Albors, Chiralt and GonzálezMartínez, 2009 Di Pierro et al., 2006 Ayranci and Tunc, 2001 Nazan and Sahbaz, 2004 Park and Chinnan, 1994 Park and Chinnan, 1994 García, Martino, Zaritzky, 2000 García, Martino, Zaritzky, 2000 Shellhammer and

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Polysaccharide Film Properties Film composition

Test conditions

WVP (g mm/m2 d kPa)

PET

28ºC/0-100%

0.17

LPDE

28ºC/0-100%

0.031

LPDE HDLE

25ºC/50% 25ºC/50%

TS (MPa)

9-17 17-35

25

E (%)

Reference

500 300

Krochta, 1997 Shellhammer and Krochta, 1997 Shellhammer and Krochta, 1997 Briston, 1986 Briston, 1986

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

HPMC: Hydroxypropylmethyl cellulose; MC:Methylcellulose; HPC: Hydroxypropylcellulose; PEG: polyethyleneglycolPVC: Polyvinylchloride; PET:Polyethylene terephthalate; LPDE: Low-density polyethylene, HPDE: High-density polyethylene.

At low to intermediate relative humidity levels polysaccharide-based films and coatings are good barriers against oxygen, due to their highly packed and ordered hydrogen-bonded networked structure (Yang and Paulson 2000), and other non-polar substances, such as aromas and oils. Nevertheless, due to their hydrophilic nature, they are indeed wettable by water and generally exhibit limited water vapor barrier ability, especially at high relative humidity levels. However, certain polysaccharides, applied in the form of high moisture gelatinous coatings, can retard moisture loss from coated foods by functioning as sacrificing agents rather than moisture barriers. Table I.2 shows the water vapor permeability (WVP) and tensile parameters (TS: Tensile strength, E: Elongation at break) of different polysaccharide based films. Comparisons are difficult because data were obtained in different studies using different film compositions, different test conditions (temperature and relative humidity) and with different methods of measurements. Polysaccharide films appear to have similar tensile strength and lower elongation at break values than synthetic polymers films. While agar, cassava and alginate films have the highest TS values, chitosan films have the lowest TS values. Because of the hydrophilic nature of polysaccharide films, they provide quite high water vapor permeability compared to synthetic materials such as low-density polyethylene (LPDE). Among polysaccharide films, starch films have the highest water barrier properties. The utilization of edible polysaccharide-based films and coatings as moisture barriers requires the formation of composite films. These multicomponent edible films and coatings are blends of polysaccharides and hydrophobic lipid materials such as edible fatty acids and waxes. In these film systems, the barrier properties may be improved by taking advantage of each

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

26

Pau Talens, María José Fabra and Amparo Chiralt

component. Polysaccharides impart cohesion and serve as a structural matrix, while lipids are added due to their hydrophobic character. Composite films can be formed as a bi-layer, when the lipid material is cast onto a dried polysaccharide-based film, or as an emulsion, when the lipid is added to the film-forming solution prior to film casting. Emulsion composite films have not achieved the excellent moisture barrier properties of bi-layer films. However, bi-layer films have the disadvantages of requiring two steps to be formed, plus they needed manipulation of either a molten lipid or a solvent. Furthermore, the films formed can suffer peeling which minimizes the water barriers. Achieving low water vapour permeabilities with emulsion composite films is favored by loading high hydrophobic lipidic materials, homogeneous distribution of lipids of small particle size, and the formation of continuous networks of interconnected lipids within the polysaccharide matrix (Krochta and The Mulder-Johnston, 1997; Wu et al., 2002 development and application of multicomponent edible coatings and films: a review). Properties of polysaccharide-lipid films have been studied extensively by different leading researchers in the field (Pérez-Gago and Krochta, 2001; Morillon et al., 2002, Karbowiak, Debeaufort and Voilley, 2007, Hambleton et al., 2008) Generally, protein-based films have more interesting mechanical and barrier properties than polysaccharides (Ou, Kwok, and Kang, 2004; Cao, Fu, and He, 2007). While proteins have a specific structure (based on 20 different monomers) which confers a wider range of functional properties, especially high intermolecular binding potential and can be modified easily, polysaccharide-based films are more readily disintegrated by absorbing water and in general have poorer barrier properties than protein-based films (Cuq et al., 1995). As a group, protein films appear to have lower oxygen permeabilities than non-ionic polysaccharide films. This may be related to their more polar nature and more linear (non-ring) structure, leading to higher cohesive energy density and lower free volume (Miller and Krochta, 1997). Biopolymer films made form mixtures of both, protein and polysaccharide, ingredients may advantageously use the distinct functional characteristics of each film-forming ingredient. Some works indicate that incorporation of polysaccharides into globular protein matrices may extend the functional properties of these ingredients (Zaleska, Ring and Tomasik, 2000; Turgeon and Beaulieu, 2001). Some edible films based on the blends of polysaccharides and proteins such as soluble starch–gelatin (Arvanitoyannis et al., 1997), hydroxypropyl starch–gelatin (Arvanitoyannis et al., 1998), soluble starch–caseinate (Arvanitoyannis et al., 1998), alginate or -carrageenan – sodium caseinate (Fabra et al., 2008) or some films based on the mixtures of

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

Polysaccharide Film Properties

27

polysaccharides such as starch–methylcellulose (Arvanitoyannis and Biliaderis, 1999), pulluan–starch (Biliaderis et al., 1999), chitosan– starch; chitosan–pulluan (Lazaridou and Biliaderis, 2002), agar-cassava starch and arabinoxylan (Phan et al., 2009b) were investigated. These publications demonstrated that depending on the interactions between components, these formulas can improve the mechanical and barrier properties of these films. For example, pectin and starch blends can be used to make a range of films with very good properties (Coffin and Fishman, 1993, Fishman and Coffin, 2005). Blends of pectin and chitosan can also be formed to improve properties of films (Hoagland and Parris, 1996). Xu, Kim, Hanna, and Nag, 2004, observed a decrease in water vapor transmission rates (WVTR) by combining chitosan with two thermally gelatinized corn starches. Composite films based on blends of pectin and -carrageenan increased mechanical properties, lowered glass transition temperatures, increased water permeability and hydrophilic properties with increased carrageenan content. These films revealed to be more permeable to water vapor than to oxygen and carbon dioxide, and the films selectivity (CO2/O2) was enhanced by adding ascorbic acid to the polymer matrix (Alves et al., 2006). Pectin can also form cross-links with proteins under certain conditions (Thakur et al., 1997). Autoclaving enhances pectin-protein interactions, resulting in a three-dimensional network with improved mechanical and barrier properties.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved. Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Chapter 4

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

APPLICATIONS OF POLYSACCHARIDEBASED FILMS IN FOOD PRODUCTS A number of edible polysaccharide-based films and coatings have been used to extend the shelf-life of fruits, vegetables, seafood, meats and confectionary products by preventing dehydration, oxidation rancidity, surface browning and oil diffusion. In some specific cases, polysaccharide-based films can improve the physicochemical, nutritional and sensorial properties of the products. During the last decade, leading researchers in the field have studied the benefits of the application of polysaccharide-based films for food products. Alginates, carrageenans, cellulose, pectin and starch derivates have all been used to improve stored meat quality. Alginate films retard development of oxidative off-flavors when applied as an edible coating to precooked pork patties and reduce weight loss as well as microflora counts in frozen shrimp, fish, sausage and stored lamb carcasses (Nisperos-Carrierdo, 1994). The use of carrageenans as edible films and coatings have been applied for a long time on a variety of foods; they are applied as a carry source for antimicrobials or antioxidants; and, to reduce moisture loss, oxidation or disintegration when applied on fresh and frozen meat, poultry and fish, or to prevent superficial dehydration on ham or sausage-casings (Macquarrie, 2002), granulationcoated powders, dry solids foods, oily foods, etc. Furthermore, they have also been used in the manufacturing process of soft capsules (Tanner et al., 2002), and especially with the manufacturing of non-gelatin capsules (Fonkwe, Archibald and Gennadios, 2003). The ability of some water-soluble polysaccharides to form thermally induced gelatinous coatings has found wide application for its ability of reducing oil absorption during frying. Research conducted by Albert et al.,

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

30

Pau Talens, María José Fabra and Amparo Chiralt

2002, compared different hydrocolloid materials (including gellan gum, κcarrageenan-konjac-blend, locust bean gum, methyl cellulose, microcrystalline cellulose and three types of pectin) for their water and fat transfer properties, their film forming abilities, and their suitability for usage with fried foods. Various selected formulation and preparation methods were tested for their effectiveness and for their heat stability when applied on the control substance, a product made from a pastry-mix. Among the polysaccharide-based films, methyl cellulose was the best coating material for reducing fat uptake during frying. Researchers, García et al., 2002, used edible coatings from methylcellulose and hydroxypropylmethylcellulose to reduce oil uptake in deep-fat frying potato strips and dough discs. Methylcellulose coatings were more effective than the hydroxypropylmethylcellulose coatings in reducing oil uptake. Non-significant differences in texture of coated and uncoated samples were observed. Interesting research by Castro-Freitas et al., 2009, used a pectin-based coating in the deep-fat frying of preformed products made of either cassava flour or cassava purée. The coating treatments were efficient for the cassava-purée preformed products but not for the cassava-flour preformed products; and thus indicating that different products can show different responses with the same type of coating material. Bravin et al., 2006, investigated the effect of the deposition process, used for film-forming dispersion (spreading and spraying), and the effectiveness of edible coatings (made of cornstarch, methylcellulose and soybean oil) in controlling moisture transfer in moisture-sensitive products. This research was conducted by coating crackers, a low water activity-type cereal food. They observed that film which was spread gave better water vapor barrier and mechanical properties than film that was sprayed, and that coated crackers had longer shelf-life and higher resistance to water vapor transmission than uncoated samples at three different storage conditions (65%, 75% and 85% relative humidity). Moreover, in order to examine potential effects on egg quality properties, Caner and Cansiz, 2007, coated eggshells with three chitosan-based coatings (produced with organic acids: acetic-[C-AA], lactic[C-LA] and propionic [C-PA]). All chitosan-coated eggs showed greater inner food quality than the non-coated eggs. When compared with the controlled, non-coated egg specimens, the coated eggs significantly kept better from weight loss; and better maintained the nutritional value amounts of minerals (especially calcium, iron and magnesium concentrations). The application of water-soluble polysaccharides on fruits and vegetables has become popular and extensive due to their ability to reduce O2 and increase CO2 levels in internal atmospheres. This effect modifies the internal

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

Applications of Polysaccharide-Based Films in Food Products

31

atmospheres and reduces respiration rates, thereby prolonging the shelf-life of fruits and vegetables, in a manner analogous to controlled atmospheres. The effects of edible coatings and plastic packaging on the quality aspects of refrigerated white asparagus spears were studied by Tzoumaki et al., 2009, using different formulations based on carboxymethyl-cellulose and sucrose fatty acid esters; and pullulan and sucrose fatty acid esters. Both edible films exhibited a beneficial impact on the quality of asparagus by retarding moisture loss, reducing hardening in their basal part and slowing down the purple-color attainment process. Viña et al., 2007, studied the effects of combinations of polyvinylchloride film and starch-based coatings on quality aspects of refrigerated Brussels sprouts. They stored different combinations of polyvinylchloride film and coatings and uncovered samples at 0 °C for 42 days. All samples were removed every 14 days to determine commercial acceptability, weight loss, surface color and texture. Sprouts in all treatments maintained optimum quality conditions over the first 14 days. At the end of the storage period, it was concluded that browning of cut zones and losses in weight and firmness are better minimized in PVC-packaged sprouts when using polyvinylchloride film and coatings. Maftoonazad and Ramaswamy, 2005, evaluated the effects of a methylcellulose-based coating on the respiration rate, color and texture of avocados stored at room temperature. Coated avocados demonstrated lower respiration rates, greener color and higher firmness when compared with the uncoated samples. Furthermore, the appearance of brown spots and mesocarp discoloration normally associated with fruit ripening were delayed in the coated fruits. Ayranci and Tunc, 2004, found that coatings of methylcellulose and polyethylene glycol with stearic acid tend to lower the water loss rate of fresh apricots and green peppers. The inclusion of ascorbic acid or citric acid in the coating formulation, as antioxidants, lowered the vitamin C loss. Yaman and Bayoindirli, 2002, studied the effects of an edible coating (composed of sodium carboxymethylcellulose; sucrose esters of fatty acids; and, mono-diglycerides of fatty acids) on the shelf-life and quality of cherries. The coating was effective in the reduction of weight loss and tended to increase firmness, ascorbic acid content, titratable acidity and skin color of cherries during storage time, and increased the shelf-life of the cherries by 21% at 30±3 °C and by 26% at 0 °C without perceptible losses in quality. The effects of edible chitosan coating on the quality and shelf-life of sliced mango fruits were studied by Chien et al., 2007. The chitosan coating retarded the deterioration of sensory qualities and delayed water loss; while increasing the soluble solid content, titratable acidity and ascorbic acid content. It also inhibited the

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

32

Pau Talens, María José Fabra and Amparo Chiralt

growth of microorganisms. The data gathered reveals that applying a chitosan coating effectively prolongs the quality attributes and extends the shelf-life of sliced mango fruit. Casariego et al., 2008, demonstrated that chitosan films inhibited fungi growth, reduced ethylene production, increased internal CO2 and decreased O2 levels, when applied to tomatoes. The effects of alginate, pectin and gellan-based edible coatings on the shelf-life of fresh-cut melons and fresh-cut pears were investigated by Oms-Oliu et al., 2008a,b. The use of polysaccharide-based edible coatings on the fresh-cut samples increased their water vapor resistance and reduced their ethylene production. Pectin or alginate was able to reduce wounding-stress induced on fresh-cut melons and thus generated the accumulation of total phenolic compounds and other compounds with antioxidant properties. The Pectin-based coating seems to have best maintained the sensory attributes of this fruit. For the pears, coating formulations were integrated with N-acetylcysteine and glutathione; this not only reduced microbial growth (when compared with those samples not containing antioxidants) but was also effective in preventing fresh-cut pears from browning, for 2 weeks, without affecting the firmness of the fruit wedges. The increased vitamin C and total phenolic content observed in coated pear wedges (coatings with alginate, gellan and pectin including antioxidants) contributed in maintaining their antioxidant potential. Coatings with alginate or pectin best maintained sensory attributes of pear wedges for 14 days. The effect of alginate and gellan-based edible coatings on the shelf-life of fresh-cut apples, packed in trays with a plastic film, was investigated by Rojas-Graü et al., 2008. Polymers were cross-linked with a calcium chloride solution, to which the anti-browning agent N-acetylcysteine was added, being incorporated to the coatings formulation and helping to maintain firmness and color of the apple wedges during the entire storage time. The application of the edible coatings also retarded the microbiological deterioration of fresh-cut apples. Both edible coatings effectively prolonged the shelf-life of the apple wedges by 2 weeks of storage time. The controlled non-coated apple slices demonstrated considerable cut-surface browning and tissue softening from the very first days of storage, having evident conditions that limited their shelf-life to less than 4 days; a considerable degeneration when compared with the coated apples. The ability of polysaccharide-based coatings to extend the shelf-life of strawberry fruit was studied by different authors (Diab et al., 2001; García et al., 2001; Han et al., 2004; Han et al., 2005; Vargas et al., 2006; Ribeiro et al., 2007; Hernández-Muñoz et al, 2008; Campaniello et al., 2008; Almenar et al.; 2009). The physiological responses of strawberries coated with pullulan-based

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

Applications of Polysaccharide-Based Films in Food Products

33

edible films have been studied by Diab et al., 2001. Application of a pullulanbased coating on strawberries resulted in substantial changes within internal fruit atmosphere composition, changes that were beneficial in extending the shelf-life of this fruit; the coated fruit showed much higher levels of CO2, a large reduction in internal O2, better firmness and color retention and a reduced rate of weight loss. García et al., 2001, used starch-based coatings to extend the storage life of strawberries. These authors analyzed the effects of a coating formulation (starch type, plasticizer, lipid and antimicrobial agent) with respect to fruit quality. Plasticizer presence reduced weight losses and maintained the surface color of fruits. Amylomaize coatings showed lower water vapor and gas permeabilities; and decreased weight losses for longer periods of time than corn starch coatings. Coatings with antimicrobial agents decreased microbial counts, extending storage life of coated fruits by 10 to 14 days, in contrast to the storage life of the controlled non-coated fruit samples. The addition of lipids to the formulations decreased the water vapor permeability of starch-based films, maintained the surface color of coated fruits and effectively limited fruit weight losses during storage. Composite starch-based coatings showed selective gas permeability (CO2 higher than O2) which helps to delay the senescence of fruits. Han et al., 2004 used three chitosan-based edible coatings (chitosan, chitosan containing 5% Gluconal® CAL, and chitosan containing 0.2% -α-tocopheryl acetate) to extend the shelf-life and enhance the nutritional value of strawberries. These coatings significantly decreased decay incidence and weight loss, and delayed the changes in color, pH and titratable acidity of strawberries during cold storage. Coatings also reduced drip loss and helped maintain textural quality of frozen strawberries after thawing. The incorporation of calcium or vitamin C into chitosan-based coatings did not alter their anti-fungal and moisture barrier functions but significantly increased the content of these nutrients in both fresh and frozen fruit. Han et al., 2005, developed three 1% chitosan-based solutions for coating strawberries (chitosan in 0.6% acetic acid solution, chitosan in 0.6% lactic acid solution, and chitosan in 0.6% lactic acid solution plus 0.2% vitamin E). Coated strawberries were packed in clam-shell boxes and stored at 2°C and approximately 88% to 89% RH for 1 week. The samples were evaluated for their acceptance attributes by consumers and evaluated descriptively for their appearance, texture, and flavor by a trained panel. Results from the consumer evaluation on the 1st day of testing, on the 1st week after coating, indicated that chitosan coatings increased the appearance acceptance of the strawberries, but according to these consumers, coatings containing vitamin E decreased the acceptable appearance of strawberries.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

34

Pau Talens, María José Fabra and Amparo Chiralt

Chitosan coatings did not change consumer acceptability of flavor, sweetness, or firmness of the samples. Trained panel results after the 1st week of storage showed that chitosan-coated strawberries have similar sensory descriptors as those of fresh berries, whereas coatings containing vitamin E developed the waxy-and-white surface of the samples. The trained panel did not detect any astringency difference among all samples, indicating that 1% chitosan coating did not change the astringency of strawberries. Edible coatings based on high molecular weight chitosan combined with an oleic acid were used by Vargas et al., 2006, to preserve quality of cold-stored strawberries. Coatings had no significant effects on the acidity, the pH and the soluble solids content of the sample strawberries throughout storage but they did slow down changes in their mechanical properties and did slightly modify their respiration rates. The addition of oleic acid enhanced chitosan antimicrobial activity and improved the water vapor resistance of chitosan-coated samples. Sensory analysis showed that coating application led to a significant decrease in strawberry aroma and flavor, especially when the ratio oleic acid:chitosan was high in the film. Ribeiro et al., 2007, studied the effects of the application of starch, carrageenan and chitosan based coatings (with and without calcium chloride) on the color, firmness, weight loss, soluble solids and microbiological growth of fresh strawberries. A minimum change of color and firmness loss was obtained for strawberries coated with carrageenan and calcium chloride. The minimum loss of mass was obtained for fruit with chitosan and carrageenan coatings, both with calcium chloride. In all cases, the addition of calcium chloride to the coatings reduced the microbial growth rate on the fruit. The minimum rate of microbial growth was obtained for strawberries coated with chitosan and calcium chloride. Hernández-Muñoz et al., 2008, studied the effect of chitosan coating combined with a postharvest calcium treatment on strawberry quality during refrigerated storage. The effectiveness of the combined treatment in extending fruit shelf-life was evaluated by determining fungal decay aspects, respiration rate, quality attributes and overall visual appearance. Chitosan coatings better delayed changes in weight loss, firmness and external color when compared to the untreated samples, and reduced respiration activity, thus delaying ripening and the progress of fruit decay due to senescence. Depending on the content level of chitosan, different antimicrobial activity levels were observed for the coatings. Also, the addition of calcium gluconate to the chitosan coating formulation increased the nutritional value by incrementing the calcium content of the fruit. Campaniello et al., 2008, coated strawberries with chitosan films. This research showed that chitosan coatings have the potential to prolong storage life of fresh

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

Applications of Polysaccharide-Based Films in Food Products

35

strawberries; and, chitosan coatings on strawberries tend to inhibit fungi growth, reduce ethylene production, increase internal CO2 and decrease O2 levels. Almenar et al., 2009, reported the potential use of chitosan coatings on strawberries during the storage of the fruits to maintain desired flavor attributes. Different research has been conducted (Durango et al., 2006; Casariego et al., 2008; Adriano et al., 2009; Villalobos-Carvajal et al., 2009; Vargas et al., 2009) in order to analyze the ability of polysaccharide-based coatings to extend the shelf-life of carrots. Durango et al., 2006, applied a starch-chitosan edible coating on minimally processed carrots in order to evaluate a possible antimicrobial effect. The results of this study showed that the combined use of a chitosan coating and an edible antimicrobial yam starch promises to be a viable alternative for controlling microbiological growth in minimally processed carrots. Casariego et al., 2008, applied a chitosan coating on carrots and determined its effect on gas permeability, internal gas composition, and shelf-life. The coating inhibited fungi growth, reduced ethylene production, increased internal CO2 and decreased O2 levels. Adriano et al., 2009, propose a combined application of a chitosan-based coating and the use of modified atmosphere packaging as a postharvest treatment process to maintain quality and prolong shelf-life of carrots. The study showed that the use of a chitosancontaining edible coating preserved the overall visual quality of carrots and reduced surface whiteness during storage. The combined application of an edible coating containing chitosan, along with moderate O2 and CO2 levels, maintained quality and enhanced phenolic content in carrot sticks. VillalobosCarvajal et al., 2009, developed hydroxypropyl methylcellulose-based coatings containing surfactant mixtures of sorbitan monostearate and sucrose palmitate in aqueous and hydroalcoholic media and analyzed the effect of the hydrocolloid/surfactant ratio; the hydrophilic–lipophilic balance of the surfactant mixtures; the solvent type used as a dispersing media on the water vapor barrier properties of the films; and, their optical effect when applied to carrot slices. The results showed that the solvent type, the hydrocolloid/surfactant ratio and the hydrophilic–lipophilic balance significantly affected viscosity, surface tension, and stability of the filmforming dispersions, which in turn had a great influence on the extensibility and final film structure of the coating on the carrot surface. All these aspects affected the water vapor barrier properties and color of coated carrot slices. Edible coatings based on high molecular weight chitosan, pure or combined with methylcellulose or oleic acid, were applied to fresh-cut carrots by simple immersion and with the application of a vacuum pulse by Vargas et al., 2009.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

36

Pau Talens, María José Fabra and Amparo Chiralt

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

Coatings improved sample appearance, since they diminished the occurrence of the white blush during storage. When applied by simple immersion, they neither conferred significant barrier properties nor the preservation of the mechanical properties of fresh-cut carrot samples. In contrast, the coating application with a vacuum pulse enhanced all the positive effects, since the water vapor transmission resistance of the test samples was significantly improved; additionally, a better preservation of color and mechanical response during cold storage was obtained with the test samples. Differences in film composition did not significantly affect the coating behavior; this is probably due to the variability dynamic induced by different factors when coatings were applied to the carrot surface.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Chapter 5

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

CONCLUSIONS Polysaccharide-based films and coatings have the potential to be used in a variety of food applications. They have been used to extend the shelf-life of fruits, vegetables, seafood, meats and confectionary products by preventing dehydration, oxidation rancidity, surface browning and oil diffusion. Due to their unique features, polysaccharide-based films and coatings, provide a promising technology to food companies for enhancing the quality and extend the shelf life of their products. However, commercial applications are still very limited. For industrial use, it is necessary to conduct scientific research to indentify the film-forming mechanisms of biopolymers in order to optimize their properties. This may be done by adjusting the formulation of filmforming solutions, incorporating functional ingredients and modifying filmforming conditions. More efforts are required to develop new materials and understand their functionality and interactions among the components used in the edible films and coatings. Considerable research is needed to improve the efficiencies of forming polysaccharide films and coatings on foods and to quantify the effects of the coatings on food quality using both instrumental and sensory evaluation. The development of new technologies to improve the film properties of active packaging and coatings is the major focus for future research.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved. Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

REFERENCES Adriano D.N., Simões, Tudela, J. A., Allende, A., Puschmann, R. and Gil, M. I. (2009). Edible coatings containing chitosan and moderate modified atmospheres maintain quality and enhance phytochemicals of carrot sticks. Postharvest Biology and Technology, 51, 3, 364-370 Albert, S. and Mittal, G.S. (2002). Comparative evaluation of edible coatings to reduce fat uptake in a deep-fried cereal product. Food Research International, 35, 5, 445-458 Almenar, E., Hernández-Muñoz, P. and Gavara, R. (2009).Evolution of Selected Volatiles in Chitosan-Coated Strawberries (Fragaria x ananassa) during Refrigerated Storage. Journal of Agricultural and Food Chemistry, 57, 3, 974-980. Alves, V., Costa, N., Hilliou, L., Larotonda, F., Gonçalves, M., Sereno, A, and Coelhoso, I. (2006). Design of biodegradable composite films for food packaging. Desalination, 199, 331-333. Andrady, A. L. and Xu, P. (1997). Elastic behaviour of chitosan films. Journal of Polymer Science: Part B: Polymer Phys., 35, 517–521. Anker, M. 1996. Edible and biodegradable films and coatings for food packaging literature review. Ski-Report. No: 623: Goteberg, SWEDEN. Arvanitoyannis, I., Psomiadou, E., Nakayama, A., Aiba, S., Yamamoto, N., (1997). Edible films made from gelatin, soluble starch and polyols, Part 3. Food Chemistry 60 (4), 593–604. Arvanitoyannis, I., Nakayama, A., Aiba, S., (1998). Edible films made from hydroxypropyl starch and gelatin and plasticized by polyols and water. Carbohydrate Polymers 36 (2), 105–119. Arvanitoyannis, I.; Biliaderis, C.G., (1999). Physical properties of polyolplasticized edible blends made of methylcellulose and soluble starch. Carbohydrate Polymers 38 (1), 47–58.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

40

Pau Talens, María José Fabra and Amparo Chiralt

Aydinly, M. and Tutas, M. (2000). Water sorption and water vapour and carbon dioxide transmissions of cellulose-based edible films. Lebensm. Wiss. U. Technol. 33(1), 63-67 Ayranci, E., Buyuktas, B.S. and Cetin, E.E (1997). The effect of molecular weight of constituents on properties of cellulose-based edible films. Lebensm. Wiss. U. Technol. 30(1), 101-104 Ayranci, E. and Tunc, S (2001). The effect of fatty acid content on wáter vapour and carbón dioside transmissions of cellulose-based edible films. Food Chemistry, 72, 231-236. Ayranci, E. and Tunc, S (2004). The effect of edible coatings on water and vitamin C loss of apricots (Armeniaca vulgaris Lam.) and green peppers (Capsicum annuum L.). Food Chemistry, 87, 3, 339-342 Biliaderis, C.G.; Lazaridou, A., Arvanitoyannis, I., (1999). Glass transition and physical properties of polyol-plasticized pulluan–starch blend at low moisture. Carbohydrate Polymers 40 (1), 29–47. Bravin, B. Peressini, D. and Sensidoni, A. (2006). Development and application of polysaccharide–lipid edible coating to extend shelf-life of dry bakery products. Journal of Food Engineering, 76, 3, 280-290. Briston, J. H. (1986). “Films, Plastic” In: The Wiley Encyclopedia of Packaging Technology, ed., M. Bakker. New York: John Wiley and Sons, pp. 329-335. Brody, A. L. (2001). What’s the hottest food packaging technology today? Food Technology, 55, 82–84. Butler, B. L., Vergano, P. J., Testin, J. M., Bunn, J. M. and Wiles, J. L. (1996). Mechanical and barrier properties of edible chitosan films as affected by composition and storage. Journal of Food Science, 61(5), 953–955. Caner, C. and Cansiz, O. (2007). Effectiveness of chitosan-based coating in improving shelf-life of eggs. Journal of the Science of Food and Agriculture, 87, 2, 227-232. Caner, C., Vergano, P. J. and Wiles, J. L. (1998). Chitosan film mechanical and permeation properties as affected by acid, plasticizer and storage. Journal of Food Science, 68(6), 1049–1053. Cao, N., Fu, Y., and He, J. (2007). Preparation and physical properties of soy protein isolate and gelatin composite films. Food Hydrocolloids, 21(7), 1153–1162. Campaniello, D., Bevilacqua, A., Sinigaglia, M., and Corbo, M. R. (2008). Chitosan: antimicrobial activity and potential applications for preserving minimally processed strawberries. Food Microbiology, 25 (8), 992-1000.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

References

41

Casariego, A., Souza, B. W. S, Vicente, A. A., Teixeira, J. A., Cruz, L., and Díaz, R. (2008). Chitosan coating surface properties as affected by plasticizer, surfactant and polymer concentrations in relation to the surface properties of tomato and carrot. Food Hydrocolloids, 22(8), 1452-1459. Castro-Freitas, D., Garcia-Berbari, S.A., Prati, P., Matta-Fakhouri, F. and Vicente, E. (2009). Reducing of fat uptake in cassava product during deep-fat frying. Journal of Food Engineering, 94(3-4), 390-394. Cha, D. S., Choi, J. H, Chinnan, M. S. and Park, H. J. (2002). Antimicrobial films based on Na-alginate and k-carrageenan. Lebensmittel Wissenschaft und Technologie, 35, 715–719 Choi, J. H., Choi, W. Y., Cha, D. S., Chinnan, M. J., Park, H. H., Lee, D. S. and Park, J. M. (2005). Diffusivity of potassium sorbate in -carrageenan based antimicrobial film. Lebensmittel Wissenschaft und Technologie, 38, 417-423. Chen M.C., Yeh G.H.-C. and Chiang B.H.. (1996). Antimicrobial and physicochemical properties of methylcellulose and chitosan films containing a preservative. Journal of Food Processing and Preservation, 20,379-390. Chien, P.J., Sheu, F. and Yang, F.H. (2007). Effects of edible chitosan coating on quality and shelf life of sliced mango fruit. Journal of Food Engineering, 78, 1, 225-229. Coffin, D. R.; Fishman, M. L. (1993). Viscoelastic properties of pectin/ starch blends. Journal of Agriculture and Food Chemistry, 41, 1192-1197 Coma, V., Martial-Gros, A., Garreau, S., Copinet, A., Salin, F. and Deschamps, A. (2002). Edible antimicrobial films based on chitosan matrix, Journal of Food Science, 67 (3), 1162-1169. Conca, K. R. and Yang, T. C. S. (1993). Edible food barrier coatings, In C. Ching, D. Kaplan and E. Thomas (Eds), Biodegradable Polymers and Packaging (pp. 357-369). Technomic Publishing: Lancaster, PA. Cuq, B., Gontard, N. and Guilbert, S. (1994). Edible films and coatings as active layers. In M. Rooney (Ed.), Active Food Packaging (pp.111-142). Blackie Academic and Professional. Cuq, B., Aymard, C., Cuq, J., and Guilbert, S. (1995). Edible packaging films based on fish myofibrillar proteins: Formation and functional properties. Journal of Food Science, 60, 1369–1374. Di Pierro, P., Chico, B., Villalonga, R., Mariniello, L., Damiao, A., Masi, P. and Porta, R. (2006). Chitosan-whey protein edible films produced in the absence or presence of transglutaminase: analysis of their mechanical and barrier properties. Biomacromolecules, 744-749.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

42

Pau Talens, María José Fabra and Amparo Chiralt

Diab, T., Biliaderis, C.G., Gerasopoulos, D. and Sfakiotakis, E. (2001). Physicochemical properties and application of pullulan edible films and coatings in fruit preservation. Journal of the Science of Food and Agriculture, 81, 10, 988-1000. Dziezak, J.D. (1991). Special report: A focus on gums. Food Technology, 45(3), 116-132. Doman-Pytka, M. and Bardowski, J. (2004). Pullulan degrading enzymes of bacterial origin. Critical Reviews in Microbiology, 30, 107–121. Durango, A.M., Soares, N.F.F. and Andrade, N.J. (2006). Microbiological evaluation of an edible antimicrobial coating on minimally processed carrots. Food Control, 17, 5, 336-341. Dutta, P. K., Tripathi, S., Mehrotra, G. K. and Dutta, J. (2009). Perspectives for chitosan based antimicrobial films in food applications. Food Chemistry, 114, 1173-1182. El Ghaouth A., Arul, J., Ponnampalam, R. and Boulet, M. (1991). Chitosan coating effect on storability and quality of fresh strawberries. Journal of Food Science, 56, 1618-1631. El Ghaouth, A., Arul, J., Wilson, C. and Benhamou, N. (1994). Ultrastructural and cytochemical aspects of the effect of chitosan on decay of bell pepper fruit. Physiological and Molecular Plant Pathology, 44, 417-432. Fabra, M.J., Talens, P. and Chiralt, A. (2008). Effect of alginate and carrageenan on tensile properties and water vapour permeability of sodium caseinate-lipid based films. Carbohydrates Polymers, 74, 419-426. Fabra, M.J., Hambleton, A., Talens, P., Debeaufort, F., Chiralt, A. and Voilley, A. (2009). Influence of interactions on water and aroma permeabilities of - carrageenan–oleic acid–beeswax films used for flavour encapsulation. Carbohydrates Polymers, 76 (2), 325-332. Fishman, M.L., and Coffin, D.R. (2005). Biodegradable films from pectin/starch and pectin/poly(vinyl alcohol). In: Polymer Biocatalysis and Biomaterials. Ed. H. N. Cheng, R. Gross, ACS Symposium Series. Volume 900. American Chemical Society Publ., Washington D.C. p.119140. Fonkwe, L., Archibald, D. and Gennadios, A. U.S. Patent (2003) 0138482 A1. Fang SW, Li, C.F. and Shih, D.Y.C. (1994). Antifungal activity of chitosan and its preservative effect on low-sugar candied kumquat. Journal of Food Protection, 56,136-140. García, M. A., Ferrero, C., Bértola, N., Martino, M. and Zaritzky, N. (2002). Edible coatings from cellulose derivatives to reduce oil uptake in fried

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

References

43

products. Innovative Food Science and Emerging Techinologies, 3, 4, 391-397. Garcia, M.A., Martino, M.N.; Zaritzky, N.E. (2000). Lipid addition to improve barrier properties of edible starch-cased films and coatings. Journal of Food Science, 65 (6), 941-947. García, M. A., Martino, M. N. and Zaritzky, N. E. (2001). Composite starchbased coatings applied to strawberries (Fragaria ananassa). Nahrung/Food, 45 (4), 267-272. Gounga, M. E., Xu, S. Y. and Wang, Z. (2007). Whey protein isolate based edible films as affected by protein concentration, glycerol ratio and pullulan addition in film formation. Journal of Food Engineering, 83 (4), 521-530. Hambleton, A., Debeaufort, F., Beney, L., Karbowiak, T. and Voilley, A. (2008). Protection of active aroma compound against moisture and oxygen by encapsulation in biopolymeric emulsion-based edible films. Biomacromolecules, 9(3), 1058–1063. Han, J. H. and Gennadios, A. (2005). Edible films and coatings: a review. In J. H. Han (Ed.), Innovations in Food Packaging (pp.239-260). London: Elsevier Academic Press. Han, C., Zhao, Y., Leonard, S.W. and Traber, M.G. (2004). Edible coatings to improve storability and enhance nutritional value of fresh and frozen strawberries (Fragaria × ananassa) and raspberries (Rubus ideaus). Postharvest Biology and Technology, 33, 1, 67-78. Han, C., Lederer, C., McDaniel, M. and Zhao, Y. (2005). Sensory Evaluation of Fresh Strawberries (Fragaria ananassa) Coated with Chitosan-based Edible Coatings. Journal of Food Science, 70, 3, 172-178. Hernández-Muñoz, P., Almenar, E., Del Valle, V., Velez, D. and Gavara, R. (2008). Effect of chitosan coating combined with postharvest calcium treatment on strawberry (Fragaria x ananassa) quality during refrigerated storage. Food Chemistry, 110, 2, 428-435. Hoagland, P. D. and Parris, N. (1996). Chitosan/pectin laminated films. Journal of Agriculture and Food Chemistry, 44, 1915-1919. Hosokawa, J., Nishiyama M., Yashihora, K. and Kuba T. (1990). Biodegradable film derived from chitosan and homogenized cellulose. Industrial and Engineering Chemistry Research, 29, 800- 805. Immirzi, B., Santagata, G., Vox, G. and Schettini, E. (2009). Preparation, characterization and field-testing of a biodegradable sodium alginatebased spray mulch. Biosystems Engineering, 102, 461-472.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

44

Pau Talens, María José Fabra and Amparo Chiralt

Jansson, P. E., Kemnne, L. and Lindberg, B. (1975). Structure of the extracellular polysaccharide from Xanthomonas campestris. Carbohydrates Research, 45, 275-282. Karbowiak, T., Debeaufort, F. and Voilley, A. (2007). Influence of thermal process on structure and functional properties of emulsion-based edible films. Food Hydrocolloids, 21(5-6), 879-888. Kendra, D.K., Christian, D. and Hadwiger L.A. (1989). Chitosan oligomers from Fusarium solani/pea interactions, chitinase/bð-glucanase digestion of sporelings and from fungal wall chitin actively inhibit fungal growth and enhance disease resistance. Physiological Molecular Plant Pathology, 35, 215-230. Kester, J. J. and Fennema, O. R. (1986). Edible films and coating: a review. Food Technology, 54, 47-58. Kim, K.W., Ko, C.J. and Park, H.j. (2002). Mechanical properties, water vapour permeability and solubilities of highly carboxymethylated setarch.based edible films. Journal of Food Science, 67(1) 218-222 Kristo, E. and Biliaderis, C. G. (2006). Water sorption and thermo-mechanical properties of water/sorbitol-plasticized composite biopolymer films: caseinate-pullulan bilayers and blends. Food Hydrocolloids, 20(7), 10571071. Kristo, E., Biliaderis, C. G. and Zampraka, A. (2007). Water vapour barrier and tensile properties of composite caseinate-pullulan films: biopolymer compositions effects and impact of beeswax lamination. Food Chemistry, 101(2), 753-764. Krochta, J. M. and Mulder-Johnston, C-de. (1997). Edible and biodegradable polymer films: Challenges and opportunities. Food Technology, 51(2), 61–74. Lacroix, M. and Le Tien, C. (2005). Edible films and coatings from non-starch polysaccharides. In. J. H. Han, Innovations in Food Packaging (pp.338361). London: Elsevier Academic Press. Langendorff, V., Cuvelier, G., Michon, C., Launay, B., Parker, A., and De Kruif, C. G. (2000). Effects of carrageenan type on the behaviour of carrageenan/milk mixtures. Food Hydrocolloids, 14, 273-280. Lazaridou, A., and Biliaderis, C.G. (2002). Thermophysical properties of chitosan, chitosan–starch and chitosan–pullulan films near the glass transition. Carbohydrate Polymers, 48 (2), 179–190. Lezica, R. P.; Quesada-Allue, L. (1990). Chitin. In J. B. Harbourne (Ed.) Methods in Plant Biochemistry.Carbohydrates. Vol 2. (pp.443-481). New York: Academic Press.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

References

45

León, P.G. and Rojas, A.M. (2007). Gellan gum films as carriers of l-(+)ascorbic acid. Food Research International, 40(5), 565-575. Li J-Y. and Yeh, A-I. (2001). Relationships between thermal, rheological characteristics and swelling power for various starches. Journal of Food Engineering, 50, 141-148. Liu, Z. (2002). Starch: from granules to biomaterials. In S. G. Pandalai (Ed.), Recent research developments in applied polymer science, Vol. I, Part I. (pp. 189-219). Research Signpost, Trivandum, India. Liu, Z. (2005). Edible films and coatings from starches. In J. H. Han (Ed.), Innovations in Food Packaging (pp.318-337). London: Elsevier Academic Press. Lizarraga, M.S., De Piante Vicin, D., González, R., Rubiolo, A. and Santiago, L.G. (2006). Rheological behaviour of whey protein concentrate and λcarrageenan aqueous mixtures. Food Hydrocolloids, 20(5), 740-748. Lourdin, D., Bizot, H. and Colonna, P. (1997). « Antiplasticization » in starchglycerol films? Journal of Applied Polymer Science, 63, 1047-1053. Maftoonazad, N. and Ramaswamy, H.S. (2005). Postharvest shelf-life extension of avocados using methyl cellulose-based coating. LWT – Food Science and Technology, 38, 6, 617-624. Maftoonazad, N., Ramaswamy, H. S and Marcotte, M. (2007). Evaluation of factors affecting barrier, mechanical and optical properties of pectin-based films using response surface methodology. Journal of Food Process Engineering, 30(5). 539-563. Maftoonazad, N., Ramaswamy, H. S and Marcotte, M. (2007). Moisture Sorption Behavior, and Effect of Moisture Content and Sorbitol on Thermo-Mechanical and Barrier Properties of Pectin Based Edible Films. International Journal of Food Engineering, 3(4), article 10. Macquarrie, R., U.S. Patent (2002) 0155200 A1. Melton, L. D., Mindt, L., Rees, A. and Sanderson, G. R. (1976). Covalent structure of the polysaccharide from Xanthomonas campestris: Evidence from partial hydrolysis studies. Carbohydrates Research, 46, 245-257. Miller, K. S. and Krochta, J.M. (1997). Oxygen and aroma barrier properties of edible films: A review. Trends in Food Science and Technology, 8, 228-237. Moe, S. T., Draget, K. I., Skjäk-Bræk, G. and Smidsrød, O. (1995). Alginates. In A. M. Stephen (Ed.), Food polysaccharides and their applications (pp. 245–286). New York: Marcel Dekker. Morris, V. J. (1995). In A. M. Stephen (Ed.), Food polysaccharides and their applications (pp. 341–375). New York: Marcel Dekker.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

46

Pau Talens, María José Fabra and Amparo Chiralt

Muetgeert, J., Bus, W. C., and Hiemstra, P. (1962). Influence of formaldehyde on viscosity stability of concentrated aqueous amylase solutions. Journal of Chemical and Engineering Data, 7, 272-276. Muzzarelli, R., Tarsi. R., Filippini, O., Giovanetti, E., Biagini, G., and Varaldo, P.R. (1990). Antimicrobial properties of N-carboxybutyl chitosan. Antimicrobial Agents Chemotherapy, 2019-2023. Muzzarelli, R. A. A. (1996). Chitosan-based dietary foods. Carbohydrates Polymers, 29, 309–316. Nispero–Carriedo, M. (1994). Edible coating based on polysaccharides. In: J. M. Krochta, E. Baldwin and M. Nispero-Carriedo (Eds.), Edible coatings and films to improve food quality (pp.201-277). Technomic Publishing, Lancaster. Nazan Turhan, K. ; Sahbaz, F. (2004). Water vapor permeability, tensile properties and solubility of methylcellulose-based edible films. Journal of Food Engineering, 61, 459-466. Nussinovitch, A. and Hershko, V. (1996). Gellan and alginate vegetable coatings. Carbohydrate Polymer, 30, 185-192. Oms-Oliu, G., Soliva-Fortuny, R. and Martín-Belloso, O. (2008a). Using polysaccharide-based edible coatings to enhance quality and antioxidant properties of fresh-cut melon. LWT – Food Science and Technology, 41, 10, 1862-1870 Oms-Oliu, G., Soliva-Fortuny, R. and Martín-Belloso, O. (2008b). Edible coatings with antibrowning agents to maintain sensory quality and antioxidant properties of fresh-cut pears. Postharvest Biology and Technology, 50, 1, 87-94. Ou, S. Y., Kwok, K. C., and Kang, Y. J. (2004). Changes in in vitro digestibility and available lysine of soy protein isolate after formation of film. Journal of Food Engineering, 64(3), 301–305. Park, H. J.; Chinnan, M. S. (1994). Gas and water vapor barrier properties of edible films from protein and cellulosic materials. Journal of Food Engineering, 25, 497-507. Park, H. J. (1996) Gas and mechanical barrier properties of carrageenan-based biopolymer films. Food Science and Industry, 29, 47–53. Pavlath, A. E., Gosset, C. Camirand W. and Robertson, H. (1999). Ionomeric films of alginic acid. Journal of Food Science, 64, 61-63. Peterson, K., Nielsen, P.V., Bertelsen, G., Lawther, M., Olsen, M. B., Nilsson, H., Mortensen, G. (1999). Potential of biobased materials for food packaging. Trends in Food Science and Technology, 10, 52-68.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

References

47

Phan The, D., Péroval, C., Debeaufort, F., Despré, D., Courthaudon, J. L.; Voilley, A. (2002). Arabinoxylan-lipids-based edible films and coatings.2. Influence of sucroester nature on the emulsion structure and film properties. Journal of Agriculture and Food Chemistry, 50, 266-272. Phan, T.D., Debeaufort, F., Luu, D. and Voilley, A., (2009a). Influence of hydrocolloid nature on the structure and functional properties of emulsified edible films. Food Hydrocolloids, 23 (3), 691-699. Phan, T.D., Debeaufort, F., Voilley, A. and Luu, D. (2009b). Biopolymer interactions affect the functional properties of edible films based on agar, cassava starch and arabinolyxan blends. Journal of Food Engineering, 90, 548-558. Pérez-Gagó, M. B. and Krochta, J. M. (2001). Lipid particle size effect on water vapor permeability and mechanical properties of whey protein/beeswax emulsion films. Journal of Agricultural and Food Chemistry, 49, 996-1002. Protzman, T. F., Wagoner, J. A. and Young, A. H. (1967). US Patent 3344216. Rhim, J.W. (2004). Physical and mechanical properties of water resistant sodium alginate films. Lebensmittel-Wissenschaft und-Technologie 37, 323-330. Ribeiro, C., Vicente, A.A., Teixeira, J.A. and Miranda, C. Optimization of edible coating composition to retard strawberry fruit senescence. (2007). Postharvest Biology and Technology, 44, 1, 63-70. Rojas-Graü, M.A., Tapia, M.S. and Martín-Belloso, O (2008). Using polysaccharide-based edible coatings to maintain quality of fresh-cut Fuji apples. LWT – Food Science and Technology, 41, 139–147. Rhim, J.W. (2004). Physical and mechanical properties of water resistant sodium alginate films. Lebensmittel-Wissenschaft und-Technologie 37, 323-330. Ryu, S.Y., Rhim, J.W., Roh, H.J. and Kim, S.S (2002). Preparation and physical properties of zein-coated high-amylose corn starch film. Lebesm. Wiss. U. Techonol, 35(8), 680-686. Sanderson, G. R. (1981). Polysaccharides in foods. Food Technology, 35, 5057, 83. Sebastien, F., Stephane, G., Copinet, A. and Coma, V., (2006). Novel biodegradable films made from chitosan and poly(lactic acid) with antifungal properties against mycotoxinogen strains. Carbohydrate Polymers 65, 185–193.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

48

Pau Talens, María José Fabra and Amparo Chiralt

Singh, R. S., Saini, G. K. and Kennedy, J. F. (2008). Pullulan: Microbial sources, production and applications. Review. Carbohydrates Polymers, 73, 515-531. Singh, N., Singh, J., Kaur, L., Singh-Sodhi N. and Singh-Gill, B. (2003). Morphological, thermal and rheological properties of starches from different botanical sources, Food Chemistry, 81, 219-231. Smidsrød, O. (1974). Molecular basis for some physical properties of alginates in the gel state. Faraday Discussions Chemical Society, 57, 263–274. Tanner, K., Getz, J., Burnett, S., Youngblood, E. and Draper, P. U.S. Patent (2002) 0081331 A1. Thakur, B. R., Singh, R. K., and Handa, A. K. (1997). Chemistry and uses of pectin-a review. Critical Review in Food Science and Nutrition, 37, 47-73. Turgeon, S. L., and Beaulieu, M. (2001). Improvement and modification of whey protein gel texture using polysaccharides. Food Hydrocolloids, 15, 583-591. Shellhammer, T.H.; Krochta, J. M (1997) Edible coatings and film barriers. In: Lipids-Industrial Applications and Technology, eds. F. D. Gunstone and F. B. Padley, New York: Marcel Dekker, pp. 453-479. Sothornvit, R and Krochta, J. M. (2000). Plasticizer effect on oxygen permeability of β-lactoglobulin films. Journal of Agricultural and Food Chemistry, 48, 6298-6302. Sothornvit, R and Krochta, J. M (2005). Plasticizers in edible films and coatings In J. H. Han (Ed.), Innovations in Food Packaging (pp.239-260). London: Elsevier Academic Press. Tharanthan, R. N. and Kittur, F. S. (2003). Chitin-the undisputed biomolecules of great potential. Critical Review in Food Science and Nutrition. 43(1), 61-87. Thomas, D. J. and Atwell, W. A. (1997). Starches. Eagan Press, St Paul, MN. Tong, Q., Xiao, Q. and Lim, L.T. (2008). Preparation and properties of pullulan-alginate-carboxymethylcellulose blend films. Food Research International, 4(10), 1007-1014. Tsai, G.J., Wu, Z.Y. and Su, W.H. (2000). Antibacterial activity of a chitooligosaccharide mixture prepared by cellulase digestion of shrimp chitosan and its application to milk preservation. Journal of Food Protection, 63,747-752. Tsujisaka, Y. and Mitsuhashi, M. (1993). Pullulan. In R. L. Whistler and J. N. BeMiller (Eds.), Industrial gums, polysaccharides and their derivatives (pp. 447–460). San Diego, CA: Academic Press.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

References

49

Tzoumaki, M.V., Biliaderis C.G. and Vasilakakis, M (2009). Impact of edible coatings and packaging on quality of white asparagus (Asparagus officinalis, L.) during cold storage. Food Chemistry, 1, 55-63. Vargas, M., Albors, A., Chiralt A. and González-Martínez, C. (2006). Quality of cold-stored strawberries as affected by chitosan–oleic acid edible coatings. Postharvest Biology and Technology, 41, 2, 164-171. Vargas, M., Chiralt, A., Albors, A. and González-Martínez, C (2009). Effect of chitosan-based edible coatings applied by vacuum impregnation on quality preservation of fresh-cut carrot. Postharvest Biology and Technology, 51, 2, 263-271 Viña. S. Z., Mugridge, A., García, M. A., Ferreyra, R. M., Martino, M. N., Chaves, A. R. and Zaritzky, N. E. (2007). Effects of polyvinylchloride films and edible starch coatings on quality aspects of refrigerated Brussels sprouts. Food Chemistry, 103, 3, 701-709. Villalobos-Carvajal, R., Hernández-Muñoz, P., Albors, A. and Chiralt, A. (2009). Barrier and optical properties of edible hydroxypropylmethylcellulose coatings containing surfactants applied to fresh cut carrot slices. Food Hydrocolloids, 23, 2, 526-535. Whistler, R. L. and Daniel, J. R. (1985). Functions of polysaccharide in foods. In O. R. Fennema (Eds.) Food Chemistry, 2nd edn. (pp 69-137). Marcel Dekker, New York, NY. Wolff, I. A., Davis, H. A., Cluskey, J. E., Gundrum, L. J. and Rist, C. E. (1951). Preparation of films from amylose. Industrial and Engineering Chemistry Research, 43, 915-919. Wu, Y., Weller, C. L., Hamouz, F., Cuppett, S. L. and Schenepf, M. (2002). Development and application of multicomponent edible coatings and films: a review. Advances in Food and Nutrition Research, 44, 347-394. Xu, Y. X., Kim, K. M., Hanna, M. A., and Nag, D. (2004). Chitosan–starch composite film: Preparation and characterization. Industrial crops and products, 21(2), 185–192. Xu, X., Li, B., Kennedy, J. F., Xie, B. J. and Huang, M. (2007). Characterization of konjac glucomannan-gellan gum blend films and their suitability for release of nisin incorporated therein. Carbohydrates Polymers, 70 (2), 192-197. Yalpani, M. (1988). Polysaccharides: Synthesis, modifications, and structureproperty relations. In M. Yalpani (Ed.), Studies in organic chemistry (Vol.36). Amsterdam: Elsevier.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

50

Pau Talens, María José Fabra and Amparo Chiralt

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

Yaman, Ö and Bayoindirli, L. (2002). Effects of an Edible Coating and Cold Storage on Shelf-life and Quality of Cherries. Lebensmittel-Wissenschaft und-Tecnologie, 35, 2, 146-150. Yang, L. and Paulson, A.T. (2000). Mechanical and water vapour barrier properties of edible gellan films. Food research International, 33, 563570. Yuen, S. (1974). Pullulan and its applications. Process Biochemistry, 9, 7-9, 22. Yuguchi, Y., Thu Thuy, T.T., Urakawa, H. and Kajiwara, K. (2002) Structural characteristics of carrageenan gels: temperature and concentration dependence. Food Hydrocolloids, 16, 515-522. Zaleska, H., Ring, S., and Tomasik, P. (2000). Apple pectin complexes with whey protein isolate. Food Hydrocolloid, 14, 377-382.

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

INDEX

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

A acetic acid, 33 acid, 8, 10, 11, 14, 19, 21, 31, 33, 35, 40, 42, 46, 49 acidity, 31, 33 activity level, 34 additives, xi, 1 adhesion, 4, 5, 9, 12, 14, 18, 19 agar, 11, 19, 25, 27, 47 agent, 8, 12, 13, 21, 32, 33 aggregates, 14 aggregation, 14 alcohol, 42 alternative, 35 amino acids, 2 amylase, 3, 9, 17, 46 antioxidant, 20, 32, 46 apples, 32, 47 aqueous solutions, 7, 12, 13, 20 ascorbic acid, 20, 27, 31, 45 availability, 2, 18

B bacteria, 22 bacteriocins, 19 barriers, 4, 5, 7, 18, 19, 20, 23, 25, 48 beer, 12 behavior, 21, 36 behavioral aspects, 13

beverages, 13 binding, 4, 9, 22, 26 biodegradability, xi, 2 biomaterials, 45 biomedical applications, 9 biopolymer, 11, 44, 46 blend films, 48, 49 blends, 21, 25, 26, 39, 44, 47 blocks, 11, 19 bonding, 3, 10, 18 bonds, 3 breakdown, 9 brittle film, 8

C calcium, 5, 6, 8, 14, 18, 21, 30, 32, 33, 43 calorie, 11, 12 carbohydrate, 11 carbon dioxide, xi, 2, 5, 18, 23, 27, 40 carrier, 20 casein, 5, 18 cast, 17, 20, 26 casting, 17, 26 cation, 5, 19 cell, 9, 14 cellulose, xi, 2, 3, 4, 5, 7, 9, 10, 15, 18, 19, 25, 29, 30, 31, 40, 42, 43 cellulose derivatives, 10, 42 chemical properties, 10 chitin, 15, 44

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

52

Indext

CMC, 10, 18, 20 CO2, 27, 30, 33, 35 coffee, 13 cohesion, 26 components, xi, 1, 2, 5, 11, 18, 23, 27, 37 composition, xi, 1, 11, 24, 33, 35, 40, 47 compounds, 2, 19, 32 concentration, 17, 43, 50 consumers, 33 continuity, 17 control, 1, 8, 11, 21, 30 cooking, 10 cooling, 8, 12, 14 corn, 3, 27, 33, 47 crack, 23 crops, 49 crystal growth, 11 crystalline, 10 culture, 12, 14

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

D decay, 33, 42 dehydration, xi, 29, 37 density, 25 deposition, 30 derivatives, xi, 2, 3, 10, 13, 48 diffusion, xi, 29, 37 digestibility, 46 digestion, 44, 48 discs, 30 dispersion, 18, 30 distribution, 7, 26 dough, 30 dressings, 12, 13, 14 durability, 23

encapsulation, 42, 43 energy density, 26 environment, xi, 11, 13, 23 enzymes, 42 equilibrium, 21 ethanol, 18 ethers, 10, 18 ethylene, 23, 32, 35 ethylene glycol, 23 extraction, 8 extrusion, 4, 18 exudate, 12

F family, 14 fat, 8, 21, 30, 39, 41 fatty acids, 25, 31 fermentation, 12, 14 film formation, 2, 4, 9, 17, 43 fish, 1, 29, 41 flavor, xi, 5, 8, 18, 19, 21, 33 flour, 30 foams, 12 food, xi, xii, 1, 2, 3, 4, 6, 8, 9, 10, 11, 13, 17, 18, 19, 20, 21, 23, 29, 30, 37, 39, 40, 41, 42, 46 food industry, 3, 11 food products, xi, xii, 1, 4, 9, 11, 17, 29 formaldehyde, 22, 46 free volume, 26 fruits, xi, 1, 5, 18, 29, 30, 33, 37 FTIR, 20 fungi, 22, 32, 35 fungus, 13

G E earth, 10 egg, 30 elasticity, 21 elongation, 21, 25 emulsions, 11

gel formation, 4, 9, 14 gelation, 7, 12, 17 glass transition temperature, 27 glucose, 3, 9, 15 glutathione, 32 glycerol, 18, 19, 23, 24, 43, 45

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Index glycol, 18, 23, 31 grades, 14 granules, 45 groups, 11, 20 growth, 11, 32, 34, 35, 44 growth rate, 34

H heat, 19, 30 heating, 8, 14, 18 homogeneity, 4, 9 HPC, 10, 18, 23, 24, 25 humidity, 2, 23, 25, 30 hydrogen, 2, 3, 10, 18, 20, 25 hydrogen bonds, 2, 20 hydrolysis, 9, 10, 17, 45 hydrophobicity, 2 hydroxyl, 2, 10, 23 hydroxyl groups, 2, 10, 23

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

I immersion, 35 impregnation, 49 in vitro, 46 incidence, 33 inclusion, 31 industry, 3, 15 integrity, 1, 2, 23 interactions, 18, 27, 37, 42, 44, 47 ions, 6, 8, 21, 30

L lactic acid, 33, 47 lamination, 44 links, 27 lipid oxidation, 5, 19 lipids, xi, 2, 19, 21, 26, 33, 47 listeria monocytogenes, 22 lysine, 46

53

M magnesium, 30 manipulation, 26 mannitol, 23 manufacturing, 29 matrix, 20, 26, 41 MC films, 18 meat, 1, 9, 13, 18, 29 mechanical properties, 2, 4, 6, 7, 9, 17, 20, 21, 23, 27, 30, 34, 36, 44, 47 media, 8, 35 melon, 46 melting, 6, 7, 12 melting temperature, 6 membranes, 13 methyl cellulose, 30, 45 methylcellulose, 5, 27, 30, 31, 35, 39, 41, 46 microcrystalline cellulose, 10, 30 microstructure, 20 migration, 1, 4, 8, 14, 18, 21 milk, 12, 44, 48 mobility, 13 modulus, 21 moisture, 1, 2, 4, 5, 7, 8, 9, 14, 18, 19, 20, 21, 25, 29, 30, 31, 33, 40, 43 moisture content, 7, 19, 20, 21 moisture sorption, 21 molecular weight, 2, 10, 14, 15, 34, 35, 40 molecules, 2, 3, 19 monomers, 11, 26 monosaccharide, 3

O oil, xi, 1, 4, 5, 11, 18, 23, 29, 30, 37, 42 oils, 4, 18, 25 oligomers, 44 optical properties, 45, 49 organic solvents, 4, 5, 6, 7, 10, 11, 13 organism, 14 orientation, 14 oxidation, xi, 1, 17, 19, 29, 37

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

54

Indext

oxygen, xi, 1, 2, 4, 5, 6, 7, 9, 17, 18, 19, 20, 21, 23, 25, 26, 27, 43, 48

room temperature, 31

S

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

P packaging, xi, 1, 6, 13, 17, 19, 21, 31, 35, 37, 39, 40, 41, 46, 49 particles, 2 permeability, xii, 4, 7, 17, 19, 20, 21, 24, 25, 33, 35, 42, 44, 46, 47, 48 permeation, 40 physical properties, xi, 4, 9, 40, 47, 48 physicochemical properties, 2, 41 plants, 9 plasticizer, 33, 40, 41 polymer chains, 7 polymer films, 1, 44 polymer matrix, 27 polymer molecule, 9 polymerization, 9 polymers, 6, 11, 17, 21, 22, 23 polyvinyl chloride, 22, 31, 49 poor, 2, 19 potassium, 6, 19, 41 potato, 3, 30 poultry, 29 power, 45 preservative, 41, 42 pressure, 10 production, 1, 4, 10, 17, 21, 32, 35, 48 propylene, 10, 18, 23 proteins, xi, 2, 7, 13, 20, 26, 41 pulse, 35 PVC, 22, 24, 31

R range, 8, 14, 18, 26, 27 reactive groups, 13 reagents, 10 residues, 11, 14 resistance, 2, 4, 17, 21, 30, 32, 34, 36, 44 respiration, 1, 31, 34 retention, 4, 9, 33

safety, 6, 19, 22 salts, 18 sample, 34, 36 seafood, xi, 29, 37 seed, 12, 13 selectivity, 27 senescence, 33, 47 shellfish, 15 shrimp, 29, 48 skin, 31 sodium, 10, 18, 19, 20, 26, 31, 42, 43, 47 sodium hydroxide, 10 solubility, 13, 20, 46 solvents, 4, 10, 11 sorption, 21, 40, 44 sorption isotherms, 21 soybean, 30 species, 11, 12 stability, 8, 9, 14, 30, 35, 46 stabilizers, 6, 13, 19 starch, 3, 7, 10, 17, 19, 24, 25, 26, 29, 31, 33, 35, 39, 40, 41, 42, 43, 44, 45, 47, 49 starch blends, 27, 41 starch polysaccharides, 44 storage, 30, 31, 33, 35, 40, 43, 49 strength, 5, 9, 18, 25 stress, 32 substitution, 3, 4, 10 sucrose, 31, 35 sugar, 6, 8, 11, 14, 18, 42 sulfuric acid, 10 surface properties, 41 surface tension, 35 surfactant, 35, 41 swelling, 45 synthetic polymers, 25

T temperature, 7, 9, 10, 12, 17, 25, 50

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,

Index tensile strength, 6, 19, 21, 25 tissue, 32 transition, 10, 40 transmission, 21, 27, 30, 36

55

viscosity, 4, 5, 7, 9, 10, 13, 14, 18, 35, 46 vitamin C, 31, 33, 40 vitamin E, 33

W V water permeability, 27 water vapor, 7, 9, 19, 20, 21, 25, 27, 30, 32, 33, 35, 46, 47 weight loss, 29, 30, 31, 33 wheat, 3

Copyright © 2010. Nova Science Publishers, Incorporated. All rights reserved.

vacuum, 35, 49 values, xi, 19, 25 vapor, 19, 20, 21, 24, 25, 27, 30, 33, 35, 46 variability, 36 vegetables, xi, 1, 5, 18, 29, 30, 37

Edible Polysaccharide Films and Coatings, Nova Science Publishers, Incorporated, 2010. ProQuest Ebook Central,