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Joseph William Holloway Jianping Wu

Red Meat Science and Production Volume 2. Intrinsic Meat Character

Red Meat Science and Production

Joseph William Holloway • Jianping Wu

Red Meat Science and Production Volume 2. Intrinsic Meat Character

Joseph William Holloway Animal Science Texas A&M University Uvalde, TX, USA

Jianping Wu Gansu Academy of Agricultural Sciences Lanzhou, Gansu, China

ISBN 978-981-13-7859-1    ISBN 978-981-13-7860-7 (eBook) https://doi.org/10.1007/978-981-13-7860-7 Jointly published with Science Press The print edition is not for sale in China. Customers from China please order the print book from: Science Press. © Springer Nature Singapore Pte Ltd. and Science Press 2019 This work is subject to copyright. All rights are reserved by the Publishers, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publishers, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publishers nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publishers remain neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Singapore Pte Ltd. The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore

Preface

Red Meat Science is a comprehensive compilation of research performed to reveal the science of red meat in order to understand the fundamentals undergirding its production. Red meat not only is the product of a lifetime embodied in the muscles of ruminant animals but also is characterized by processes that take place after the animal dies when muscle becomes meat. The science of red meat, therefore, concerns the analysis of these complex biological processes. The production of red meat involves the synthesis of these processes into holistic production systems orchestrating them toward red meats desired by consumers. Thus, Red Meat Science begins with the consumer who determines the product character desired. The product character is described according to definable attributes. The biological and necrological sciences underlying the formation of these attributes are analyzed in order to synthesize them into production systems designed to consistently produce red meat products desired by discerning targeted markets. Unlike many texts, Red Meat Science is a thorough, comprehensive review of the literature of science and practice of red meat production on a global scale, thereby reviewing about 4,000 original and review technical publications. Because of the scope and scale of the text, the authors chose to limit its commentary and let the research “speak for itself.” Therefore, nearly every sentence in the text is referenced in the scientific literature. Many of the conclusions drawn are not the ideas of the authors but the conclusions drawn by scientists based on research evidence. The authors are careful to give credit to the originating scientists for every conclusion drawn in the text. The conclusions, evidence, and scientific publication citations are given so that the readers can make their own conclusions and draw hypotheses for further exploration of the science and production of red meat. The authors are deeply indebted to colleagues who have performed the research reported herein. The authors are in awe of the volume and quality of research performed worldwide during the most recent decades, linking the ruminant production system to the character of red meat. The authors are also indebted to Mr. Clayton

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Ferdinand, chief executive officer of Enhanced Exchange, for his inspiration and motivation that provided the initiative for this work. This comprehensive work could not have been completed without the editing skills and diligence of Cindy Davis and Karen Dean. Uvalde, TX, USA  Joseph William Holloway Lanzhou, Gansu, China  Jianping Wu  

Introduction

Meat quality is a complex concept but can be defined as the characteristics of meat which satisfy consumers and potential consumers (Hocquette et al. 2012a, 2013). Quality is a matter of both intrinsic and extrinsic character traits. Intrinsic traits are the characteristics inherent in the product itself that can be sensed at the time of consumption, and extrinsic traits are the characteristics associated with the product not verifiable during the eating experience. Volume 1 of this text is concerned with consumer acceptance and the extrinsic character of red meat, whereas this volume focuses on the intrinsic character of red meat including appearance, aroma, tenderness, juiciness, and flavor. Since the consumer controls the red meat production process, it is necessary to begin any discussion of beef quality with the desires of the consumer. Volume I of this text begins with an exhaustive review of these desires. Therefore, at the risk of being redundant with Volume 1, this volume will reiterate these desires, focusing on the intrinsic character of red meat that provides the eating experience as perceived by the array of global consumers. The red meat industry is similar to many food industries in the world in that it depends on “mass inspection” (e.g., US Department of Agriculture (USDA) quality grading) of completed products at the end of the production process to classify the products as to their suitability for the market or as a sort to decide the market for which each product is suited and to establish product value. Even though this system results in general categorization according to measurable proxy variables for eating quality, product value is compromised due to the imprecision of the sorting methodology, inaccuracy of the methodology for estimating eating quality, and untimeliness of information. At that point, it is too late to alter the production according to outcome desired, and thus, “inferior” products already have been produced and must be sold at discounted prices (Tatum et al. 1999). Each quality characteristic of the product is a composite attribute that results from the cascade of genetics, production, processing, transit, and cookery. Each of the components of this cascade interacts with the others to present the consumer with a product that may or may not meet his/her cultural/sensorial expectations. As discussed in Volume I, various attempts have been made to judge the success of the vii

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different perturbations of this cascade in producing consistent quality experiences for consumers (e.g., Meat Standards Australia, the USDA quality grading scheme, and total quality management). W. Edwards Deming originated the concept of total quality management (TQM), which often is cited as the basis for the current modern “quality revolution.” He recommended that industries “cease dependence on product inspection to achieve quality” and “eliminate the need for inspection on a mass basis by building quality into the product in the first place” (Tatum et al. 1999). A TQM approach to ensure beef tenderness was proposed at the 1994 National Beef Tenderness Conference (Tatum et  al. 1999). Application of such a system requires the identification of causes of nonconformance (e.g., toughness) and then focuses on the prevention of nonconformance through control of inputs and processes (Tatum et al. 1999). This approach only addresses one component of beef quality—a component that is dominant in many markets but of only minor consequence in others. But, the approach has merit as a model for developing unified processes that assure red meat products exceed market expectations. Implementation of best practice genetics, preharvesting cattle management (e.g., hormonal growth promotants, stress reduction, and growth path manipulation), early postmortem processing (e.g., chilling rate and electrical stimulation), and postmortem aging are indicated in this system as critical steps to reduce the incidence of tough beef. No system in the world attempts to orchestrate the beef production system to affect a cascade designed to achieve satisfaction in the array of global market niches that exist. Tatum et al. (1999) reported a prototype of TQM that has the potential to improve consistency in tenderness of American beef, but this system does not address all the components important in contribution to consistent quality eating experiences. It does not address all the intrinsic characteristics important in global markets, much less the extrinsic characteristics. Development of TQM for red meat requires: 1. Definition of the eating experience desired by the targeted market as the goal of the production system 2. Interpretation of the eating experience desired into product specifications according to attributes perceived important by the targeted market 3. Understanding the biology involved in the attributes considered of value by the targeted market 4. Construction of production/delivery systems orchestrating the biology toward the desired product 5. Identification of critical control points along the production system: a. Where production units can be evaluated by objective criteria dictated by the pertinent biology b. So that nonconforming production units can be identified c. Remedial system alterations be prescribed to cause them either to conform or fit them to another market

Introduction

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This text is oriented to address all the points required for total quality management in the production of red meat. The hypothesis is that the only method that can guarantee that the consumer has a quality and safe eating experience every time is the orchestration of certain production system elements aimed toward a product that has the eating and safety characteristics desired by each market niche. The other possibility is the one usually chosen to produce beef. That possibility is to perform a “cooler sort” to identify from a large number of carcasses a desired subset. Since many of the traits associated with certain intrinsic factors, such as eating quality and safety, are difficult to assess at this time, the cooler sort is not likely to succeed in classifying meat according to eating quality. Volume I of this text began at the beginning, with the market the reason for beef production including the determinants of its character. This volume continues with a delineation of the intrinsic characteristics thought to be associated with quality eating experiences for red meat. For beef, these intrinsic characteristics are the following: safety, visual appearance (lean and fat color, firmness, marbling, subcutaneous and intramuscular fat content), eating quality (tenderness, juiciness, flavor, fat content, and fatty acid profile), aroma, and cut size. These classifications are somewhat arbitrary since the traits in each class may influence the traits in the other classes. For example, marbling has been associated with juiciness, flavor, and tenderness (Savell and Cross. 1988). For lamb, the important intrinsic characteristics reported by Oltra et al. (2015) are the following: intensity of aroma, visual appearance in terms of caramelized external appearance, juicy external and internal appearance, and brown internal appearance, flavor attributes including intensity and roast lamb flavor, tenderness, and dry aftertaste. These characteristics are indicative of the most marked attributes of grilled lamb and include aspects of appearance, texture, aroma, flavor, and to a lesser degree tenderness (Oltra et al. 2015). The eating quality attributes identified as driving the consumer preferences of lamb loin steaks are tenderness, sweet flavor, meaty aftertaste, roast lamb flavor, and roast lamb aftertaste (Oltra et al. 2015). The negative influencers are the texture attribute described as rubbery (toughness) and the flavor attributes of bitterness and bitter aftertaste (Oltra et al. 2015). Much has been made of differences among consumers in preferences for lamb, especially the differences between markets in the Middle East and Australia as compared to those in America. Consumers in these markets reportedly prefer stronger flavors than consumers in America. Differences in preference criteria for lamb eating quality were more aligned with sensory preferences and not demographic factors for English consumers (Oltra et al. 2015) and for Japanese and New Zealand consumers (Prescott et al. 2001). However, if consumers have access to more information, such as price, brand, and quality claims, demographic characteristics, such as age and sex, can be important determinants of preference (Guinard 2002). Because the results of many experiments have indicated that the overriding f­ actor influencing eating quality is tenderness, this text will emphasize this characteristic, discussing other characteristics influencing eating quality in terms of their impact

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on tenderness. Pertinent literature will be reviewed to evaluate production system effects on each of the intrinsic traits impacting the eating experience. Because many of these traits are heritable, the influence of genetics on these traits will be a prominent part of the review. The goal of the text is to identify production system elements that can be orchestrated into cohesive production systems with the idea of building upon the system of Hazard Analysis at Critical Control Points (HACCP, discussed in Volume I) to develop a parallel system of Quality Analysis of Critical Control Points (QACCP). Because red meat quality is a complex, multifaceted characteristic, it can only be understood by consideration of each separately through analysis while acknowledging that all facets are related. Although the eating experience is the culmination of many aspects, the bottom line is that it is one experience that is either desirable or not. Therefore, understanding the quality of red meat ultimately requires a synthesis approach designed to understand the holistic nature of beef quality. In this text, each aspect of red meat quality is discussed separately especially as to the impact production system elements have on each component. At the same time, it is understood that each production system element occurs in the context of other elements and that each element impacts more than one facet of red meat quality. Therefore, as each attribute is discussed, there is some redundancy in discussing relationships with other facets. The ultimate goal of the text is to identify production system elements sensitive to all important aspects of red meat quality and to identify means to orchestrate these elements into cohesive production and delivery systems that consistently produce red meat products desired by a wide array of markets.

Contents

1 The Red Meat Consumer������������������������������������������������������������������������    1 2 Intrinsic Quality Factors: Carcass Quality Grading Systems ������������    3 2.1 Major Global Beef Grading Systems������������������������������������������������    3 2.1.1 USDA Quality Grade����������������������������������������������������������    5 2.1.2 Meat Standards Australia����������������������������������������������������   12 2.1.3 Wagyu Carcass Grading System����������������������������������������   13 2.1.4 Modeling Beef Quality ������������������������������������������������������   13 3 Aroma Intrinsic Character ��������������������������������������������������������������������   15 3.1 Consumer Preferences����������������������������������������������������������������������   15 3.2 Science����������������������������������������������������������������������������������������������   15 3.3 Production System Elements (Critical Control Points)��������������������   16 4 Visual Intrinsic Character����������������������������������������������������������������������   19 4.1 Portion Size��������������������������������������������������������������������������������������   20 4.2 Lean Color����������������������������������������������������������������������������������������   20 4.2.1 Consumer Preferences��������������������������������������������������������   20 4.2.2 Real-Time Objective Measurement������������������������������������   20 4.2.3 Science��������������������������������������������������������������������������������   22 4.2.4 Production System Elements (Critical Control Points)������   23 4.3 Fat ����������������������������������������������������������������������������������������������������   36 4.3.1 Fat Color ����������������������������������������������������������������������������   36 4.3.2 Fat Distribution in Cuts������������������������������������������������������   36 4.3.3 Firmness of Fat ������������������������������������������������������������������   37 5 Tenderness Intrinsic Character��������������������������������������������������������������   39 5.1 Consumer Preferences����������������������������������������������������������������������   39 5.2 Estimation Methods��������������������������������������������������������������������������   42 5.2.1 Real-Time Measurement����������������������������������������������������   43 5.2.2 Beef Biomarkers ����������������������������������������������������������������   47

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5.3 Science����������������������������������������������������������������������������������������������   47 5.3.1 The Sarcomere��������������������������������������������������������������������   49 5.3.2 Rigor Mortis������������������������������������������������������������������������   54 5.3.3 Proteomics and Meat Tenderness ��������������������������������������   54 5.3.4 Muscle to Meat Conversion������������������������������������������������   55 5.3.5 Proteolysis Post-Slaughter: The Basis of Aging ����������������   59 5.3.6 Postmortem Glycogen Metabolism and pHu����������������������   60 5.3.7 Heat Shock Proteins and Postmortem Proteolysis��������������   62 5.3.8 Muscle Fiber Type��������������������������������������������������������������   67 5.3.9 Connective Tissue ��������������������������������������������������������������   68 5.3.10 Intramuscular Fat����������������������������������������������������������������   71 5.3.11 Interactions ������������������������������������������������������������������������   72 5.4 Production System Elements (Critical Control Points)��������������������   73 5.4.1 Premortem Management����������������������������������������������������   73 5.4.2 Perimortem Management����������������������������������������������������  121 5.4.3 Postmortem Management ��������������������������������������������������  123 6 Juiciness Intrinsic Character������������������������������������������������������������������  143 6.1 Consumer Preferences����������������������������������������������������������������������  143 6.2 Science����������������������������������������������������������������������������������������������  144 6.2.1 Water Content ��������������������������������������������������������������������  144 6.2.2 Proteins and Water��������������������������������������������������������������  144 6.2.3 Carbohydrates ��������������������������������������������������������������������  144 6.2.4 Intramuscular Fat����������������������������������������������������������������  145 6.2.5 Fatty Acids��������������������������������������������������������������������������  146 6.3 Production System Elements (Critical Control Points)��������������������  147 6.3.1 Animal Genetics ����������������������������������������������������������������  147 6.3.2 Animal Temperament ��������������������������������������������������������  147 6.3.3 Animal Gender��������������������������������������������������������������������  147 6.3.4 Growth Stimulants��������������������������������������������������������������  147 6.3.5 Dietary Vitamin A ��������������������������������������������������������������  147 6.3.6 Aging����������������������������������������������������������������������������������  148 6.3.7 Fabrication��������������������������������������������������������������������������  148 6.3.8 Cut Surface Area����������������������������������������������������������������  149 6.3.9 Cooking������������������������������������������������������������������������������  149 7 Flavor Intrinsic Character����������������������������������������������������������������������  151 7.1 Consumer Preferences����������������������������������������������������������������������  151 7.1.1 Flavor Dimensions��������������������������������������������������������������  152 7.1.2 Effect of Seasoning������������������������������������������������������������  152 7.2 Science����������������������������������������������������������������������������������������������  153 7.2.1 Fat ��������������������������������������������������������������������������������������  155 7.2.2 Fatty Acid Profile����������������������������������������������������������������  161 7.2.3 Muscle��������������������������������������������������������������������������������  164 7.2.4 Carbohydrate����������������������������������������������������������������������  164

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7.2.5 Vitamins������������������������������������������������������������������������������  165 7.2.6 Adverse Flavors������������������������������������������������������������������  165 7.3 Production System Elements (Critical Control Points)��������������������  167 7.3.1 Elements Directly Associated with Flavor��������������������������  167 7.3.2 Associations with Level of Fat ������������������������������������������  185 7.3.3 Associations with Fatty Acid Profile����������������������������������  194 7.3.4 Associations with Other Compounds Impacting Flavor����  198 Summary����������������������������������������������������������������������������������������������������������  201 Acronyms����������������������������������������������������������������������������������������������������������  209 Abbreviations and Common Names for Muscles������������������������������������������  213 References ��������������������������������������������������������������������������������������������������������  215 Index������������������������������������������������������������������������������������������������������������������  301

Chapter 1

The Red Meat Consumer

Abstract  This text is concerned with the biological and ecological sciences that set the stage for red meat production. Before production systems can be organized, the producer must understand the demand for the product to be produced. So, the place to begin in constructing any system of red meat production is the projected consumer of the meat. So, the first chapter in both volumes of this text are focused on the identification and definition of the projected consumer of the meat to be produced. The discussion in Volume I of Beef Science and Production was exhaustive; an overview of that discussion is in this chapter with specific detail given for the intrinsic character of red meat. If people have no desire to eat beef, there is no reason to produce it. The corollary to this statement is there is no reason to produce beef having character not desired by the targeted market. Because the consumer is the reason for beef production, a discussion of beef production must begin with the consumer. Therefore, both volumes of this text begin with a discussion of the desires of consumers. Volume I presented a comprehensive discussion of all aspects of red meat desired by the consumer. This volume also begins with the consumer and is redundant to that discussion but focuses on a subset of that overview emphasizing the desires consumers have for the eating experience. Experience attributes, the most important of which is eating quality such as flavor, tenderness, and texture, are only experienceable at time of consumption and possibly either verify or deny expectations established earlier in the decision process (Henchion et  al. 2014, 2017; Acebron and Dopico 2000). Thus, the eating experience informs the consumer as to the relative value of cues available earlier in the purchasing process (Banovic et al. 2009). Technology advancement for rapid and accurate detection of hazards (HACCP) as described in the food safety section volume 1 has led to a new era in quality assessment rooted in control of the production process (QACCP). This has entered the public domain through governmental regulations such as those mandated by the European Union on food safety standards (Webber et al. 2012; Black et al. 2016; Mullen et al. 2006). These regulations are now oriented toward quality as well as

© Springer Nature Singapore Pte Ltd. and Science Press 2019 J. W. Holloway, J. Wu, Red Meat Science and Production, https://doi.org/10.1007/978-981-13-7860-7_1

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food safety control (Henchion et al. 2017), including process verification, labeling, and traceability (Albisu et al. 2010). Several schemes have attempted to guarantee consistent eating quality for consumers such as those mentioned by the EU and the Meat and Livestock Australia’s Meat Standards Australia (MSA) eating quality grading system based on a modeling approach implemented as Palatability Assessed at Critical Control Points (PACCP) (Polkinghorne et al. 1999). Other systems based on modeling consumer sensory experience have been employed in France, Poland, Korea, Japan, South Africa, New Zealand, Northern Ireland, and the Republic of Ireland based on different weightings for the array of experience attributes relating to tenderness, juiciness, flavor (Henchion et  al. 2017; Hocquette et  al. 2014), or muscle biochemistry (Hocquette et al. 2014). Emergence of this array of models recognizes differences between markets in characterization of quality eating experience. The most important intrinsic visible cue in this array of attributes was visible fat (subcutaneous, intermuscular, and intramuscular fat) and its color (Henchion et al. 2017). Consumer perception of fat differs according to the relative importance given to health or sensory drivers (Pethick et al. 2011; Killinger et al. 2004a, b, c). Meat color is traditionally thought of as an important cue and has been thought to be indicative of freshness, taste, and texture but more recently of the extrinsic characteristics of healthfulness and production scheme environmental friendliness (Font-­ i-­ Furnols and Guerrero 2014; Carpenter et  al. 2001). For American markets, tenderness has usually been found as the dominant criterion of eating quality, but this is possibly because most beef consumed in America is corn-fed and thus is relatively uniform in flavor (Koohmaraie and Geesink 2006). In order to meet consumer expectations, it is necessary to assess what they consider to be important. Potential consumer purchasing decision processes can be predicted from knowledge about consumers’ preferences (Verbeke and Vackier 2004). This knowledge embodies the hedonic value of the product that could be deterministic in terms of future purchasing decisions. This knowledge provides the background for product labeling giving the consumer evidence for product authenticity or quality reassurance (Di’ez et al. 2006). This process can also provide information necessary to identify the factors that could contribute to the success or failure of different beef types in each market segment (Di’ez et al. 2006). Consumptive niches fit along two continuums. The primary continuum is rooted in the fact that people are omnivores ranging from herbivores to carnivores. People in the West are on the carnivore end of the spectrum, while those in the East traditionally are on the herbivore end. Within this spectrum lies the other continuum. On one end are people who prefer tender, bland meat; on the other are people who prefer robust flavor, tough meat (Swatland 2010). Perhaps no one really prefers tough meat or bland meat, but when push comes to shove, perhaps one sector puts more value on tenderness than flavor, while the other puts more value on flavor than tenderness. Because tender red meats tend to be bland, and flavorful red meats tends to be tough, the dominant dimension desired predisposes acceptance of the correlated character of the other dimension.

Chapter 2

Intrinsic Quality Factors: Carcass Quality Grading Systems

Abstract  The history of red meat production across the globe has focused on marshaling available resources to produce cattle, sheep, goats, camels, yak, or other ruminant animal without too much regard to the end user of the total process of red meat production. Therefore, a food purveyor was confronted with an array of wholesale raw products at the marketplace of which only some would be acceptable to his/ her market. Thus, a discontinuity in the production chain occurred with animals being produced on one side and meat being served to consumers on the other side. So, classifications were developed to aid in sorting the array of products at the fulcrum of the process, the meat packer (where animals became meat). This chapter describes the classification systems employed in the world that have attempted to sort these raw wholesale products according to their value to the end user. This chapter also presents the research delineating the relative successes of the various systems used in the world. Red Meat Science and Production takes a different perspective of the production, delivery system than this historic method. That is, the orientation is to understand the consumer’s desires for red meat; translate those desires into red meat specifications; then understand control points in the production, delivery system sensitive to the character of these specifications; and then orchestrate the production, delivery system to consistently deliver the desired products to the targeted consumer. Although Red Meat Science and Production takes a different approach to the historical approach, it is necessary to understand the methods commonly used to characterize red meat in order to develop the new approach. Thus, this chapter provides a “springboard” for launching different approaches to red meat science and production.

2.1  Major Global Beef Grading Systems The major beef quality grading systems in the world are the following: for the European Union, EUROP; for the USA, the USDA Quality Grading System (USDA); for Australia, MSA; and for Japan, the Japan Meat Grading Association (JMGA). For countries in the EU, beef carcasses are evaluated under the EUROP classification system. This system entails evaluation of carcass conformation and © Springer Nature Singapore Pte Ltd. and Science Press 2019 J. W. Holloway, J. Wu, Red Meat Science and Production, https://doi.org/10.1007/978-981-13-7860-7_2

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external fatness (scored 1–5) but does not report marbling, being focused on describing yield although presently considering inclusion of a marbling estimate (Konarska et al. 2017). The USDA, MSA, and JMGA include estimations of marbling. These classification systems are more complex than the EUROP system in that their goal is to assign levels of consumer satisfaction in addition to yield-based measures. The JMGA and the USDA systems have independent quality and yield grades for carcasses, whereas the MSA system only describes eating quality for specific cuts but not at the carcass level (Konarska et al. 2017). The JMGA system employs an image analysis to produce official standards (Kuchida et al. 2006) and may provide a more sophisticated and objective tool for marbling classification than those systems based on subjective marbling evaluation (USDA, MSA; Kuchida et al. 1997, 1998, 2000, 2001). Camera grading of marbling utilizing image analysis of the quartered LD is allowed under USDA and is now being practiced (Moore et al. 2010). MSA grades are determined for each cut on the basis of observed or measured carcass traits (Ferguson et al. 1999; Polkinghorne et al. 2008a, b; Thompson 2002). Marbling is an important component of the MSA and is assessed subjectively by graders on a scale of 100–1190 in 10-point increments, judged against 10 digitally produced pictorial standards (Polkinghorne et al. 2008a, b). In all three systems, graders are trained to consider the individual marbling fleck size and the distribution of marbling flecks because it is accepted that fine, evenly distributed marbling relates to a more consistent and superior eating experience than coarse irregularly distributed marbling, even if the total intramuscular fat is the same (Smith et  al. 2005a). Even though marbling scores take into consideration more variables than just the amount of fat in the muscle, there is a relationship between marbling score and intramuscular fat (Table 2.1; Savell et al. 1986). For all three systems, marbling is only assessed on a single cross section of the longissimus thoracis (JMGA) or longissimus thoracis (USDA and MSA) with this single assessment providing the basis for assessing the value of the entire carcass. In the MSA system, marbling assessment for individual muscles is defined in relation to the observed LTL marbling site (Konarska et al. 2017). The marbling of Table 2.1  Fat and moisture content as related to marbling USDA marbling score Moderately abundant Slightly abundant Moderate Modest Small Slight Traces Practically devoid Savell et al. (1986)

n 52 61 84 90 80 80 47 24

Ether extract, % 10.42 8.56 7.34 5.97 4.99 3.43 2.48 1.77

Moisture, % 68.14 69.56 70.35 71.35 72.36 73.61 74.29 75.37

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individual muscles varies greatly from the LTL observed site (Watson et al. 2008). Konarska et al. (2017) validated the methodology of measuring marbling in the LTL and predicting the marbling of other muscles in that correlations are robust. Konarska et al. (2017) also found that image analysis-based marbling measures are capturing something different from the assessments made by trained personnel although there is a strong relationship between near-infrared spectroscopy estimated marbling and that assessed by trained personnel. Because the USDA system has a long experiential history, this system will be described in detail.

2.1.1  USDA Quality Grade Since tenderness (and other eating quality traits) cannot be determined directly at time of harvest, easily obtained “proxy variable” systems have been developed that are designed to classify carcasses as to potential tenderness (as well as other eating quality traits) at the time of harvest. The USDA beef quality grading system is the system that has been used in the USA since the early 1900s to approximate beef eating quality. The purpose of the USDA beef quality grading system is to segment a heterogeneous beef population into discrete, homogeneous groups based on expected palatability. The fundamental criteria are the estimated animal physiological age and marbling (Tatum 2012). 2.1.1.1  Physiological Age Dikeman et al. (1986) reported a sigmoidal increase in Warner-Bratzler Shear Force (WBSF) for bulls and steers from 12 to 24 months of age. Since the actual age of the animal is seldom known, the physiological age is assessed indirectly through the proxy variable of degree of bone ossification and relative darkness of the lean. The animal’s age at harvest is highly associated with meat tenderness. As animals mature, their meat becomes progressively tougher. To account for the impact of the maturation process on beef tenderness, subjective maturity evaluations are employed to determine USDA quality grades. This subjective evaluation is performed by assessing the size, shape, and ossification of the bones and cartilages in the carcass and the color and texture of the rib eye muscle (Tatum 2012). In young animals, a “button” of cartilage protrudes at the anterior tip of each vertebrae. As maturation occurs, these buttons gradually ossify becoming bone. Because ossification occurs in a definite pattern, the animal’s approximate age can be assessed subjectively. The sacral vertebrae (backbone associated with the rump) are the first to ossify. Ossification gradually progresses anteriorly through the lumbar (loin) and then the thoracic (rib and shoulder) regions of the backbone (Tatum 2012). Ossification is also associated with a gradual change in shape and color of the rib bones. A young animal has red, narrow, oval-shaped ribs. As the animal matures, the ribs become gray along with being wider and flatter. Texture and color of the muscle

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also change during maturation. Youth is associated with light pink, fine-textured muscle. With maturity, muscle becomes progressively darker and coarser. Five maturity classifications are used in the USDA Quality Grading System, designated as A through E. Approximate ages corresponding to each maturity classification are A, 9–30  months; B, 30–42  months; C, 42–72  months; D, 72–96  months; and E, more than 96 months (Tatum 2012). Since animal age is related to meat tenderness, work has been performed on methods to directly estimate animal age at time of slaughter. Raines et al. (2008) reported that lens weight and bone dentention were the best predictors of chronological age for cattle 13- to 37-month-old and yielded the most accurate age prediction when used in combination (R2 = 0.67). Miller et al. (1983), Field et al. (1997), and Acheson et al. (2014) found that for grain-fed cattle with dententions indicating ages less than 30 months, there was no relationship between age and tenderness, juiciness, or flavor. López-Campos et al. (2015) found that both implanting regime and production system (calf-fed vs. yearling-fed) influence bone ossification of cattle killed at the same chronological age. Growth promotants advanced the physiological age of cattle of the same chronological age. Most (>95%) US fed steers and heifers are less than 30 months of age (MOA) based on dentition assessments at the time of slaughter (McKeith et al. 2012), and cattle 9–30 MOA are expected to produce A-maturity carcasses (USDA 1996). However, due to premature skeletal ossification, not all of these cattle produce A-maturity carcasses as expected (Tatum 2012). According to Moore et al. (2012), 7.2% of carcasses produced by fed steers and heifers are classified as B maturity or older based on USDA carcass maturity indicators. Acheson et al. (2014) examined the relationship between USDA carcass maturity and sensory attributes of longissimus steaks from steers and heifers classified as less than 30 MOA using dentition. In that study, no differences in tenderness, juiciness, or flavor were detected between steaks from A-maturity carcasses and steaks from carcasses classified as B or C maturity. These findings challenged the validity of USDA maturity classification when applied to carcasses of cattle with dental ages less than 30 MOA; however, based on results of that study, no inferences could be made concerning the effectiveness of USDA maturity for identifying differences in sensory properties of beef from cattle with dental ages older than 30 months (Acheson et al. 2014). Acheson et al. (2014) and Semler et al. (2016) reported that USDA carcass maturity does not effectively identify differences in longissimus sensory attributes in the population of beef carcasses routinely offered for grading in the US commercial beef processing facilities. 2.1.1.2  Marbling The other fundamental characteristic used in the USDA Quality Grading System that is thought to be related to eating quality (including tenderness) is marbling. Marbling is the most important criterion in both the American and Japanese beef grading systems (Table 2.2, Figs. 2.1 and 2.2; Hale et al. 2010; Busboom and Reeves

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Table 2.2  Equivalence of US and Japanese marbling scores USDA quality grade

Prime

Choice Select

USDA marbling score Extremely abundant 50+ Extremely abundant 0–49 Very abundant 50–99 Very abundant 0–49 Abundant Moderately abundant Slightly abundant Moderate Modest Small Slight Traces

BMS no. 11–12 10 9 8 7 6 5 4 3

Japanese quality grade 5 (excellent) 5 5 5 4 (good) 4 3 (average) 3 3

There are no official grades above abundant in the USDA specifications. The terms very abundant and extremely abundant are arbitrary Busboom and Reeves (2013)

2013). More direct measures of tenderness can be assessed through the use of WBSF and sliced shear force (SSF) or through the use of trained or untrained taste panels. These methods, however, cannot be conducted in “real time” and are destructive to the product. Within a maturity group, marbling (the amount and distribution of intramuscular fat) of the rib eye is the main determinant of USDA quality grade (Tatum 2012). Rib eye marbling (12th rib cross section of the longissimus) is thought to be related to variation in eating quality of beef. Ten marbling scores are used to determine USDA quality grades for beef; six are shown in Fig.  2.1 (www//meat.tamu.edu/beefgrading, Hale et al. 2010). Marbling is also known as interfascicular or intramuscular adipose tissue (Hausman et al. 2009). As such and as described above in the section on visual quality, marbling represents a unique depot being distinguished from other fat depots by its location within perimysial connective tissues alongside myofibers (Moody and Cassens 1968) and by its unique pattern of metabolism. Marbling adipocytes sustain fatty acid biosynthesis rates that are only 5–10% of that sustained by subcutaneous adipose (Hood and Allen 1978; Smith and Crouse 1984). Intramuscular adipose incorporates palmitic acid into triacylglycerols at a more rapid rate than subcutaneous adipose (Lin et al. 1992). The process of triacylglycerol biosynthesis is more sensitive to starvation in subcutaneous than in intramuscular adipose tissue (Smith et al. 1998b). Glucose contributes a greater percentage of carbon to fatty acid biosynthesis in intramuscular than in subcutaneous adipose tissue (Smith and Crouse 1984). The differences between adipose tissue depots probably result from cellular (preadipocytes and adipocytes) differences. The preponderance of evidence suggests that the interaction of adipokines impacts skeletal muscle growth and that cytokines secreted from skeletal muscle have an impact on intramuscular adipocytes (Argiles et  al. 2005; Nielsen and Pedersen 2007). This body of research has been evaluated to

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Fig. 2.1  Marbling scores, USDA Quality Grading System. www//meat.tamu.edu/beefgrading, and Hale et al. (2010)

indicate that, whereas marbling has been considered to be a matter of feeding cattle high-concentrate rations for long periods of time, it is now thought to be an animal lifetime issue (Smith et  al. 2000b; Bumpus et  al. 2005). Long et  al. (2012) have reported that nutrient restriction during the first third of gestation increased adipocyte size of the offspring at slaughter. Intramuscular lipid is positively correlated with juiciness (Jeremiah et al. 2003c), flavor (Mottram 1998), and tenderness (May et  al. 1992) of beef. Dubost et  al. (2013b) reported that intramuscular lipids played a positive role in meat tenderness and juiciness and a negative role in contributing to residues (oily films) remaining after chewing. Even though visible fat in beef is discriminated against by many consumers because of the perceived negative impact on health, intramuscular lipids (marbling) contribute to the eating and taste quality of meat (Webb and O’Neill

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Fig. 2.2  Marbling scores, Japanese beef grading system: BMS 12, Grade 5; BMS 11, Grade 5; BMS 11, Grade 5; BMS 10, BMS 9, Grade 5; BMS 8, Grade 5; BMS 7, Grade 4; BMS 6, Grade 4; BMS 5, Grade 3; BMS 4, Grade 3; BMS 3; Grade 3; BMS 2, Grade 2; BMS 1, Grade 1. Japanese meat grading J.R. (Busboom and Reeves 2003)

2008). Lipid content affects juiciness directly and tenderness indirectly. In highly marbled beef, intramuscular lipid cells are primarily deposited within the perimysium and between bundles of muscle fibers (Nishimura et  al. 1999). Excessive development of adipocytes caused disorganization of the perimysial connective tissue (Nishimura et al. 1999). Perimysial fibers are also separated by this fat, leading to the dilution of perimysial fibers and weakening of the intramuscular connective tissue resulting in increased levels of tenderness. Since marbling has pervasive impacts on the intrinsic quality of beef, it will be discussed in every section of this review with some necessary redundancies. The primary discussion of marbling is reserved for the flavor section. 2.1.1.3  Physiological Age x Marbling Interaction The maturity and marbling designations are combined to classify each carcass into a USDA quality grade. The relationship between marbling and maturity used to determine the quality grade of a carcass is presented in Fig. 2.3 (www//meat.tamu. edu/beefgrading, and Tatum (2012); e.g., a carcass in the A-maturity group with a small degree of marbling would be graded USDA Choice). In the USDA Quality Grading System, animal maturity and degree of marbling are considered to interact in terms of eating quality. If the lean is dark and ossification of the vertebrae has occurred, greater levels of marbling are required to qualify for the same quality grade as compared to the case of lighter colored lean and lesser ossification of vertebrae (Hale et al. 2010; Tatum 2012; Fig. 2.3). In this case, lean color is a proxy variable for animals of advanced age or that had experienced pre-harvest stress. In general, USDA Prime, Choice, Select, and Standard grade designations are restricted to beef from youthful cattle (A or B maturity; however, carcasses designated as B maturity are not eligible for the Select grade) (Tatum 2012; Fig. 2.3). Similarly, USDA Commercial, Utility, Cutter, and Canner designations are reserved for older cattle (C, D, and E maturity; Tatum 2012; Fig. 2.3). Carcasses produced by

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Fig. 2.3  Relationship of marbling and maturity in the USDA Quality Grading System. www//meat. tamu.edu/beefgrading, Hale et al. (2010) and Tatum (2012)

bullocks (A-maturity bulls) are eligible only for the USDA Prime, Choice, Select, Standard, and Utility grades, while mature bulls are ineligible for the USDA Quality Grading System (Tatum 2012). 2.1.1.4  Degree of Success Both the American and Canadian beef evaluation programs depend upon cooler sorts. The success of the American system in producing quality beef has been evaluated by four types of audits: 1. The National Beef Quality Audit conducted in 1991 (Lorenzen et al. 1993), in 1995 (Smith et al. 1995; Boleman et al. 1998), in 2000 (Lorenzen et al. 2003), in 2005 (Garcia et al. 2008a, b) and in 2011 (Igo et al. 2013) 2. The National Beef Tenderness Survey in 1990 (Morgan et  al. 1991), in 1999 (Brooks et al. 2000) and in 2006 (Voges et al. 2007) 3. The Beef Customer Satisfaction study in 1993 and 1994 (Neely et  al. 1998, 1999; Lorenzen et al. 1999; Savell et al. 1999;) 4. The North American Beef Tenderness Survey in 2011 and 2012 (Howard et al. 2013) The success of the Canadian system has also been assessed in the Canadian Beef Quality Audit of 1995–1996 (Van Donkersgoed et al. 1997) and of 1998–1999 (Van Donkersgoed et al. 2001). These assessments of the relative success of the “cooler

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sort method” have indicated that the method does not result in consistent consumer satisfaction. 2.1.1.5  Relation to Tenderness Lorenzen et al. (2003) and Acheson et al. (2014) reported that tenderness increased as quality grade (marbling) improved. This relationship may at least partially be associated with a tendency for marbling to serve as a buffer against overcooking, since higher grades tended to decrease in toughness less than lower grades as relative doneness increased (Neely et  al. 1999; Lorenzen et  al. 2003). Gruber et  al. (2006) analyzed 17 individual beef muscles aged for 2 days and found an overall advantage for upper two-thirds USDA Choice over USDA Select of 0.49 kg WBSF with the greatest advantage for the semimembranosus of 1.47 kg WBSF and with little advantage for the teres major and supraspinatus. Part of the advantage for highly marbled beef is in the fact that fat has a lower shear force than lean. Although the USDA Quality Grading System involves some proxy variables shown to be related to tenderness such as animal age and lean color, the primary variable utilized is marbling. Marbling, however, has been reported to not be related to tenderness (when variation in cooking is removed) explaining, at most, 5% of the variation in beef tenderness (Wheeler et al. 1994; Li et al. 1999; Li and Shatadal 2001; Tian et al. 2005). Although marbling is generally an integral part of any beef grading scheme, the literature suggests that it has only a minor association with palatability (Thompson 2002). Dikeman (1987) concluded that marbling accounted for only 10–15% of the variance in tenderness. Several markets in the world, however, pay large premiums for increased levels of marbling. This is associated with the fact that, in many carcass grading schemes, marbling is given a very high weighting (e.g., Japanese and American, Figs. 2.1 and 2.2). The Meat Standards Australia database has quantified the relationship between strip loin marbling score and the palatability of a variety of cuts. The regression coefficient for palatability score as a function of USDA marbling score ranges from about 0.03 for cuts such as the strip loin and cube roll (longissimus and infraspinatus) to 0.01 for the chuck tender (infraspinatus) and eye of the round (semitendinosus). These coefficients indicate that an increase of 300 USDA marbling units is associated with an increased palatability of about six and three units in these muscles, respectively. In spite of this low affect, Meat Standards Australia’s model utilizes marbling as a dependent variable in predicting palatability (tenderness) even though it explains only a small amount of the variation. The reason for inclusion as stated by Thompson (2002) is that the effects tend to be additive. On the other hand, a report by Garmyn et al. (2011b) indicated that higher USDA quality grades were associated with increased tenderness (Table 2.3). Acheson et al. (2014) found linear increases tenderness as marbling score increased from Slight to Small for both A and B/C maturities for grain-fed animals with dententions indicating less than 30 MOA.

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Table 2.3  Least squares means for USDA quality grade effect on WBSF and trained sensory panel traits of beef longissimus USDA quality grade N WBSF, kg Initial juicinessb Sustained juicinessb Initial tendernessb Overall tendernessb

Select 160 3.92 5.41 4.97 5.66 5.56

Choice 772 3.75 5.27 4.89 5.74 5.73

Top choice 683 3.58 5.45 5.06 5.90 5.87

Prime 123 3.27 5.65 5.30 6.09 6.07

SEMa 0.042 0.071 0.030 0.035 0.036

Pooled SE of the treatment means Scale: 1 = extremely dry, extremely tough; 8 = extremely juicy, extremely tender Garmyn et al. (2011a) a

b

2.1.2  Meat Standards Australia Even though muscle type and cooking method greatly impact eating quality (Modzelewska-Kapituła et al. 2012; Sullivan and Calkins 2011; Thompson 2002), more than 70% of the variability in beef tenderness can be explained by integrative approaches employing pertinent elements of production including crossbreed, production system, use of hormonal growth promoters, carcass suspension, and aging time with postmortem elements having greater impact (Juarez et al. 2012a, b). The MSA grading scheme integrates production system elements designated as critical control points designed to predict eating quality for individual muscles under specified aging times and cooking methods (Polkinghorne et  al. 2008a, b; Thompson 2002). The success of the MSA system is due to standardization of the consumer evaluation protocols (Watson et al. 2008) and the accumulation of large amounts of data providing an ever-increasing data set for statistical analyses identifying the critical control points (Watson et al. 2008). This process culminated in the establishment of a new variable: the MQ4 (a meat quality score which is a weighted amalgam of the four quantitative assessments of tenderness, juiciness, flavor, and overall liking). This amalgamated variable was shown to be the best predictor of consumer eating satisfaction. MQ4 consists of four gradations of this amalgamation: ungraded, 3-star, 4-star, or 5-star (Watson et al. 2008). The MSA system has been tested in other parts of the world outside Australia: Korea (Thompson et al. 2008), the USA (Smith et al. 2008a), France (Hocquette et al. 2011a, 2013), Japan (Polkinghorne et al. 2011), South Africa (Thompson et al. 2010), New Zealand, Northern Ireland (Farmer et al. 2009b), and the Irish Republic (Brandon et al. 2006). In general, the findings showed similar consumer responses, but differences were observed in relative preferences for tenderness, juiciness, and flavor that define market niches. The MSA provides a grading system with the flexibility required to allow production system alterations at critical control points to produce products designed for different market niches.

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2.1.3  Wagyu Carcass Grading System Carcasses are evaluated by two indices (yield and quality grades) into 15 categories (Motoyama et al. 2016). Yield grade is the ratio of meat to dressed carcass weight and is classified into three grades from A to C with A being the highest yield according to measurements made in four categories: thoracic longissimus muscle area, rib thickness, cold split carcass weight, and subcutaneous fat thickness (Motoyama et al. 2016). Quality grading is based on the surface of the 6th/7th rib cross section and is categorized from 1 to 5 (with 5 being highest quality) according to marbling, meat color and brightness, meat firmness and texture, and fat color, luster, and quality (Motoyama et  al. 2016). Marbling is evaluated according to a beef marbling standard (BMS) ranging from 1 to 12 with larger values indicating more abundant marbling (Motoyama et  al. 2016). Japanese beef cut trading standards have also been delineated in which carcasses are dissected between and along muscles (Motoyama et al. 2016) enabling production of relatively expensive products that require large areas of single muscle sections, such as slices for sukiyaki and steak, while reducing the number of end-cuts. Hard tissues such as tendons and fascia, which cannot be eaten unless cooked for a long period of time, are removed.

2.1.4  Modeling Beef Quality Prediction of intrinsic sensory quality necessitates a multidimensional metric ascribing a meat product’s value to a particular market niche (Polkinghorne and Thompson 2010; Hocquette et al. 2014). Developing this metric requires identification of product traits elastic to the product’s eating quality and then integration of these traits into multivariate evaluation models (Bouyssou et al. 2000; Roy 1996; Hocquette et al. 2014). This includes (1) defining the criteria characterizing eating quality for a particular market niche (i.e., the intrinsic quality traits of beef) to be assessed; (2) identifying the easily measured indicators (from direct measures and/ or their predictors) to assess each criterion; (3) constructing each criterion separately (by interpreting and if necessary aggregating the indicators); and (4) aggregating the pertinent criteria and their interactions to form a comprehensive metric (Hocquette et al. 2012a). The European beef market has been studied in the ProSafeBeef consumer studies (Verbeke et  al. 2010a, b) which employed consumer focus groups in Germany, Spain, France, and the UK, concluding general consumer receptiveness to a beef eating quality guarantee conditional to it successfully delivering upon its promises but with discontinuities among consumers indicating significant consumer market niches in Europe (Hocquette et al. 2014). As described above, four attitudinal profiles explained the differences between these niches (Almlie et  al. 2013). These were enthusiastic beef eaters, open-minded beef eaters, indifferent beef eaters, and carefree beef eaters (Almlie et al. 2013).

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The UK Meat and Livestock Commission (MLC) Blueprint and New Zealand Q Mark systems attempt to identify carcasses expected to provide consumers with good eating quality through postharvest process control of elements such as carcass suspension, electrical stimulation, and aging. The USDA system classifies beef carcasses into quality grades based on the degree of maturity and intramuscular marbling. The MSA system classifies individual beef muscles into eating quality grades. Farmer et al. (2010) compared the USDA, MLC, MSA, and Q Mark models as to their ability to correctly identify beef with better consumer scores for 36,000 beef samples from 192 animals assessed by 6000 consumers. The results indicated that the MLC system performed well provided that the low conformation animals were not excluded, while the MSA system performed best for the greatest number of muscles and for both roast and grilled beef (Farmer et al. 2010; Hocquette et al. 2014). Private brands across the world further differentiate quality by providing production system element controls (e.g., Certified Angus Beef, Nolan Ryan Tender Beef in USA; Label Rouge in France; Celtic Pride in Wales; True Aussie Beef and Prestige Beef in Australia; Beef and Lamb New Zealand; and Kobe and Ohmi Beef of Japan) (INAO 2009; Hocquette et al. 2014). The main drivers of food product purchases in France are safety and a competitive price and to a lesser degree origin, the brand, and/or the quality level (Hocquette et al. 2013). Many brands only require that the source animal be of a certain breed or be produced in a certain geographic area such as Kobe Beef from the Tajima strain of Wagyu cattle raised in Japan’s Hyogo Prefecture according to rules as set out by the Kobe Beef Marketing and Distribution Promotion Association. Other brands are more intrusive in the production process. For example, the production protocol for Celtic Pride requires that all animals be born and raised in Wales, be restricted on number of movements during the animal’s lifetime, meet targeted growth rates during the primary growth and finishing phases, and have the inclusion of high vitamin E levels in the final 90 days prior to slaughter (Hocquette et al. 2014).

Chapter 3

Aroma Intrinsic Character

Abstract  Volume II of Red Meat Science and Production addresses the character of red meat that can be sensed at the time of consumption. The consumer is conditioned to the eating experience, and his/her expectations are set before the actual eating experience through the senses of sight and smell. Therefore, the first discussion of the intrinsic character of red meat that is in this chapter is concerned with, perhaps the threshold sensation setting the stage for the eating experience, aroma. This chapter reviews the scientific literature concerning the consumer’s perception of red meats as delivered through the air, the chemical nature of the red meat responsible for this perception, and production system elements that may be sensitive to this perception.

3.1  Consumer Preferences Raw meat has little aroma and a bloodlike taste (Crocker 1948; Bender and Ballance 1961). Aroma, therefore, is only sensed after the meat is cooked. The sensation of aroma is a component of flavor. The nose senses aroma, the tongue senses taste, and the composite sensation is called flavor. But, because aroma is sensed prior to the other sensory attributes of red meat, it is discussed first; howbeit, it is further discussed as a component of flavor.

3.2  Science Although aroma is an important integral part of the eating experience of red meat (especially for lamb and mutton), little has been reported concerning the biochemistry of aroma or the production system elements impacting aroma. Perhaps, the reason for this is that, by definition, aroma is the result of volatiles released from the meat during the cooking process. Volatile compounds are elusive and difficult to capture and study. It is natural, however, to assume that since raw meats have little

© Springer Nature Singapore Pte Ltd. and Science Press 2019 J. W. Holloway, J. Wu, Red Meat Science and Production, https://doi.org/10.1007/978-981-13-7860-7_3

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or no aroma and that cooking releases the volatiles causing aroma, the Maillard reaction is probably involved. Ribose, as a substrate in the Maillard reaction, and through its role in decreasing the formation of lipid oxidation products, is a major contributor to roasted and meaty aromas, as well as umami (Farmer et al. 1999). Because of their relatively high concentrations, glucose and glucose-6-phosphate may have equal or more importance for roasted and meaty aromas than the 5-carbon reducing sugars, ribose, and ribose-5-phosphate (Farmer et al. 2009c). Aroma compounds in cooked beef have been evaluated and ranked according to their intensities and potential contributions to cooked beef flavors (Farmer and Patterson 1991; Gasser and Grosch 1988; Specht and Baltes 1994). However, the magnitude of flavor dilution factors differed between studies because of differences in extraction and concentration rates. The primary contributors are methional, 2-ethyl-3,5-dimethylpyrazine, 2-propyl-3-methylpyrazine, 2-methyl-3-furanthiol, bis(2-methyl-3-furyl) disulfide, 2-acetyl-1-pyrroline, 2-acetylthiazole, 2(E)-octenal, 2(E)-nonenal, 2(E),4(E)-nonadienal, 2(E),4(E)-decadienal, 1-octen-3-one, 2-­ octanone, 2-decanone, 2-dodecanone, phenylacetaldehyde, β-ionone, and 2-­furfuryl 2-methyl-3-furyl disulfide which have been reported to be active aroma compounds in cooked beef (Khan et al. 2015). “Mutton” aroma in cooked sheep meat is caused by the formation of short branched-chain fatty acids (BCFAs) as an implication of diet (Khan et al. 2015). Animals fed with a grain-based finishing diet showed higher concentrations of BCFA compounds (Young et al. 2003; Young and Braggins 1998).

3.3  Production System Elements (Critical Control Points) Animal genetics has been reported to influence beef aroma. Wagyu beef has a sweet and fatty aroma known as “Wagyu beef aroma,” which is preferred by Japanese consumers (Motoyama et al. 2016). This aroma is not present after slaughter but is generated during storage in the presence of oxygen (Matsuishi et  al. 2001). The optimum cooking temperature to generate this aroma is 80 °C which is consistent with the optimum temperature for cooking typical Japanese Wagyu dishes sukiyaki and shabushabu (Motoyama et al. 2016). One of the candidate compounds possibly contributing to this aroma is γ-nonalactone which has a coconut- or peach-like aroma and an unusually high flavor dilution factor (Matsuishi et al. 2004). Also, alcohols and aldehydes with fatty aroma and diacetyl and acetoin with butter-like aroma appear to contribute to the fatty sensation associated with Wagyu beef aroma (Matsuishi et  al. 2004). Many volatile compounds are the derivatives of fat; therefore, the character of the fat has an important role in aroma (Motoyama et al. 2016). Another production system element that has been implicated in aroma development of beef is the method of slaughter. Öneç and Kaya (2004) reported that stunning improved the odor of beef and, therefore, halal and kosher beef might be

3.3  Production System Elements (Critical Control Points)

17

Table 3.1  Influence of method of stunning on beef quality of longissimus lumborum after aging for 14 daysa Item Glycogen, mmol/l pH 24 h Odor Flavor Tenderness Acceptability

Stunning method Non-stunned 8.84b 5.99b 46.9b 47.8b 45.1b 50.7b

Electrically stunned 10.12c 5.96b 51.8c 49.9c 50.4c 51.1b

Percussion stunned 11.25c 5.75b 56.0c 58.0d 57.3c 58.3c

Judgments were recorded by marking a 10-point scale with determined explanations (from 1=extremely bad to 10=extremely good). Ten evaluation sessions were held. Eight panelists attended in each evaluation. Values are total scores for eight panelists in each evaluation session for each sensory attributes b, c, d Means within rows with different letters are significantly different (PT). They also tested four marbling and four feed efficiency GeneSTAR markers. The marbling and feed efficiency markers did not predict the expected differences. However, the tenderness markers did predict the expected differences, and their efficacy was consistent across breeds. The amount of variation explained by the four tenderness markers gives evidence that they are useful aids in selection although the predicted breeding values have low-to-moderate accuracies based on gene marker data alone (Johnston and Graser 2010). Café et al. (2010a, b) reported that selection procedures based on the CAST or CAPN3 gene markers improved beef tenderness in Bos indicus cattle, with no deleterious effects on other hedonic traits. The CAPN1–4751 gene marker also improved beef tenderness with little alteration of other sensory attributes for either heterozygotes or homozygotes for the unfavorable allele. Genetic maps have been published that identify markers related to quantum trait loci (QTL) for application in marker-assisted selection (MAS) of cattle for tenderness. Potential candidate genes for QTL include micromolar CAPN1 (Smith et  al. 2000c) and myostatin alleles that cause the double-muscled phenotype (Kambadur et al. 1997). The associations between the calpain-calpastatin tenderness markers and meat quality traits were quantified within two concurrent experiments using 377 Brahman cattle for Meat Standards Australia (Warner et al. 2010). Cattle were selected for the study at weaning based on their genotype for calpastatin (CAST, CAST: c.2832ANG: Barendse 2002), calpain 3 (CAPN3, CAPN3: c.1538+225GNT: Barendse et  al. 2008), and μ-calpain (CAPN1-316, CAPN1: c.947CNG: Page et  al. 2002). Each marker represents a SNP within genes controlling the calpain proteolytic system. Cattle with favorable genotypes for the markers had reduced longissimus WBSF compared to those with the unfavorable genotypes. The combined effects of the favorable marker alleles resulted in up to a 15.8 Newton reduction in WBSF following 7 days aging (Table 5.14, Warner et al. 2010). Certain SNP haplotypes of CAPN1 and CAST have been identified as being related

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Table 5.14  Effect of tenderstretch and gene markers on longissimus WBSF (Newton) of Australian Brahman cattle aged 7 days Genotype Unfavorable alleles Favorable allelesa Improvement

New South Wales Achilles hung 80.4 64.6 15.8

Tenderstretch 48.2 43.6 4.6

Western Australia Achilles Hung Tenderstretch 55.2 53.9 42.2 47.9 13.0 6.0

Warner et al. (2010) a Favorable alleles: marker combination of favorable alleles for CAST_CAPN3_CAPN1-4751. Note: 2_2_1 is a favorable combination and should result in more tender meat

to muscle tenderness: SNP: CAPN1-316 (BTA 29; rs17872000; Page et al. 2002, 2004) and CAPN1-4751 (BTA 29; rs17872050; White et  al. 2005). CAPN1-316 segregates C and G alleles, whereas CAPN1-4751 segregates C and T alleles. CAPN1-316 and CAPN1-4751 SNP were used to define haplotypes within the CAPN1 gene. Tait et al. (2014) reported that haplotypes thought to be especially related to protein turnover and meat tenderness are CAPN1-316 allele C with CAPN1-4751 allele C (CAPN1hCC) and CAPN1-316 allele G with CAPN1-4751 allele T (CAPN1hGT). Haplotypes not thought to be related are CAPN1-316 allele C with CAPN1-4751 allele T (CAPN1hCT) and CAPN1-316 allele G with CAPN1-­4751 allele C (CAPN1hGC) (Tait et al. 2014). Among CAPN1 haplotypes with >1% frequency in cattle populations, White et al. (2005) reported the largest difference for 14 days WBSF between CAPN1hCC haplotype and CAPN1hGT haplotype, neither of which were the major haplotype in that study. Tait et  al. (2014) found that both CAPN1 and CAST exhibit additive modes of inheritance for slice shear force and neither exhibited dominance. They reported no interaction between CAPN1 and CAST for slice shear force. Estimated additive effects of CAPN1 (1.049 kg) and CAST (1.257 kg) on slice shear force were reported to be relatively large in this study. Animals homozygous for tender alleles at both CAPN1 and CAST are predicted to have 4.61 kg lower slice shear force (38.6% of the mean) than animals homozygous tough for both markers (Tait et al. 2014). CAST was also reported to influence yield grade (Tait et al. 2014). The tender CAST allele was found to be associated with more red meat yield and less trimmable fat. Tait et al. (2014) indicated that the risk of a tough steak from the undesired CAST genotype is increased through both an increase in mean and an increase in variation in slice shear force in Angus cattle (Tait et al. 2014). The implication of calpain and calpastatin markers in the genetic variation in tenderness indicates that at least some of this variation is due to among-animal variation in protein turnover. This linkage has been found to be related to residual feed intake (RFI, a performance neutral measure of feed efficiency) in cattle (Richardson and Herd 2004) and pigs (Cruzen et al. 2013). Richardson and Herd (2004) estimated that 37% of the variation in cattle for RFI was due to protein turnover, tissue metabolism, and stress. Cruzen et al. (2013) found that pigs with low RFI were more efficient, at least partly, because of reduced protein turnover. They reported that this reduction resulted in greater activity of calpastatin and concomi-

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tant reduced activity of calpain culminating in increased meat toughness. Because tissue turnover rate is highly related to maturity and animals mature at different rates, physiological age is somewhat independent of chronological age (Stockton et al. 2013). Among-animal variation in tenderness, therefore, is probably associated with among-animal variation in rate of maturation. For living animals to maintain skeletal muscle integrity, they necessarily must accomplish protein turnover in a manner not to disrupt myofibrillar structure (Goll et al. 2008). Dayton et al. (1976) indicated that myofibrillar proteins are continually turned over through the process of the release of filaments from the surface of the fibril enabling them to be catabolized by a protease system. The μ- and m-calpains are differentiated in that they are comprised of different large 80 kDa subunits. But they are similar in their smaller 28 kDa subunit, and they are encoded by the Capn4 gene (Sorimachi et al. 1989). Calpains have been implicated in maladies such as the muscular dystrophies (Badalamente and Stracher 2000; Briguet et al. 2008) and the wasting conditions associated with muscle disuse (Dargelos et al. 2008; Brule et al. 2010). μ-Calpain is required for turnover of skeletal muscle proteins (Geesink et al. 2006), for myoblast fusion and proliferation, and for cellular growth (Dedieu et al. 2004; Moyen et al. 2004). In summary, as fundamental background to the important role of the calpain system in postmortem meat tenderization, it is important to understand the role of the system in the live animal. It is realized that animals evolved these systems to aid them in survival with no regard to the satisfaction of saprophytes predating on their carcasses. μ-Calpain has critically important roles in the growth and maintenance of live animal tissues but also in tissue wasting maladies. Consequently, understanding how muscle proteins are turned over metabolically and how this turnover is regulated has important implications in muscle growth and loss as well as understanding their continued effect postmortem on muscle tenderization. Kemp et  al. (2013) reported that turning off the μ-calpain gene causes the compensatory upregulation of m-calpain and caspases 3/7. This compensation is necessary to enable the animal to maintain muscle protein homeostasis and to enable growth, particularly while the animal is young (Kemp et al. 2013). The bottom line is that these protease systems are functionally and intimately associated with the viability of skeletal muscle in the living animal and then in the character of the meat ultimately produced. 5.4.1.1.8  Double-Muscling Gene Markers Some of the well-muscled animals in European breeds of cattle (e.g., Belgian Blue and Piedmontese, Charolais) owe their phenotype to mutations in the gene regulating myostatin (MSTN or growth differentiation factor 8 (GDF8); Bellinge et  al. 2004, and Lines et al. 2009). Inactivation of the gene through mutation causes an alteration in myostatin, resulting in the phenotype “double muscling” (Joulia-Ekaza and Cabello 2006). Cattle can be homozygous for the mutation having the phenotype of extreme muscling or heterozygous, having the phenotype of intermediate muscling between

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the homozygous mutant and the wild-type. In the Belgian Blue breed, the mutation has been shown to result in decreased WBSF and collagen content (Ngapo et al. 2002). Wheeler et  al. (2001) reported that for calves influenced by the double-­ muscled breed, Belgian Blue had more tender beef than those of British breeding. Bidner et al. (2009), however, reported that Belgian Blue-sired calves had greater WBSF than Angus-sired calves when they also had ¼ Brahman genetics. Expression of the GDF8 gene in cattle induces myostatin synthesis inhibiting proliferation and differentiation of myogenic cells (Grobet et al. 1997; McPherron and Lee 1997). Several mutations in the gene (e.g., nt821, Q204X, C313Y) code for the synthesis of altered forms of myostatin. These altered forms precipitate increased muscle mass under the condition of the homozygote for the inactive alleles (Kambadur et al. 1997; Grobet et al. 1998). Expression in the homozygote results in phenotypes that have positive muscling traits but are less fit to stressful environments. Their positive muscling traits include increased red meat yield, increased dressing percentage (reduced digestive tract volume), reduced fatness, increased bone size, and increased tenderness (Menissier 1982a; Arthur 1995; Wheeler et al. 2001). Their negative fitness traits include dystocia, stress susceptibility, and low fertility. These beef traits were first observed in experiments in which the genotype was unknown but was made through inferences from phenotypic observations. These empirical observations could not accurately distinguish between the homozygote with the heterozygote, leading to the inaccurate hypothesis that the muscle hypertrophy [mh] gene was partially recessive (Menissier 1982b). Now, molecular tests are available to make this distinction. Allais et al. (2011) determined genotypes for two disruptive mutations, Q204X and nt821, for three French breeds: Charolais, Limousine, and Blonde d’Aquitaine. For the heterozygote (Q204X or nt821) in Charolais and Limousin, carcass trait superiority was about 1 standard deviation (SD) over noncarrier animals, but for Blonde d’Aquitaine, no advantage was seen for the heterozygote (Allais et al. 2011). The frequency for the heterozygote was greatest for the Charolais (7%). Growing bulls with one copy of the Q204X mutation presented a carcass with less total fat, less intramuscular fat, smaller amounts of collagen, and more tender meat than those that were homozygous wild-type. The meat of these animals also had slightly less flavor (Allais et al. 2011). For the Charolais, 13 of 48 sires were heterozygous. For each sire, the substitution effect of the wild-type allele by the mutant allele was in the order of +1 SD for carcass conformation and red meat yield. The effect was less for beef that had been tenderstretched. A gene variant of myostatin, F94L, has been discovered only in the Limousin breed. This variant increases muscle mass resulting in more tender beef, at least partially the result of a reduction in the collagen/elastin content of muscle (Lines et al. 2009). O’Rourke et al. (2009) studied level of muscling in Australian Angus resulting from either wild-type myostatin (low level of muscling) or heterozygotes for myostatin (heterozygous for the 821 del11 myostatin allele that results in nonfunctional myostatin). The two genotypes had the same longissimus WBSF. A mutant myostatin allele present in heterozygotes has been shown to increase tenderness in Piedmontese (Tatum et al. 1990; Wheeler et al. 2001) and for Charolais

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(Casas et al. 1998; Levéziel et al. 2006). However, Gill (2009) found no advantage for tenderness for heterozygosity for the allele. In summary, mutations in the myostatin gene in cattle often, but not always, cause increased tenderness. This improvement has been associated with a decline in the amount of collagen in muscle relative to myofibers (Boccard 1982; Uytterhaegen et  al. 1994) and in the amount of stable non-reducible cross-links (Bailey et  al. 1982). Another mechanism that might relate the heterozygote for myostatin gene and tenderness is through the influence of the gene on ability to withstand heat stress. As will be shown in this text, animals subject to heat stress produce heat shock proteins that protect structural proteins from proteolysis interfering with the postmortem aging process producing tougher meat. The heterozygote for the myostatin gene has been shown to tolerate both extreme heat and extreme cold to a greater degree than other animals (Howard et  al. 2013). However, the myostatin gene is also associated with traits considered detrimental for production such as the conditions known as “post legged” and “teat thinness” (Vallée et al. 2016). A contrast to the callipyge (double muscling) in sheep (discussed later in this text) points to another mechanism involved in the double muscling in cattle (Carpenter et al. 1996; Cockett et al. 1994; Freking et al. 1998; Jackson et al. 1997; Koohmaraie et  al. 1995). Callipyge sheep express muscle hypertrophy through reduced protein degradation (Lorenzen et al. 2000) because of reduced calpastatin activity (Koohmaraie et al. 1995), thus reducing the rate and extent of postmortem proteolysis causing the meat, in contrast to double muscling in cattle, to be tough (Koohmaraie et  al. 1995). Therefore, it appears that the tenderness in double-­ muscled cattle results from both reduced connective tissue and increased rate of protein turnover. 5.4.1.1.9  Heterosis As shown above, breed and finishing systems are among the factors that have a major influence on the tenderness of beef (De Smet et al. 2004; Nuernberg et al. 2005a, b). Specifically, as discussed above, Bos indicus cattle and crosses involving them tend to produce beef with reduced tenderness (Elzo et al. 2012; Wheeler et al. 2001). In spite of the negative impact of Bos indicus genetics on meat quality, crossbreeding among Bos taurus and Bos indicus breeds has been practiced worldwide in the beef cattle industry for a long time, primarily because of improvements in productivity in both the dam and calf segments, especially in stressful environments (Long 1980). This is accomplished by taking advantage of the complementarity among the two species and of the benefits of heterosis in their crosses (Dickerson 1973). The impact of heterosis on different production traits has been recognized for a long time, and structured crossbreeding programs have been designed to take advantage of these benefits (Dickerson 1969). Reliable estimates of the heterotic impacts on production traits in different breed crosses are essential for the development of optimal crossbreeding programs for different production environments and targeted

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markets. It is accepted that the greatest heterotic effects are in stressful environments where “hybrid vigor” can be expressed (Barlow 1981; Brown et al. 2000). Since beef tenderness is impacted by the failure of animals to manage environmental stresses, it seems logical that a heterotic effect on beef tenderness would be expressed in stressful environments. The information available for beef cattle on the benefits of heterosis for meat characteristics is scarce (Elzo et al. 2012; Gregory et al. 1994; Slanger et al. 1985; Vaz et al. 2002; Villarreal et al. 2006). Meat tenderness is a trait of intermediate heritability (Burrow et al. 2001; Warner et al. 2010) and is generally thought to have low-to-moderate levels of heterosis. This has been found to be the case for Bos taurus crosses fed with high-concentrate rations in temperate climates (Burrow et al. 2001; Slanger et al. 1985; Villarreal et al. 2006), but more variable results have been found among grain-finished Bos taurus and Bos indicus in subtropical climates with heterosis for WBSF usually not exceeding a reduction of 10% (DeRouen et  al. 1992; Elzo et al. 2012; Franke 1980; Gregory et al. 1994). Gama et al. (2013) reported that crossbreeding between Bos taurus and Bos indicus is beneficial for meat quality, when finished either on pasture or with grain finishing, even though the relative benefits arising from heterosis differ among the two finishing systems. In pasture-finished animals, a major reduction in WBSF due to crossbreeding was observed. Longissimus from the pasture-fed Bos taurus x Bos indicus crossbred aged for 24  h exhibited 25.9% heterosis (reduction of 2.2  kg WBSF from the midparent). When aged for 10 days, the heterosis was 18.4% (reduction of 1.08 kg WBSF from the midparent). Under grain finishing, the more tangible effect of heterosis was a reduction in intramuscular fat and cholesterol content and a lower atherogenic index in crossbred animals when compared with the mean of Bos taurus and Bos indicus. Longissimus from grain-finished crossbreds exhibited 18.4% heterosis in terms of fat reduction and 7.5% heterosis in terms of cholesterol reduction. 5.4.1.1.10  Genotype x Environment Interactions Several management factors compound the effects of genetics in influencing protein turnover rates in the live animal, with subsequent effects on postmortal degradation rates and thus meat tenderness. Since most research indicates that about 40% of the variation in beef tenderness can be attributed to genetics, it would follow that most (60%) of the variation among animals in tenderness is associated with the environment. Also, since research has indicated a relationship between tenderness and temperament, the behavioral expression of stress (King et  al. 2006; Behrends et  al. 2009), it might also be inferred that stressful environments are indicative of tough meat. It might follow that, in stressful environments, if no other overriding factor exists, animals adapted to the prevailing stressors might have more tender meat than those not adapted. Another product of environmental conditions, age at slaughter, is also related to tenderness. Therefore, production systems and genetics conducive to early-­maturing

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animals that are eligible for harvest at relatively young ages might produce more tender red meat. A factor that may partially counter this effect is the fact that lighter, less fat carcasses may cool faster than heavier, fatter carcasses resulting in more cold shortening and tougher meat (Marsh et al. 1968). Therefore, the most appropriate postmortem management may be predicated by the production management ­system (Tatum 1981). Merkel and Pearson (1975) substantiated the connection between pre- and postmortem management in that they reported that slow chilling could produce tender beef from lean carcasses. The culminating conclusion of the research performed to discover the biology underlying red meat tenderness is that there is no evolutionary advantage to animals or populations of animals for their red meat to be tender. The summation of evolutionary history is toward Darwin’s goal of individual and population survival with the bottom line being the fit survive. So, animals have evolved through biological processes enabling individuals and populations to survive. Whether their meat is tender or not is not a concern of conserved biological processes. But, this research also indicates that biological processes conducive to survival are also at play in the dead animal influencing red meat tenderness. As indicated in this body of research, these processes can be manipulated through management practices altering the course of life for the animals, thereby, as a by-product, altering the course of death and decay that defines meat tenderness. As concerning the animal’s survival, the live animal must have structured musculature in order to function now but must turnover that musculature in order to function in the future. The structure contributes to meat toughness, the turnover to meat tenderness. Animal management can alter the magnitude of these forces. The following discussion examines the production system elements that have the greatest impact on an animal’s life, death, and meat. 5.4.1.1.11  Uncommon Genetic Alleles Although it is known that postmortem tenderization in meat is affected by the protease μ-calpain (CAPN1), its inhibitor calpastatin (CAST; Koohmaraie 1996) and intramuscular fat levels are influenced by diacylglycerol O-acyltransferase 1 (DGAT1; Thaller et  al. 2003). Animal population studies often encounter small numbers of animals in the rare homozygous genotype classes and subsequently do not include those genotypes in analyses, for example, CAPN1 (White et al. 2005), CAST (Morris et  al. 2006), and DGAT1 (Thaller et  al. 2003; White et  al. 2007). Recently, selection to increase minor allele frequency has been used to ensure representation of all genotypes in data for analysis (Bennett 2008; Tait et  al. 2014, Mateescu et al. 2015). These studies highlight the importance of CAPN1 and CAST genetic markers on mean levels of beef tenderness. Mateescu et  al. (2015) also reported that DGAT1 influences subcutaneous fat.

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5.4.1.2  Animal Temperament Some of the variation in tenderness between and within breeds of cattle is related to variation in temperament (Tables 5.15 and 5.16; Burrow et al. 1998; Reverter et al. 2003; King et al. 2006; Behrends et al. 2009; Bass et al. 2010; Café et al. 2011). Beef cattle vary in their behavioral (Watts and Stookey 2001; Kilgour et al. 2006) and physiological (Fell et al. 1999; Curley et al. 2006) response to handling. Calm temperaments are related to: (1) Greater growth rates (Fordyce et al. 1985, 1988a, b; Burrow and Dillon 1997; Voisinet et al. 1997a, b; Petherick et al. 2002; Phocas et al. 2006;Nkrumah et al. 2007; Reinhardt et al. 2009; Behrends et al. 2009) (2) More desirable meat tenderness (Fordyce et al. 1988a, b; Reverter et al. 2003, Kadel et al. 2006; King et al. 2006; Behrends et al. 2009; Bass et al. 2010; Café et al. 2011) (3) Initial pH and heat shortening conducive to tender meat (Petherick et al. 2002) (4) More desirable juiciness and lean color (Burnham et al. 2005; Kadel et al. 2006) Most of this work employed Bos indicus-influenced cattle managed under extensive conditions (Phocas et al. 2006; Sapa et al. 2006; Voisinet et al. 1997a, b; Burrow 2001). Burrow (1997) hypothesized that relationships between temperament, growth, and meat quality could be less apparent in Bos taurus breeds intensively managed. Turner et al. (2011), however, found that cattle that were acclimated to the presence of humans were calmer and had more tender meat as judged by a sensory panel. Behrends et al. (2009) also showed a relationship between WBSF and exit

Table 5.15  Relation of temperament to beef longissimus tenderness Trait Pen Scorea WBSF, 3d, Newton Cortisol, ng/mL Calpastatin activity

Calm 1.59 35.06 10.18 1.02

Intermediate 2.38 35.15 11.91 0.97

Excitable 3.57 37.41 14.99 0.93

King et al. (2006) 1 = no excitement, 2 = runs, 3 = high head, 4 = runs into fence, 5 = runs over people

a

Table 5.16  Relationship between temperament and longissimus tenderness Item Speed N Plasma epinephrine, ng/dL Plasma norepinephrine, ng/dL Blood lactate, mmoles/L WBSF, kg Bass et al. (2010)

Chute exit speed Walk Trot 70 445 0.03 0.32 0.04 0.19 10.9 10.7 3.70 3.88

Run 29 1.06 0.55 12.1 4.09

P>F