Meat Processing (eBook)

Improving Quality

John F. Kerry, Joseph P. Kerry, David Ledward (Herausgeber)

eBook Download: PDF

2002 | 1. Auflage
480 Seiten
Elsevier Science (Verlag)
978-1-85573-666-5 (ISBN)

Infos

Meat is both a major food in its own right and a staple ingredient in many food products. With its distinguished editors and an international team of contributors, Meat processing reviews research on what defines and determines meat quality, and how it can be maintained or improved during processing.Part one considers the various aspects of meat quality. There are chapters on what determines the quality of raw meat, changing views of the nutritional quality of meat and the factors determining such quality attributes as colour and flavour. Part two discusses how these aspects of quality are measured, beginning with the identification of appropriate quality indicators. It also includes chapters on both sensory analysis and instrumental methods including on-line monitoring and microbiological analysis. Part three reviews the range of processing techniques that have been deployed at various stages in the supply chain. Chapters include the use of modelling techniques to improve quality and productivity in beef cattle production, new decontamination techniques after slaughter, automation of carcass processing, high pressure processing of meat, developments in modified atmosphere packaging and chilling and freezing. There are also chapters on particular products such as restructured meat and fermented meat products.With its detailed and comprehensive coverage of what defines and determines meat quality, Meat processing is a standard reference for all those involved in the meat industry and meat research. - Reviews research on what defines and determines meat quality, and how it can be measured, maintained and improved during processing - Examines the range of processing techniques that have been deployed at various stages in the supply chain - Comprehensively outlines the new decontamination techniques after slaughter and automation of carcass processing

Inhalt

Front Cover 1
Meat Processing: Improving Quality 4
Copyright Page 5
Table of Contents 6
Contributors 12
Chapter 1. Introduction 18
Chapter 2. Defining meat quality 20
2.1 Introduction: what is quality? 20
2.2 Consumer perceptions of quality 23
2.3 Supplier perceptions of quality 31
2.4 Combining consumer and supplier perceptions: the quality circle 33
2.5 Regulatory definitions of quality 36
2.6 Improving meat and meat product quality 38
2.7 References 40
Part I: Analysing meat quality 42
Chapter 3. Factors affecting the quality of raw meat 44
3.1 Introduction 44
3.2 Quality, meat composition and structure 44
3.3 Breed and genetic effects on meat quality 54
3.4 Dietary influences on meat quality 66
3.5 Rearing and meat quality 69
3.6 Slaughtering and meat quality 69
3.7 Other influences on meat quality 73
3.8 Summary: ensuring consistency in raw meat quality 73
3.9 Future trends 74
3.10 References 74
Chapter 4. The nutritional quality of meat 81
4.1 Introduction 81
4.2 Meat and cancer 83
4.3 Meat, fat content and disease 86
4.4 Fatty acids in meat 88
4.5 Protein in meat 95
4.6 Meat as a ‘functional’ food 96
4.7 Meat and micronutrients 99
4.8 Future trends 105
4.9 Conclusion 109
4.10 References 109
Chapter 5. Lipid-derived flavors in meat products 122
5.1 Introduction 122
5.2 The role of lipids in generation of meaty flavors 123
5.3 Lipid autoxidation and meat flavor deterioration 125
5.4 The effect of ingredients on flavor quality of meat 127
5.5 The evaluation of aroma compounds and flavor quality 133
5.6 Summary 134
5.7 References 134
Chapter 6. Modelling colour stability in meat 139
6.1 Introduction 139
6.2 External factors affecting colour stability during packaging and storage 140
6.3 Modelling dynamic changes in headspace composition 140
6.4 Modelling in practice: fresh beef 141
6.5 Modelling in practice: cured ham 145
6.6 Internal factors affecting colour stability 148
6.7 Validation of models 150
6.8 Future trends 151
6.9 References 152
Chapter 7. The fat content of meat and meat products 154
7.1 Introduction 154
7.2 Fat and the consumer 155
7.3 The fat content of meat 155
7.4 Animal effects on the fat content and composition of meat 158
7.5 Dietary effects on the fat content and composition of meat 161
7.6 Future trends 164
7.7 Sources of further information and advice 166
7.8 References 167
Part II: Measuring quality 172
Chapter 8. Quality indicators for raw meat 174
8.1 Introduction 174
8.2 Technological quality 174
8.3 Eating quality 177
8.4 Determining eating quality 183
8.5 Sampling procedure 183
8.6 Future trends 185
8.7 References 185
8.8 Acknowledgemnts 191
Chapter 9. Sensory analysis of meat 192
9.1 Introduction 192
9.2 The sensory panel 193
9.3 Sensory tests 195
9.4 Category scales 202
9.5 Sensory profile methods and comparisons with instrumental measurements 203
9.6 Comparisons between countries 206
9.7 Conclusions 206
9.8 References 207
Chapter 10. On-line monitoring of meat quality 210
10.1 Introduction 210
10.2 Measuring electrical impedance 212
10.3 Measuring pH 216
10.4 Analysing meat properties using NIR spectrophotometry 218
10.5 Measuring meat colour and other propertie 218
10.6 Water-holding capacity 220
10.7 Sarcomere length 220
10.8 Connective tissue 221
10.9 Marbling and fat content 223
10.10 Meat flavour 224
10.11 Boar taint 224
10.12 Emulsions 224
10.13 Measuring changes during cooking 225
10.14 Conclusion 228
10.15 Sources of further information and advice 228
10.16 References 229
Chapter 11. Microbiological hazard identification in the meat industry 234
11.1 Introduction 234
11.2 The main hazards 235
11.3 Analytical methods 248
11.4 Future trends 250
11.5 Sources of further information and advice 251
11.6 References 251
Part III: New techniques for improving quality 254
Chapter 12. Modelling beef cattle production to improve quality 256
12.1 Introduction 256
12.2 Elements of beef cattle production 257
12.3 Challenges for modellers 261
12.4 Simple model of herd structure 268
12.5 Future developments 271
12.6 References 272
Chapter 13. New developments in decontaminating raw meat 276
13.1 Introduction 276
13.2 Current decontamination techniques and their limitations 277
13.3 Washing 279
13.4 The use of chemicals 280
13.5 New methods: steam 284
13.6 Other new methods 289
13.7 Future trends 290
13.8 Sources of further information and advice 293
13.9 References 294
Chapter 14. Automated meat processing 300
14.1 Introduction 300
14.2 Current developments in robotics in the meat industry 301
14.3 Automation in pig slaughtering 302
14.4 Case study: the evisceration process 304
14.5 Automation of secondary processes 307
14.6 Future trends 311
14.7 References and further reading 313
Chapter 15. New developments in the chilling and freezing of meat 314
15.1 Introduction 314
15.2 The impact of chilling and freezing on texture 316
15.3 The impact of chilling and freezing on colour 317
15.4 The impact of chilling and freezing on drip loss and evaporative weight loss 319
15.5 The cold chain 321
15.6 Temperature monitoring 323
15.7 Optimising the design and operation of meat refrigeration 325
15.8 Sources of further information and advice 327
15.9 References 327
Chapter 16. High pressure processing of meat 330
16.1 Introduction: high pressure treatment and meat quality 330
16.2 General effect of high pressure on food components 331
16.3 Structural changes due to high pressure treatment of muscle 332
16.4 Influence on enzyme release and activity 335
16.5 High pressure effects on the sensory and functional properties of meat 335
16.6 Pressure assisted freezing and thawing 337
16.7 Effects on microflora 338
16.8 Current applications and future prospects 340
16.9 References 341
Chapter 17. Processing and quality control of restructured meat 349
17.1 Introduction 349
17.2 Product manufacture 350
17.3 Factors affecting product quality: temperature, ice content, particle size and mechanical properties 355
17.4 Factors affecting product quality: protein solubility and related factors 360
17.5 Factors affecting product quality: cooking distortion 364
17.6 Sensory and consumer testing 366
17.7 Future trends 368
17.8 Sources of further information and advice 370
17.9 References 370
Chapter 18. Quality control of fermented meat products 376
18.1 Introduction: the product 376
18.2 The quality concept 377
18.3 Sensory quality and its measurement 378
18.4 Appearance and colour: measurement and development 380
18.5 Texture: measurement and development 382
18.6 Flavour: measurement and development 385
18.7 Taste and aroma: measurement and development 389
18.8 The control and improvement of quality 394
18.9 Future trends in quality development 398
18.10 References 399
Chapter 19. New techniques for analysing raw meat quality 411
19.1 Introduction 411
19.2 Defining meat quality 411
19.3 Current state of art techniques 414
19.4 Emerging technologies 416
19.5 The genetics of meat quality 422
19.6 The future 424
19.7 Sources of further information and advice 425
19.8 References 425
Chapter 20. Meat packaging 434
20.1 Introduction 434
20.2 Factors influencing the quality of fresh and processed meat products 436
20.3 Vacuum packaging 441
20.4 Modified atmosphere packaging 445
20.5 Bulk, master or mother packaging 452
20.6 Controlled atmosphere packaging and active packaging systems 454
20.7 Packaging materials used for meat products 456
20.8 Future trends 460
20.9 References 461
Index 469

Textauszug

3

Factors affecting the quality of raw meat

R.K. Miller    Texas A & M University, College Station

3.1 Introduction

Establishing an understanding of raw meat eating quality and consistency is an important component of meat production systems. It is generally understood that production of meat must be tied to the production of a product that consumers find visually appealing, that they will continually purchase and that consistently delivers an acceptable eating experience. Therefore, meat quality encompasses the visual appearance and eating quality. Both of these quality factors can be influenced by ante-mortem and post-mortem production factors. This chapter will concentrate on ante-mortem production factors of breed and genetic effects, dietary influences, and rearing effects on meat quality and the post-mortem factor of the slaughter effect will be discussed as a post-mortem production factor. This information will provide a basis of understanding for subsequent discussions on meat quality in ensuing chapters.

3.2 Quality, meat composition and structure

Meat is composed of lean tissue or muscle fiber cells, fat and connective tissue. Fat or adipose cells can be found in up to three depots or locations in meat. Fat can be deposited intramuscularly as marbling or contained between muscles (defined as seam fat) or it can be found as external fat or subcutaneous fat. Additionally, meat may include bone, but the trend has moved toward boneless meat cuts and therefore bone will not be discussed in this chapter. Nervous tissue and components of the blood system are contained within meat but their total weight or proportional contribution to meat is small and so will not be discussed. These three major components of meat, fat, lean or the myofibrillar component, and connective tissue, affect meat quality in different ways.

3.2.1 Fat component

Intramuscular fat content has been shown to affect flavor, juiciness, tenderness and visual characteristics of meat. Savell and Cross (1988) developed the Window of Acceptability to demonstrate the general relationship between the role of increased intramuscular fat on meat pork, lamb and beef palatability (Fig. 3.1). In general, as fat content increases, palatability increases; however, improvements in palatability with increasing fat percentage are not equal across all fatness levels. If fat content is less than 3%, palatability decreases markedly with each decrease in fat percentage. In fact, this is the steepest slope on the curve. As fat increases from 3% to about 6%, meat palatability improves, but not as dramatically as reported at the lower levels. As fat content exceeds 7.3%, fat is highly visible and has been identified as too fatty by health-conscious consumers. Too much visible fat has raised questions about consumption of fat in meat products and increased incidence of coronary heart disease, obesity or some forms of cancer in humans; these issues can affect consumers’ perception of acceptability. Therefore, meat with fat content between 3 and 7.3% is generally considered acceptable. Diet/health-conscious consumers may be willing to sacrifice palatability for lower fat content.

Fig. 3.1 The Window of acceptability. Adapted with permission from Designing Foods: Animal Product Options in the Marketplace. Copyright 1988 by the National Academy of Sciences. Courtesy of the National Academy Press, Washington, DC.

How does intramuscular fat affect palatability? One way is through the relationship of intramuscular fat with meat juiciness. As intramuscular fat increases, humans perceive that the meat is juicier. During mastication or during the first bites, if fat is present, some of it is released and the salivary glands are stimulated. This results in a perception of juiciness, additionally, meat with a higher fat content may give a longer sustained perception of juiciness. Savell and Cross (1988) stated that ‘fat may affect juiciness by enhancing the waterholding capacity of meat, by lubricating the muscle fibers during cooking, by increasing the tenderness of meat and thus the apparent sensation of juiciness, or by stimulating salivary flow during mastication’.

A second way that intramuscular fat affects palatability is through the relationship between fat content and tenderness. Interestingly, there is conflicting evidence as to the meat tenderness and fat relationship. Savell and Cross (1988) supported the relationship between increased intramuscular fat and meat tenderness by proposing four hypotheses. The first hypothesis, the Bulk Density Theory, states that as fat is lower in density than heat-denatured protein in cooked meat, as the fat percentage increases, the overall density of the meat decreases. As bulk density decreases within a given bite of meat, the meat is more tender. The second hypothesis is defined as the Lubrication Effect. Intramuscular fat is mainly triglycerides stored in adipose cells embedded in the perimysial connective tissue wall of the muscle. As meat is cooked, triglycerides melt and bathe the muscle fibers. As the meat is chewed, fat is released, salivation increases and the meat is perceived as juicy. Additionally, the muscle fibers give or slide more easily resulting in an increased perception of tenderness. The third hypothesis, the Insurance Theory, states that fat provides protection against the negative effects of over-cooking or high heat on protein denaturation. Meat proteins are involved in binding water in the muscle fiber. As meat is cooked, proteins denature and lose some of their ability to bind water. Fat can act to insulate the transfer of heat or slow down the heat transfer so that protein denaturation is less severe and less moisture is lost during cooking. The fourth theory or the Strain Theory relates to the weakening of the perimysial connective tissue surrounding muscle bundles. As marbling is deposited as adipose cells dispersed in perimysial connective tissue, development and an increased number of adipose cells weaken the connective tissue structure resulting in more tender meat.

To understand if marbling or intramuscular fat affected consumer acceptance and the subsequent relationship with trained sensory responses, the Beef Customer Satisfaction study was conducted (Lorenzen et al., 1999; Neely et al., 1998; Savell et al., 1999) in the United States. Beef top loin steaks from four USDA Quality Grade classifications were selected to represent four Quality Grade classifications where Low Select would contain beef top loin steaks with Slight00 to Slight50 degrees of marbling that would equate to about 3 to 3.5% chemical lipid; High Select steaks had Slight51 to Slight100 degrees of marbling or about 3.5 to 4.0% chemical lipid; Low Choice steaks had a small degree of marbling or about 4 to 5% chemical lipid; and Top Choice consisted of steaks with modest and moderate degrees of marbling or about 6 to 7% chemical lipid. Chemical lipid approximations were projected from Savell and Cross (1988). Steaks were evaluated by 300 households in four cities where each household contained two adult consumers who ate beef three or more times per week. Four top loin steaks from each carcass was served to four consumers in each city and one steak was evaluated by a trained meat descriptive attribute panel and Warner-Braztler shear force was conducted as a mechanical measurement of tenderness as described by AMSA (1995). Consumers rated Top Choice steaks highest for overall like and juiciness (Table 3.1). They liked the tenderness and flavor of Choice (Top Choice and Low Choice) steaks compared to Select steaks and they indicated that the Choice steaks had a higher intensity of flavor than Select steaks. Trained sensory panels also indicated that as marbling score increased, cooked beef top loin steaks were juicier, more tender, more intense in flavor and they had higher levels of beef flavor and beef fat flavor (Table 3.1). Warner-Bratzler shear force values decreased as marbling score increased (Table 3.1). In this same study, top sirloin and top round steaks also were evaluated. These steaks had slightly lower fat content than top loin steaks and the marbling to palatability relationship was not as strong.

Table 3.1

Least squares means of top loin steaks from US Beef Customer Satisfaction Study for consumer sensory attributes,a trained meat descriptive sensory attributes and Warner-Bratzler shear force (kg) as effected by USDA quality grade

Consumer sensory attributes a

Overall like/dislike

19.2c

19.1c

18.8c

18.7c

3.06

0.0004

Juiciness

18.5c

18.5c

18.3d

18.0c

3.57

0.0006

Tenderness like/dislike

19.0cd

19.2d

18.6cd

18.6c

3.28

0.0001

Flavor intensity

19.1c

19.2d

18.9cd

18.9c

2.87

0.0009

Flavor...

Produkt-Details

• Erscheint lt. Verlag: 6.9.2002
• Sprache: englisch
• Themenwelt: Technik ► Lebensmitteltechnologie
• Themenwelt: Wirtschaft
• ISBN-10: 1-85573-666-7 / 1855736667
• ISBN-13: 978-1-85573-666-5 / 9781855736665