Flavor of Meat and Meat Products, 1994

Flavour is an important sensory aspect of the overall acceptability of meat products. Whether we accept or reject a food depends primarily on its flavour. Both desirable and undesirable flavour effects are contemplated. Furthermore, threshold values of different flavour-active compounds have an important effect on the cumulative sensory properties of all foods. Meat from different species constitutes a major source of protein for most people. Although raw meat has little flavour and only a blood-like taste, it is a rich reservoir of non-volatile compounds with taste-tactile properties as well as flavour enhancers and aroma precursors. Non-vola­ tile water-soluble precursors and lipids influence the flavour of meat from different species. In addition, mode of heat processing and the nature of additives used may have a profound effect on the flavour of prepared meats. This book reports the latest advancements in meat flavour research. Following a brief overview, chapters 2 to 5 discuss flavours from different species of meat, namely beef, pork, poultry and mutton. In chapters 6 to 12 the role of meat constituents and processing on flavour are described. The final section of the book (chapters 13 to 15) summarizes analytical methodologies for assessing the flavour quality of meats. I wish to thank all the authors for their cooperative efforts and com­ mendable contributions which have made this publication possible.

1 Flavor of meat and meat products—an overview.- 1.1 Introduction.- 1.2 Meat flavour volatiles.- 1.3 Impact of processing and storage on meat flavour.- References.- 1 Species flavours.- 2 The flavour of beef.- 2.1 Introduction.- 2.2 Taste-active compounds.- 2.3 Flavour enhancers.- 2.4 Aroma components.- 2.4.1 Effect of heat on sugars and/or amino acids.- 2.4.2 Reactions of hydroxyfuranones.- 2.4.3 Thermal degradation of thiamine.- 2.4.4 Lipid oxidation/degradation.- 2.4.5 Selected aroma components of high sensory significance.- 2.5 Conclusion.- References.- 3 The flavour of pork.- 3.1 Introduction.- 3.2 Role of lipid degradation products in pork flavour.- 3.3 Heterocyclic constituents of pork aroma.- 3.4 Polysulphides in roasted pork.- 3.5 Effects of ingredients on the flavour of pork.- References.- 4 The flavour of poultry meat.- 4.1 Introduction.- 4.2 Primary odorants of chicken broth.- 4.3 Sulphur-containing compounds in chicken flavours.- 4.4 Lipid oxidation products in chicken flavour.- 4.5 Heterocyclic compounds in chicken flavour.- 4.5.1 Pyrazines.- 4.5.2 Pyridines.- 4.5.3 Pyrroles.- 4.5.4 Thiazoles.- 4.6 Conclusion.- References.- 5 Sheepmeat odour and flavour.- 5.1 Introduction.- 5.2 Assessment of sheepmeat odour and flavour by sensory panels and chemical analysis.- 5.3 The tissue source of mutton odour and flavour.- 5.4 Chemical components involved in sheepmeat odour and flavour.- 5.5 Factors affecting sheepmeat odour and flavour.- 5.5.1 Pre-slaughter factors.- 5.5.2 Post-slaughter factors.- 5.6 Concluding remarks.- Acknowledgments.- References.- 2 Role of meat constituents and processing on flavour.- 6 Umami flavour of meat.- 6.1 Introduction.- 6.2 Definitions.- 6.3 Historical background.- 6.4 Structural considerations.- 6.5 Stability.- 6.6 Synergism.- 6.7 Taste properties.- 6.8 Food occurrence.- 6.9 Umami compounds and meat flavour.- 6.10 Conclusions.- References.- 7 Lipid-derived off-flavours in meat—formation and inhibition.- 7.1 Introduction.- 7.2 Role of lipids in meat flavour.- 7.3 Lipid oxidation in meats.- 7.3.1 Role of haem and nonhaem iron as catalysts.- 7.3.2 Ferritin as a catalyst of lipid oxidation in meat.- 7.4 Initiation of lipid oxidation in muscle tissue.- 7.4.1 Initiators of the oxidation reaction.- 7.4.2 Enzymatic lipid oxidation.- 7.5 Prevention of lipid oxidation in meats.- 7.5.1 Antioxidant role of nitrite.- 7.5.2 Stabilization of meat lipids with nitrite-free curing mixtures.- 7.5.3 Vitamin E and meat quality.- 7.5.4 Spice extracts as antioxidants.- 7.6 Future research needs.- Acknowledgments.- References.- 8 Lipid oxidation in meat by-products: effect of antioxidants and Maillard reactants on volatiles.- 8.1 Introduction.- 8.2 Materials and methods.- 8.2.1 Materials.- 8.2.2 Chemical analysis of meat-meal.- 8.2.3 Analysis of volatiles in dry meat-meal.- 8.2.4 Analysis of volatiles in processed Maillard meat-meal water mixtures.- 8.3 Results and discussion.- References.- 9 Maillard reactions and meat flavour development.- 9.1 Introduction.- 9.1.1 Meat flavour.- 9.2 The Maillard reaction.- 9.3 The Maillard reaction and meat flavour compounds.- 9.3.1 Low molecular weight precursors of meat flavour.- 9.3.2 Pyrazines.- 9.3.3 Sulphur compounds.- 9.3.4 Synthetic flavours from the Maillard reaction.- 9.4 Summary.- References.- 10 The flavour of cured meat.- 10.1 Introduction.- 10.2 Advantages of nitrite in the meat-curing process.- 10.3 Antioxidant role of nitrite in cured meats.- 10.4 Chemistry of cured-meat flavour.- 10.5 Conclusion.- References.- 11 Contribution of smoke flavourings to processed meats.- 11.1 Introduction.- 11.2 Pyrolysis of cellulose.- 11.3 Pyrolysis of hemicellulose.- 11.4 Pyrolysis of lignin.- 11.5 Smoke colour formation in processed meats.- 11.6 Smoke flavour in processed meats.- 11.7 Fractionation of smoke flavourings.- 11.8 Miscellaneous contributions of smoke flavourings.- 11.9 Summary.- References.- 12 Some aspects of the chemistry of meat flavour.- 12.1 Introduction.- 12.2 Meat flavour precursors.- 12.3 Reactions leading to meat aroma.- 12.3.1 Maillard reaction.- 12.3.2 Lipid degradation.- 12.4 Compounds contributing to meat flavour.- 12.5 Pathways for the formation of some meat aroma volatiles.- 12.6 Interaction of lipid with the Maillard reaction.- 12.6.1 Model systems.- 12.6.2 Meat volatiles from lipid—Maillard interaction.- References.- 3 Analytical methodologies.- 13 Instrumental methods of meat flavour analysis.- 13.1 Introduction.- 13.2 Refinements to routine GC in GC—MS.- 13.2.1 Multidimensional gas chromatography.- 13.2.2 Chiral phase gas chromatography.- 13.2.3 Preparative gas chromatography.- 13.3 Refinements to routine MS in GC—MS.- 13.3.1 High resolution mass spectrometry.- 13.3.2 Selected ion monitoring mass spectrometry.- 13.3.3 Chemical ionization mass spectrometry.- 13.3.4 Negative ion chemical ionization mass spectrometry.- 13.4 Alternatives to GC as a method of separation prior to identification.- 13.4.1 High-performance liquid chromatography.- 13.4.2 Supercritical fluid chromatography.- 13.4.3 Capillary zone electrophoresis.- 13.4.4 Mass spectrometry in MS—MS.- 13.5 Alternatives to MS as a method of identification following separation.- 13.5.1 Fourier transform infrared spectroscopy.- 13.6 Conclusion.- References.- 14 Assessment of lipid oxidation and off-flavour development in meat and meat products.- 14.1 Introduction.- 14.2 Fatty acid analysis.- 14.3 Oxygen uptake.- 14.4 Conjugated dienes.- 14.5 Peroxide value.- 14.6 The 2-thiobarbituric acid test.- 14.6.1 Advantages and limitation of the TBA test.- 14.7 The Kries test.- 14.8 Anisidine value.- 14.9 Totox value.- 14.10 Carbonyl compounds.- 14.11 Hexanal and other carbonyl compounds.- 14.12 Pentane and other alkanes.- 14.13 Conclusions.- Acknowledgments.- References.- 15 Sensory and statistical analyses in meat flavour research.- 15.1 Introduction.- 15.2 Sensory evaluation.- 15.2.1 Odour control.- 15.2.2 Lighting.- 15.2.3 General comfort.- 15.2.4 Preparation area.- 15.2.5 Sample preparation and serving.- 15.3 Sensory analysis of meat.- 15.3.1 Descriptive flavour panel.- 15.3.2 Descriptor development.- 15.4 Chemical and instrumental parameters.- 15.4.1 Thiobarbituric acid reactive substances.- 15.4.2 Direct gas chromatography.- 15.5 Correlations among sensory, chemical and instrumental analyses.- 15.5.1 Experimental designs.- 15.5.2 Statistical analysis.- 15.6 Summary.- References.