ABSTRACT
Quality traits of muscle foods are in¯uenced by a number of different factors such as genetics, environmental factors, and processing conditions. While the genes remain more or less constant during the lifetime of the animal, the expression of the genes to mRNA and proteins is regulated by a large number of factors such as environmental and processing conditions, which may have an impact on different meat quality traits. However, the underlying molecular mechanisms determining these quality traits are far from understood. The proteome is the protein complement of the genome and consists of the total amount of proteins expressed at a certain time point and may thus be viewed as the mirror image of the gene activity (Wilkins et al. 1996). While the genome contains the information on genes and alleles that are present in the genome, the proteome contains information on genes that are actually being expressed and translated into proteins. In contrast to the genome, the proteome is continuously changing according to factors in¯uencing either protein synthesis or degradation. Thus, analyzing the proteome can be viewed as analyzing snapshots of
13.1 Introduction ................................................................................................ 313 13.2 Muscle Protein Solubilization and Fractionation ....................................... 314 13.3 Tools for Separation of Proteins (2-DE and MS) ........................................ 316
13.3.1 Two-Dimensional Gel Electrophoresis ........................................... 316 13.3.2 Gel-Free Methods ........................................................................... 318
13.4 Introduction to Meat/Muscle Quality ......................................................... 319 13.4.1 Meat Quality Parameters ................................................................ 319 13.4.2 Changes Occurring after Slaughter ................................................. 320 13.4.3 Tenderness ....................................................................................... 321
13.5 Changes in Protein Composition during Postmortem Storage ................... 322 13.6 Molecular Understanding of Meat Quality................................................. 324 13.7 Pre-Slaughter Conditions and Effects on Molecular Mechanisms ............. 326 13.8 In¯uence of Genetics on Muscle Biochemistry .......................................... 327 13.9 Effects of Dry Curing of Meat on Protein Composition ............................ 329 13.10 Conclusions ................................................................................................. 331 References .............................................................................................................. 331
a system in constant change. In this regard, the proteome can be seen as the molecular link between the genome and the functional quality of the muscle or meat. Thus, understanding the variations and different components of the proteome with regard to certain quality or processing parameters will lead to knowledge that can be used in optimizing the conversion of muscles to meat (Bendixen 2005, Bendixen et al. 2005, Hollung et al. 2007, Mullen et al. 2006).
