| Heat treatment is the leading and most traditional means of cooking and sterilizing meats from aquatic products and poultry product for the processing industry. The meat protein composition and structures are briefly described in this manuscript and the denaturing of the different proteins during the heat treatments are discussed. Most of the sarcoplasmic proteins either from aquatic or poultry meat aggregate between 40℃ and 60℃, but some coagulation can occur at up to 90℃. The unfolding of myofibrillar proteins in solution begins at 30℃~32℃, followed by protein–protein associations at 36℃~40℃, and subsequent gelation at 45℃~50℃ (conc.>0.5% by weight). At temperatures between 53℃ and 63℃, collagen denaturation occurs, followed by collagen fibre shrinkage. If the collagen fibres are not stabilised by heat-resistant intermolecular bonds, they dissolve and form gelatine on further heating. In addition, the structural changes and quality changes of different kinds of meat due to the heat treatment are discussed. In most cases, after meat is heated to a certain temperature, its microscopic structure shrinks, the sarcomere length shortens, the water holding capacity decreases, and the shear force which represents hardness rises once or twice. Minced meat products including surimi products, hamburger patties and emulsified sausages have disordered muscle system structures due to the effect of heat processing. Compared with emulsified sausage, hamburger patties have a higher occurrence rate of whole fiber and fiber fragments, and their content is as high as 50%~70%, and resulting in greater shrinkage after heating. Compared to poultry product, surimi products showed to be much more complicated. Salt soluble proteins in fish muscle would reform a cubic network containing water when it was heated to be surimi products due to the formation of disulfide bridge, hydrophobic interaction and hydrogen bond, etc. In emulsified sausage, the myofibrillar protein is extracted due to the crushing and stirring of muscle, resulting in a dense protein network gel during heat treatments, and water can be effectively maintained through capillary force. Understanding the structural changes of different meat proteins and the mechanism of quality changes during heat treatments can provide a theoretical basis for formulating a more reasonable meat processing methods. |
