Moderate Protein Processing: Elucidation of Thermal Aggregation and Gel Quality and Regulatory Strategies for Excessive Aggregation

Heat treatment can induce muscle protein denaturation and aggregation and eventually the sol-gel tradition of proteins. The aggregation rate, degree, morphology and pattern can affect the quality of protein gels. Traditional Chinese soy sauce and pot-roast meat products are processed at temperatures above 100 ℃, and secondary heating treatment is commonly used to extend the shelf life of canned foods, both of which can lead to excessive protein aggregation, in turn reducing the fluidity of water as well as protein digestibility, destroying the quality of meat products and reducing the nutritional value. In this paper, the mechanisms of protein aggregation are analyzed by using the Lumry-Eyring nucleated polymerization (LENP) model. Three protein aggregation modes are described including fibril aggregation, hydrogel aggregation and amorphous aggregation. Four strategies for inhibiting excessive thermal aggregation are reviewed from the perspective of the spatial conformation of proteins. pH, amino acids and polyphenol compounds along with hydrophobic and reducing small molecules can effectively inhibit excessive aggregation of myofibrillar proteins and improve the gel properties of heat-induced proteins. As a molecular chaperone, casein can obviously enhance the thermal stability and reduce the degree of aggregation of proteins. Therefore, these strategies for inhibiting excessive aggregation can enhance the gel and texture quality of meat products.