Abstract:Milk is rich in protein, with approximately 80% of it being casein, which is present in liquid milk in the form of casein micelles. Based on the differences in the amino acids at corresponding positions in the β-casein molecular structure, β-casein has a variety of subtype structures, with A1 and A2 β-casein being the predominant forms. In recent years, there has been a growing interest in the influence of β-casein genetic variants on the physicochemical properties and functional health benefits of dairy products. Single nucleotide gene mutation affects the isoelectric point and properties of β-casein, thereby influencing the structure and physicochemical properties of various dairy products during processing. β-casein is the main source of bioactive peptides, generating numerous amino acids and active peptides through the process of hydrolysis. Variations in the structure of β-casein affect the pattern of digestion enzymatic cleavage, leading to the generation of different types and amounts of peptides through hydrolysis. A1 β-casein, when subjected to enzymatic hydrolysis, results in the formation β-casomorphin-7, which is more likely to adversely affect gastrointestinal digestion and absorption compared to A2 β-casein. This paper provides a comprehensive review of the effects of micellar structure and stability, gel coagulability, and interface properties of A1/A2 β-casein on the processing of dairy products. The effects of A1 and A2 β-casein on the gastrointestinal tract after digestion have been described. Furthermore, a comprehensive analysis was conducted to systematically assess the opportunities and challenges still existing in this field, aiming at providing theoretical guidance for future development of the dairy products market.
