Relationship between β-casein genotypes (A1A1, A1A2, and A2A2) and coagulation properties of milk and the fatty acid composition and sensory characteristics of dairy products (soft cheese, sour cream, and butter)

Abstract

ABSTRACT We examined how β-casein CSN2 genotypes (A1A1, A1A2, A2A2) affected milk coagulation properties, the fatty acid composition, and sensory traits of milk products (soft cheese, sour cream, and butter). We collected 300 L of milk from 96 cows in the same herd and sorted it into 100-L milk pools according to the β-casein genotype. Rennet coagulation time and curd-firming rate were fastest in A2A2 milk and slowest in A1A1 milk. Accordingly, curd firmness was highest in A2A2 milk and lowest in A1A1 milk. A1A1 milk products had higher levels of monounsaturated fatty acids and lower levels of saturated fatty acids. Polyunsaturated fatty acids were mainly found in A2A2 milk products and were lowest in A1A2 products. Although CSN2 genotypes influenced milk coagulation traits and fatty acid content of milk products, they did not influence the latter's sensory traits. Therefore, selectively breeding genotypes with preferred qualities may improve dairy products.