Influence of kappa-casein genetic variant on rennet gel microstructure, cheddar cheesemaking properties and casein micelle size

Cheddar cheese was manufactured on three separate occasions over a two week period from milk collected from two mid-lactation, spring-calving, Holstei n-Friesian herds (n = 11) containing similar casein levels, having phenotyp e AA or BE for kappa-casein genetic variant. kappa-Casein variant did not s ignificantly (P > 0.05) influence the casein content or gross composition o f milk, kappa-Casein BE milk had significantly smaller average casein micel le diameter and superior rennet coagulation properties than that of the AA milk. Pilot-scale Cheddar cheesemaking studies showed that the kappa-casein BE milk resulted in significantly higher fat recoveries into cheese and hi gher actual and moisture-adjusted cheese yields. Cheese produced from kappa -casein BE variant milk had higher concentrations of fat and lower protein levels than that produced from the AA variant. kappa-Casein variant had no significant effect on proteolysis or on the acceptability scores awarded to the cheeses. (C) 1998 Elsevier Science Ltd. All rights reserved.