Influence of kappa-casein phenotype on the rennet coagulation time of bovine milk
Horne, D.S.; Muir, D.D.
Milchwissenschaft 49(7): 386-388
ISSN/ISBN: 0026-3788 Accession: 008867537
Using individual milks from 6 pairs of cows differing in kappa-casein phenotype, we have investigated the effect of kappa-casein phenotype on visual rennet coagulation properties. For this exercise we have adopted the HOLTER-FOLTMANN linear relationship between rennet clotting time (RCT) and reciprocal chymosin concentration to provide a response surface characteristic of each individual milk as a function of pH. Significant differences in slope and intercept, attributable to genetic variations, were observed only near natural milk pH (6.70). kappa-BB milks had on average shorter RCT values than kappa-AA. Both phases of the rennet coagulation reaction, proteolysis and aggregation, encompassed by the RCT measurement, were influenced in the same direction by kappa-casein phenotype.