CONTRIBUTION OF CELL WALL-ASSOCIATED PROTEINASES OF LACTOCOCCUS TO THE PRIMARY PROTEOLYSIS OF BETA-CASEIN IN CHEDDAR CHEESE

Beta-Casein was hydrolyzed in vitro by cell wall-associated proteinase s from Lactococcus lactis ssp. cremoris HP and L. lactis ssp. lactis J L 521 and JL 3601. Electrophoretograms of the hydrolyzates were compar ed with those of whole and water soluble extracts of Cheddar cheese ma de using these strains as starters. The peptides produced by hydrolysi s of beta-casein in vitro were not detected in the 6 month-old cheese or water extracts therefrom. Inter-strain differences were observed in the electrophoretograms of the cheeses, water extracts and beta-casei n hydrolyzates.The results of this study suggest that the cell wall-as sociated proteinases of the Lactococcus starters studied had little, i f any, activity on intact beta-casein in Cheddar cheese; it is postula ted that this is due to hydrophobic interactions in cheese of the susc eptible regions of beta-casein.