Presence of peptidase activities in different varieties of cheese

Lactic acid bacteria (LAB) counts, PepX activity towards H-Phe-Pro-beta NA, and aminopeptidase activity towards H-Arg-beta NA.HCL, H-Lys-beta NA, H-le u-beta NA, H-Pro-beta NA, H-Glu-beta NA derivatives have been evaluated in 32 commercial samples of cheese, one processed cheese, and one yoghurt. The presence of intracellular exopeptidase activities in cheese extracts free from bacterial cells was detected, even after 1 year of ripening. An invers e ratio between the presence of viable lactic microflora and peptidase acti vity in the cheese extracts was observed. The importance of LAB starter eso -peptidases in the degradation of casein oligopeptides, and the I;ey role o f autolysis in the release of peptidases in the cheese, are discussed.