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-Leu-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 exo-peptidase activities in cheese extracts free from bacterial cells was detected, even after 1 year of ripening. An inverse ratio between the presence of viable lactic microflora and peptidase activity in the cheese extracts was observed. The importance of LAB starter exo-peptidases in the degradation of casein oligopeptides, and the key role of autolysis in the release of peptidases in the cheese, are discussed.
Gatti
M
M
Istituto Sperimentale Lattiero Caseario, Lodi, Italy.
Fornasari
M E
ME
Mucchetti
G
G
Addeo
F
F
Neviani
E
E
D002611:Cheese / Q000382:microbiology*; D015169:Colony Count, Microbial; D020689:Exopeptidases; D006094:Gram-Positive Bacteria / Q000201:enzymology*; D010447:Peptide Hydrolases / Q000302:isolation & purification*
D020689:Exopeptidases; D010447:Peptide Hydrolases