Effect of heat treatment on the proteolytic/peptidolytic enzyme system of aLactobacillus delbrueckiisubsp.bulgaricusstrain

Summary Lactobacillus delbrueckiisubsp.bulgaricuscells heat treated at 67 or 68 °C for 15·5–16 s had significantly less acidification capacity and much lower endopeptidase activity than untreated cells, while they still retained high aminopeptidase activities against amino acids commonly found in bitter peptides. A stimulatory effect of heat treatment on the leakage of aminopeptidases from cells was observed at pH 5·4. These properties make them suitable as extra sources of important ripening enzymes in cheesemaking.