Activities of Various Peptidases in Barley, Green Malt and Malt

The three groups of malt peptidases (carboxypeptidases, “naphthylamidases” and (amino) peptidases acting on Leu-Tyr and Ala-Gly) are present in unmalted barley; the activities are low and of a similar order of magnitude. On germination the activities of the different carboxypeptidases increase from 10- to 20-fold; the “naphthylamidases” increase only 2-fold, and the peptidase activities increase from 3- to 6-fold. None of these enzymes is inactivated during kilning to any significant extent. There are considerable differences between the carboxypeptidase activities of malts derived from different varieties of barley and the activities are correlated with α-amylase activity.