Debittering of a tryptic digest of bovine beta-casein using porcine kidneygeneral aminopeptidase and X-prolydipeptidyl aminopeptidase from Lactococcus lactis subsp cremoris AM2

The role of leucine aminopeptidase (LAP) from pig kidney cytosol and X-prol yldipeptidyl aminopeptidase (Pep X) from Lactococcus lactis subsp. cremoris AM2 in the hydrolysis and debittering of a tryptic digest of beta -casein was studied. Hydrolysis was monitored by quantifying the release of primary amino groups and bitterness by use of a trained sensory panel, Sequential incubation of the bitter tryptic hydrolysate with LAP, Pep X and LAP result ed in higher levels of hydrolysis and significantly (P < 0.001) lower level s of bitterness than incubation with; LAP alone. The results demonstrate th e central role proline-specific aminopeptidases can play in the hydrolysis and debittering of food protein hydrolysates.