Debittering of a Tryptic Digest of Bovine p‐casein Using Porcine Kidney General Aminopeptidase and X‐Prolydipeptidyl Aminopeptidase from Lactococcus lactis subsp. cremoris AM2

The role of leucine aminopeptidase (LAP) from pig kidney cytosol and X‐prolyldipeptidyl aminopeptidase (Pep X) from Lactococcus lactis subsp. cremoris AM2 in the hydrolysis and debittering of a tryptic digest of β‐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 resulted in higher levels of hydrolysis and significantly (P < 0.001) lower levels of bitterness than incubation with LAP alone. The results demonstrate the central role proline‐specific aminopeptidases can play in the hydrolysis and debittering of food protein hydrolysates.