Degradation of a Bitter Peptide Derived from Casein by Lactic Acid Bacterial Peptidase

Abstract

In the present study, degradation of a bitter peptide derived from β-casein by lactic acid bacterial peptidase was examined. Nine species of lactococci (L. lactis ssp. lactis 303, L. lactis ssp. lactis 527, L. lactis ssp. lactis IAM 1198, L. lactis ssp. cremoris SK11, L. lactis ssp. cremoris AM2, L. lactis ssp. cremoris HP, L. lactis ssp. cremoris 317, L. lactis ssp. cremoris H61 and L. lactis ssp. cremoris IAM1150), which are extensively used as starter cultures for cheese manufacturing, were examined. The heptapeptide Gly-Pro-Phe-Pro-Ile-Ile-Val, derived from β-casein, was used as the bitter peptide. All the cell-free extracts prepared from lactic acid bacteria (LAB) could degrade the bitter peptide, but the degree of degradative activity varied depending on the type of LAB. In particular, L. lactis ssp. lactis 527 showed a higher level of degradative activity than L. lactis ssp. cremoris SK11 and L. lactis ssp. cremoris AM2; all have been reported as debittering LAB. From these results, it was concluded that L. lactis ssp. lactis 527 may be used for debittering dairy products including cheese.