Effects of Protein, Calcium, and pH on Gene Transcription, Cell-Envelope Peptidase Activity of Lactococcus lactis Strains, and the Formation of Bitter Peptides.

ABSTRACT: Calcium- and protein-rich fermented milk products, such as concentrated yoghurts and fresh cheeses, may contain undesired bitter peptides, which are generated by the proteolytic cleavage of casein. Up to now, it is not clear whether this process is caused by endogenous milk enzymes, such as plasmin and cathepsin D, or whether proteolytic enzymes from applied starter cultures, such as the lactococcal cell-envelope peptidase PrtP, are involved. A sensory analysis of fresh cheese products made from milk concentrates fermented with prtP-negative and -positive Lactococcus lactis strains revealed bitterness in the products fermented with prtP-positive L. lactis strains. Two prtP-positive strains, LTH 7122 and LTH 7123, were selected to investigate the effect of increased calcium concentrations (

SUBMITTER: Forler B 

PROVIDER: S-EPMC8307170 | biostudies-literature | 2021 Jul

REPOSITORIES: biostudies-literature