Influence of a lactococcal X-prolyl dipeptidyl aminopeptidase-negative variant on Cheddar cheese production and ripening.

Citation

St-Gelais, D. and Roy, D. (2007). "Influence of a lactococcal X-prolyl dipeptidyl aminopeptidase-negative variant on Cheddar cheese production and ripening.", Milk Science International, 62(3), pp. 287-291.

Abstract

Cheddar cheeses were produced by using an X-prolyl dipeptidyl aminopeptidase-positive (PepX(+)) Lactococcus lactis ssp. cremoris and its X-prolyl dipeptidyl aminopeptidase-negative (PepX(-)) variant. Effects of these both types of starter on cheese production, composition, ripening and sensory properties were determined. Time of processing was longer when the PepX(-) variant was used to produce cheese. As a result, moisture content was lower, while firmness was higher in PepX(-) cheese. During cheese ripening, the evolution of population of lactococci decreased slower in PepX(-) cheese. The production of trichloroacetic acid soluble nitrogen, hydrophobic peptides and amino acids was, in general, faster in PepX(+) cheese than in PepX(-) cheese. The release of proline was very fast in PepX(+) cheese comparatively to PepX(-) cheese. However, sensory evaluation indicated that PepX(+) cheese showed bitterness. In this study, the use of a PepX(+) strain could not allow reducing bitter taste in cheese. As the production of hydrophobic peptides was high in PepX(+) cheese, it is possible that bitterness could be also due to excessive accumulation of unhydrolyzed bitter peptides.

Publication date

2007-12-31