Freeze-dried cell-free extracts (CFE) from Lactobacillus casei LC01, Weissella cibaria 1XF5, Hafnia alvei
Moller ATCC 51815, and Debaryomyces hansenii LCF-
558 were used as sources of enzyme activities for conditioning the ripening of ewe milk cheese. Compared with
control cheese (CC), CFE did not affect the gross composition and the growth of the main microbial groups
of the cheeses. As shown through urea-PAGE electrophoresis of the pH 4.6-soluble nitrogen fraction and the
analysis of free AA, the secondary proteolysis of the
cheeses with CFE added was markedly differed from
that of the CC. Compared with CC, several enzyme
activities were higher in the water-soluble extracts from
cheeses made with CFE. In agreement, the levels of 49
volatile compounds significantly differentiated CC from
the cheeses made with CFE. The level of some alcohols,
ketones, sulfur compounds, and furans were the lowest
in the CC, whereas most aldehydes were the highest.
Each CFE seemed to affect a specific class of chemical
compounds (e.g., the CFE from H. alvei ATCC 51815
mainly influenced the synthesis of sulfur compounds).
Apart from the microbial source used, the cheeses with
the addition of CFE showed higher score for acceptability than the control cheese. Cheese ripening was
accelerated or conditioned using CFE as sources of
tailored enzyme activities.