Protease, peptidase and esterase activities by lactobacilli and yeast isolates from Feta cheese brine.
OBJECTIVE
The study of peptidase, esterase and caseinolytic activity of Lactobacillus paracasei subsp. paracasei, Debaryomyces hansenii and Sacchromyces cerevisiae isolates from Feta cheese brine.


RESULTS
Cell-free extracts from four strains of Lact. paracasei subsp. paracasei, four strains of D. hansenii and three strains of S. cerevisiae, isolated from Feta cheese brine were tested for their proteolytic and esterase enzyme activities. Lactobacillus paracasei subsp. paracasei strains had intracellular aminopeptidase, dipeptidyl aminopeptidase, dipeptidase, endopeptidase and carboxypeptidase activities. Esterases were detected in three of four strains of lactobacilli and their activities were smaller with higher molecular weight fatty acids. The strains of yeasts did not exhibit endopeptidase as well as dipeptidase activities except on Pro-Leu. Their intracellular proteolytic activity was higher than that of lactobacilli. Esterases from yeasts preferentially degraded short chain fatty acids. Lactobacilli degraded preferentially beta-casein. Caseinolytic activity of yeasts was higher than that of lactobacilli.


CONCLUSIONS
The results suggest that Lact. paracasei subsp. paracasei and yeasts may contribute to the development of flavour in Feta cheese.


CONCLUSIONS
Selected strains could be used as adjunct starters to make high quality Feta cheese.
Bintsis
T
T
Laboratory of Food Microbiology and Hygiene, Faculty of Agriculture, Aristotle University of Thessaloniki, Thessaloniki, Greece.
Vafopoulou-Mastrojiannaki
A
A
Litopoulou-Tzanetaki
E
E
Robinson
R K
RK
D000626:Aminopeptidases / Q000378:metabolism; D002268:Carboxypeptidases / Q000378:metabolism; D002364:Caseins / Q000378:metabolism; D002611:Cheese / Q000382:microbiology*; D004150:Dipeptidases / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D010450:Endopeptidases / Q000378:metabolism; D004950:Esterases / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism; D005516:Food Microbiology; D007778:Lactobacillus / Q000201:enzymology*; D008066:Lipolysis / Q000502:physiology; D008970:Molecular Weight; D010447:Peptide Hydrolases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D015003:Yeasts / Q000201:enzymology*
D002364:Caseins; D005227:Fatty Acids; D004950:Esterases; D002268:Carboxypeptidases; D010450:Endopeptidases; D010447:Peptide Hydrolases; D000626:Aminopeptidases; D004150:Dipeptidases; C038937:dipeptidase