TITLE:
Autolytic and Proteolytic Properties of Strains of Lactococcus lactis Isolated from Different Vegetables, Raw-Milk Cheeses and Commercial Starter Cultures
AUTHORS:
Carolina Nájera-Domínguez, Nestor Gutiérrez-Méndez
KEYWORDS:
Com Autolysis; Proteolysis; L. lactis; Wild-Strains
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.4 No.11A,
November
1,
2013
ABSTRACT: The autolysis and proteolysis are
important features in the strains of L. lactis used in the manufacture of cheese. The autolytic and proteolytic activity of L. lactis has been linked with the
development of flavor and texture in the cheese. On the other hand, there is a
growing interest in new strains isolated from raw-milk cheeses and vegetables.
These wild-strains have showed different features of industrial importance in
comparison with those observed in commercial cultures. However, it still not
clear if the autolytic and proteolytic properties of these wild-strains differ
from the industrial
strains. The objective of this work was to assess the autolytic and proteolytic
activities of 21 strains of L. lactis isolated from
diverse sources. The rates of autolysis and proteolysis observed in vitro were
highly strain-dependent. The pH and the NaCl concentration in the media
affected significantly the autolysis of L.
lactis. The strains isolated from vegetable showed in general low and
medium autolytic activity, whereas the strains isolated from raw-milk cheeses
had medium to high autolytic activity. The strain with highest proteolytic
activity was a strain isolated from corn leaves. Although still not clear how
this strain acquired this pronounced characteristic.