Sugar addition affects the final product of L. paracasei subsp. paracasei CRL 207 on soy solid state fermentation

RODRIGUEZ DE OLMOS, A.; LEBLANC, J.G.; GARRO, M.

Egmond aan Zee

Simposio; 11th International Symposium on Lactic Acid Bacteria; 2014

Soy is a great substrate for its high nutritional value and low cost. In previous studies the behavior of Lactobacillus (L.) paracasei subsp. paracasei CRL 207 on soy solid state fermentation (SSF) with different moisture content, temperatures and inoculums sizes was analyzed. These results demonstrated that this strain is able to develop on proposed SSF and the optimized conditions were 65% moisture, 37ºC and 2% of inoculum. The aim of this study was to analyze the addition of sugars (glucose or sucrose) on the β-glucosidase and proteolytic activities of this strain on soy SSF previously optimized. Pastes were made from commercial soy flour and distillated water, sugar was added at 2%; then were sterilized and inoculated. These were incubated at 37ºC for 24 and 72 h. The pH reached at 4,65 in presence of glucose but was practically maintained respect to the control with sucrose and without sugars at 24 h, in these both conditions the acidification increased at 72h. On the other hand, the β-glucosidase activity was evidenced in all tested conditions at 24 and 72h. It was higher in presence of sucrose at 24 h. Besides, an increase of amino acids amount was found. The addition of glucose enhanced the amount of free aminoacids at 24h. The proteolytic activity of this strain was evidenced with SDS-PAGE. We can conclude that for this strain the addition of sugar in the soy substrate affects their metabolism and it is important to lead the fermentation to a high β-glucosidase activity or proteolytic activity.