Modeling of lactic acid fermentation of soy formulation with Lactobacillus plantarum HM1.

Lactic acid bacteria alone or with special adjunct probiotic strains are inevitable for the preparation of various specific functional foods. Moreover, because of their growth and metabolism, the final products are preserved for a certain time. Thus, growth dynamics of the lactic acid bacteria of the Fresco DVS 1010 culture ( Lactococcus lactis spp. lactis, Lactococcus lactis spp. cremoris, Streptococcus salivarius spp. thermophilus) during liquid-state fermentation of soya mashes and pH values within the process were analyzed in this study. Although milk is the most typical growth medium for the lactic acid bacteria, presumable viable counts of Fresco culture reached levels 109  CFU ml-1 after 8 h, representing 2-3 log increase in comparison to initial state (specific growth rates ranged from 1.06 to 1.64 h-1 ). After 21 days of storage period, the pH levels in the products were reduced to 4.50-4.70, representing a decrease of about 1.5-1.7 units. All prepared soybean products contained detectable amounts of raffinose-series oligosaccharides (0.25-0.68 g per 100 g) that were reduced in average by about 30.5% during period of 21 days.