The Study On Fermentation Characteristic In Soy Milk With Six Lactobacillus Plantarum

Six strains of potential probiotic characteristics which were L. plantarum IMAU10156, P8, IMAU40126 etc.were used as starter cultures , the fermentation characteristics of their soybean milk was determined by HPLC, microplate method, sensory evaluation etc, and L. plantarum P8 of good fermentation characteristics and flavor was screened out for fermentation of soybean milk. The results showed,Through the determination of viable counts, pH, viscosity, syneresis, titration acidity value and free amino nitrogen of soy milk fermented by six L. plantarum strains, viable counts were achieved as much as 108 CFU/mL and there was no significant difference of the viable counts of six fermented strains.The ACE inhibition rate , GABA content and activity ofα-Gludosidase of soy milk fermented by L. plantarum P8 were significantly higher than other five strains (p<0.05) . At the end of storage, the content of raffinose, stachyose and sucrose were reduced by 41.9%, 46.3% and 17.35%, suggesting the favorable saccharide utilization of L. plantarum P8. Meanwhile, the content of lactic acid was ten times as high as unfermented soy milk and the content of acetic acid was 2.61 g/L which significantly higher than other five strains(p<0.05).The concentration of Vitamin B1 in soy milk fermented by L. plantarum IMAU10156 was 112.25mg/L which was higher than other strians(p<0.05) and the concentration of Vitamin B2 and Vitamin B6 in soy milk fermented by L. plantarum IMAU60042 was higher than other strians (p<0.05) .The activity ofα-Gludosidase of soy milk fermented by L. plantarum P8 for 6h was 146.47 U/ml which was higher than other strians(p<0.05). At the end of storage, the content of daidzin, genistin and glycitin were reduced by 55.2%, 47.5% and 47.43%. Meanwhile, the content of daidzein, genistein and glycitein was 6.48, 10.72 and 6.21 times as high as unfermented soy milk.Soy milk fermented by L. plantarum P8 was of favorable soy flavor, moderate sweet, smooth surface, no whey separation, no adverse flavor, great quality, better stablility of storage, higher scores of smell and taste than other five strains products. Above all, L. plantarum P8 is a better ideal strain for fermentation of soy milk by synthetic evaluation of the fermentation characteristics plus with sensory.