Study On Characteristics Of Lactobacillus Being Of Antifungal Activity And Their Application In Yogurt

Three lactobacillis being of antibacterial activity were isolated from traditional grain fermentation food Acid-Gruel in Inner Mongolia. The biological characteristics and application in yogurt as biological preservative were studied too. The results were showed as follows:(1) The strains entered basically a period of stability after20hours at37℃, and the growth activity of the SLA-C was the best. Although SLA-C grew more slowly, and the growth cycle was longer, the acid productivity was the highest;3Lactobacillus can grow when salt concentration was less than6%, and grow best when the salt concentration was2%. The growth of strains inhibited when the salt concentration was more than8%; The optimal initial pH of culture medium is6-7, and strains can not grow in the medium of pH less than4.(2) Through the research of different strains proportion, the inoculation quantity, culture temperature and sugar amount, the fermentation condition of yoghurt production using the antifungal Lactobacillus was optimized. The result showed:for SLA-B, the optimum mixed proportion of strains was1:4:4, inoculation quantity was3%,culturing temperature was42℃, sugar amount was6%; For SLA-C, the optimum mixed proportion of strains was1:4:4, inoculation quantity was5%,culturing temperature was42"C, sugar amount was8%; For SLA-NB, the optimum mixed proportion of strains was1:4:2, inoculation quantity was3%,culturing temperature was42℃, sugar amount was6%.(3) The antimold effect of the special yogurt produced by adding antifungal strains was compared with the traditional yogurt. The inhibition effects of mold contamination of SLA-B, SLA-C and SLA-NB were notable, and the inhibitory effect can be arraged from strong to weak:SLA-B>SLA-NB> SLA-C.