The analysis of fermentation process of 5 kinds of vegetables and the studies on the probiotic properties of lactic acid bacteria (LAB)

In this study, 5 kinds of vegetables (cucumber, beans, lettuce, sweet potato and green pepper) were made into pickles by the fermentation of lactic acid bacteria (LAB) and the total number of colonies, pH, total acid and reducing sugar were determined.Furthermore, LAB were isolated from 5 kinds of pickles and identified, and then the probiotic properties of LAB were studied.The results showed that, in the fermentation process, the total number of colonies in 5 kinds of vegetables increased at first and then decreased and pH continued to decline to a steady trend.The total acidity of fermentation finally reached more than 1.6%.The reducing sugar content of sweet potato pickle juice increased at first and then decreased, while that of other pickles juice was very low all along.17 strains of LAB were isolated from 5 vegetables, including 14 Lactobacillus plantarum, 1 Lactococcus lactis subsp.cremoris (O- E1) ;2 Weissella cibaria (O- M7 and O- M11) .Wherein, Lactobacillus plantarum and Lactococcus lactis subsp.cremoris had better acid tolerance, and O-S44, O-S49, W-11 had better ability to lower cholesterol.The cholesterol removal rates of O- S44, O- S49, W- 11 were 30.9%, 19.88% and 8.24%, respectivly.There was no GABA production of all strains.