Quality Changes of Litchi Juice after Fermentation and the Stability during Low-temperature Storage

In this study,litchi juice was fermented at 30 ℃ by probiotics of Lactobacillus casei,Lactobacillus bulgaricus and Leuconstoc mesenteroides,and the changes of microbial count and quality of fermented litchi juice during storage at 4 ℃ were also investigated. Results showed that the three lactic acid bacteria grew rapidly in litchi juice,and received the highest number(above 9.0 log) after fermented 12 h. The three lactic acid bacteria showed obvious difference in utilizing sugar and organic acid of litchi juice,where Lactobacillus casei and Lactobacillus bulgaricus produced as much as 37.5 g/L exopolysaccharides. Moreover,after 12 h fermentation,the polyphenol and Vc contents appeared no significant change(p0.05). But L* values were significantly decrease(p0.05),and the color became more pale in all fermented litchi juice. During storage of 28 d at 4 ℃,no further fermentation was found in all fermented litchi juice,but the number of Leuconostoc mesenteroides dropped to less than 7 log,whereas Lactobacillus casei and Lactobacillus bulgaricus only decreased 0.5 log.