Abstract:Fermented kiwifruit extract is rich in vitamins, enzymes, minerals, secondary metabolites and other nutrients, which belongs to the new type of food with potential health effects. In this study, 6 kinds of lactic acid bacteria and 2 kinds of yeast were inoculated into kiwifruit juice for fermentation to detect the changes of ingredients in the process of probiotic fermentation of fruit juice. The bioactive substances in the fermentation process of each group were detected and analyzed by using spectroscopy and chromatography technology. The results showed that the lactic acid bacteria and yeast strains in the experiment played an important role in the microbial counts, physicochemical properties, and biological activity of the fermented kiwifruit extract. The microbial counts, of lactic acid bacteria and yeast bacteria reached the peak value on the 5th day, which ranged (7.89-9.30) lg(CFU/mL) and (7.05-8.18) lg(CFU/mL), respectively. The number of Bacillus rhamnosus LG0262 reached 9.30 lg(CFU/mL). After fermentation, the acidity of the lactic acid bacteria fermentation group was higher than that of the yeast fermentation group. The pH of the lactic acid bacteria fermentation group is between 3.25-3.45, and that of the yeast fermentation group was between 3.51-3.70. The soluble solid content and ethanol concentration ranged (10.3-30.6)。Brix and (13.549-50.82) mg/mL, respectively and there was a positive correlation between the two indicators (R2 = 0.963, P<0.01). The types and concentrations of GABA, polysaccharides and organic acids increased fermentation. At the 60th day of fermentation, the polysaccharide content in the fermented kiwifruit extract prepared by Lactobacillus helveticus LG4316, Lactococcus lactis LG0827, and Lactiplantibacillus plantarum LG1034 reached 0.30%, 0.30%, and 0.29%, respectively. The concentration of lactate, tartaric acid and succinic acid in the fermented kiwifruit extract prepared by Lactiplantibacillus plantarum LG1034, Bacillus rhamnosus LG0262, and Saccharomyces cerevisiae J2861 was the highest, reaching 2 482.03, 1 842.18 μg/mL and 168.78 μg/mL, respectively.