Investigation on the nutrient and quality features of jujube juice fermented by selected Lactobacillus acidophilus 6074

The primary objective of this study was to investigate the effect of fermentation with Lactobacillus acidophilus 6074 on the nutrient transformation and quality characteristics of jujube juice. The screened L. acidophilus 6074 with acid and bile salt resistance was used to ferment jujube juice, and the sensory properties and nutrient biotransformation of the fermented product were comprehensively evaluated. The results showed that the acid and bile salt resistance of L. acidophilus 6074 were 94.06 % and 84.56 %, respectively, and the viable counts after fermentation reached 8.75 lg CFU/mL. Total sugar and polysaccharide content decreased after fermentation, while total flavonoids, cAMP and triterpenoic acid increased significantly, as did organic acids and free amino acids (p < 0.05). Moreover, the L. acidophilus 6074 fermentation reduced the molecular weight of the main polysaccharide component from 746,111.957 Da to 573,809.851 Da, and its microstructure changed. A total of 62 volatile compounds were identified in fermented jujube juice, among which acids were the highest, followed by esters. Particularly, L. acidophilus 6074 fermentation increased the content of phenylethyl acetate and lactic acid, generating new substances clopenthixol and phenylethyl alcohol of jujube juice. Sensory evaluation indicated that L. acidophilus 6074 fermentation improved the coloration of jujube juice and increased the overall acceptability of the fermented product. This study will provide theoretical basis and technical support for the industrial production of probiotic fermentation jujube juice related products.