Development And Technology Research Of Jujube Lactic Acid Bacteria Beverages

Rich in active components,jujube is an excellent raw material for functional food.However,since jujube is difficult to store and too sweet to eat directly,the jujube industry is facing various problems,including the small volume and low added value.With the expansion of the functional food market,fruit lactobacillus fermented beverages have also become one of the most popular functional foods.To solve the problem of deep processing of jujube and improve its economic value,in this study,the jujube suitable for production was identified and the processing of raw materials was optimized,then a lactic acid bacteria（LAB）suitable for fermentation of jujube juice was selected.The optimum fermentation process of jujube lactic acid beverage was determined by optimizing the pure fermentation and co-culture fermentation.Finally,the jujube lactic acid bacteria fermented beverage was compared with the commercial products.The main findings of the paper are as follows:First of all,the physical and chemical indexes of jujube samples from different regions were analyzed.The content of water,sugar content,total polyphenols and total flavonoids were10.52%,722.52 mg·g^-1,1.56 mg·g^-1,26.24 mg·g^-1.Jujube juice had the highest juice yield（63.23%）under conditions of 100℃,for12 min with the ratio of 1:8,0.3%(w·w^-1)of pectinase addition,and the enzymatic reaction was conductrd at 50℃for 3 hours.Next,204 potential fermentation strains were screened from strains conserved in the laboratory and natural fermentation broth of fruits.After analyzing the growth characteristics,probiotic potential and the flavor substance in the fermented products,a strain of MY-12 with the features of probiotics and excellent fermentation flavor in jujube juice was obtained.It was identified as Lactiplantibacillus plantarum MY-12 by 16S r DNA sequencing.Then the fermentation process of jujube lactic acid beverage was optimized by single factor and Box-Behnken response surface method,and the optimum product type of jujube lactic acid beverage was obtained by using sensory score as response value.The results showed that the optimal fermentation conditions of MY-12 were 140 g·L^-1,with initial sugar content,7log CFU·m L^-1 with 48h fermentation time and 33℃fermentation temperature.On the basis of determining the optimum fermentation process of LAB,the growth characteristics of LAB and non-S.C and the aroma characteristics of their products were further studied.The results showed that the addition of non-S.C generally improved the aroma of jujube products,with MY-12/MY-00 co-culture fermented jujube beverages scoring highest in overall acceptance and corresponding validation in volatile compound analysis.The inoculation process of the two strains were further investigated,and the results showed that MY-00 and MY-12 were inoculated at the same time with 1000:1 as the optimal co-culture inoculation process.The co-culture fermented jujube beverage has less sugar and better taste than the commercial beverage.The co-culture beverage,a jujube processing product with great potential and competitiveness,with a harmonious taste and rich aroma.