Isolation And Screening Of Lactic Acid Bacteria From Pickle And The Immunoregulatory Effect Of Goji Berry Juice Fermented On Mice

Lycium barbarum L.can be used as daily food and medicine.Lycium barbarum L.is rich in nutrients,including polysaccharides,peptides,alkaloids,flavonoids,terpenes,organic acids,lignans,phenolic amides,carotenoids and other compounds,which have different pharmacological activities and health care effects.It can not only nourish the liver and kidney,clear the liver and clear the eyes,tonify the blood and tranquilize the nerves,prolong life and benefit the essence,but also prevent and treat influenza by blocking influenza virus surface protein and stimulating the body's immune system.Lycium barbarum protein,fat,sugar and a variety of amino acids,carotene,a large number of vitamins,trace elements can improve the body's blood circulation,improve the body's antioxidant capacity,enhance human immunity.The experiment was conducted by the fermentation experiment of lactic acid bacteria isolated and screened in natural fermented pickles of Ningxia,and the best fermentation strain was obtained according to the changes of active components and antioxidant activity experiments.The fermentation technology was optimized by single factor and response surface method.SPME-GC-MS was used to analyze and compare the changes of volatile components in the fermentation process of Goji berry juice;and the dynamic method was used to analyze and compare the volatile components in the fermentation process of Lycium barbarum juice The improvement of mice immunity was studied by the physical model.The main research contents and conclusions are as follows:1.Isolation,screening and resistance test of Lactobacillus:five fermented pickles collected from Yinchuan City,Ningxia Province were selected as the source of isolation.Through morphological observation,physiological and biochemical tests and molecular biological identification,five strains with high acid yield were screened,and one strain was identified as Lactobacillus plantarum,which was named as Lactobacillus plantarum NXU?19010,one strain was Lactobacillus rhamnosus,which was identified as Lactobacillus rhamnosus NXU?19023,one strain was Lactobacillus pentosus,which was named as Lactobacillus pentosus NXU?19006,one strain was Lactobacillus helveticus,which was named as Lactobacillus helveticus NXU?19022,one strain was Lactobacillus paracasei,which was designated as Lactobacillus paracasei NXU?19004.The isolated lactic acid bacteria were tested for acid resistance,bile salt resistance and fermentation performance,and the lactic acid bacteria with excellent performance were selected.Finally,the optimal strain was used as the starter to ferment wolfberry juice.The results showed that the strain of Lactobacillus helveticus NXU?19022 has good acid resistance,bile salt resistance and growth performance.Inoculation of Lactobacillus helveticus NXU?19022 The results showed that the content of polysaccharides and polyphenols in fermented Goji berry juice was greatly affected,and the free radical scavenging rate and flavor quality of fermented Goji berry juice were significantly improved.2.Determination and optimization of fermentation conditions of lactic acid bacteria:the effects of different sugar content,inoculation amount and fermentation time on the quality of fermented Goji berry juice were evaluated by lactic acid yield and sensory quality.The optimal fermentation conditions were determined as follows:4%sugar,4.5%inoculated bacteria and 12h fermentation time.Under these conditions,the lactic acid yield and taste of fermented Goji berry juice were the best.Under the optimal conditions,the polysaccharide content,polyphenol content and lactic acid yield of fermented Goji berry juice changed significantly.Polysaccharide increased by 29%and polyphenol decreased by 90.96%.3.The volatile components of the fermented Groji berry juice were analyzed and compared with that of the fermented Goji berry juice at different time periods.The results showed that the components of the fermented Goji berry juice were significantly changed in different time periods.4.The study on the effect of Lactobacillus fermented Goji berry juice on mice immunity:the control ability of the fermented Goji berry juice and unfermented Goji berry juice can be improved by reducing the weight loss induced by CTX,improving the activity state of mice,improving the proliferation function of spleen lymphocytes,improving organ index and improving spleen state.The fermented juice has excellent regulatory ability on mice with low immunity It is showed that the fermented juice has the potential to improve the immunity of mice.