Study On Optimization Fermentation Conditions Of Probiotics In Jujube Fruit Pulps And Its Protective Effect On Acute Liver Injury In Mice

Red dates(Zizyphus jujuba Mill.),plants of the genus Rhamnus,are widely planted in Ningxia.Jujube fruits are rich in polysaccharides,amino acids,flavonoids and other active substances.They have extremely high nutritional health value and medicinal value,and are included Medicine and food homology directory.At present,Ningxia red jujube products are mainly fresh food and dry jujube,with a single product,low processing conversion rate,and low added value.The research and development of red date deep-processed products and functional products are of great significance for enriching the market of red date products and improving the economic benefits of red dates.In this study,Ningxia jujube was used as the raw material to discuss the fermentation characteristics of three commonly used lactic acid bacteria in jujube pulp and its effect on product quality.Screening was carried out to obtain the most suitable lactic acid bacteria strain for jujube pulp fermentation;the response surface method was used to ferment jujube pulp Process optimization to obtain the optimal fermentation parameters of jujube pulp;through animal experiments,the protective effects of fermented jujube pulp under the optimal conditions on acute alcoholic liver injury in mice were studied to provide the development of functional jujube pulp fermentation products Theoretical guidance.The main findings are as follows:1.Screening of the most suitable lactic acid bacteria for red jujube pulp fermentation and research on its fermentation characteristics.Taking Ningxia jujube as the research object,the fermentation performance of Lactobacillus plantarum TK9,Lactobacillus paracasei TK1501 and Pediococcus lactis TK530 in jujube pulp was compared,and the number of live lactic acid bacteria,pH value,polyphenols,DPPH and Changes in sensory indicators.The results show that the fermentation cycle of Lactobacillus plantarum TK9 is the shortest;Lactobacillus plantarum TK9 has a strong fermentation capacity in jujube pulp,and the number of viable bacteria reaches above 8.41 logCFU/mL,pH 4.15,polyphenol content 1.59 mg/mL,DPPH58.34%and sensory index total score is 86.45±0.32a;it can be seen that the number of viable bacteria of Lactobacillus paracasei TK1501 and Pediococcus lactis TK530 reached 8.12 and 8.28 logCFU/mL,pH value 4.18 and 4.33,polyphenol content 1.42mg/mL,DPPH56.21%and 51.48%;the total sensory indicators were 79.10±0.63 and 68.23±1.13b.According to the comprehensive evaluation of the fermentation capacity,antioxidant activity and sensory evaluation of the strain fermentation,Lactobacillus plantarum TK9 can be used as the most suitable strain for jujube pulp fermentation.2.Optimization of technological conditions and product index analysis of Lactobacillus plantarum TK9 fermented jujube pulp.Using single factor and response surface analysis,using viable cell count and sensory score as evaluation indicators,the fermentation process temperature,fermentation time and inoculation volume were used to optimize the quality of Lactobacillus plantarum TK9 fermented jujube pulp,and the best process conditions were:The fermentation temperature was 37?,the fermentation time was 18h,and the inoculation amount was 6%.Under this fermentation condition,the number of live bacteria in the fermented jujube pulp was 8.6 logCFU/mL,and the sensory score was 95.1 points.Product index analysis shows that the content of polyphenols and flavonoids before and after fermentation were significantly reduced by 1.33±0.01,1.14±0.04mg/mL;the content of polysaccharide was significantly reduced by 16.48mg/100mL;total acid content,DPPH free radical scavenging rate and iron The ion reduction capacity increased significantly;16.85mg/mL,80.23%,9.166.48mg/100mL;malic acid decreased significantly after fermentation compared to before fermentation,which was 0.87mg/L;the content of tartaric acid increased significantly before fermentation,which was 0.078 mg/L;the citric acid content did not change much before and after fermentation;the lactic acid content increased significantly.3.Study on the protective effect of red date syrup fermented by Lactobacillus plantarum TK9 on acute alcoholic liver injury in mice.The red jujube pulp fermented with Lactobacillus plantarum TK9 was used for mouse experiments.The results showed that compared with mice in the normal group,the levels of ALT,AST,TG,TC and ADH in the blood of the model group increased by 41.52%,35.93%,51.34%,48.57%and 17.82%,respectively.The SOD activity and GSH-Px content in mouse liver decreased by 54.63%and 88.87%,and the MDA content in mouse liver tissue increased by 53.20%.Fermented jujube juice can reduce the blood levels of ALT,AST,TG,TC and ADH in mice with acute alcoholic liver injury,enhance the SOD activity and GSH-Px content in the liver of mice,and reduce the content of MDA oxides in the liver of mice.Observation of the pathological section of the liver of mice showed that the hepatocytes of the normal group had normal morphology,and the liver cells of the model group were arranged disorderly and had individual punctate necrosis.Fermented jujube juice can effectively inhibit the swelling and deformation of liver cells and maintain the normal morphology of cells,indicating that fermented jujube juice can effectively alleviate acute alcoholic liver injury in mice.