Study On Solid-State Fermentation Of Jujube Probiotic Powder By Lactic Acid Bacteria

Fermentation of lactic acid bacteria can improve the nutritional composition and taste of raw materials,and increase the digestibility of food.At the same time,a large number of active lactic acid bacteria can perform many physiological functions after entering the animal body with food,such as promoting animal growth,maintaining intestinal microecological balance,and reducing serum cholesterol And inhibit the growth of spoilage bacteria in the intestinal tract.Lactic acid bacteria are mostly used in liquid fermentation.In recent years,studies have shown that solid-state fermentation can increase the number of viable lactic acid bacteria,and solid-state fermentation has the characteristics of environmental friendliness,low raw material costs,and the generation of secondary metabolites.It was used in biological manufacturing and food industries.Receive more and more attention.Solid-state fermentation with lactic acid bacteria can reduce the loss of active ingredients in raw materials,and at the same time,by increasing the content of active lactic acid bacteria,the product's ability to regulate intestinal flora is enhanced.In this experiment,four kinds of lactic acid bacteria were selected through pre-selection to further screen out lactic acid bacteria suitable for solid-state fermentation of red dates.Then red dates were used as the main material,soy flour and wheat bran were added,and the substrate formula and fermentation process were optimized through single factor and response surface experiments.The number of viable bacteria is further increased,and a red jujube solid probiotic powder with a high content of viable bacteria is prepared.The stability and quality indicators of the prepared product were tested,and a comprehensive sensory evaluation was performed.Finally,in vivo and in vitro experiments were conducted to compare the effects of solid-state fermentation of Lactobacillus paracasei on the antioxidant properties,antibacterial properties and intestinal flora regulation of raw materials.The main findings are as follows:(1)Four lactic acid bacteria,Streptococcus thermophiles,Lactobacillus plantarum,Pediococcus acidilactici and Lactobacillus paracasei,were used to ferment red dates.The results showed that Lactobacillus paracasei was fermented.It has the shortest logarithmic growth period and the largest viable cell count,which is suitable for solid-state fermentation of red dates.(2)Optimize the substrate formula and fermentation process through single factor and response surface experiments to improve product taste and viable cell count content.The final solid-state fermentation process for red dates is:24%soybean flour addition,9%wheat bran addition,material-to-water ratio 1:0.9,inoculation amount 10%(v/m),fermentation time 24 h,fermentation temperature 37?,-50? freeze drying 24 h.The highest viable cell count under this process condition is 7.21×108 CFU/g,which has a good stability of viable cell count.The contents of crude polysaccharides,organic acids,y-aminobutyric acid(GABA),free amino acids and other substances in the fermented product are increased,and various quality indicators and microbial safety indicators can meet the standard requirements.The comprehensive sensory evaluation of the product is 7.3 points,and the coordination of taste and aroma is high.(3)In vitro anti-oxidation,antibacterial and intestinal flora similarity testing experiments were carried out on the fermented product.The results showed that the anti-oxidation and antibacterial ability was significantly improved compared with that before fermentation.Comparing the regulation of the intestinal flora diversity of experimental mice by samples before and after fermentation,the results show that red jujube probiotic powder can make the mice's daily activities and food intake recover faster.The cecal index and fecal water content are 6.38 mg/g,respectively.37.48%are close to normal mice,and the intestinal flora diversity phylum level,genus level and PCA analysis results are the closest to normal mice.In summary,the jujube probiotic powder prepared by solid-state fermentation of red dates by Lactobacillus paracasei contains a large number of live bacteria,increases the production of some active substances,and enhances the product's antibacterial,anti-oxidant and intestinal flora regulation capabilities;It is a good-tasting intestinal probiotic product.