Optimization Of Fermentation Conditions Of Goji Berry Juice By Lactobacillus Paracasei NXU-19004 And Its Improvement On Constipation In Mice

Ningxia goji berry(Lycium barbarum L.)is a characteristic plant resource in Ningxia.It is not only rich in a variety of active ingredients,but also has unique physiological functions that are beneficial to human health.The puree of goji berry produced by using goji berry alone as the raw material has a poor taste,which seriously affects the production and market development of goji berry beverages.In order to improve the utilization rate and sensory quality of goji berry,and to conduct an in-depth discussion on the efficacy of fermented goji berry juice,this study took Ningxia goji berry as the research object,and used pure culture to screen out lactic acid bacteria with potential probiotic functions from traditional fermented pulp.The influence of dominant lactic acid bacteria on the fermentation characteristics of goji berry juice and the quality of its products.On the basis of single factor experiment,the response surface optimization experiment was carried out to determine the best fermentation technology.At the same time,based on non-targeted metabonomics technology to explore the changes of differential metabolites in the fermentation broth,and use animal models to study the effect of probiotics fermented goji berry juice on mice with constipation.The main research contents and conclusions are as follows:1.Isolation and identification of lactic acid bacteria from slurry water and research on its probiotic characteristics:In this experiment,22 strains of lactic acid bacteria were isolated from the collected pulp water,and all of them were Lactobacillus.According to microscope observation,Gram staining and 16S rDNA sequence analysis,a total of 5 strains were identified,and the results were plants.Lactobacillus plantarum,Lactobacillus acidophilus,Lactobacillus paracasei,Lactobacillus brevis,and Lactobacillus pentosus.Among them,JS8-9 not only has strong growth and reproduction ability,and the number of viable bacteria is still higher than 106CFU/mL after treatment with pH 2.0 artificial gastric juice for 2 hours,and the survival rate is as high as 91.25±1.92%;after treatment with 0.9%bile salt,it survives The rate can still reach more than 45%.Therefore,JS8-9 was selected as the experimental strain for subsequent probiotic research and named Lactobacillus paracasei NXU-19004.2.Lactobacillus paracasei NXU-19004 fermented goji berry juice conditions optimization and nutrient composition analysis:The effect of different white sugar addition,inoculation amount and fermentation time on the quality of Lactobacillus paracasei NXU-19004 fermented goji berry juice was evaluated by lactic acid production and sensory quality.The optimal fermentation parameters were determined as follows:the amount of white sugar added 5%,the amount of lactic acid bacteria inoculated 4.5%,and the fermentation time 14h Under this condition,the sensory score reached 95±0.03,the number of viable lactic acid bacteria was 1.24×109 CFU/mL,the pH value was 3.6,the lactic acid content was(443.31±3.61)mg/100mL,and the total phenol content was(4.96±1.31)mg/mL,total sugar content(414.07±4.18)mg/100mL,DPPH free radical scavenging rate 80.15±2.05%,ABTS free radical scavenging rate 70.57±0.02%probiotic fermented goji berry product.3.Non-targeted metabonomics analysis of the quality of goji berry fermentation broth at different stages:non-targeted metabonomics technology based on GC-MS,4 of non-fermented,inoculated fermentation 0 h,inoculated fermentation 10 h,and inoculated fermentation 22 h 63 different metabolites were identified and analyzed from three kinds of goji berry fermentation broth.Among them,amino acids,organic acids,lipids and other components were generally up-regulated in the goji berry fermentation broth.In addition,47 metabolic pathways involving differential metabolites were retrieved,and 9 key pathways with more enriched metabolites and high significance were screened out,and 10 key metabolites were mapped.It was found that different fermentation stages can regulate the metabolism of amino acids in goji berry,and significantly affect the formation of special flavor substances in the fermented goji berry products.4.Study on the effect of Lactobacillus paracasei NXU-19004 fermented goji berry juice on improving constipation in mice:An animal model of constipation induced by loperamide was established,and the same dose of probiotic bacteria suspension,unfermented goji juice and probiotic fermented goji(turbid/supernatant)juice were respectively administered.Through the detection of constipation-related indicators,it was found that both probiotic bacterial suspension and probiotic fermented goji juice can increase the number of stools,fecal water content and small intestinal propulsion rate of constipated mice,and can reduce the damaged integrity of the ileal wall of constipated mice And the thinner muscle layer increases the number of goblet cells and mucin in colon tissue.At the same time,it also down-regulated the expression of aquaporin AQP3/4 and epithelial sodium channel ENaC-?/? at the mRNA level,decreased the secretion of pro-inflammatory factors IL-1?,TNF-?,and TLR4 in mice,and made tight junctions The expression of protein in the intestine is significantly increased.Both showed the potential to improve constipation,and it was found that the main effect on constipation was the synergistic effect of Lactobacillus paracasei NXU-19004 strain and goji.