| Kombucha is a symbiotic mix of acetic acid bacteria,a small amount of lactic acid bacteria,and different yeasts,known as Scoby,whose fermentation broth has detoxifying and refreshing properties.This research USES the medicine food homology of lycium barbarum and jujube kernel benevolence as the substrate SCOBY as preparation of lycium barbarum fermented liquid fermentation strains,fermented liquid of jujube kernel and lycium barbarum(mixed)fermented liquid of jujube kernel,explore the fermentation process of fermented product of antioxidants,antioxidant activity,antibacterial activity,characteristics of biological active substances and the changes of flavor,the main conclusions are as follows:(1)Compare the lycium barbarum fermentation prepared by conventional fermentation,fermentation after ethanol reflux extraction,and ultrasonic extraction after fermentation,the changes of physical and chemical indicators(p H,total acid,total sugar)and antioxidant components(total phenols,total Flavonoids)of lycium barbarum fermentation was measured during the fermentation to determine the best fermentation method for plant raw materials first ultrasonic extraction and then fermentation,and through single factor experiments to optimize the ultrasonic time,ultrasonic power,material-to-liquid ratio in the ultrasonic extraction process,thereby determining the best preparation technology of the lycium barbarum fermentation,jujube kernel fermentation and mixed fermentation.(2)On the basis of the above experiments,three fermentation broths and three infusions were prepared to explore the changes of antioxidant components,antioxidant activities,and enzyme activities,and further analyze the antioxidant influence of simulated in vitro gastrointestinal digestion treatment on the three fermentation broths.The results of the study showed that the total phenol content in the fermentation broth of the lycium barbarum,in the fermentation broth of jujube kernel,in the fermentation broth of mixed was 1.71 g/L,1.19 g/L,and 2.07 g/L,respectively,which increased by 36.61%,14.59% and 18.90% compared with the initial fermentation broth,respectively.the total flavonoid content in the fermentation broth of the lycium barbarum,in the fermentation broth of jujube kernel,in the fermentation broth of mixed was 0.48 g/L?0.56 g/L?0.85 g/L,DPPH free radical scavenging rates were 78.97%,81.65% and 82.34%,respectively,the reducing power increased by 16.98%,8.36% and 22.34%,respectively,compared with the initial reduction power,the content of antioxidant components and antioxidant activity of the three fermentation broth were higher than that of the infusion.The activity of SOD enzyme and cellulase in the three fermentation broths were positively correlated with the fermentation time,after the fermentation,the SOD enzyme activity in the fermentation broth of Lycium barbarum was the highest,which was 30.54 U/m L,the cellulase activity of the mixed fermentation broth was the highest,which was 18.26 U/m L.After simulated gastric juice digestion and simulated intestinal juice digestion,the changes of total phenol,total flavonoids,DPPH free radical scavenging rate and reducing power were determined,which indicated that the antioxidant properties of the three fermentation juices were increased and decreased.(3)The antibacterial activity of Lycium barbarum fermentation,jujube kernel fermentation and mixed fermentation against Escherichia coli and Staphylococcus aureus at different fermentation times and the antibacterial components of the fermentations were investigated by plate agar diffusion method.Research shows that Lycium barbarum fermentation,mixed fermentation antibacterial activity of two kinds of pathogenic bacteria that increases as the fermentation time extended,the end of the fermentation of Lycium barbarum in Escherichia coli and Staphylococcus aureus determination by inhibition zone diameter of 20.1 mm and 22.3mm respectively,10 days of mixed fermentation in Escherichia coli and Staphylococcus aureus to determine the inhibition zone diameter of maximum diameter,14.6 mm and 19.0 mm respectively.The antimicrobial activity of Lycium barbarum fermentation was higher than that of the mixed fermentation,but the jujube kernel enzyme had no antimicrobial activity against the two tested strains.It was found that the antibacterial components of lycium barbarum and mixed fermentation were mainly organic acids and contained a small amount of temperaturesensitive antibacterial proteins through the experiments of p H stability,temperature stability and treatment stability of antibacterial activity.(4)The main characteristic active substance in the Lycium Barbarum and jujube kernel were studied to explore the relationship between LBP,total saponin and fermentation time,the experimental results show that through the chemical analysis and spectrum analysis of the chemical extraction of LBP for acidic protein,polysaccharide,pre-column derivatization HPLC analysis of polysaccharide was known before 6 kinds of LBP were found in 9 different kinds of monosaccharide and monosaccharide content,further determination of 6 kinds of antioxidant activity of polysaccharides extracted from lycium fermentation found LBP2 antioxidant activity than LBP1 and LBP3,extracted from mixed fermentation LBP5 antioxidant activity than LBP4 and LBP6,it means that microbial fermentation can modify the molecular composition and proportion of polysaccharides and thus affect the antioxidant activity of polysaccharides.The content of saponins in the mixed fermentation that were fermented for 10 days and soaked for10 days were 0.499 g/L and 0.481 g/L,respectively,and the content of saponin in the jujube kernel fermentation that were fermented for 10 days and soaked for 10 days were 0.366 g/L,0.323 g/L,respectively,the content of jujuboside A and jujuboside B in the mixed fermentation broth(infusion)is higher than that of the respective fermented jujube seed(infusion).(5)Human sensory evaluation,electronic tongue technology and headspace solid phase microextraction GC-MS technology were used to study the flavor of the three fermentations after fermentation.It was found that the total score of Lycium barbarum enzyme was the highest,followed by mixed enzyme and jujube kernel fermentation.The results of electronic tongue test showed that there were obvious differences in the acidity,bitterness,astringency and umami of the three fermentations,Lycium barbarum fermentation had the strongest acidity,jujube kernel fermentation had the strongest bitterness and astringency,and the mixed fermentation had the strongest umami taste.The aroma components of the three fermentations were analyzed by headspace solid phase microextraction GC-MS technology,and 31,29 and 37 aroma components were identified by lycium barbarum fermentation,jujube kernel fermentation and mixed fermentation,respectively,the contents of organic acids accounted for 53.37%,59.34%and 56.93% of the total aroma components,respectively,organic acids were the main aroma components of the fermentations. |
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