Research On Optimization Of Fermentation Conditions And Antioxidant Properties Of Biological Selenium Jiaosu

In recent years,edible Jiaosu products have been praised highly because of many kinds of health care functions.The fermentation materials are mostly fruit,grain and so on.Because of the high pH value of the vegetable itself,the fermentation process is easily contaminated by the mixed bacteria,so there are few vegetable Jiaosu in the market now.At the same time,due to the late development of edible Jiaosu,so far,there is no perfect and strict production regulation,and the market is chaotic.Therefore,this experiment mainly focuses on the production process of Jiaosu and selects the common agricultural product cucumber and tomato as the raw material to ferment the edible Jiaosu,adding the Saccharomyces cerevisiae,Acetobacter aceti and Lactobacillus plantarum as the fermentation strain,adding yeast selenium as the additional function material,and obtaining the Biological Selenium Vegetable Jiaosu product through the process optimization test.Its main physicochemical indexes and antioxidant properties in vitro were determined,providing a theoretical basis for the standardization of edible Jiaosu market and production.In addition,this experiment also includes the optimization of the production process conditions of the Tea Jiaosu.The main contents and results of this experiment are as follows:（1）We use Saccharomyces cerevisiae,Acetobacter aceti and Lactobacillus plantarum 1:1:1 as the mixed strain of the fermented,pH value and ethanol concentration as the detection indicators.We did the optimization through single factor and orthogonal test,and the result showed that the Tea Jiaosu production process was:8 g/L black tea,100 g/L white sugar,20 mL/L inoculum,and 7 days fermentation at 30°C.（2）The number of bacteria in the symbiotic system of mixed strains was（2.6±0.12）×10⁷ CFU/mL.We used fermentation pH、sensory scores and Polyphenol content as testing indicators.We did the optimizeation through single factor and orthogonal experiments,and the result showed that production process of Biological Selenium Vegetable Jiaosu was:200 g/L cucumber and tomato with the ratio 7:3,30 mL/L inoculum,150 g/L white sugar,1.5 mL/L Yeast selenium liquid,and 14 days fermentation at 30°C.The pH value of the product was 2.31±0.012,the ethanol concentration was0.42%,the total content of acid was 0.0135±0.0013 g/mL,the total content of phenol was 0.233±0.007 mg/mL,the protein content was 0.0157±0.00012mg/mL,the residual sugar content was 11.54±0.035 mg/mL,the content of soluble dietary fiber was 3.24±0.04 mg/mL,and the organic selenium accounted for 79.32%of the total selenium.（3）The antioxidant activity of Biological Selenium Vegetable Jiaosu and common Jiaosu in different fermentation time was measured,and Vitamin C was used as positive control.The total reducing power of 50μg/mL 85-day fermented Biological Selenium Vegetable Jiaosu was 0.1325(A_{700 nm}),the·OH removal ability was 49.27%,the DPPH radical scavenging capacity was 30.95%,and the ABTS radical scavenging capacity was 91.35%.The·O₂^-scavenging capacity was 56.986%and the hydrogen peroxide scavenging capacity was 67.5%.Among the 6 selected indexes,the ABTS free radical scavenging ability of Biological Selenium Vegetable Jiaosu and common Jiaosu was basically equal to that of Vc,and the scavenging ability of hydrogen peroxide was slightly stronger than that of Vc,and the other indexes were lower than Vc,the antioxidation in vitro of Biological Selenium Vegetable Jiaosu is better than that of ordinary Jiaosu.The antioxidative ability of the Biological Selenium Vegetable Jiaosu in different fermentation time was different.In addition to some antioxidant indexes,most indexes,such as total reducing power,ABTS free radical scavenging ability and·O₂^-scavenging ability,showed that the antioxidant capacity in vitro increased with the increase of fermentation time.