Technology Optimization of Grape-Begonia Jiaosu and Its Antimicrobial and Antioxidant in Vitro

Grape and Begonia crabapple were used as main raw materials and fermentation parameters of inoculum quantity,temperature,initial pH,mass ratio and fermentation time were optimized by single factors combined orthogonal experiment in order to make a fermented beverage with short fermented cycle,low cost and safety. The effects on yeast biomass and superoxide dismutase activity were also studied. The optimum fermentation conditions were determined as follows:Yeast fermentation of grape begonia was conducted for 24 h at 25 ℃ with an mass ratio of 5:1 and an inoculum size of 0.20% at an initial pH of 3.8,and then the fermented mash was adjusted to inoculated with Lactobacillus at an inoculum size of 0.50% for further fermentation for 28 h at 37 ℃. The concentration of yeast in the Fermented grape begonia was 7.7×10⁸ CFU/mL,lactic acid bacteria was 5.2×10⁸ CFU/mL,and the activity of SOD was 485.25 U/mL. Concentration and vacuum freeze drying of the final product gave a powder with an aroma and good quality. The probiotic fermentation had certain antioxidant properties and antibacterial effects,when the enzyme concentration was 320 mg/mL,the diameters of the inhibitory circles for Staphylococcus aureus,Escherichia coli and Candida albicans were(16.1±0.44),(13.8±0.42),(13.2±0.38) mm,respectively. When the enzyme concentration was 200 mg/mL,the clearance rates of DPPH·,ABTS⁺· and hydroxyl radical were 85.22%,67.71% and 72.08%,respectively.