Optimization of fermentation process and antioxidant activity of ginger Jiaosu

In this study, using turmeric as raw material, the ginger Jiaosu was prepared by lactic acid bacteria and yeast mixed fermentation. The inoculation time sequence, fermentation temperature, sugar content and fermentation time were taken as independent variables, and the activity of superoxide dismutase (SOD) was taken as the evaluation index, the fermentation process of ginger Jiaosu was optimized by single factor tests and Box- Behnken response surface tests. Under the optimal fermentation process conditions, the antioxidant capacity of ginger Jiaosu was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide anion radical scavenging tests. The Pearson correlation analysis was analyzed by the results. The results shown that the optimal fermentation process of ginger Jiaosu were obtained as follows: 0.15% lactic acid bacteria was added first, and 0.15% yeast was added 24 h later, sugar addition 20%, fermentation temperature 29.5 ℃ and fermentation time 86 h. Under these optimal conditions, the activity of SOD was 75.33 U/ml and the total phenol content was 0.073 mg/g. The scavenging rates of DPPH and superoxide anion free radical of ginger Jiaosu were 90.64% and 18.69%, respectively, indicating that ginger Jiaosu had certain antioxidant activity. Pearson correlation analysis revealed that total phenol content was significantly positively correlated with DPPH free radical scavenging rates, superoxide anion radical scavenging rates and SOD enzyme activity (P<0.01).