Optimized the Process of Enzymes Coupled with Lactobacillus plantarum and Saccharomyces cerevisiae to Ferment Ginkgo Seeds by Response Surface Methodology

This study aimed to optimize the process of enzymes coupled with Lactobacillus plantarum and Saccharomyces cerevisiae to ferment ginkgo seeds by response surface methodology,in order to obtain a kind of ginkgo fermentation powder with high antioxidant activity. The effects of solid-liquid ratio,total amount of compound enzyme,mass ratio of glucoamylase and α-amylase,enzymolysis time,total amount of mixed fermentation agent,mass ratio of Lactobacillus plantarum and Saccharomyces cerevisiae,fermentation time on soluble protein content and DPPH radical scavenging capacity of ginkgo fermentation powder(GFP)were studied by single factor experiment,and based on the DPPH radical scavenging capacity,response surface analysis was used to optimize the process conditions of Lactobacillus plantarum and Saccharomyces cerevisiae coupled with enzymes to ferment ginkgo seeds. The results showed that on the basis of adding 0.3 g/100 g of compound enzyme,enzymolysis 2 h and fermentation 12 h,the best technology of cooperation of bacteria and enzyme fermentation was as follows:1:6 of solid-liquid ratio,2:1 of glucoamylase and α amylase,3.12 g/100 g of mixed fermentation agent,1:1 of Lactobacillus plantarum and Saccharomyces cerevisiae,the DPPH radical scavenging capacity was 69.7%±1.1%,which was basically consistent with the model prediction. Compared with the untreated ginkgo powder(G),the DPPH free radical scavenging rate of Ginkgo fermentation powder(GFP)increased by 257.4%,the soluble protein content was 4.47±0.13 g/100 g,increased by 330%,the flavone content was 0.15±0.01 mg/g,increased by 50%,the polyphenol content was 2.49±0.04 mg/g,increased by 118%,the ginkgolic acid content was 2.96±0.32 μg/g,the removal rate was 85.4%. It showed that enzymes coupled with Lactobacillus plantarum and Saccharomyces cerevisiae fermentation could significantly improve the antioxidant activity of ginkgo seeds,and the contents of antioxidant components as soluble protein,flavonoids and polyphenols in the GFP were significantly increased,and the contents of toxic components ginkgolic acid was significantly decreased,which provided the material basis for the deep processing of ginkgo seeds.