Technic Optimization And Antioxidant Characterization Of Compound Strain Fermented Grape-Rose Beverage

Vitis vinifera and Rosa rugosa were selected as raw materials in this study.The raw materials were fermented by the compound strains Geotrichum candidum and Lactobacillus plantarum.The natural plant chemical composition of raw materials and the unique metabolic products produced by the compound strains were utilized to improve the sensory and antioxidant capacity,furthermore,enhance the utilization rate of raw materials.(1)Fermentation strains were determined by fermentation smelling test of aroma-producing microorganisms and acid-producing test of lactic acid bacteria in fermentation broth.Finally,compound strains were identified by BLAST and classified as Geotrichum candidum and Lactobacillus plantarum.Physiological and biochemical identification of these two strains were carried out.Geotrichum candidum entered the logarithmic phase after 8 hours and the stationary phase after 32 h.Under the environment of pH was 8 and temperature was 28? Geotrichum candidum had a better growing rate,Lactobacillus plantarum entered logarithmic growth phase after 12 h and stationary phase after 28 h.Under the environment of pH was 8 and temperature was 36?Lactobacillus plantarum had a high value of total acids content.(2)The sensory evaluation of the extract of raw materials determined that the addition of rose was 0.75%,and the addition of grape juice was 30%.The fermentation process was optimized by response surface with ratio of compound strains,fermentation temperature and fermentation time asbox-behken's factors,total polyphenol content as response value.The results showed that the addition ratio of compound strains Geotrichum candidum and lactic acid bacteria was 5.5:4.5(%),fermentation temperature was 33? and fermentation time was 48 h,the total polyphenol content reached 9.92×102 mg/L.Sensory evaluation of grape rose fermentative beverage under this optimized conditions showed that the highest sensory score was 92.(3)The aroma substances of grape rose fermentative beverage were analyzed by GC-MS.According to the peak area,the content of Citronellene,Vanillin Formate and beta-phenylethanol in grape rose fermentative beverage were higher.Determining antioxidant capacity in vitro showed the activity of SOD reached 5.28×103 U/L,the content of anthocyanin remained around 27 mg/L,and the scavenging ability of DPPH free radicals was also determined.From 500 ?mol/L to 857 ?mol/L.(4)ALT(alanine aminotransferase)and AST(glutamic oxalate aminotransferase)in the serum of mice were measured.Antioxidant capacity in liver was determined.It was found that the index of antioxidant capacity increased after fermentative beverage administration,and compared with the body weight before and after administration,it had relatively some role in controlling body weight.