Preparation and antioxidant activity in vitro of Fortunella margarita and black tea wine

Using Fortunella margarita and black tea as raw materials, and Saccharomyces cerevisiae SY as a strain, the F. margarita and black tea wine with the flavor and nutrition of F. margarita and black tea was prepared. The fermentation process of F. margarita and black tea wine was optimized by single factor tests and response surface tests using sensory score, alcohol content and residual sugar as evaluation indexes, and its basic physicochemical and microbiological indexes, functional components and antioxidant activity in vitro were determined. The results showed that the optimal fermentation parameters of F. margarita and black tea wine were as follows: black tea broth and F. margarita juice volume ratio 2∶1, S. cerevisiae SY inoculum 0.3%, and initial sugar content 23 °Bx. Under these conditions, the sensory score, alcohol content, residual sugar content, pH, total flavonoid content and total polyphenol content of F. margarita and black tea wine were 88.62 points, 11.83%vol, 9.07 °Bx, 3.26, 0.71 mg/ml and 0.25 mg/ml, respectively. Meanwhile, the total count of bacteria and Escherichia coli were not detected. The physicochemical and microbiological indexes of F. margarita and black tea wine all met the relevant standards. The hydroxyl radical and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging rates of F. margarita and black tea wine were 84.45% and 92.14%, respectively, indicating that F. margarita and black tea wine had some antioxidant activity.