Optimization of watermelon peel yogurt fermentation process and study on antioxidant capacity

This study aims to explore the variation patterns of total flavonoid and other antioxidant activities in watermelon peel yogurt, providing a basis for the production of a functional yogurt. Using watermelon peel as the raw material and total flavonoid content as the indicator, the optimal process of watermelon peel yogurt was optimized through single-factor and orthogonal experiments. The results indicate that yogurt fermented with a mass ratio of watermelon juice to milk at 1:3, fermentation time of 10 hours, and fermentation agent dosage of 0.10% exhibits a refreshing watermelon aroma, excellent texture, and almost no whey separation. After process optimization, the polysaccharide content of watermelon peel yogurt increased by 19%, and water-holding capacity rose to 63.3%. Texture analysis revealed a hardness of 81.50 g, viscosity of 20.00 g, adhesiveness of 1.20 mJ, elasticity of 8.83 mm, and a draw length of 6.76 mm. The physicochemical and microbiological properties of watermelon peel yogurt meet national standards, and it possesses a good free radical scavenging ability.