Optimization of the Formula and Quality Evaluation of Polygonatum kingianum Yogurt

Milk powder, Polygonatum kingianum paste and sucrose were used as the main ingredients and a P. kingianum yogurt was fermented and developed. The optimal formula of P. kingianum yogurt was optimized by sensory evaluation, single-factor combined with response surface test. In addition, yoghurt was prepared with the optimised formula to compare the physicochemical and microbiological indices and antioxidant capacity of P. kingianum yoghurt with that of plain yoghurt (without P. kingianum). The results showed that the optimal formula for P. kingianum yoghurt was 1.5% addition of P. kingianum paste, 10% addition of sucrose and 0.02% addition of starter culture. P. kingianum yogurt had a delicate taste, with a moderate ratio of sweet and sour, with a light flavor of P. kingianum and sensory score of 87.62. All physicochemical and microbiological indexes met the national standards. The antioxidant capacity and texture analysis showed that compared with plain yoghurt, the addition of P. kingianum paste significantly improved the antioxidant capacity and stability of the yoghurt. Microstructural analysis showed that P. kingianum paste was tightly bound to milk protein, forming a densely structured milk gel and improving the viscosity value of yogurt. Therefore, a functional yogurt was developed by compounding P. kingianum, which had a certain market value.