Optimization of Fermentation Technology of Purple Potato Wine and Dynamic Changes of Anthocyanin and Color in Main Fermentation Period

Using purple potato as raw material, on the basis of single factor, the fermentation parameters of purple potato wine were optimized by response surface methodology. The optimum fermentation parameters were as follows: the ratio of potato to flour was 1:0.6, the ratio of material to water was 1:1 (g/mL), the dosage of alpha-amylase was 8.5 U/g, the dosage of distiller's yeast was 0.45%, and the fermentation was carried out at 28 ℃ for 14 days. The purple potato wine obtained by this process has an alcohol content of 13.5%vol and anthocyanin content of 166.34 mg/mL. The wine was clear and transparent, purplish red, with moderate sweet and sour taste. The comprehensive sensory evaluation score was 90 points. The dynamic changes of anthocyanin and color in the main fermentation period were measured. The analysis showed that the anthocyanin in the purple potato wine increases first and then decreases, while the chroma decreases first and then tends to be flat, while the hue was opposite. The overall polymerization chromaticity and browning index showed a gradual upward trend. The experimental results provide theoretical basis for industrial production of purple potato wine.