Optimization of Mopan Persimmon Wine Fermentation with Pectinase and Analysis of Its Mechanism of Action

Abstract

Due to the high sugar content of Mopan persimmon, which has an annual output of more than 0.5 million tons in China, it can be processed to make fruit wine. In this study, a strain of yeast screened from different persimmon samples was used for persimmon wine fermentation. The optimal conditions of persimmon wine fermentation were determined through single-factor experiments as follows: Yeast addition of 0.08 g/kg; a fermentation temperature of 28 °C; sucrose addition of 18%; and pectinase addition of 0.01%. Under these conditions, the alcohol content of persimmon wine reached 12.9%. The addition of pectinase during persimmon wine fermentation was found to decompose pectin at high speed, reduce the viscosity of the fermentation liquid, increase the dissolved oxygen content in the fermentation liquid, promote the growth and reproduction of yeast, and effectively convert the sugars into alcohol. After fermentation, alcohol, residual sugars, and total phenolic content with or without pectinase treatment were 12.9 and 4.4%, 2.2 and 13.4 g/L, and 738.7 and 302 µg/mL, respectively. Scanning electron microscopy (SEM) results showed that compared with the mash without pectinase treatment, the mash with pectinase had a larger network structure and more pores and yeasts.

Process Optimization for Production of Persimmon Wine with Lower Methanol

“…is a health-promoting fruit that is rich in phenolic compounds, carotenoids, fiber, vitamins, and minerals. Over 350 species of persimmon are distributed in tropical and subtropical regions, and the global production of persimmon surpasses 5.75 million tons annually [ 1 , 2 ]. Due to its nutritional compositions, persimmon has a strong antioxidant capacity [ 3 , 4 , 5 ].…”

“…However, persimmon beverage production is usually characterized by a poor juice yield. Owing to the presence of quantitative pectin, the crushed persimmon pulp exhibits a highly viscous state quite different from the liquid states of grapes and apples [ 2 , 7 ].…”

“…The methanol concentration in fruit wines can be affected by several aspects including the pectin content and esterification level in the fruits, the glycine metabolic activity of the chosen starter, the enzymatic hydrolysis of pectin by pectinase, and the fermentation process [ 9 , 10 ]. Although the fermentation process for persimmon wine production has been optimized before, the content of methanol in persimmon wine was not given special attention [ 2 , 5 , 6 ].…”