Abstract:In this experiment, peach fruit and kombucha liquid were used as the raw materials for brewing kombucha liquid-peach fruit wine. The kinetic changes of cell growth, substrate consumption and product generation in the fermentation process were investigated and their correlation was analyzed. Two antioxidant substances and three free radical scavenging rates were also measured and their correlation analyzed. The results showed that the SGompertz model could better reflect the change of yeast growth, the Boltzmann model had the best fitting degree for the change of ethanol production, and the DoseResp model could better reflect the change of reducing sugar consumption. The correlation coefficients (R2) for all the three models exceeded 0.98, indicating very high fitting degree between the experimental values and the model predicted values, reflecting the kinetic characteristics of the fruit wine during the fermentation process. The results of the antioxidant assay showed that the changes with the fermentation time generally showed a trend of initial increase then decrease, reaching the highest at the 192th h of fermentation where the total phenolic and flavonoid mass concentrations were 3 802 mg/mL and 549 mg/mL, respectively, and the DPPH, ABTS+ and hydroxyl radical scavenging rates were 86.73%, 81.87% and 82.45% respectively. Taking comprehensive considerations into account, 192 h of fermentation can be used as the basis for determining the end of the main fermentation. This study revealed the changing patterns of metabolites and antioxidant activity during the fermentation of kombucha liquid-peach fruit wine. It was preliminarily determined that the established models were valid and can provide a theoretical basis for the industrial production of kombucha liquid-peach fruit wine.
