Effects of mixed fermentation on the flavor quality and in vitro antioxidant activity of Zaosu pear-Merlot grape composite alcoholic beverage

In this study, a mixed fermentation strategy using grape-blended pear juice co-inoculated with <i>Metschnikowia pulcherrima</i> 346 and <i>Saccharomyces cerevisiae</i> ES488 was used to characterize the modifications of the flavor and antioxidant activity of Zaosu pear-Merlot grape alcoholic beverage. The optimum fermentation parameters identified using a fuzzy mathematical sensory evaluation model were an initial pH of 4.22, a ratio of <i>M. pulcherrima</i> 346 and <i>S. cerevisiae</i> ES488 inoculated 1.13:1, sequential inoculation time 47.02 h and making temperature 19 °C. The optimal mixed fermentation increased the content of terpenes and ethyl esters in pear-grape beverage by 16.5 % and 11.2 % respectively, enhancing floral and fruity aromas and attaining the highest sensory score. Due to the accumulation of flavonoid, anthocyanin, and phenol, the optimized alcoholic beverage exhibited the highest DPPH (97.6 %) and OH (93.3 %) radical scavenging rate as well as iron ion reducing power (3.25), which is conducive to extending the shelf life of beverages.