Effects of Dihydromyricetin and Rosmarinic Acid on the Fermentation Kinetics and Aroma Quality of Low-Alcohol Apple Cider

In this study, Fuji apple juice was used as raw material for the production of apple cider by fermentation with Saccharomyces cerevisiae. Prior to alcoholic fermentation, different mass concentrations of dihydromyricetin (DMY) or rosmarinic acid (RA) were added. The fermentation kinetics was monitored. The physicochemical indices, color parameters, and aroma quality were analyzed after the completion of alcoholic fermentation. Results showed that the addition of DMY or RA to apple juice significantly accelerated the fermentation process, and the resultant cider met the basic requirements for low-alcohol fruit wine (alcohol content < 7%). Compared with SO₂ addition, RA and DMY were less effective in inhibiting the browning of apple cider, yet they did not affect the sensory score. Moreover, the browning inhibitory effect and sensory score of the RA treatment group were both higher than those of the DMY addition group. The addition of RA or DMY significantly increased the content of volatile compounds in apple cider, with a more pronounced effect being observed at 60 mg/L RA. RA significantly increased the contents of differential aroma compounds including citronellol, (E)-nerolidol, menthol, and geranyl acetone and elevated the total amount of aroma substances by 6.87%. Principal component analysis combined with sensory evaluation revealed that linalool, farnesol, ethyl decanoate, and ethyl octanoate were responsible for the floral and fruity aroma characteristics of the cider with 60 mg/L of RA added. Comprehensive analysis indicated that the addition of 60 mg/L RA to apple juice as a substitute for SO₂ not only allowed for the successful completion of alcoholic fermentation but also effectively enhanced the volatile aroma compound content and sensory quality of apple cider.