Effects of sulfur dioxide on the volatile composition and aroma of blueberry wine

Blueberry wine is a nutritional wine which aroma is affected severely by the fermenting condition. In this study, the influence of sulfur dioxide on the volatile composition and aroma of blueberry wine was comprehensively explored. The results indicated that in normal blueberry wine (NBW) fermented with sulfur dioxide, the titratable acid (TA) and total soluble solids content (TSSC) decreased slightly, whereas the ethanol, total phenolic, and vitamin C (Vc) contents increased significantly. The amount of volatile compounds declined significantly to 575 compared to 670 in traditional blueberry wine (TBW), and the relative concentrations of alcohols, acids, esters, and aldehydes markedly reduced. The relative odor activity value (ROAV) of 2,3-butanedione was the highest, and the number of the key aroma compounds shrunk obviously. The sweet, green, and fruity odors declined mainly ascribing to the reduction of 2-heptanol, acetic acid hexyl ester and 2-methyl-butanoic acid ethyl ester. The herbal, woody and floral odor mainly attributed to high contents of linalool, cyclohexene, 4-dimethyl-3-cyclohexene-1-ethanol, and ethyl nonanoate. These results indicated that sulfur dioxide retained some nutritional components, while it decreased the variety of the volatile compounds and affected the aroma of blueberry wine. Graphical abstract