Analysis of Volatile Flavor Compounds in Kiwi Fruit Wines from Different Varieties Fermented with Four Yeasts

In order to investigate the influence of various yeast strains on the volatile flavor profile of kiwifruit wines, this study aimed to identify suitable aroma-producing yeasts and optimal kiwifruit cultivars. Four enological yeast strains (ADT, CECA, VIC, and BV818) were employed to ferment wines produced from five kiwifruit varieties (Xu Xiang, Hai Ward, Hua You, Jin Yan, and Hong Yang). The volatile compounds were analyzed using solid-phase microextraction combined with gas chromatography-mass spectrometry (SPME-GC-MS). The results revealed that alcohols and esters were the predominant volatile compounds. Both principal component analysis and heat map visualization indicated that ethyl n-hexanoate, ethyl caprylate, phenylethanol, ethyl butyrate, and caprylic acid were the primary compounds influencing the aroma profiles of the wines. Among the 93 compounds with an odor activity value (OAV) greater than ethyl butyrate and ethyl caproate were identified as the key flavor contributors common to all samples. Overall, 126 volatile compounds were detected in the wines fermented by the four yeast strains, comprising 21 alcohols, 53 esters, 14 acids, 19 aldehydes and ketones, and 19 other compounds. Notably, the CECA yeast-fermented Hayward kiwifruit wine exhibited the highest concentration of volatiles (874.36 µg/L) and achieved the top aroma score. Electronic nose tests further confirmed that the flavor intensity attributed to alcohols and esters was particularly pronounced in this wine. These findings underscore that ethyl butyrate and ethyl caproate are critical volatile components in kiwifruit wines, and that the CECA yeast-fermented Hayward wine—characterized by a rich profile of alcohols and esters, balanced by acids and aldehydes/ketones—offers a particularly pleasant aroma. This study provides a theoretical foundation and empirical data to support efforts aimed at enhancing the flavor quality of kiwifruit wines.