Effect of Fermentation Using Whole Kiwifruit on Volatile Compounds in Kiwifruit Wine Explored by Gas Chromatography-Ion Mobility Spectrometry and Headspace-Solid Phase Microextraction-Gas Chromatography-Mass Spectrometry

In order to investigate the effect of fermentation using whole kiwifruit on the flavor profile of kiwifruit wine, the flavor profiles of kiwifruit wine fermented from whole and peeled kiwifruit were analyzed by gas chromatography-ion mobility spectrometry (GC-IMS), headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and sensory evaluation. The results showed that a total of 124 volatile compounds were detected in the two wine samples by the combined use of GC-IMS and HS-SPME-GC-MS, which were much more than those detected by single techniques. This suggests that the combination of multiple techniques provides more comprehensive and systematic flavor characterization of kiwifruit wine than their separate use. Compared with the wine made from peeled kiwifruit, the one made from whole kiwifruit contained 13 more eater and aldehyde compounds and four less acids and ketones. Moreover, the relative contents of ethyl decanoate, n-octanal, isoamyl hexanoate, 2-methylethyl acetate, ethyl valerate, butyl valerate, and cis-rose oxide were significantly higher in whole kiwifruit wine (P < 0.05) while the relative contents of 3-octanol and 2,6-dimethylpyridine were significantly lower (P < 0.05), compared with that made from peeled kiwifruit. Sensory evaluation results showed that whole kiwifruit wine had higher overall scores with a prominent characteristic aroma, which was superior to peeled kiwifruit wine in terms of overall balance. In summary, this study showed that fermentation using whole kiwifruit improved the flavor quality of kiwifruit wine. This finding provides a theoretical basis and data support for the optimization of the kiwifruit wine brewing process and quality improvement.