Insights into the Aroma Profile in Three Kiwifruit Varieties by HS-SPME-GC-MS and GC-IMS Coupled with DSA

Three main varieties of kiwifruit exhibiting marked differences in flavor were selected for the study. Volatile profiles of three representative kiwifruit varieties were separated and identified by headspace-solid phase microextraction coupled with gas chromatography mass spectrometry (HS-SPME-GC-MS) and gas chromatography-ion mobility spectrometry (GC-IMS). A total of 48 compounds were identified by GC-MS in three samples, including aldehydes (16), alcohols (11), esters (16), and other compounds (5). Meanwhile, methyl hexanoate, ethyl hexanoate, hexanol, (E)-2-hexenal, hexanal, ethyl butanoate, and ethyl acetate were identified at a higher level by GC-IMS in all three varieties. Descriptive sensory (DSA) analysis was also performed to distinguish subtle differences of the kiwifruit varieties. Further partial least square regression analysis (PLSR) revealed that the fruity attribute was positively associated with ethyl butanoate, methyl hexanoate, and hexyl benzoate, while the grass aroma might be mainly due to (E)-2-hexenal, 3-hexenal, hexanol, and (E)-2-hexen-1-ol. As for sweet note, some esters, such as methyl butanoate ethyl butanoate and methyl hexanoate, were the main contributors. In addition, the cucumber-like and pungent notes were positively associated with (E,Z)-2,6-nonadienal and 1-penten-3-one, respectively.