Impact of Drying Processes for Camellia Seeds on the Volatile Compounds of Camellia Seed Oil

Abstract

The drying process employed for camellia seeds has a significant impact on the quality of camellia seed oil (CO), but research on its influence on the flavor of CO is limited. This study investigated the effects of two typical drying processes, sun-drying and hot-air-drying, on the volatile composition of CO using Gas Chromatography-Ion Mobility Spectrometry (GC-IMS) technology. The results revealed that the CO obtained from hot-air-drying seeds exhibited a higher content of saturated fatty acids, while the levels of unsaturated fatty acids decreased. Additionally, the acid value and peroxide value of the CO obtained from hot-air-drying seeds were also elevated. GC-IMS analysis detected a total of 53 volatile compounds (including monomers and dimers) in the CO. Notably, aldehyde compounds exhibited the highest relative content (38.56–40.75%), followed by alcohols (32.14–38.01%), acids (4.86–14.58%), and esters (3.61–17.73%), while ketones exhibited relatively lower content (2.33–3.75%). The fingerprint profiles indicated that most of the flavor compounds exhibited differences in their content between the two samples. Specifically, the relative abundance of complex aldehyde and ester compounds was higher in the hot-air-dried sample compared to the sun-dried one, while the relative content of acid compounds decreased significantly. The relative odor activity value (ROAV) method identified hexanal as the most important key aroma component in both oil samples. The fingerprint profiles combined with principal component analysis (PCA) demonstrated that GC-IMS can effectively distinguish samples obtained from different drying treatments. Therefore, through the adjustment of drying methods, CO with various flavor characteristics can be obtained. This study provides valuable theoretical and technical references for CO production and flavor research.