Abstract: Satsuma mandarin fruit were subjected to heat treatment (HT) or ozone fumigation (OF) treatment after harvest for quality preservation. The change of volatile compounds in the fruit peel before and after treatment was analyzed by gas chromatography-ion mobility spectrometry (GC-IMS). In total, 49 volatile compounds were identified, including 13 alcohols, 12 aldehydes, 9 terpenes, 7 esters, 4 ketones, 3 furans and 1 acid. A GC-IMS fingerprint was developed for each group. It was found that principal component analysis (PCA) could effectively distinguish the different treatment groups. Seventeen volatile marker compounds (variable importance in the projection, VIP > 1) were selected by partial least squares discriminant analysis (PLS-DA), and heat map clustering analysis was performed on these compounds, revealing that the volatile marker compounds of HT and OF samples were similar to each other. The results showed that both treatments significantly increased the contents of alcohols, aldehydes, esters and terpenes in citrus peel, thereby having the potential to enhance disease resistance and prolong the shelf life. Meanwhile, GC-IMS could allow rapid identification of the differences in volatile compounds in samples subjected to different postharvest treatments.

Key words: citrus peel; volatile components; gas chromatography-ion mobility spectrometry; heat treatment; ozone fumigation treatment; chemometrics