Effects of dehydration methods on the volatile components of lemon slices with GC-IMS

<b>Objective:</b> In order to investigate the effects of freeze drying （FD）, air drying （AD）, infrared drying （IRD） and vacuum drying （VD） on volatile components content of lemon slices. <b>Methods:</b> Gas chromatography-ion mobility spectroscopy （GC-IMS） was used in this study, and the principal components analysis was performed to analyze the volatile components of lemon slices exposed to different drying methods. <b>Results:</b> 72 kinds of volatile components were detected in fresh lemon slices treated with FD, AD, IRD and VD, and their contents were different in the slices treated with FD, AD, IRD and VD, which influenced the flavor of lemon slices., including 20 terpenes, 16 esters, 13 aldehydes, 13 alcohols, 7 ketones, 2 acids and 1 furan. Comparing with fresh lemon （Control）, and treating with 4 kinds of drying methods, the contents of volatile alcohols and esters decreased, the contents of aldehydes increased, while the contents of terpenes remained stable. The results of fingerprint spectra showed that IRD and AD treatments had better retention effect on ethyl butyrate and methyl acetate, and the contents of furfural and hexal increased. PCA results showed that fresh lemon slices were significantly different from dry lemon slices, and heat map clustering showed that IRD treatment was similar to AD and VD treatment. <b>Conclusion:</b> Compared with other drying methods, IRD treatment had a better retention effect on the ester volatile components of lemon slices, which is 11%~27% higher than other treatments. Meanwhile, the content of marker volatile aldehydes increased more, which is 53% higher than that of fresh lemon, which has a positive effect on the flavor of lemon slices. This study will provide a reference for flavor quality control of lemon slices during drying process.