In this study, headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) was employed for the analysis of volatile substances in healthy potatoes and those with different degrees of dry rot (light, moderate and heavy). The results showed that 43 volatile components were identified, including 18 aldehydes, 9 alcohols, 5 ketones, 5 alkenes, 2 esters, 2 amines, 1 furan and 1 ether. The contents of octene, α-carcelene, cyclohexanone, heptyl aldehyde and acetaldehyde went up with increasing severity of dry rot, and dipropyl disulfide, styrene, isobutanol and nonenal were produced in samples with heavy soft rot as the specific volatile components related to metabolites of Fusarium sambucinum. Fingerprints were developed that allowed to visually discern the differences in volatile components between samples with different degrees of rot severity. Principal component analysis (PCA) showed that the healthy and rotten potatoes could be effectively distinguished based on volatile components. We concluded that HS-GC-IMS allows visual comprehensive identification of the differences in volatile components between potatoes with different degrees of rot severity and effective identification of the specific volatile components of potatoes with dry rot, which can provide the theoretical basis for the diagnosis and identification of dry rot in potatoes based on odor sensing information.

The major bioactive components and flavor characteristics of Toona sinensis buds from different production areas such as Sichuan, Shaanxi, Shandong, Shanxi, Hebei and Yunnan were explored. The overall odor was evaluated by sensory evaluation, and the volatile components were analyzed using electronic nose and gas chromatography-ion mobility spectrometry (GC-IMS) in order to analyze the differences in the flavor characteristics of T. sinensis buds from different production areas. The sensory evaluation results showed that the odor of T. sinensis buds from Yunnan was rich and pleasant, while the odor of T. sinensis buds from Shaanxi was irritating. The results of electronic nose analysis showed that the contents of aromatics and long-chain alkanes in T. sinensis buds from the six production areas were similar, while the contents of nitrogen oxides and sulfides were quite different. A total of 76 volatile substances were identified by GC-IMS, including 12 alcohols, 10 esters, 9 pyrazines, 9 ketones, 8 terpenoids, 7 organic sulfides, 7 aldehydes, 6 acids, 4 phenols and 4 other compounds. The principal component analysis (PCA) of electronic nose and GC-IMS data showed that the flavor of T. sinensis buds from Yunnan was unique, and the flavors of T. sinensis buds from Sichuan, Shaanxi and Shandong were similar. T. sinensis buds from Shanxi was different from those from other geographical origins, and the content of flavor substances in T. sinensis buds from Hebei was low. The results of this study may provide a theoretical basis for the screening of T. sinensis for deep processing.