Effects of Hot Air-drying and Vacuum Freeze-drying on Flavor Components in Different Parts of Hericium erinaceus

In order to explore the changes of flavor characteristics of Hericium erinaceus before and after drying, the effects of hot air-drying and vacuum freeze-drying on flavor components of pileus and stipe of H. erinaceus were studied using high performance liquid chromatography (HPLC) and gas chromatography-ion mobility spectrometry (GC-IMS) in this paper. The results showed that the contents of soluble sugar, 5’-nucleotide and free amino acid in H. erinaceus significantly decreased after drying (P<0.05). And the loss of them in hot air-drying samples was higher than that of vacuum freeze-drying samples. The total content of organic acids in different H. erinaceus samples increased in the order of vacuum freeze-drying samples>hot air-drying samples>fresh samples. A total of 64 volatile compounds in fresh and dried H. erinaceus were detected by GC-IMS, mainly alcohols (17) and aldehydes (14), followed by ketones (11) and esters (10). In general, vacuum freeze-drying was more conducive to retain eight carbon atom (C8) compounds and other alcohols and aldehydes of H. erinaceus than hot air-drying, while hot air-drying was easier to form ketones and esters than vacuum freeze-drying. Meanwhile, the content of total soluble sugar, total 5’-nucleotides and total free amino acids in the pileus was significantly higher than that of stipe (P<0.05), but the total content of organic acids was on the contrary. The variation trend of volatile compounds fingerprint spectra of pileus consists with that of stipe. This study provided reference for the processing of the H. erinaceus.