Effect of Drying Methods on the Volatile Flavor Compounds of the Pileus and Stipe of Hypsizygus marmoreus

The effects of hot air drying (60, 70 and 80 ℃), freeze drying and natural air drying on the volatile flavor compounds in the pileus and stipe of Hypsizygus marmoreus were investigated by headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and an electronic nose, and the contribution of flavor compounds to the overall flavor of dried samples was analyzed by relative odor activity value (ROAV). Results showed that there were marked differences in the electronic nose data of the ten dried samples; therefore, the electronic nose could effectively distinguish their volatile flavor. Moreover, 32, 41, 40, 53 and 48 volatile flavor compounds were identified in dried pileus obtained by hot air drying at 60, 70 and 80 ℃, freeze drying and natural air drying, respectively, and 34, 33, 33, 43 and 44 volatile flavor compounds in dried stipe obtained by hot air drying at 60, 70 and 80 ℃, freeze drying and natural air drying, respectively. The content of volatile flavor compounds in dried pileus was higher than that dried stipe with the same drying treatment, and hot air drying produced higher contents of new flavor compounds compared with natural air drying and freeze drying. In addition, 25 flavor compounds were obtained from ROAV analysis, among which trimethylamine, isovaleraldehyde, and 1-octen-3-ol contributed more to the overall flavor. Furthermore, principal component analysis (PCA) was carried out on these 25 flavor compounds to generate a quality evaluation model. It was found that the pileus sample obtained by hot air drying at 80 ℃ had the highest score, indicating it had the best flavor quality.