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.

This study investigated the effects of pasteurization (80 ℃ for 30 min), electron beam irradiation (3, 5 and 7 kGy) and ultra-high pressure treatment (400, 500 and 600 MPa for 6 min) on the flavor of jujube pulp. Untreated samples were used as control. The content of taste compounds such as free amino acids and reducing sugar was determined, and flavor quality was evaluated by electronic nose and electronic tongue and sensory evaluation. The results showed that compared with the control sample, free amino acid contents were significantly reduced by pasteurization and electron beam irradiation, and the contents of bitter amino acids such as arginine, valine and leucine were significantly increased by pasteurization. Electron beam irradiation and ultra-high pressure treatment could significantly increase the content of fructose in jujube pulp. Significant differences in electronic nose sensor responses were found among the eight groups. The electron tongue results showed significant differences in taste characteristics between the electron beam irradiated, ultra-high pressure treated and the control samples, while the taste characteristics of the pasteurized samples were closer to those of the control group. In addition, the samples treated with electron beam irradiation had higher sensory values for taste, color and reconstitutability than the other treatments. In conclusion, both electron beam irradiation and ultra-high pressure treatment could effectively improve the flavor quality of jujube pulp.