Abstract: To systematically evaluate the processing adaptability of Armillaria mellea, this study compared the effects of four drying methods: natural drying (ND), hot air drying (HD), microwave drying (MD), and vacuum freeze drying (VFD) on its physicochemical properties, nutritional components, and volatile flavor compounds. Results indicated significant differences in the effects of drying methods on the quality of A. mellea. Regarding physical characteristics, HD A. mellea exhibited color difference (ΔE) and browning levels closest to fresh A. mellea, while VFD A. mellea exhibited the lowest hardness ((718.32 ± 13.06) g) and rehydration property (rehydration ratio of (6.72 ± 0.07) g/g), attributed to its loose, porous microstructure with uniform pore distribution. Nutritionally, VFD A. mellea exhibited the highest total sugar and soluble protein contents of (143.29 ± 2.91) and (88.35 ± 2.24) mg/g, respectively. MD A. mellea exhibited a significantly higher content of 17 free amino acids (P < 0.05) than the other groups, while VFD A. mellea demonstrated a more balanced amino acid profile with an essential amino acid/total amino acid ratio (0.37) most closely aligned with the World Health Organization/Food and Agriculture Organization of the United Nations recommended value (0.40), indicating higher protein nutritional value. A total of 46 volatile flavor compounds were identified among the analyzed samples using gas chromatography-ion mobility spectrometry (GC-IMS). Among these, VFD A. mellea exhibited the highest relative content of aldehydes and ketones responsible for the characteristic flavor of A. mellea (68.51%), represented by butanal, 2,3-pentanedione, and 3-octanone. VFD provided better retention of flavor-active aldehydes and ketones, imparting a prominent creamy aroma. HD and MD A. mellea exhibited relatively high relative contents of acids (10.76% and 10.01%, respectively). Orthogonal partial least squares discriminant analysis (OPLS-DA) revealed differences in aroma profiles among A. mellea dried by different methods, identifying 15 characteristic flavor markers including 2-hexanol, hydroxyacetone, and butyl butyrate. These findings provide a scientific basis for the efficient processing and quality improvement of A. mellea.

Key words: Armillaria mellea; drying methods; physicochemical properties; nutritional components; volatile compounds; correlation analysis