Hot-air drying temperature regulates volatile organic compounds in Dictyophora rubrovalvata based on the correlation of dynamic enzymes and precursors, and characteristic volatile organic compounds.

BACKGROUND: The characteristics of volatile organic compounds (VOCs) in Dictyophora rubrovalvata (DR) were systematically elucidated under varying hot-air drying temperatures (40-80 °C). The dynamic evolution of key flavor-synthesizing enzymes and precursor substances, and their correlations with characteristic VOCs, were highlighted. RESULTS: Odor activity value analysis (OAV) identified 34 characteristic VOCs in DR, with aldehydes dominating the aroma profile. Orthogonal partial least squares-discriminant analysis (OPLS-DA) demonstrated that the abundance of VOCs peaked at 80 °C. Enzymatic reactions predominated during the early drying stage, as indicated by initial increases in enzyme activity within 2-6 h at lower temperatures (40-60 °C). Conversely, thermal degradation and Maillard reactions became the dominant processes in the later stages, particularly at higher temperatures. Pearson correlation analysis revealed that pyruvate kinase (PK), pyruvate dehydrogenase (PDH), glucosamine, and aldehydes were strongly correlated. Aromatic amino acid aminotransferase (ARAT) and branched-chain amino acid aminotransferase (BCAT) catalyzed the conversion of most amino acids into alcohols, aldehydes, and acids. Palmitic acid and linoleic acid exhibited strong correlations with seven characteristic VOCs (e.g., heptanal-D and n-hexanal-D); however, the correlation between fatty acids and lipoxygenase (LOX) was relatively weak, suggesting that fatty acids might generate volatiles mainly through non-enzymatic reactions. CONCLUSION: Overall, the optimal aroma quality of DR was achieved at 80 °C, where the abundance and diversity of characteristic VOCs were highest. This superior flavor formation was predominantly governed by non-enzymatic pathways (thermal degradation and Maillard reactions), with enzymatic reactions playing an auxiliary role during the early drying stage. These results provide a theoretical basis for precisely controlling high-temperature drying processes to maximize aroma retention in DR and offer practical guidance for the flavor-oriented production of DR. © 2026 Society of Chemical Industry.