Effect of species on the flavor profile of boletes: insights from GC-MS, LC-MS, ATR-FTIR spectroscopy and chemometrics

Flavor is a decisive trait that shapes consumer preference and purchasing choices of boletes, which motivates the comprehensive flavor-related analysis carried out in the present study. Boletes is a highly valued edible fungus with prominent interspecific flavor disparities. In this work, a targeted metabolomics strategy based on UPLC-ESI-MS/MS was adopted to systematically characterize the flavor chemical profiles of five bolete species for taste-related metabolites (amino acids and organic acids), combined with widely-targeted volatilomics via HS-SPME-GC-MS, ATR-FTIR spectroscopic detection, and chemometric modeling. A total of 68 amino acid metabolites, 57 organic acids, and 773 volatile compounds were identified. Key differential flavor-active compounds (fumaric acid, glycine, arginine, aspartic acid, and lysine) and six key aroma-active compounds (3(2H)-furanone, dihydro-2-methyl-, pyrazine, 2-ethyl-3,5-dimethyl-, pyrazine, 2,3-diethyl-5-methyl-, butanoic acid, 3-methyl-, ethyl ester, benzeneacetaldehyde; (Z,Z)-3,6-nonadienal) were screened by TAV, ROAV, VIP, and OPLS-DA. Metabolic pathway analysis suggested that the TCA cycle and urea cycle are associated with the formation of flavor differences. Molecular docking results showed that key aroma compounds exhibited strong binding affinity to OR1A1. Furthermore, ATR-FTIR combined with the CNN-LSTM model achieved accurate and stable quantitative prediction of key flavor components (R2 ≥ 0.95, RPD > 4). This study revealed the chemical basis and discriminant compounds of flavor divergence among bolete species and established a reliable and rapid detection method for flavor evaluation and species identification.