Optimization of HS-SPME-GC-MS for the Characterization of Key Volatile Compounds in Lentinus edodes at Different Maturity Stages

The volatile organic compounds (VOCs) in Lentinus edodes at different maturity stages were identified by optimized headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (GC-MS) and analyzed by odor activity value (OAV) and partial least squares discriminant analysis (PLS-DA). The results showed that the optimal extraction conditions were as follows: 1.0 g of sample was extracted at 50 ℃ for 25 min and then the analytes adsorbed on the fiber were desorbed in the GC-MS injection port for 3 min. A total of 71 VOCs were identified in L. edodes, and there were significant differences in the types and contents of volatile compounds at different maturity stages (P < 0.05). Out of these, 18 VOCs that could be used as biomarkers to distinguish L. edodes at different maturation stages were selected by PLS-DA and variable importance in projection (VIP). Besides, 16 volatile compounds with OAV ≥ 1 were identified. Among these compounds, 1-octen-3-ol, 3-octanol, 1-octen-3-one, 3-octanone, benzeneacetaldehyde, dimethyl disulphide, dimethyl trisulphide, 2,3,5-trithiohexane, and 1,2,4-trithiohexane showed VIP greater than 1, thus making them the most significant differential volatile compounds among different maturity stages of L. edodes. This study provides a theoretical foundation for understanding the mechanism of aroma formation during the maturation process of L. edodes.