Analysis of volatile components in Pheretima and its extracts using HS-GC-IMS and HS-SPME-GC-MS combined with ROAV

Pheretima products are widely used, but the stenchy odor is a constraint to their application. In this study, 86 and 673 volatile components (VOCs) were identified in Pheretima and its extracts using headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS), respectively. An increase in acid and amine contents after processing was found, which may explain the increased stenchy odor. Through orthogonal partial least squares discriminant analysis (OPLS-DA), 14 differential markers between aqueous and alcoholic extracts were screened, and 3-methylbutanal, pentanal, and trimethylamine were identified as the key differential odor components. Combined with relative odor activity value (ROAV) analysis, 10 key odor components were identified, including: 3-methylbutanal, 1-octen-3-ol, dimethyl trisulfide, (2 E ,6 Z )-nona-2,6-dienal, methyl mercaptan, guaiacol, isobutyraldehyde, 1,8-cineole, 2-pentylfuran, and pentanal. This study provides theoretical support for the optimization of the odor of Pheretima-containing products and promotes their application.