Identification of aroma active compounds in walnut oil by monolithic material adsorption extraction of RSC18 combined with gas chromatography-olfactory-mass spectrometry

A novel extraction method of volatile aroma compounds (VACs) from walnut oil (WO) using monolithic material adsorption extraction (MMSE) was developed herein, and its efficiency was compared with the conventional extraction method based on solid-phase microextraction (SPME) combined with gas chromatography-olfactory-mass spectrometry (GC-O-MS). After protocol optimization of MMSE-RSC18, 77 volatile compounds (38 ones can be sniffed) were extracted from WO, thus having a better performance compared to SPME (56 volatile compounds, 35 ones can be sniffed). Subsequently, based on flavor dilution factors (FDs), odor activity values (OAVs), and recombination and omission experiments, key aroma-active compounds in WO were 1-octen-3-ol (OAV = 82.58), (E)-2-decenal (OAV = 4.10), linalool (OAV = 2.37), γ-dodecalactone (OAV = 2.30), 2-pentylfuran (OAV = 1.62), (E)-2-nonenal (OAV = 1.14) and pentanal (OAV = 1.04). Collectively, compared to HS-SPME, MMSE-RSC18 provided higher capture efficiency of VACs, enabling efficient extraction and analysis of sample aromas.