Headspace Solid-phase Microextraction Coupled to Gas Chromatography-Mass Spectrometry and Electronic Nose to Analyze the Aroma Characteristics of Cyperus esculentus Oils Obtained by Different Methods

In this study, headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to analyze the composition and relative content of volatile compounds in Cyperus esculentus oils obtained by different methods (supercritical CO₂ extraction, pressing, leaching, and aqueous enzymatic extraction), and these oils were classified by using principal component analysis (PCA) and electronic nose. The key flavor compounds were determined by their relative odor activity values (ROAV). The results showed that the composition and relative content of volatile compounds were significantly different among the C. esculentus oils. A total of 101 volatile compounds were identified across all samples, 22 of which were common to them, the predominant ones being aldehydes, ketones, esters and alkanes. The relative content of aldehydes was higher in the samples obtained by supercritical CO₂ extraction (36.71%) and pressing (25.64%) than the other methods, and the relative contents of alkanes and esters were the highest in the samples obtained by leaching (31.07%) and aqueous enzymatic extraction (45.66%), respectively. Electronic nose combined with PCA effectively distinguished the four oil methods. Nonanal, cedrol and D-limonene were identified as key flavor compounds and were found in each sample.