Analysis of Volatile Components of Osmanthus fragrans Extracts from Different Varieties by GC-MS and Electronic Nose Combined with Chemometrics

Gas chromatography-mass spectrometry (GC-MS) and electronic nose combined with chemometrics were used to analyze the volatile components and overall odor of Osmanthus fragrans extracts from four different varieties. The results showed that a total of 65 volatile components from eight chemical classes were identified, including 28 alcohols, 6 ketones, 4 aldehydes, 4 phenols, 4 acids, 5 alkanes, 8 esters and 6 other substances. Alcohols, ketones and esters were the main volatile components in O. fragrans extracts. Venn diagram and cluster heatmap showed that the types and contents of volatile components in the four O. fragrans extracts were significantly different. By partial least squares discriminant analysis (PLS-DA), nine differential volatile components between these O. fragrans extracts were identified, namely, tetracontane, propanoic acid, 1-cyclohexene-1-propanol, 1-octacosanol, palmitic acid, 9,12-tetradecadien-1-ol, cyclohexanol, 2-butanone, and stigmasterol. The results of electronic nose showed that W2W, W2S, W1W, W1S and W5S were the main sensors to distinguish the odors of different O. fragrans extracts. The overall odors of the four O. fragrans extracts were discriminated well. The volatile components of Liuyang Luteus Group and Liuyang Albus Group extracts were more similar, while those of Xianning Luteus Group and Liuyang Aurantiacus Group extracts were significantly different, which was consistent with the results from GC-MS and cluster analysis. The research findings showed that it was feasible to distinguish O. fragrans extracts from different varieties based on volatile substances.