Citrus monstruosa discrimination among several citrus species by multivariate analysis of volatiles: A metabolomic approach

The origin and taxonomy of Citrus monstruosa (Rutaceae) are currently unknown and thus a nontargeted metabolomic analysis on the flavedo volatiles was performed. Headspace solid-phase micro extraction coupled with gas chromatography analysis was applied to eight Citrus spp. including Citrus monstruosa, and the chemical composition of the volatile organic compounds (VOC) was analyzed to give a chemical comparison between different Citrus species. Forty-four metabolites were detected across the species: several monoterpenes were found in all Citrus spp. and among them limonene comes first in all Citrus spp. ranging from 96.7 to 66.7%. Conversely, some molecules were found to be specific for only a few of the samples. The classical univariate evaluation of the VOC data is unlikely to give objective data for the cultivar classification; a multivariate approach, principal component analysis, is an easy to use, powerful tool. Therefore, a chemometric comparison between chromatographic data of all Citrus spp. was performed with the aim of understanding the role of VOC in the discrimination of the eight studied cultivars