Citrus monstruosa discrimination among several citrus spp 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.