Discrimination Among New Vegetative Materials of Passiflora edulis Sims. From Canary Islands by Their Volatile Profile

Abstract

This study shows the successful discrimination among different passion fruit samples cultivated in the Canary Islands, specifically purple, yellow, and a new cultivar labelled as purple selection (obtained to ensure disease resistance, yield, and adequate taste of the cultivated materials), based on their distinctive volatile profile. The headspace solid-phase microextraction (HS-SPME) method (using under optimum conditions the commercial CAR/PDMS fibre at 62°C for 60 min and 15% (w/w) NaCl with 10 mL of juices of passion fruit samples) was applied to estimate the volatile profile of up to eighteen passion juice fruit samples, coupling the technique to gas chromatography tandem mass spectrometry (GC–MS). The method permitted the identification of up to 135 volatile compounds such as esters, terpenes and alcohols, among others. The qualitative study indicated that the most abundant compounds in yellow and purple passion fruit are the same (hexyl hexanoate (21%–14%), hexyl butanoate (19%–11%) and ethyl hexanoate (11%–6%)), while the most abundant compounds for this new vegetative material are ethyl octanoate (with almost 53%), hexyl hexanoate and ethyl 3-hexanoate. Advanced statistical techniques, such as linear discrimination analysis (LDA), were used to explore each data sample, with samples analysed by HS-SPME-GC–MS in quadruplicate. 106 peaks were coincident in all chromatograms of the samples, but only 13 variables (compounds) were sufficient to discriminate the new vegetative species. Besides, the HS-SPME-GC–MS method proved to be efficient and sustainable, with application of modern metrics of greenness, particularly when compared with other techniques commonly applied for this type of analysis.