Chemical profile of terpene glycosides from Meili grape detected by GC–MS and UPLC–Q-TOF-MS

This work is designed to reveal the varietal characteristics of terpene glycosides (TGs) in ripe Meili grapes. TGs in grape skins were extracted using three ethanol/water solvents, purified and enriched using XAD-2 resin, and collected using ethyl acetate/methanol (9:1, v/v). The aglycones released from TGs were analyzed by headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME–GC–MS). TGs were detected by ultra-high-performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UPLC–Q-TOF-MS), the identification was conducted by both mass fragmentation and TGs database, and the quantitation was realized by octyl-β-d-glucopyranoside. Results showed that 19 aglycones for TGs were found in grape skins by GC–MS, which was mainly monoterpenol with molecular formula C₁₀H₁₈O (linalool, l-α-terpineol, geraniol, nerol, etc.), C₁₀H₂₀O (citronellol), and C₁₀H₁₈O₂ (pyranoid/furanoid linalool oxide, etc.). C₁₀H₁₈O aglycones may be the most stable ones, and linalool was the most abundant, occupying 44.88–47.99% of the total content. Forty-nine TGs were detected by UPLC–Q-TOF-MS. Monoterpenol pentosyl-glucosides were the main TGs, especially C₁₀H₁₈O₂ pentosyl-glucoside, which constituted 51.94–52.72% of the total concentration.