Chemical profiles and aroma contribution of terpene compounds in Meili (Vitis vinifera L.) grape and wine.

The chemical profiles and aroma contribution of terpene compounds in Meili grapes and wine were analyzed. Bound terpene compounds were extracted using methanol, purified using Amberlite XAD-2 resin, concentrated in methanol/ethyl acetate, and enzymatically hydrolyzed to release aglycones. Free terpene compounds were identified using solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Wine aroma characteristics were quantified by a trained sensory panel. Seventeen terpene glycosides were quantified in grapes and wines as pentosyl-glucopyranoside, the content of which ranged from 804 to 836 μg/kg, and from 155 to 192 μg/L, respectively. Eight free terpenes were present in wines with their content ranging from 40.1 to 59.7 μg/L. Linalool was abundant both in bound and free terpenes, and mathematical regression revealed that terpenes, especially linalool (contribution efficient > 0.4), contributed heavily to Meili wine aroma. Finally, a molecular rearrangement scheme based on linalool was proposed in Meili grape and wine.