Abstract
Grape (Vitis vinifera L.) berry skin accumulates high amounts of secondary metabolites, such as catechin, resveratrol, and anthocyanin. Metabolome analysis using liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) was performed to profile and compare metabolites of grape berry skin before veraison and at harvest. Anthocyanines, such as marvidine 3-glucoside, were the most abundant phenolic compounds found in grape skins at harvest, whereas the amount of catechin was higher before veraison. Principal component analysis revealed seven stage-specific peaks of metabolites in grape berry skin. Two unidentified peaks were speculated by MS/MS databases searches, annotated or characterized as amino acids, with one annotated as arginine and the other characterized as neutral loss ion of glutamate and glutamine. Amino acids, including arginine, are important for grape berry taste and wine quality. Our metabolome analysis showed not only well known metabolites related to ripening of grape berry skin, including anthocyanines, but also speculated some amino acids, are important for grape berry quality.
