# Diversity of volatile phenols and their newly identified precursors during different grape species development

## TL;DR

The study explores how volatile phenols and their precursors develop in different grape species, revealing significant differences between East Asian and European grapes.

## Contribution

The study identifies new glycosidic precursors and highlights species-specific metabolic differences in volatile phenol accumulation.

## Key findings

- East Asian grape species showed higher precursor concentrations and progressive accumulation of volatile phenols compared to V. vinifera.
- Six precursors were exclusive to East Asian species, suggesting unique glycosyltransferase activities.
- Widespread precursors correlated strongly with their volatile phenols, indicating predictive potential for wine aroma.

## Abstract

Grape-derived volatile phenols significantly contribute to wine aroma, yet their developmental dynamics and species-specific regulation in grapes remain poorly understood. This study monitored 18 volatile phenols and identified 20 glycosidic precursors during berry development in three East Asian grape species (Vitis davidii, V. quinquangularis, V. amurensis) and V. vinifera cv. Cabernet Sauvignon from two regions (Ningxia and Changli). Using a pseudo-targeted metabolomic approach coupled with UHPLC-qTOF-MS/MS, we profiled precursors of m/p-cresol, guaiacol, 4-vinyl-phenol, 4-vinyl-guaiacol, isoeugenol, and coniferaldehyde. Time-series analysis revealed markedly distinct accumulation patterns: East Asian species showed progressive accumulation of volatile phenols and higher precursor concentrations than V. vinifera, with V. davidii exhibiting the highest levels. Cabernet Sauvignon displayed contrasting regional patterns—gradual accumulation in Changli versus an early peak followed by decline in Ningxia. Six precursors were exclusive to East Asian species, indicating species-specific glycosyltransferase activities and serving as potential markers for predicting varietal identity. Widespread precursors (e.g., glycosidic m/p-cresol, isoeugenol, and coniferaldehyde) showed strong positive correlations with their volatile phenols, demonstrating predictive potential. Collectively, these results provide a systematic analysis of the expression of volatile phenols and their precursors and reveal pronounced metabolic differences between East Asian and V. vinifera grapes, as well as between growing regions. This knowledge provides actionable guidance for vineyard management, varietal selection, and wine style development.