Linking Grape Cell Wall Composition and Phenolic Release to Wine Quality: Effects of Methyl Jasmonate-Loaded Chitosan...

This study explored the effects of three elicitor treatments-methyl jasmonate (MeJ), chitosan nanoparticles (ChNPs), and their combination (MeJ-ChNPs)-on cell wall characteristics in Monastrell grapes during the 2024 vintage. The central aim was to determine whether incorporating MeJ into chitosan nanoparticles could reduce its volatility, enhance its stability, and ultimately strengthen its elicitation effect when applied in vineyards. By applying these formulations, particularly the MeJ-ChNPs complex, the research sought to understand how grape maturation, cell wall morphology, and phenolic composition could be altered, and how these changes might translate into differences in wine quality. The implementation of these MeJ formulations, and particularly MeJ-ChNPs, resulted in delayed grape maturation and pronounced changes in cell wall morphology, including increased thickness and altered phenolic composition. Grapes treated with MeJ-ChNPs showed enhanced anthocyanin biosynthesis and distinct colour properties compared to untreated controls. The findings revealed that MeJ-ChNPs delayed grape ripening and induced notable modifications in cell wall structure, including increased thickness and shifts in phenolic composition. These structural changes influenced the extractability of phenolic compounds and shaped the chromatic attributes of the resulting wines. Multivariate analyses, including principal component and correlation analyses, highlighted clear differences amongst treatment groups, emphasising the effectiveness of nanoparticle-based elicitors in changing grape skin morphology and composition and improving wine quality.