Achieving a satisfactory aroma and phenolic maturity at harvest is key to producing quality wines. A foliar spraying treatment with yeast derivatives was tested on the grape (Vitis vinifera L.) varieties Chardonnay, Cortese, Barbera, and Nebbiolo. The treatment was carried out at veraison with two different formulations for white and black varieties (LalVigne Aroma and LalVigne Mature, respectively) to enhance aroma and phenolic quality. The influence of the treatments on berry skin thickness was also evaluated. The analyses were carried out on grapes at harvest and experimental wines were produced and analyzed. The berry distribution of Chardonnay and Cortese grapes in density classes, obtained by flotation in saline solutions, evidenced smoother ripening of treated berried and resulted in an average increase in must acidity without affecting sugars accumulation (Brix). Furthermore, berry skin thickness also increased in treated berries. This textural result was also found in Nebbiolo, while Barbera did not show a clear difference. Skin phenolic quality, evaluated by maceration in wine-like solutions, of Barbera was not significantly affected, probably because this variety is characterized by low skin flavanol concentrations. Instead, Nebbiolo evidenced a positive influence of the treatment in extracted and total anthocyanins and flavanols. Overall, the treatments influenced the grapes quality, providing a tool to winemakers for differentiation of the products.

Funding Support: Università degli Studi di Torino