Selective Wine Aroma Enhancement through Enzyme Hydrolysis of Glycosidic Precursors

Abstract

Selective enhancement of wine aroma was achieved using a broad spectrum of exogenous glycosidases. Eight different enzyme preparations were added to Verdejo wine, resulting in an increase in the levels of varietal volatile compounds compared to the control wine after 15 days of treatment. The enzyme preparations studied were robust under winemaking conditions (sulfur dioxide, reducing sugars, and alcohol content), and no inhibition of β-glucosidase activity was observed. Significant differences were detected in four individual terpenes (α-terpineol, terpinen-4-ol, α-pinene, and citronellal) and benzyl alcohol in all the treated wines compared to the control wine, contributing to the final wine to varying degrees. In addition, a significant increase in the other aromatic compounds was observed, which showed different patterns depending on the enzyme preparation that was tested. The principal component analysis of the data revealed the possibility of modulating the different aromatic profiles of the final wines depending on the enzyme preparation used. Taking these results into account, enhancement of the floral, balsamic, and/or fruity notes of wines is possible by using a suitable commercial enzyme preparation.

Keywords: aroma; glycosidases; terpenes; varietal aroma; white wine.

Figure 1

Pareto chart of Box–Behnken design for β-glucosidase activity of the commercial enzyme preparations (E1–E8) (FS: free sulfur dioxide; RS: reducing sugars; AG: alcoholic grade). Black and blue bars represent positive and negative standardized effect values, respectively. Factors that extend beyond the vertical dashed line are significant at p < 0.05.

Figure 2

Principal component analysis of VOCs of wines. VOC codes: T1: α-Terpineol; T2: Eucalyptol; T3: Terpinen-4-ol; T4: Citronellal; T7: α-Pinene; T8: Citronellol; T9: Linalool; T10: Limonene; P2: Benzyl alcohol; P3: Eugenol; P4: Methyl eugenol. Wine codes: E1–E8: enzyme-treated wines; C: control wine. For this analysis, VOCs with statistically significant differences (p < 0.05) among the wines have been used.