Enzymes Impact During Fermentation On Volatile And Sensory Profile Of White Wines

Abstract

Favoring the formation of volatile compounds and their precursors in must and wine represent one of the principal goals during winemaking technology. In recent years, most attention has been placed on using glycosidases to enlarge the aroma profile of white wines. The effect of enzymes makes odorless glycosidically-bound precursors be converted into aromatic compounds. This paper focuses to study the influence of enzymes (pectolytic and β-glycosides) administered before alcoholic fermentation, even if most studies analyze their use in different winemaking stages. Two semi-aromatic varieties such as Fetească regală and Sauvignon blanc were chosen.
Identification and separation of volatile compounds were performed using an Agilent 7890A gas chromatography system coupled with a mass spectrometer detector 5975 C inert XL EI/CI MSD. The sensory profile of the wines was evaluated by a panel of 20 licensed tasters, consisting of 12 men and 8 women. Data processing and statistical representation (Principal Components Analysis, Anova, Fisher’s Least Significant Difference, Pearson correlation coefficient) was performed using Statgraphics® software 19.  
Following the analyses performed by gas chromatography, there were identified over 65 volatile compounds, depending on the grape variety. Fetească regală wines were described by higher proportions of ethyl octanoate (peach, pear, exotic fruits notes), 3-methylbutyl acetate (with fruity, pear, banana aroma), hexanoic acid (lactate, phenolic and exotic fruits odors), propan-2-yl acetate ethereal, ripe fruits, banana odor) and ethyl decanoate (floral, fruity, woody notes), while Sauvignon blanc wines were distinguished by considerable proportions of 2-methylpropan-1-ol (with spirits and solvent odor), 3-methylbutan-1-ol (banana, solvent notes), diethyl butanoate (fruity, floral, waxy, dusty odors), 1-phenylethanol (floral and honey flavors), and acetic acid (vegetal, rancid, sour perceptions). Numerous positive correlation were identified in both varieties, including propan-1-ol vs 3-methylbutan-1-ol, 3-methylbutyl acetate vs ethyl hexanoate and butan-1-ol vs octandecanoic acid in Fetească regală wines and diethyl butanoate vs 3-methylbutan-1-ol, ethyloctanoate vs propan-2-yl acetate, ethyl octanoate vs ethyl 4-hydroxybutanoate in Sauvignon blanc. Data confirmed a significant influence.