Impact of enological enzymes on aroma profile of Prosecco wines during second fermentation and sur lie aging

Abstract

Proseccco is a famous italian Protected Designation of Origin (PDO) produced in two regions: Veneto e Friuli Venezia Giulia, however, the production is mainly concentrated in the province of Treviso. These territories are characterized by plains with some hilly areas and temperate climate. Its Production regulation provides a minimum utilization of 85% of Glera grapes, a local white grape variety, and up to a maximum of 15% of other local and international varieties. Prosecco second fermentation takes place, according to the Charmat method, in autoclaves.

As a results of this, Prosecco is characterized by floral and fruity notes being perceived as a every-day wine. However, a possible product differentiation in order to reach new market niches could be achieved though wine aging on yeast lees in autoclave after secondary fermentation in order to promote yeast lysis and compounds extractions from their cells (mannoproteins, polysaccharide, amino acid). These compounds have an impact on mouthfeel and could improve wine organoleptic characteristics. A strategy to accelerate this process, it is the usage of specific enzymes during second fermentation.

The aim of this study was to investigate the effect of the addition of enzymes during secondary fermentation and aging on Prosecco wine volatile compounds composition by GC-MS techniques.

For the purpose of this study a base wine prepared for second fermentation, supplemented with five different pectolytic enzymes (plus a control) and fermented with two different yeasts. Second fermentation was performed at 16 °C. Samples were analyzed at the end of second fermentation and after one and three months of sur lie aging.

The results showed few differences between the different enzymes in the aromatic profile, more differences were found in the later stages of aging. In light of the use of different yeasts, a fair yeast-enzyme interaction was observed. In particular, a significant effect in both batches was observed for the biochemical classes of norisoprenoids (TPB, TDN, and vitispirane), terpinen-4-ol, ethyl cinnamate, and DMS. The significant effect of ethyl cinnamate was associated with increased cinnamyl esterase activity of a particular enzyme preparation. Effects due to yeast-enzyme interaction have been observed on other compounds, particularly terpenoids such as linalool, geraniol, α-terpineol and geranyl acetate.

In conclusion, the use of pectolytic enzymes is an excellent way to modulate mouthfee