Abstract
Background: To obtain wines with a lower percentage of alcohol, the simplest approach would be an earlier harvest of the grapes. However, this has implications for the wine composition and quality, due to the lack of phenolic maturity that these grapes may present. A technological innovation that could help in this situation could be the use of ultrasound in wineries. Methods: Grapes were harvested with two different ripening levels (25.4 °Brix and 29 °Brix), transported to the winery, and vinified. Also, a large-scale high-power ultrasound system was used to treat part of the less mature grapes just after crushing. These grapes were also vinified. The three different vinifications were skin-macerated for 7 days. The wine aroma compounds and physicochemical, chromatic, and sensory characteristics were analyzed at the time of bottling. Results: The wine made with the ultrasound-treated grapes showed very similar characteristics to the wine made with the more mature grapes, especially regarding total phenol and tannin content, but with an alcohol content 15% lower than the latter. Conclusions: The results indicate that this technology could be applied to grapes to favor the extraction of grape phenolic compounds, even when grape phenolic maturity is not complete, allowing the production of quality wines with a reduced alcohol content.
Highlights
Color is one of the most important quality attributes in red wine
Many of the studies about the characteristics of wines made from grapes with different ripening degrees were done on grapes sampled at different times during ripening
It is important to point out that the system used in this study differs from those used in previous studies, where high-power ultrasounds (HPUs) have been applied during wine elaboration, since almost all of them used laboratory scale systems, either ultrasonic baths or probes, whereas in this study a winery scale system with a continuous on-line must treatment has been used
Summary
Color is one of the most important quality attributes in red wine. It depends on the phenolic composition of the wine (a composition that does affects wine color, and body and mouthfeel), and is closely bound to the grape phenolic composition.Grape phenolic compounds are mainly located in the skin (anthocyanins and tannins) and seeds (tannins), and are extracted to must during the crushing and maceration period. When grapes are phenolically immature, the skin phenolic compounds are not extracted, even when present at high concentration, yet high concentrations of the astringent seed tannins can be present [4,5]. This situation changes when phenolic maturity is reached, cell walls are degraded, and phenolic compounds are extracted [2]. To obtain wines with a lower percentage of alcohol, the simplest approach would be an earlier harvest of the grapes This has implications for the wine composition and quality, due to the lack of phenolic maturity that these grapes may present. Results: The wine made with the ultrasound-treated grapes showed very similar characteristics to the wine made with the more mature grapes, especially regarding total phenol and tannin content, but with an alcohol content
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
