Evolution of cabernet sauvignon wines macerated with their own toasted vine-shoots

Abstract

Toasted pruning vine-shoots represent a promising new enological tool for developing wines with chemical and organoleptic high quality, allowing that the resources of the vineyard to be returned to the wine through a “circular process”.
In this work, Cabernet Sauvignon wines were macerated after malolactic fermentation with their own toasted vine-shoots fragments in two different doses and after removed them, aged in bottle. The quality of wines was analyzed at bottling time and after  120 days, in terms of phenolic compounds by HPLC-DAD, volatile composition by SBSE-GC-MS and at sensory level by a specific scorecard.
Regarding volatile compounds, results showed that at bottling time the greatest differences with respect to the control wine were observed when the lowest dose of toasted vine-shoots was used. These wines showed an increase in the total of alcohols and aldehydes, along with some volatile phenols such as guaiacol or syringol and some terpenes as geraniol or linalool. However, after  bottling time the content of volatile compounds in wines from vine-shoot treatments increased significantly to higher total levels of volatile compounds than the control wine. Moreover, vanillin was detected in all wines after ageing in bottle with slightly higher content in wines macerated with the lowest dosage of vine-shoots.
In terms of phenolic compounds, wines elaborated in contact with vine-shoots showed a lower content of total phenolic compounds than the control wine at bottling time.
Nevertheless, after  bottling time, wines treated with the lower dose of vine-shoots showed an increase in total phenolic compounds until similar levels of control wine, which reduced their content along bottling. This suggests a better evolution of wines macerated with lower doses of toasted vine-shoots. In detail, stilbenes were the only family of phenolic compounds that increased its concentration as a consequence of vine-shoots maceration. trans-Resveratrol increased significantly when vine-shoots were used, reaching levels up to 9 times higher than the control wine, and viniferine was observed at the endo of bottling time in all wines, but with a higher concentration in treated wines. In addition, and as expected, the total anthocyanin content was reduced in all wines with bottle aging, which was less in wines from the lowest dose of vine-shoots.
Finally, in terms of sensory analysis, wines from vine-shoots treatments showed enhanced notes like nuts, toasted, and sweet woody, being this last one associated with the use of toasted vine-shoots, as well as a reduction in the vegetal descriptors characteristic of the Cabernet Sauvignon variety.