Nanoencapsulated carvacrol: a new fungicide for grapes that has no impact on the fermentation and remains undetectable in the wine aroma
摘要
Carvacrol is recognized as a potentially effective natural antifungal agent. Encapsulation has been proposed to mitigate the characteristic odor of this monoterpene derived from oregano oil. The objective of this study was to evaluate the influence of the grape treatment with carvacrol on the physicochemical properties and volatile profile of the resulting wines. Encapsulation was carried out using a synthetic (Eudragit®) and a natural option (chia mucilage) of wall material. The alcohol content, total acidity, volatile acidity and pH of wines produced from grapes treated with carvacrol were similar to those of the control wine. A total of 66 compounds were identified in the volatile profile of Cabernet Sauvignon wines analyzed by HS-SPME-GC/MS. The Fisher ratio indicated that 44 compounds had discriminatory power to be included in a heatmap and hierarchical cluster analysis. The unencapsulated carvacrol impacted the metabolic pathways of winemaking, as the levels of 89% of compounds (39 of the 44 volatiles included in the heatmap) were lower than in control wines. Conversely, grapes treated with encapsulated carvacrol resulted in wines with a volatile profile similar to the control wine, which predominantly exhibited positive odor descriptions for quality (floral, waxy, and fruity, among others). Furthermore, encapsulation attenuated the odor perception of carvacrol, since the levels of this terpene were 6 times lower than its perception threshold (18 µg L-1) and around 40 times lower than in wines made with grapes treated with unencapsulated carvacrol. The nanoencapsulation of carvacrol using Eudragit® or chia is a novel alternative for controlling fungi in viticulture, without compromising fermentation and wine quality.