This research note explored the sensory and analytical effects of adding grape seed extract (GSE; 0.0, 0.5, 1.0, 2.5 and 5.0 g/L) to a commercial red wine. Total phenol, color intensity and hue analyses were conducted. 

Sensory profiling, using 12 trained judges, evaluated the intensity of astringency, fruity and woody/earthy aromas, and red color of the wines. Special care was taken to avoid perceptual biases among the sensory attributes, by conducting the astringent, aromatic and color determinations independently of one another. 

Analyses of variance were used to evaluate the sensory effects, while regression analyses were used to relate the mean sensory attributes to the GSE concentrations. 

Positive linear regressions were observed between GSE and astringency (R2 = 0.841), woody/earthy aroma (R2 = 0.933) and color (R2 = 0.925), while a negative linear regression was observed for fruity aroma (R2 = 0.911). 

The presence of GSE significantly enhanced the woody/earthy aroma and suppressed the fruity aroma. 

This research note demonstrated that GSE not only influenced the mouthfeel of a wine, but also the color and aroma. Because the perceived sensory attributes (astringency, color, fruity and woody/earthy) are highly correlated [0.801 ≤ R ≤ 0.982] and dependent on the type of wine and GSE, winemakers are advised to conduct in-house trials prior to tannin adjustments in the cellar. 

As demonstrated in this research note, the sensory changes can be successfully modeled using linear regression to allow winemakers to predict the change in aroma, color and astringent attributes, associated with the addition of GSE.

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