| The wine matrix includes a variety of compounds that influence wine quality. The overall objective of this study was to examine the relationship between the matrix components and sensory attributes of wine. To address the issue on wine quality as related to tannin and polymeric pigments, the effect of initial tannin concentration, storage time and temperature on chemical and sensory properties of young bottled Cabernet Sauvignon and Merlot wines was studied. In general, storage treatment resulted in a significant increase in small polymeric pigment (SPP) with a decrease in anthocyanin ( p ≤ 0.05). Tannin concentration was directly related to large polymeric pigment (LPP) and correlated with perceived astringency (r = 0.882). Increased perceived bitterness was associated with storage at 32ºC for 70 days. In addition to tannin content in wine, further experiments investigated the interaction of tannin with ethanol and fructose concentrations on the headspace concentration of eight odorants in model wine. In general, increased tannin concentration exhibited a salting-out effect while fructose induced a salting-in effect, both of which were largely dependent upon ethanol concentration. The net magnitude effect was a reduction in the odorants' headspace concentration dominated by ethanol. Odor detection thresholds increased between 2 and 10,000-fold, lowering the odor unit values (OUV). The impact of ethanol, tannin and fructose concentrations on the sensory properties of model red wines was also evaluated. Principal component analysis (PCA) differentiated the model wines based on factor 1 (floral, fruity and caramel), factor 2 (earthy and herbaceous) and factor 3 (sulfur, spicy, woody, and bitterness). Analysis of variance (ANOVA) results showed a significant impact of ethanol concentration on these factors (p<0.05). Tannin and fructose, and all interaction effects were not significant. These results highlighted the influence of major wine components and their interactions on sensory perception. Viticulturists and winemakers are suggested to consider the information obtained in this research when making decisions to optimize wine quality. |
