Effect of polyphenol concentrations on astringency perception and its correlation with gelatin index of red wine

Abstract

The aims of this work were to investigate the effect of polyphenol concentrations on astringency perception and gelatin index measurements in noncommercial red wines, as well as evaluate astringency evolution over time. Spearman coefficients showed a positive correlation between polyphenols at low concentration with gelatin index (P < 0.001), and astringency (P < 0.05). Gelatin index values and polyphenol concentrations were related by a power function at low polyphenol levels, but no correlation was shown when total polyphenol levels overcame 5.20 g/L. Similar relationships were found between perceived astringency/gelatin index, and astringency/polyphenol concentrations. It was evident that gelatin index was a better estimator of astringency when polyphenol levels were low, and astringency intensity did not increase when polyphenol concentrations were higher than 5.20 g/L. Timeintensity measurements of astringency showed that maximum intensity governed the evolution of sensation.