Comparison Between Sensory and Nephelometric Evaluations of Tannin Fractions Obtained by Ultrafiltration of Red Wines
Rébénaque, Pierrick ; Rawyler, André ; Boldi, Marc-Olivier ; Deneulin, Pascale
In: Chemosensory Perception, 2015, vol. 8, no. 1, p. 33-43
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- Introduction: Although the assessment of red wine quality relies primarily on a sensory description of tannins, it may be usefully completed by some knowledge of the physicochemical properties of these tannins. The present study has a double aim: (1) to gain insight into the sensory properties of subpopulations of proanthocyanidic tannins of different molecular sizes (obtained through several ultrafiltration steps), as well as into the kinetics of the haze formed by these fractions when reacted with polyvinylpyrrolidone (as measured by nephelometry) and (2) to determine whether a correlation exists between the sensory and the nephelometric data. Materials and Methods: To this end, two wines from different grape varieties were sequentially ultrafiltered to provide three tannic fractions which differed by the range of their polymerization degrees. Then, these fractions were added (individually or in combination) into their native wine matrix (previously deprived of all its polyphenols via charcoal treatment) according to a specific experimental design. These reconstituted wines were characterized by nephelometry and by a static (quantitative descriptive analysis) and a dynamic (temporal dominance of sensations) sensory method. Results and Discussion: Wines containing the largest size tannins (highest range of polymerization degrees) were perceived as more astringent and cause drying in the mouth and after spitting. Concerning the temporality of perception, wines containing the fraction with the largest tannins provide long in-mouth drying, and the astringency and in-mouth drying perceptions were the most persistent features. Conclusion: Finally, a highly positive correlation between nephelometric and quantitative descriptive analysis data was shown.