Effect of a commercial tannin on the sensorial temporality of astringency

Abstract

Astringency is a tactile sensation that is generated by a reduction in lubrication in the oral cavity and is generally attributed to the interaction of procyanidins or condensed tannins with salivary proteins. Several factors influence tannin-protein interactions, such as pH, alcohol, sweetness, oxygen and polyphenol content. A scarcely studied factor is the effect of the tannin content on the perception of astringency. The objective of this study was to evaluate the effect of different concentrations of commercial oenological tannin (COT) on the timing of the perception of astringency. For this model, a vinous solution enriched with three concentrations of COT was used. The samples were subjected to a storage period of three months. Additionally, a panel was trained in the perception of astringency in red wines using a method of temporal dominance of sensations (TDS). Astringency descriptors were selected, and the TDS method was used to characterize the astringency. The samples were evaluated using traditional descriptors in TDS and astringency descriptors in TDS.In traditional TDS curves, treatments with higher concentrations of COT showed a higher and more persistent dominance index in the descriptor astringency. Moreover, the stimulus duration variable increased as the COT level increased. Likewise, temporary astringency was dominant over alcohol. For astringency TDS, at low concentrations of COT, the soft and adhesive descriptors were dominant, whereas at high COT concentrations, aggressive and drying were perceived as the dominant descriptors. An increasing concentration of tannin in the vinous solution generated an increased duration and dominance of astringency and reduced the duration of the sensation of alcohol. Finally, the type of perceived astringency was closely related to the tannin concentration.