INTERACTIONS OF ASTRINGENT SUBSTANCES

Two-component mixtures of astringent materials were rated for perceive d intensity of astringent and taste attributes over time. Components i ncluded alum (a complex salt), gallic acid (the monomeric component of hydrolyzable tannins), catechin (the monomeric component of condensed tannins) and citric acid. Mixtures of alum and gallic acid showed mix ture suppression, in that the 50/50 mixture was less intense than eith er component in astringency, drying, roughing and puckery/drawing sens ations. Suppression was seen at concentration levers producing moderat e to strong astringency but was absent or less pronounced at lower con centration levels. A similar pattern held for citric acid, although th e suppressive effects were less pronounced. Catechin and garlic acid m ixtures were additive. Sensory interactions between astringent materia ls appears to depend on the substances involved and their concentratio ns (or intensity levels).