Interaction of astringency and taste characteristics

The perception of astringency and basic taste in mixtures and their interac tion effects were investigated by two procedures. In Experiment 1, focused and nonfocused testing procedures were compared using mixtures of low and h igh concentrations of alum and basic taste solutions. Both procedures yield ed taste and astringency intensities that were modality-dependent. Nonfocus ed testing was used in Experiment 2 to investigate the interactions of astr ingent phenolic (tannic acid) and nonphenolic (alum) compounds with each ba sic taste. Sweetness of sucrose increased with increased concentration with or without alum or tannin present. Changes in salty, bitter, and sour tast e intensities were modality-dependent. Astringency either remained unchange d or decreased with the addition of sucrose, sodium chloride, citric acid, or caffeine depending upon the taste concentration. Bitterness of tannin an d alum at high concentrations was suppressed by the addition of sucrose, so dium chloride, or citric acid; sourness also decreased in the presence of s ucrose or sodium chloride as well as a high level of caffeine.