| Abstract: | Astringency, astringent subqualities (drying, roughing and puckering)and sourness were compared among six acids: hydrochloric, lactic,citric, acetic, fumaric and malic acids. The attribute profilesof organic acids were similar to each other but different fromhydrochloric acid, the only inorganic acid, which was the mostastringent and the least sour. In a second experiment, two inorganicacids (hydrochloric and phosphoric) and two organic acids (citricand malic) were tested at three concentration levels. At approximatelyequal levels of overall sensory impact, the inorganic acidswere alike in astringency and sourness, receiving higher ratingsfor roughing and drying, and lower ratings for sourness thanthe organic acids. Interactions with concentration (differencesin psychophysical functions) for the subquality of drying werenoted, in addition to the differences in the astringent subqualitiesof roughing and drying seen across acids in both experiments.The higher level of astringency for inorganic acids suggeststhat the current model for tannin binding to salivary proteinsas an explanation of astringency needs to be extended to includea direct pH-dependent effect. Chem. Senses 20: 593–600,1995 |
