Suppression of sourness: a comparative study involving mixtures of organic acids and sugars

The degree of sourness suppression of perceptually equisour levels of citric, lactic, and malic acids by equal molar and weight amounts of sucrose, fructose, and glucose was determined in binary mixtures. Equisour acid levels were obtained by magnitude estimation. Mixture intensity ratings were collected on a categorical scale, using trained panelists. In general, equal sugar molarities and weights did not effect equivalent suppression. Instead, the perceived intensity of the sugars appeared to suppress sourness more systematically, implying that dominantly central neural mechanisms underlie suppression. This was confirmed when no significant differences were found between the suppressive abilities of sweetness-matched levels of sucrose, fructose, and an equiratio mixture of the two on citric acid sourness. The possibility of a separate receptor site/mechanism for glucose and a small peripheral component to suppression is also suggested.