| Abstract: | Taste interactions between salts (NaCl, LiCl, KCl, L-arginine:L-asparticacid, Na-acetate and Na-gluconate) and bittertasting compounds(urea, quinine HCI, magnesium sulphate, KCI, amiloride HCI andcaffeine) were investigated. In each study binary combinationsof three or four concentrations of one bitter compound withfour concentrations (0, 0.1, 0.3 and 0.5 M) of one salt wererated for bitterness and saltiness using the method of magnitudeestimation. In most cases, perceived bitterness was suppressedby salts, although the degree of suppression varied. In general,bitterness suppression was not accompanied by an equivalentreciprocal suppression of saltiness. Only MgSO4 and amiloridehad suppressing effects on the saltiness of NaCl at the intermediateconcentrations and no bitter compound affected the saltinessat the high concentrations of NaCl. Since salt suppressed thebitterness of urea effectively, a detailed analysis of suppressionof the bitterness of urea by different salts was conducted.Those studies indicated that the key component in this effectwas the sodium or lithium ion for two reasons: first, all threesodium salts and the lithium salt had a suppressive effect onbitterness, whereas KCl did not; secondly, the effect of a salton suppression of the bitterness of urea was independent ofits perceived saltiness; that is, NaCl, Na-acetate (which isperceived as less salty than NaCl), and Na-gluconate (whichis perceived as less salty than Na-acetate) reduced bitternesscomparably. These results suggest that there is a major peripheralcomponent to the suppression of the bitterness of urea, andperhaps other bitter tasting compounds, by sodium. Chem. Senses20: 609–623, 1995. |
