苦味に対するNaClおよび塩化合物の抑制作用

Suppression of bitterness by the addition of NaCl was investigated in detail using the quantitative sensory evaluation method reported by Tanaka et al. (2024). NaCl at 5 to 80 mM suppressed the bitterness of caffeine, quinine hydrochloride, and urea in a NaCl concentration-dependent manner, regardless of the type of bitter substance. Suppression by NaCl was observed at concentrations below the recognition threshold of saltiness. Na salts (NaHCO3, Na2SO4, sodium acetate, sodium lactate, and sodium gluconate) suppressed the bitterness of caffeine equivalent to NaCl. In contrast, effects of Cl salts (KCl, CaCl2, MgCl2) and Na and Cl-free salts (MgSO4, calcium lactate) were very weak. However, N-methyl-D-glucamine (NMDG) salts (NMDG-Cl, NMDG-gluconate) that taste sweet for humans suppressed the bitterness of caffeine to the same extent as sweeteners (sorbitol, glucose). These results suggested that Na, but not Cl, suppressed bitterness at low concentrations (5 to 80 mM) in a NaCl concentration-dependent manner. NaCl effect was mainly explained by the concentration of Na in the Na salts.