Sodium chloride suppresses vegetable bitterness only when plain vegetables are perceived as highly bitter

The efficacy of sodium salts as bitterness suppressors is highly variable depending on the tastants used, and few studies have investigated whether salt can mask the bitterness of nutritious vegetables. We compared how sodium chloride (NaCl) affected bitterness ratings of vegetables and quinine hydrochloride (QHCl). In Experiment 1, Brussels sprouts and cauliflower were rated plain and with the addition of NaCl on hedonic and sensory attributes. In Experiment 2, multiple concentrations of NaCl were given on the vegetables, and participants tasted QHCl plain and with the addition of NaCl. In both experiments, reported bitterness and liking of the vegetables did not change with the addition of NaCl; all p values > 0.3. Hierarchical linear regression modeling revealed that NaCl decreased the bitterness ratings of the vegetables most for participants who perceived the plain vegetables as highly bitter, R ² = 0.211, and increased hedonic ratings of the vegetables most for participants who disliked the plain vegetables, R ² = 0.243. The addition of NaCl to QHCl significantly reduced bitterness ratings, p < 0.001, especially for participants who found the plain QHCl highly bitter, R ² = 0.339. Sodium chloride suppressed bitterness and increased liking for participants who disliked plain vegetables and tasted them as highly bitter. These results suggest that NaCl would be efficacious as a bitterness masking agent for people particularly vulnerable to vegetable underconsumption. Furthermore, NaCl might interact fundamentally differently with a full food matrix than it does with QHCl, limiting the generalizeability of chemical suppression studies.