The Psychophysical Relationship Between Color and Sodium Chloride Concentrations in Model Systems

A 10-member taste panel evaluated the effect of color on salt perception using magnitude estimation. Samples, colored to simulate commercial chicken broth were formulated by addition of increasing amounts (0.00 - 4.10%) of 0.05% FD&C Red 40 to a constant volume of 0.10% FD&C Yellow 5 in double-distilled deionized water. In each of four experiments, five color intensities were evaluated at five NaCl concentrations over a range of 0.14 - 1.06% (w/v). The Gardner XL - 23 colorimeter was used to obtain L, a and b values from which the objective color parameter log cot^-1 (a/b) was calculated. Log cot^-1 (a/b) correlated well with log color intensity and was therefore, suitable as a predictor. In all experiments, panelists were able to detect differences among the NaCl concentrations (P<0.001) regardless of color. The perception of saltiness increased with increasing salt concentration as a linear power function with slopes greater than one. Although color tended to confuse the perception of saltiness, this effect was not significant.