A flow procedure was used to measure the sensitivity of two subjects to NaCl stimuli after adaptation to 10 mM and 30 mM NaCl. The signal detection rating procedure was used and thirteen receiver operating characteristic (R.O.C.) curves obtained. Assumptions of normality and equal variance for the noise and signal plus noise distributions were upheld while d′ and nonparametric P( A) values were found to be comparable to those reported in earlier threshold studies. Advantages of the technique are discussed.

Taste intensity functions were constructed for the salt taste, using variations of the method of direct magnitude estimation, to study the effects of adaptation to residuals from prior tastings. The prediction that mouthrinsing would reduce residuals, lower the level of adaptation, and thus yield lower exponents was confirmed. The effect of the residuals tended to be reduced, however, when the power functions were adjusted for such threshold changes. Power function deviations from linearity were also discussed. The literature on intensity scaling for the salt taste was examined and seen to support these findings. It was concluded that the interstimulus procedure, by altering residual stimulus levels, played a major role in determining salt taste intensity functions.

Descriptive analysis of foods involves the communication of sensory concepts which are defined using standard stimuli. The concept created by a single NaCl standard stimulus was measured as a set of probabilities. It was found not to be the same for each judge. Disagreement between judges can thus be caused by variations in conceptualization, as well as sensation. This has important implications for the definition of terms in descriptive analysis. The concept was found not to generalize to strong monosodium glutamate (MSG) stimuli which raises questions about reports that MSG tastes salty at high concentrations. Effects on the concept of context, time and variation of standards were also noted.

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The umami taste concept for a group of judges was measured by a categorization task with food stimuli. The concept was defined to the judges in two ways: jirst, by verbal description and second, by presenting the judges with standard stimuli: broths made from kombu, katsuobushi and shiitake. The concepts obtained in both instances were close, both for Japanese and American judges. Thus. the umami term could be communicated relatively accurately in sales and marketing without the need for physical standards.