DIFFERENCE TASTE THRESHOLDS FOR SUCROSE IN WATER AND IN ORANGE JUICE: AN INTERLABORATORY STUDY

Abstract

Difference taste thresholds, expressed as jnd values or Weber ratios, were determined for sucrose in water and in orange juice at laboratories in Sweden, U.S.A., Poland and Switzerland using a method of constant stimuli. The following total arithmetic mean values of all 172 individual jnd values were obtained: 0.266 and 0.400% sucrose at 2 and 5% sucrose in water, respectively; 0.977 and 1.19% sucrose at 1.5 and 3.75% sucrose in orange juice, respectively. The frequency distributions of the individual values were asymetrical and showed a large variation among subjects. The results of some additional experiments at 2 and 5% sucrose in orange juice, performed only by the Polish laboratory, are reported also. Significance analyses performed according to one parametric method (t-test), using pooled data of groups of subjects, and one non-parametric method (Mann-Whitney's U-test), using individual threshold values, gave the same conclusion in practically all cases. The data indicated that females had slightly lower average discrimination thresholds than males. There was a significant degree of correlation between subjects' discriminatory ability at different concentrations of sucrose in each of the two media. Few significant differences between the laboratories were found for sucrose in water, whereas for sucrose in orange juice the following rank order, from lowest to highest average jnd value, among the laboratories was obtained for both concentrations tested: Poland < U.S.A. < Sweden = Switzerland. Some speculations were advanced as partial explanation for the differences among the laboratories.