STUDIES ON AFTER-TASTE OF VARIOUS TASTE STIMULI IN HUMANS

This series of experiments was performed in order to evaluate the physiological characteristics and patterns of after-taste of various taste substances. The durations of after-taste following monosodium glutamate (MSG), inosine-5′-monophosphate (IMP) and guanosine-5′-monophosphate (GMP) (umami substances) were longer than those for sucrose, NaCl, tartaric acid and quinine-HCI at concentrations corresponding to the recognition threshold. The periods of after-taste of solutions of MSG and IMP, and MSG and GMP, were longer than those for the single component solutions. Most subjects recognized sucrose as sweet, NaCl as salty, tartaric acid as sour and quinine-HCI as bitter, both in terms of immediate taste and after-taste. According to the patterns of after-taste for umami substances, the subjects were divided into three groups. In group A, umami (appealing, savory taste in Japanese cuisine) was the main quality of the after-taste sensation; in group B, an indefinite, equivocal taste was the characteristic quality of the aftertaste; and no difference was reported in group C between the immediate taste and after-taste. These results suggest that the characteristics of after-taste for MSG, IMP and GMP are different from those of the four basic tastes. © 1990 Oxford University Press.