SENSORY CHANGES IN UMAMI TASTE OF INOSINE 5'-MONOPHOSPHATE SOLUTION AFTER HEATING

Discrimination in umami taste of inosine 5'-monophosphate (IMP) solution caused by thermal degradation was investigated by sensory evaluation. The difference threshold of umami taste of 0.005% IMP solution in the presence of 0.05% monosodium glutamate (MSG) was 0.002%. The difference threshold of a 0.005% IMP solution decreased by about one half when heated at 95-degrees-C for 15 h. Inosine, one of the main products of the thermal degradation of IMP, had a bitter taste. The detection threshold of inosine varied widely among panelists. Heating a 0.005% IMP solution at 95-degrees-C for 15 h formed inosine at about one tenth of its lowest detection threshold.