ELECTRICAL RESPONSES OF A WATER OCTANOL/WATER LIQUID MEMBRANE TO TASTE SUBSTANCES/

Examination was made of electrical potential oscillation across the li quid membrane of a water/octanol/water system in the presence of five types of primary taste substances, imparting bitterness (quinine hydro chloride and berberine hydrochloride), sweetness (sucrose and glucose) , sourness (hydrochloric acid and citric acid), saltiness (sodium chlo ride and potassium chloride) and umami (sodium glutamate and sodium in osinate) at concentrations from 0.01 mM to 1 M. Each exerted effect on the mode of oscillation, particular so on the potential of the liquid membrane immediately following contact of the octanol solution with t he aqueous solutions, potential just before oscillation and low potent ial of the first oscillation. The effects of substances in the same ta ste category on oscillation were essentially the same. Effect intensit y showed the following order: bitter approximate to sour < salty appro ximate to umami < sweet substances. The oscillation mode for drugs (de xtromethorphan hydrobromide and doxycycline hydrochloride) corresponde d to that due to bitter substances, and the drugs and 10% simple syrup (a flavoring agent prescribed by the Japanese Pharmacopoeia), sweet s ubstances. It thus follows that the degree of modification of drug bit terness by simple syrup may be evaluated by the octanol membrane.