Analysis of saltiness and bitterness of inorganic salts using taste sensors

The response of a taste sensor to inorganic salts was investigated. It is known that in a series of halides of monovalent alkali metals, salts with low molecular weights are salty, whereas those with high molecular weights are bitter. Salty substances such as NaCl changed the potential of positively charged membranes of the sensor in the same way as negatively charged ones. On the other hand, bitter substances affected both membranes differently. For example, inorganic salts which contain iodine ions markedly changed the potential of positively charged membranes. Large changes in membrane potential were induced by the adsorption of taste substances to lipid membranes. Hence a bitter taste seems to be attributable to adsorption.