Selective Inhibitors of Bitter Taste

Abstract

The development of a method to mask bitter taste has been actively sought after in pharmaceutical and food science. A lipoprotein (PA-LG) was found in the present study to be composed of phosphatidic acid (PA) and β-lactoglobulin (LG) was noted to selectively and reversibly suppress frog taste nerve response and human taste sensation to various bitter substances without affecting sweetness, saltiness and sourness. PA would thus appear importantly involved in inhibiting bitterness since PA-containing lipoproteins showed inhibitory action irrespective of protein species. As for the mechanism of bitter suppression, PA-LG would appear to mask the receptor site for bitterness on taste receptor membrane. Inhibitory action forward bitterness by PA itself without protein or other phospholipids in humans was examined. PA and phosphatidylinositol (PI) inhibited the bitterness of various bitter substances without affecting the taste sensation of other taste stimuli, although inhibitory activity was less than that of PA-LG. A lecithin fraction containing high content PA and PI was thus prepared from soybean lecithin on an industrial scale. The lecithin fraction showed inhibitory activity forward bitterness. This fraction and PA were thus concluded effective means for masking the bitter taste of drugs and food.