ADAPTATION OF SWEETENERS IN WATER AND IN TANNIC-ACID SOLUTIONS

Adaptation of sweeteners in water and in tannic acid solutions. PHYSIO L BEHAV 55(3) 547-559, 1994.-Repeated exposure to a tastant often lead s to a decrease in magnitude of the perceived intensity; this phenomen on is termed adaptation. The purpose of this study was to determine th e degree of adaptation of the sweet response for a variety of sweetene rs in water and in the presence of two levels of tannic acid. Sweetnes s intensity ratings were given by a trained panel for 14 sweeteners: t hree sugars (fructose, glucose, sucrose), two polyhydric alcohols (man nitol, sorbitol), two terpenoid glycosides (rebaudioside-A, stevioside ), two dipeptide derivatives (alitame, aspartame), one sulfamate (sodi um cyclamate), one protein (thaumatin), two N-sulfonyl amides (acesulf ame-K, sodium saccharin), and one dihydrochalcone (neohespelidin dihyd rochalcone). Panelists were given four isointense concentrations of ea ch sweetener by itself and in the presence of two concentrations of ta nnic acid. Each sweetener concentration was tasted and rated four cons ecutive times with a 30 s interval between each taste and a 2 min inte rval between each concentration. Within a taste session, a series of c oncentrations of a given sweetener was presented in ascending order of magnitude. Adaptation was calculated as the decrease in intensity fro m the first to the fourth sample. The greatest adaptation in water sol utions was found for acesulfame-K, Na saccharin, rebaudioside-A, and s tevioside. This was followed by the dipeptide sweeteners, alitame and aspartame. The least adaptation occurred with the sugars, polyhydric a lcohols, and neohesperidin dihydrochalcone, Adaptation was greater in tannic acid solutions than in water for six sweeteners. Adaptation of sweet taste may result from the desensitization of sweetener receptors analogous to the homologous desensitization found in the beta adrener gic system.