Selective inhibition of sweetness by the sodium salt of +/- 2-(4-methoxyphenoxy)propanoic acid

The purpose of this study was to determine the degree to which the sodium s alt of +/-2-(4-methoxyphenoxy)propanoic acid (Na-PMP) reduced sweet intensi ty ratings of 15 sweeteners in mixtures, Na-PMP has been approved for use i n confectionary/ frostings, soft candy and snack products in the USA at con centrations up to 150 p.p.m. A trained panel evaluated the effect of Na-PMP on the intensity of the following 15 sweeteners: three sugars (fructose, g lucose, sucrose), three terpenoid glycosides (monoammonium glycyrrhizinate, rebaudioside-A, stevioside), two dipeptide derivatives (alitame, aspartame ), two N-sulfonylamides (acesulfame-K, sodium saccharin), two polyhydric al cohols (mannitol, sorbitol), 1 dihydrochalcone (neohesperidin dihydrochalco ne), one protein (thaumatin) and one sulfamate (sodium cyclamate). Sweetene rs were tested at concentrations isosweet with 2.5, 5, 7.5 and 10% sucrose in mixtures with two levels of Na-PMP: 250 and 500 p.p.m. in addition, the 15 sweeteners were tested either immediately or 30 s after a pre-rinse with 500 p.p.m. Na-PMP. in mixtures, Na-PMP at both the 250 and 500 p.p.m. leve ls significantly blocked sweetness intensity for 12 of the 15 sweeteners. H owever, when Na-PMP was mixed with three of the 15 sweeteners (monoammonium glycyrrhizinate, neohesperidin dihydrochalcone and thaumatin), there was l ittle reduction in sweetness intensity. Pre-rinsing with Na-PMP both inhibi ted and enhanced sweetness with the greatest enhancements found for monoamm onium glycyrrhizinate, neohesperidin dihydrochalcone and thaumatin, which w ere not suppressed by Na-PMP in mixtures. The mixture data suggest that Na- PMP is a selective competitive inhibitor of. sweet taste. The finding that pre-treatment can produce enhancement may be due to sensitization of sweete ner receptors by Na-PMP.