NA+ BINDING AS MEASURED BY NA-23 NUCLEAR-MAGNETIC-RESONANCE SPECTROSCOPY INFLUENCES THE PERCEPTION OF SALTINESS IN GUM SOLUTIONS

Binding of Na+ in aqueous gum systems as determined by Na-23 nuclear magnetic resonance (NMR) spectroscopy and its relations to perceived saltiness were examined. Two levels of NaCl (0.1% and 0.2%) were added to two concentrations (0.1% and 0.3%) of two ionic (xanthan and kappa carrageenan) and two non-ionic (locust bean and guar) gum solutions. Saltiness perception was affected by the ionic properties of the gums. NMR transverse relaxation rates (R(2), sec(-1)) indicated Na+ was less mobile in ionic than nonionic systems. Ionic gums correspondingly suppressed saltiness perception compared to nonionic gums. As Na+ increased in both ionic and nonionic systems, R(2) values converged and perceived saltiness equalized. Food components that bind Na+ may suppress saltiness perception, which may be important in low-sodium foods.