Na+ Binding as Measured by 23Na Nuclear Magnetic Resonance Spectroscopy Influences the Perception of Saltiness in Gum Solutions

Binding of Na⁺ in aqueous gum systems as determined by ²³Na 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 (R₂, see^?l) 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, R₂ values converged and perceived saltiness equalized. Food components that bind Na⁺ may suppress saltiness perception, which may be important in low-sodium foods.