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Title:Sodium binding as measured by sodium-23 nuclear magnetic resonance spectroscopy and its influence on saltiness perception as determined by sensory analysis
Author(s):Rosett, Terri Robertson
Doctoral Committee Chair(s):Klein, Barbara P.
Department / Program:Human and Community Development
Discipline:Human and Community Development
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Psychology, Psychobiology
Agriculture, Food Science and Technology
Health Sciences, Nutrition
Abstract:Interactions of the sodium ion (Na$\sp+$) with other food components and the effects on saltiness perception must be considered when modifying food formulations to produce reduced sodium products. This research focuses on the binding of Na$\sp+$ in aqueous gum systems as determined by $\sp{23}$Na nuclear magnetic resonance (NMR) spectroscopy and its relations to perceived saltiness. Additionally, multidimensional scaling (MDS), a non-traditional sensory testing method, and Decision Boundary (DB) theory, a comparative judgement theory never before tested with chemosensory stimuli, were studied to determine their efficiencies and applications to sensory science.
Two levels of NaCl (0.1% and 0.2%, w/v) were added to two concentrations (0.1% and 0.3%, w/v) of two ionic (xanthan and kappa carrageenan) and two nonionic (locust bean and guar) gum solutions. Aqueous nonionic locust bean (0.3%, w/v) and ionic xanthan (0.1% and 0.3%, w/v) gum systems containing NaCl, or equal weights of NaCl plus KCl, or NaCl plus CaCl$\sb2$ were also examined. $\sp{23}$Na NMR transverse relaxation rates (R$\sb2$, sec$\sp{-1}$) values indicated Na$\sp+$ was less mobile, on average, in ionic than nonionic gum systems. Ionic gums correspondingly suppressed saltiness perception compared to nonionic gums. As Na$\sp+$ increased in both ionic and nonionic systems, R$\sb2$ values converged and perceived saltiness equalized. At equivalent molar concentrations of added ions, $\sp{23}$Na NMR R$\sb2$ (sec$\sp{-1}$) values showed an increase in average Na$\sp+$ mobility with the addition of K$\sp+$ or Ca$\sp{2+}$ to the ionic gum systems. Correspondingly, salt taste increased with the addition of KCl. Enhancement of salt taste of NaCl by KCl is due, in part, to competitive binding of Na$\sp+$ and K$\sp+$ in a system. Maximizing saltiness in food formulas may be helped by selecting nonionic thickeners such as locust bean as opposed to ionic xanthan gum; adding calcium in the form of non-fat dry milk or whey; or adding potassium rich ingredients. ANOVA of saltiness intensity ratings typically used to study the sensory qualities of these systems did not provide as much information as MDS of paired comparison judgements and identification judgements analyzed by a newly developed DB model. MDS and DB theory have potential applications in basic science and applied research in both academic and food industry settings.
Issue Date:1994
Rights Information:Copyright 1994 Rosett, Terri Robertson
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9503303
OCLC Identifier:(UMI)AAI9503303

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