MSG: Psychophysical Evaluation and Biomolecular Analysis of Saltiness

OTERO-LOSADA, M.

Harrogate, North Yorkshire, England

Congreso; 6th Pangborn Sensory Science Symposium; 2005

Psychophysical Evidence of Monosodium Glutamate Enhancing Effect on Saltiness Perception. Monosodium glutamate (MSG) is a known flavor enhancer. We reported that MSG shortens reaction time to saltiness perception (SP) at low NaCl concentrations. This work provides objective records of MSG-induced enhancement of SP using conventional psychophysical methodology (converging limits, CL). Stimuli: aqueous solutions of NaCl, NaCl+MSG, NaCl+KCl, NaCl+MSG+KCl, KCl, MSG and KCl+MSG. Concentrations: NaCl 12.5, 25, 50, 100, 200 mM; KCl:NaCl ratio 2:1; MSG 4.32, 10.80, 27.00, 67.50, 168.75 mM (27 mM in mixtures). CL estimations were plotted against concentration and psychophysical slopes (b, Steven´s coefficient) calculated. Results were analysed by two-way ANOVA followed by the least significant difference test (LSD). b values , r2 (regress. coeff.) were: 0.80 ± 0.06, r2=0.98 (NaCl); 0.60 ± 0.01, r2=0.99 (NaCl+MSG); 0.69 ± 0.04, r2=0.99(NaCl+KCl); 0.65 ± 0.04, r2=0.99 (NaCl+MSG+KCl); 0.49 ± 0.05, r2=0.97 (MSG); 0.66 ± 0.02, r2=0.99 (KCl); 0.58 ± 0.04, r2=0.99 (KCl+MSG). Concentration (P<0.0001), panelist (P< 0.0001) and salt (P< 0.001) affected SP and salt interacted with concentration (P<0.0001). KCl and (NaCl+MSG+KCl) solutions were different to MSG, NaCl and NaCl+MSG solutions (LSD, P<0.05). Thus b NaCl >bKCl >b MSG. MSG or KCl flattened response to NaCl. MSG specifically affected NaCl. MSG addition to NaCl+KCl mixtures was ineffective. b NaCl reduction by MSG or KCl resulted from increased SP at low NaCl levels (salt-concentration interaction) probably reflecting increased affinity of NaCl for its receptor sites. The flavor enhancing effects of MSG are NaCl specific. Proposed alternatives to reduce NaCl without reducing food flavor are: KCl or MSG combinations with NaCl. Qualitative differences in sensation usually turn consumers´ acceptance towards MSG choice.