12-3 |
Zinc and taste; implications for food and oral care products |
R. S. J. KEAST and P. A. S. Breslin. Monell Chemical Senses Center, 3500 Market St., Philadelphia, PA 19104-3308 Zinc is an essential micronutrient with multiple potential health benefits for humans; these include a treatment for the common cold, co-factor of numerous enzyme reactions, and a component of biomembranes. Zinc salts are added to food, pharmaceutical and oral care products. However, this alters the taste of the product. The objective was to assess the taste and somatosensations of a variety of zinc salts, and the impact of zinc on other taste stimuli using human psychophysical methodology. First, five zinc salts were described (chloride, acetate, sulfate, iodide, bromide) at three different concentrations (5, 25, 50mM). Second, the same salts were adapted in the mouth for 10 seconds and the taste of subsequent water rinses was described. Third, the effect of zinc salts on sweetness (sucrose, aspartame, sodium saccharin, sodium cyclamate and glucose) and bitterness (pseudoephedrine, dextromethorphan, quinine, and tryptophan) was examined. Subjects (16) were trained to identify separate taste qualities and somatosensations. Subjects were asked to rate five taste qualities (sweet, sour, bitter, savory, salty) and two somatosensations (tingle, astringency) using the Labeled Magnitude Scale. Each possible binary stimulus combination was presented to each subject on 3 separate occasions. Zinc was described as a weak combination salty, savory, bitter and sour although the choice of anion significantly (p<0.001) affected these qualities. Astringency was the predominant sensation from zinc and there were significant differences between anions (p<0.001). The lingering taste of zinc was washed away by water; however, the astringency remained. Zinc salts significantly inhibited sweetness (p<0.001) and differentially inhibited bitterness (p<0.05). Addition of zinc to orally consumed products will add astringency and affect the taste quality of the product by inhibiting sweetness and possibly bitterness. Inhibition of sweetness could also cause an increase in bitterness in products due to a release of suppression by sweetness. Implications of the results for food producers will be discussed.
Session 12, Sensory Evaluation: Sensory techniques - Descriptive analysis
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