A Basic Study on the Sensory Evaluation of the Halitosis

The sensory threshold effects of the mouth odors may be dependent on or concurrent with the interaction among the odor components. It is a fact that when we add physically two odorous substances, the judgements of intensity of the mixtures do not simply represent the sum of the judgement made to either of the components alone. From previously published studies, the components of the halitosis had been demonstrated by gas chromatography but the sensory thresholds of the mixtures present only in restricted sensory evaluation. The relationship of the concentration and the sensory thresholds of the halitotic components was important to qualify the halitosis.In the present study, the author was concerned with the sensory evaluation method by selecting five halitotic components-Hydrogen Sulfide, Methylmercaptan, Dimethylsulfide, Methylamine and iso-Valeric acid, and combining freely two among them to research the interaction between each of the two-component mixtures. The concentration of the odorants was estimated by gas chromatography. And the sensory evaluations were performed by 6-8 from 50 screening panelists with the olfactometer under the established circumstances, in order to find out the Population Perception Threshold 50% (PPT50) through the Mills'Odor Response Chart.The odor results of the Binary Combinations were calculated and analyzed. The data were treated as described and led to the following conclusion.(1) Odor mixtures of Hydrogen Sulfide & Methylmercaptan, Hydrogen Sulfide & Methylamine and Methylmercaptan & Methylamine show suppressive tendency of the threshold.(2) The mixture of Hydrogen Sulfide & iso-Valeric acid may indicate additivity.(3) The addition of Hydrogen Sulfide, Methylmercaptan, Methylamine or iso-Valeric acid into Dimethylsulfide may show some synergism in the threshold sensation of the mixtures.(4) As Methylmercaptan or Methylamine is combined with iso-Valeric acid the synergistic phenomena are comfirmed in the threshold sensation of the mixtures.