Abstract 102
The relationship between expectorant pH and astringency perception
J. Sens. Stud. 23 (2): 222-233, 2008
K.J. Siebert and C. Euzen
Saliva from a single individual was adjusted in pH, with or without added polyphenol (tannic acid); this produced a sharp peak in light scattering near pH 4. This result is in reasonably good agreement with a prior result. A sensory panel was conducted in which panelists were presented with 10 mL sample portions including dilute HCl in water (0, 0.0022 N or 0.004 N), with or without 500 mg/L TA. Panelists were instructed to rinse their mouths with the entire sample contents, then to expectorate the sample back into the sample cup and to rate astringency. The expectorant pHs were measured and found to vary with the sample. They showed only modest buffering by saliva. Astringency also varied between samples and there appeared to be a relationship between the expectorant pH and the intensity of astringency, with lower pH producing greater astringency. The total polyphenol content of saliva from a single individual was collected at various times after consuming tea and after overnight abstention. The polyphenol content was highest soon after tea drinking and diminished over two hours toward a plateau that was clearly above zero. After abstaining from all but water overnight, the polyphenol content of the subject′s saliva was 8.1 mg/L. This confirms that saliva normally contains polyphenol and that the level is affected by dietary habits.
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