Methods: Forty-one subjects without missing teeth (19 females and 22 males, mean age: 25.4 years) were selected for this study after obtaining informed consent. Four types of newly-designed sample foods made from 15% gelatin were prepared, which contained sucrose (sweet), sodium chloride (salty), tartaric acid (sour), or quinine hydrochloride (bitter). Five or six concentrations representing weak to strong taste were prepared for each tastant. The subjects were instructed to chew the sample foods, and the numbers of chewing strokes necessary to recognize the taste were counted.
Results: The numbers of chewing strokes decreased as the concentration of the taste in the sample food increased, and a significant difference was observed among five or six concentrations (Kruskal-Wallis test：p<0.05). For each of the four tastants representing the recognition threshold level, the average number of chewing strokes was approximately ten. Female subjects recognized the sweet taste more correctly than male subjects (Friedman test：p<0.01).
Conclusion: The findings suggest that newly－designed sample foods containing one of the four tastants with a fixed concentration are appropriate for testing the recognition of the spread of the taste, and that by using this sample food, counting the number of chewing strokes necessary for recognizing the taste would be useful as a new gustatory test to investigate the taste sensation.