A new gustatory test depending upon spread of taste

Objectives:

The sense of taste has been evaluated by putting some taste solutions and then by investigating the taste perceptive threshold. However, there have been few studies examining the spread of taste in the mouth, in terms of masticatory process. The purpose of this study was to develop a new gustatory test depending upon a quantitative evaluation of the spread of taste by counting the number of chewing strokes till recognizing the taste.

Methods:

43 subjects without missing teeth (19 females and 24 males, mean age: 30.0 years) were selected for this study after obtainment of informed consent. Newly designed sample foods made from 3% agarose containing 2% or 5% sucrose were prepared. The subjects were instructed to chew the sample foods and the numbers of chewing strokes were measured till they recognize sweetness at either small area or whole area of their tongues. Five factors (masticatory performance, salivary flow rate, gustatory test [filter-paper disk test], maximum bite force, scores of oral health related to quality of life [OHIP]) concerning the stomatognathic function were carried out to confirm their relationships with taste.

Results:

Male subjects exhibited larger numbers of chewing strokes to perceive taste than female subjects for 5% sucrose sample food. The numbers of chewing strokes for whole area of tongue or for 2% sucrose sample food were larger than those for small area of tongue or for 5% sucrose sample food, respectively. Moreover, for some experimental conditions, numbers of chewing strokes were significantly associated with masticatory performance (Spearman's correlation coefficient by rank test: rs=0.49), salivary flow rate (rs=-0.53), maximum bite force (rs=-0.43) and scores of OHIP (rs=0.44~0.66).

Conclusion:

The findings suggested that our new gustatory test would be useful to clarify the taste sensation.