An Electromyography-Based System for Measuring the Flavor Detection Time in Healthy Adults

This study aimed to develop a system to measure the flavor detection time for chewed solid and semi-solid foods. Twelve healthy young adults (seven males and five females) were asked to chew gummy candies with three different fruit flavors (grape, lemon, and pineapple) in a random order while their masseter activities were recorded by surface electromyograms on their habitual working and non-working sides. The participants were also asked to press a button as soon as possible with their preferred hand once they detected the flavor. The time interval between the start of chewing and the button press was measured;the start of chewing was defined as the start of a burst in the masseter electromyogram on the habitual working side. The average interval ranged from 2.82 s (lemon in males) to 4.63 s (grape in males);no significant differences were found between the three tested gummy candies or between the sexes of the participants. The present system can perform the measurements of the following two conventional measurement systems: 1) simple reaction time task for the taste and olfactory stimuli of fluids and vapors, respectively, and 2) time-intensity analysis of the flavor from solid and semi-solid foods, which does not generally consider the flavor detection time.

Influence of Sex Differences on Temporal Sequence of Sensations after Ingesting Fruit-Flavored Tea—A Preliminary Study

The goal of this preliminary study was to examine the effect of participants’ sexes on the temporal sequence of dominant sensations elicited by fruit-flavored teas. Twelve healthy young adults were assigned to male (n = 6) and female (n = 6) groups. Both groups were evaluated for four sensations using four fruit-flavored teas with 0.05 M sucrose using the temporal dominance of sensations (TDS) method. Only two sensations, sweetness and fruitiness, were consistently reported in the two groups. The male group first reported fruitiness and then sweetness as the dominant sensation following ingestion of the samples. Conversely, the female group reported these two dominant sensations in the reverse order. Significant dominant durations between the two sensations largely varied among the samples in both groups. These results suggest that there are sex-based differences in the temporal sequence of dominant sensations elicited by fruit-flavored teas as evaluated by the TDS method.

Factors Determining the Detection Time to Flavor in Healthy Adults

This study analyzed the factors responsible for determining the flavor detection time for chewed semi-solid foods. Thirteen healthy young adults (eight males and five females) were asked to chew gummy candies with five different fruit flavors (i.e., apple, grape, orange, pear, and strawberry) in a random order. The detection time to flavor was measured using an electromyography-based system, which was recently developed by the authors. Briefly, each participant was recorded with surface masseter electromyograms on both sides to determine the start of chewing. Each participant was asked to press a button as soon as possible with his/her preferred hand after detecting the flavor. The time elapsed between the start of chewing and the button press was measured. Two taste components, sugars and organic acids, of the gummy candies were chemically analyzed, and two major sugars and organic acid were individually detected. The odor intensity was also analyzed for the gummy candies. The average detection time significantly differed among the five gummy candies and among the participants. Simple regression analyses revealed that the intensity of the odors was significantly associated with the average time intervals, but the amounts of the two major sugars and the organic acids were not. The analysis yielded the following equation for the regression estimation:?? (y = the time interval, x = the intensity of odors). The results suggest that the intensity of odors of the gummy candies, not the taste components, is responsible for determining the flavor detection time.

Influence of Breathing and Chewing on Timing of Flavor Detection

This study aimed to analyze frequencies of flavor detection signals occurring in any of the three respiratory phases and either of the two masticatory phases. Flavors of three fruity (grape, orange, and strawberry) gummy candies in the mouth were detected after chewing in 24 young healthy participants. The results revealed that: 1) more detection signals occurred in the expiratory phase than in the inspiratory or pausing phases and 2) more detection signals occurred in the jaw-closing phase than in the jaw-opening phase. Statistical analysis showed that the difference between the frequencies among the three respiratory phases was significant (P < 0.001) but not between the two masticatory phases. Further analysis showed that the frequencies occurring within individual respiratory phases were not significantly biased. The present results suggest that flavor detection during chewing depends more on the expiratory phase rather than the inspiratory and pausing phases, whereas detection is dependent to a lesser extent on either of the masticatory phases.