ANALYSIS OF PHYSIOLOGICAL PARAMETERS OF MASSETER MUSCLE ACTIVITY DURING CHEWING OF AGARS IN HEALTHY YOUNG MALES

Abstract

ABSTRACT This study examined the influences of rheological properties on mastication in eight healthy male subjects by recording an electromyogram (EMG) of the masseter (MS) muscle during chewing. Four different agars were tested: 0.5 and 1.5% ordinary agars (0.5OA and 1.5OA), and 2.5 and 4.0% Ina‐agar (2.5IA and 4.0IA). The hardness, adhesiveness and cohesiveness differed among the four agars, which is most likely because of the differences in the concentrations and constituents of the agars. Mastication time and the average amplitude of the MS EMG during chewing were longest and largest, respectively, with the 1.5OA followed by the 4.0IA. The activity pattern of the MS EMG differed between the first and last cycles of chewing sequences in each of the agars used; there were no differences between the first cycle activity patterns or the last cycle activity patterns when comparisons were made between the four agars. These results suggest that the rheological properties of the agars modify mastication and that the activity patterns of the MS muscle change during chewing. PRACTICAL APPLICATIONS The present findings obtained by the analyses of rheological properties and physiological parameters, especially by the “T P ” technique, suggest the following possible uses: (1) the T P technique can analyze foods at different angles from analysis by rheological properties; (2) a combination of rheological properties and physiological parameters (sensory evaluation as well) can lead more diversified analysis of foods in normal adults and (3) the combinational analysis of foods may be more useful in very young and disabled people who have difficulty of expressing impressions and experiences because of the objectiveness of the T P technique. The combinational analysis contributes to development of foods especially for very young and disabled people.