INSTRUMENTAL UNIAXIAL COMPRESSION TEST OF GELLAN GELS OF VARIOUS MECHANICAL PROPERTIES USING ARTIFICIAL TONGUE AND ITS COMPARISON WITH HUMAN ORAL STRATEGY FOR THE FIRST SIZE REDUCTION

摘要

Instrumental compression test using artificial tongue was carried out to compare the fracture profile of gels with the first oral strategy for size reduction by humans (termed as the first size reduction). Gellan gel samples, whose size and shape were the same as those of artificial tongue, were prepared in a wide mechanical range and were compressed uniaxially on artificial tongue at crosshead speed of 10 mm/s. When apparent Young's modulus of artificial tongue was approximately 55 kPa, fracture probability of gels corresponded to the ratio of subjects who decided to use tongue-palate compression instead of mastication. This was applicable to the gels whose fracture strain was below 65% but not to the gels whose fracture strain was above 70% within the range of fracture stress tested; approximately 30-100 kPa. Fracture strain should be a critical initial mechanical parameter that relates to the decision of oral strategy.