• Agar gels;
  • artificial tongue;
  • oral strategy;
  • size reduction;
  • uniaxial compression


An in vitro evaluation system of food texture was developed using artificial tongue and a conventional uniaxial compression apparatus to mimic the tongue-palate compression. Deformation behavior of agar gels on artificial tongues from silicone rubber with three levels of elastic modulus was observed during compression by a nondeformable plate. The results were compared with the oral strategy for size reduction from sensory evaluation by human subjects. Agar gels fractured upon compression when the strain of the gels was larger than that of artificial tongue, whereas they did not when the strain of the gels was equivalent to or smaller than that of the artificial tongue. When apparent elastic modulus of artificial tongue was approximately 5.5 × 104 Pa, fracture profile of the gels corresponded well to human tests. Results suggest that the oral strategy for size reduction might be determined by sensing the relative strain of the gels to the tongue during compression to a somewhat small strain.

Practical Applications

In an aged society, there is an increasing demand for properly texturized foods for safe consumption by those who have mastication or chewing difficulty. Food of soft texture is often preferred by these people because of easy tongue-palate compression and no need of the teeth mastication. An in vitro evaluation system of food texture developed in the present study provides a simple method for food manufactures in assessing textural acceptability of products without using human subjects. This evaluation system can lead to the innovation of food product design for textural diversity and thus improved quality of life for these disadvantaged populations.