Texture is one of the sensory attributes of foods and usually evaluated both subjectively and objectively. In order to establish the systematic subjective method for textural evaluation, it is necessary to find out the fundamental characteristics of textural quality. As fundamental textural characteristics seem to be different from food to food, classification of solid foods has been examined on the basis of textural quality, in advance of studies on fundamental characteristics. Classification and matching procedures were used. In classification procedure, solid foods were classified based on conceptual similarity of texture of foods, and, in matching procedure, solid foods were clustered by subjective judgments on correspondence of tactile sensation for actual foods with conceptual texture. By both procedures, mathematical treatment resulted in that solid foods used in these experiments can be classified into three categories; gel, sponge and porous rigid foods.
Amylograph measurements were applied for the aqueous agar solutions, which traced viscosity changes with increasing and decreasing temperatures. In the most usual performances, the following conditions were applied; agar solution around 4% concentration level, rotation speed of 75 rpm and dissolving temperature 95°C. For 16 kinds of commercial agar, the apparent gelation temperatures which were graphically obtained from the resultant amylograms were proportional to the values of water holding capacity which were obtained by the previously described method. Some other factors which probably relate with gelation of agar were investigated.