Affiliations: [a] National Food Research Institute, Tsukuba 305, Japan | [b] Department of Home Economics, Showa Women’s University, Taishido, Setagaya-ku, Tokyo 154, Japan | [c] Department of Biology, Ohtsuma Women’s University, Sanbancho, Chiyoda-ku, Tokyo 102, Japan | [d] Faculty of Liberal Arts, Shizuoka University, Ohya, Shizuoka 422, Japan
Note: [*] Current address: Department of Food and Nutrition, Faculty of Science of Living, Osaka City University, Sumiyoshi, Osaka 558, Japan.
Abstract: Viscoelastic parameters for mixtures of gelatin and methy1cellulose were measured as a function of temperature, in order to study the gel-sol transition of the system in which biopolymers forming thermosetting and thermo-melting gels coexist. At higher temperatures than 45°C, the gel network is mainly formed by methylcellulose while at lower temperatures around 5°C, it is mainly formed by gelatin. At higher temperatures than 45°C, gelatin inhibits the gelation of methylcellulose. A small amount of methylcellulose helps gelatin to form a network at lower temperatures. However, excessive amounts of methylcellulose inhibit the growth of network structure. Therefore, this mixture forms a phase separated gel at higher temperatures while it is not completely phase separated at lower temperatures, probably by some interaction between non-substituted hydroxyl groups in methylcellulose with carboxylic groups in gelatin.
