POLYSACCHARIDE-PROTEIN INTERACTION - A RHEOLOGICAL STUDY OF THE GEL SOL TRANSITION OF A GELATIN METHYLCELLULOSE WATER-SYSTEM

Viscoelastic parameters for mixtures of gelatin and methylcellulose we re measured as a function of temperature, in order to study the gel-so l transition of the system in which biopolymers forming thermo-setting and thermo-melting gels coexist. At higher temperatures than 45-degre es-C, the gel network is mainly formed by methylcellulose while at low er temperatures around 5-degrees-C, it is mainly formed by gelatin. At higher temperatures than 45-degrees-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 m ethylcellulose inhibit the growth of network structure. Therefore, thi s mixture forms a phase separated gel at higher temperatures while it is not completely phase separated at lower temperatures, probably by s ome interaction between non-substituted hydroxyl groups in methylcellu lose with carboxylic groups in gelatin.