Rheological Behaviour of Biopolymer Gels in Relation to Structure

摘要: The rheological behaviour of biopolymer gels with different network structures was studied to elucidate how the structure gel influences its properties. Non-destructive viscoelastic measurements and fracture techniques were used. types fine-stranded gels, particulate inhomogeneous mixed gels. chosen as model systems one protein, b-lactoglobulin, two polysaccharides, k-carrageenan locust bean gum. b-Lactoglobulin forms on heating develops depending pH: a at intermediate pH (4-6) below above this interval. It can also form networks or rate. polysaccharides formed various ionic type concentration cations. b-lactoglobulin compared same biopolymer. stiffer higher modulus, G', than equal concentrations lower concentrations. gelation started temperatures denaturation temperature, Td, proceeded in steps second step coinciding Td. A method for measuring properties tension developed. low brittle whereas those high rubber-like. stiffness large deformations, E, had maxima, 4, where around 6 an formed. shown that 5.3 7.5 if is slow heating. At inhomogeneities result microphase separation incipient network. G' these showed stronger frequency dependence frequencies high, caused by relaxation times dense loose regions containing some pores started. strand differed between homogeneous causing storage moduli. Mixed potassium gum synergistic effects KCl-concentration 0.1M KCl. probably originated from effect KCl-concentration. sodium calcium did not show any effects, neither (0.2M).