Acidic solution properties of beta-casein-graft-dextran copolymer prepared through Maillard reaction

The copolymer of beta-casein-graft-dextran was prepared using the Maillard reaction and the acidic solution properties of the copolymer were studied with dynamic light scattering. At pH range 4-5 where is close to the isoelectric point of beta-casein, the copolymer forms micelles which are spherical verified by atomic force microscopy imaging. The size and existent time of the micelles depend on the graft degree and the length of dextran side chains of the copolymers. During storage at pH 4.6, the micelles formed by the copolymers with short side chains and low graft degree tend to precipitate, while the micelles formed by the copolymers with long side chains and high graft degree tend to dissociate. The micellization of the copolymers can be suppressed by adding NaCl. Optical microscopy and turbidity studies show that the copolymers dissolved in molecular state and with higher hydrophilicity have better emulsifying ability.