Formation and characteristics of bovine serum albumin-dextran conjugate

Abstract

Bovine serum albumin (BSA)-dextran conjugates were prepared by the Maillard reaction to improve the functionality of native BSA. The covalent attachment of dextran to BSA was confirmed by SDSPAGE, and binding ratio of dextran to BSA was determined by multi-angle laser light scattering (MALLS) detector connected to high performance size exclusion chromatography. With an increase in reaction ratio of dextran to BSA, about 0.5-1 mol of dextran was bound to 1 mol of native BSA. Structural analyses by fluorescence spectroscopy and circular dichroism indicated that the surface of BSA was covered by dextran without great disruption of native conformation in each conjugate. After preparation of oil/water emulsions by sonication, the emulsifying properties of these conjugates were investigated by evaluating the emulsifying activity, emulsion stability, protein load at the oil-water interface, and emulsion droplet size. BSA-dextran conjugates showed excellent emulsifying properties compared to native BSA. The improvement in the emulsifying properties of BSA might be due to covalently linked dextran. Dynamic oscillatory viscoelasticity of heat-induced conjugate gel was investigated using rheometer. The result showed that BSA-dextran conjugate can improve the solid-like behavior of BSA gel. Thus, BSAdextran conjugate could be utilized as a functional ingredient in processed foods.