Improving emulsifying activity of ε-polylysine by conjugation with dextran through the Maillard reaction

ε-Polylysine (PL) was conjugated with dextran through the Maillard reaction to improve its emulsifying activity. The covalent attachment of dextran to PL was confirmed by Sephadex G-150 gel filtration chromatography and SDS–polyacrylamide gel electrophoresis (SDS–PAGE). The resulting PL–dextran conjugate possessed an excellent emulsifying activity as compared with commercial emulsifiers. The emulsifying activity of conjugate was not affected even in the presence of 1.0 M NaCl and above pH 7. In addition, the PL–dextran conjugate retained most of the original antimicrobial activities of PL. The PL–dextran conjugate thus prepared could be used for the formulation of processed foods as a bifunctional food additive, emulsifier and antibacterial reagent.