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

epsilon-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. (C) 2000 Elsevier Science Ltd. All rights reserved.