Investigation into the Maillard reaction between ɛ-polylysine and dextran in subcritical water and evaluation of the functional properties of the conjugates

•The conjugates between ɛ-polylysine and dextran was generated in subcritical water.•The emulsifying activity of the conjugates was improved with the rise of reaction temperature (below 120 °C).•The antimicrobial activity of the conjugates formed below 110 °C remained the same as ɛ-polylysine.

The effects of temperature and pressure on the Maillard reaction between ɛ-polylysine and dextran in subcritical water were investigated. Browning index was determined at 420 nm, and degree of graft was estimated by O-phthaldialdehyde (OPA) method. The formation of conjugates by Maillard reaction was testified by UV-vis spectrum and SDS-polyacrylamide gel electrophoresis (SDS-PAGE). The emulsifying activity of the conjugates was greatly improved with the rise of temperature. The antimicrobial activity of the conjugates formed below 110 °C remained the same as ɛ-polylysine, and then decreased obviously when the reaction temperature was above 120 °C. The reaction pressure (0-10 MPa) had no effect on the emulsifying and antimicrobial activities, but higher pressure could effectively inhibit the formation of browning compounds.