Abstract: In this study, the conjugation of whey protein isolate (WPI) and chitosan through Maillard reaction under different dry heating conditions was studied. Emulsifying properties of WPI-chitosan conjugates were compared at different reaction temperatures, WPI-pectin mass ratios and reaction time by determining the changes in droplet size, emulsifying stability and turbiscan analysis. The fluorescence spectra of WPI-chitosan conjugates confirmed the conjugation of WPI and chitosan. Meanwhile, the primary stage of Maillar reaction was completed after 1－4 days of reaction under the conditions of 50 ℃ and a relative humidity of 79%, and reaction products with improved emulsifying properties were obtained. The product formed after 1 day of reaction between WPI and chitosan at a mass ratio of 1:4 at 50 ℃ showed a 10-fold increase in emulsion stability compared to their physical mixture.

Key words: whey protein isolate (WPI), chitosan, Maillard reaction, emulsifying property