Characterization and emulsifying properties of whey protein isolate-basil seed gum conjugates prepared by Maillard reaction
Farzaneh Kouravand, Fakhri Shahidi, Arash Koocheki, Milad Fathi
Abstract
The present study was conducted to optimize the preparation conditions of whey protein isolate-basil seed gum (WPI-BSG) conjugates resulting from the Maillard reaction in different weight ratios and reaction times. In addition, the stability of the emulsions stabilized by WPI-BSG conjugate was investigated. The covalent attachment of BSG to WPI was effectively confirmed by OPA method, FTIR and fluorescence spectrometry analysis. Results indicated that the maximum zeta potential (-79.83 ± 1.62 mV), emulsifying activity (29.33 ± 2.71 m2/g) and emulsifying stability (45.16 ± 5.14 min) of conjugates were obtained in the weight ratio of 1:2 (WPI to BSG) and reaction time of 2 h. It was also found that a longer heating time may lead to an increase in the browning intensity and a significant decrease in the emulsifying properties of the conjugates. Moreover, according to the results of particle size, zeta potential and creaming index, the emulsions stabilized by WPI-BSG conjugates were more stable than those stabilized by unheated WPI and WPI-BSG mixture. This study indicates that the Maillard reaction can successfully improve the emulsifying properties of WPI. Besides, WPI-BSG conjugates are able to increase physical stability of oil-in-water emulsions.