Preparation of chemically modified canola protein isolate with gum Arabic by means of Maillard reaction under wet-heating conditions

• Canola protein isolate was chemically modified with gum Arabic by Maillard reaction.
• SDS-PAGE confirmed the covalent attachment of canola protein isolate to gum Arabic.
• Fluorescence intensity and free amino group of conjugate were evaluated.
• The secondary structure of canola protein isolate after conjugation was reported.

The aim of this study was to produce covalently attached conjugate between canola protein isolate (CPI) and gum Arabic (GA) in aqueous solutions via the Maillard reaction at 90 °C in a model system consisting of 2% CPI and 1, 2 or 4% GA. Upon decreasing of free amino group content in the glycosylated CPI to 72%, a new band near the loading end of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and a shift of CPI peak in high performance size exclusion chromatography confirmed that the covalent attachment of CPI to GA was successful. The results of secondary structure analysis suggested that grafted CPI had decreased α-helix and β-sheet levels and increased random coils level. The solubility of CPI at isoelectric point was improved remarkably after grafting with GA. The optimal conjugation conditions chosen from the further experiments were 1% of GA, 90 °C and reaction time 15 min.