Preparation and Characterization of Maillard Reaction Products from a Trinary System Composed of the Soy Protein Isolate, Chitosan Oligosaccharide, and Gum Arabic

To extend the application of chitosan oligosaccharide (COS) in complex coacervation between the soy protein isolate (SPI) and gum Arabic (GA), Maillard reaction among SPI, COS, and GA was induced under different conditions. High-performance gel permeation chromatography and sodium dodecyl sulfate polyacrylamide gel electrophoresis illustrated that products with high molecular weights (1.17 × 106 and 2.79 × 106 Da) were generated in the trinary system, and the Maillard reaction promoted the cross-linking of SPI, COS, and GA. The Maillard reaction was observed the most under conditions where SPI, COS, and GA (4:2:4, w/w) were kept at 80 °C for 12 h, and the results of thermogravimetry indicated that Maillard reaction products (MRPs) with the best thermal stability, which were positively charged, were generated. The results revealed that the extent of Maillard reaction was enhanced with the increase of time SPI being involved in the complex rather than GA. X-ray diffraction and Fourier transform infrared analysis indicated that Maillard reactions between SPI, COS, and GA under different conditions did not impact the crystal particle structures among them. Even though the extent of Maillard reaction among SPI, COS, and GA was lower than that between SPI and COS, MRPs with various viscoelastic properties were obtained under different conditions. Thus, as one kind of difunctional reactant in Maillard reaction, COS could react with either proteins or polysaccharides, and the MRPs have potential utilization in the food industry.