Effects of fibrillation combined with glycation by different chain length sugars on structural and functional properties of soybean protein

The key objective of this study was to investigate the effects of fibrillation combined with glycation of soybean protein isolate (SPI) on the protein structure and functional properties. SPI fibrils alone, glycated proteins and glycated fibrils with different chain lengths (glucose–G, maltose–M and dextran–D) were prepared and characterized by spectroscopy and microscopy methods. The results of the O-phthalaldehyde assay, ultraviolet–visible spectroscopy and fluorescent advanced glycation endproducts indicated the degree of glycation. The thioflavin T fluorescence assay, transmission electron microscopy (TEM) and Fourier-transform infrared (FTIR) spectroscopy results demonstrated that the fibril morphology improved, and more flexible and aggregated fibrils were produced after glycation, further improving the protein functional properties. With EAI and ESI values of 37.31 m2/g and 33.80%, respectively, the emulsifying properties of SPI fibrils glycated by dextran were higher than the others. Foam properties and antioxidant activity were highest for the fibrils glycated by glucose. These results are of scientific significance for in-depth understanding and reasonable regulation of protein functional properties for industrial production in a complex food system.