Improvement of emulsifying properties of oat protein isolate-dextran conjugates by glycation

In order to improve the emulsifying properties of oat protein, oat protein isolate (OPI)-dextran (Dex) conjugates were prepared by glycation reaction. Emulsifying properties of emulsions stabilized by native OPI (OPIN), OPI-Dex conjugates (ODC) and heated OPI (OPIH) were characterized by zeta-potential, mean droplet size and microstructure. The results showed that the covalent attachment of OPI and dextran was confirmed by determining degree of graft and SDS-PAGE. OPI-Dex conjugates were capable of forming a finer emulsion, which exhibited smaller average particle size and better storage stability under different homogenization pressures (30, 60, 90 MPa) compared with OPIN and OPIH. When assessed in different pH and ionic strength, emulsions stabilized by OPI-Dex conjugates resulted in improved emulsion stability to environmental stresses. Confocal laser scanning microscopy depicted more uniform and smaller oil droplets that had a reduced tendency to coalesce for emulsions prepared with ODC.