Effect of ascorbic acid treatment on physicochemical and emulsifying properties of highland barley protein

The current study investigated the impact of ascorbic acid (AA) on physicochemical and emulsifying properties of highland barley protein (HBP). Emulsifying and solubility of AA-modified HBP increased compared to its native state. However, excessive AA concentration induced protein reaggregation, leading to a deterioration of these properties. At a concentration of 0.3 % (w/v) AA, the highland barley protein emulsion (HBPE) exhibited the smallest average particle size (0.59 mu m), and the protein demonstrated superior emulsification properties. The observed alterations stem from the formation of covalent bonds between HBP and AA through the Maillard reaction. These changes also relate to modifications in the secondary structure, marked by a notable increase of 60.25 % in beta-turns, accompanied by reductions of 16.45 % in alpha-helices and 33.84 % in beta-sheets. This was confirmed through analyses of disulfide bond content and FTIR. The outcomes of this study hold promise for enhancing the stability of emulsion formulations based on HBP, achieved by harnessing the complex formation between HBP and AA.