Unravelling the Role of Oat β-Glucan on the Surface Behavior of an Oat Protein-Rich Coextract: An Enzymatic Approach

Despite extensive research linking oat β-glucan (OBG) to improvements in cardiometabolic health, little is known about how OBG influences the structure and surface behavior of oat protein. To this end, enzymatic hydrolysis of an oat protein-β-glucan coextract (OPBG) from defatted oat flour was performed. The effect of OBG cleavage was characterized using asymmetric flow field-flow fractionation with ultraviolet-visible (UV-vis) and in situ fluorescence detection, allowing for deconvolution of protein and OBG signals. Partial OBG cleavage increased oat protein dispersibility and accelerated adsorption to the air-water interface, albeit partly driven by thermal treatment during enzymatic hydrolysis. Although full cleavage resulted in protein aggregation, all OPBG samples offered decreased air-water surface tension and faster solid surface-water adsorption kinetics compared to oat protein isolate (OPI). Novel findings highlight that oat protein surface behavior can be adjusted by omitting isoelectric precipitation, while retaining inherent OBG in the system to ultimately reduce protein-protein hydrophobic aggregation.