Influence of non-thermal microwaveradiationon emulsifying properties of sunflower protein

•Sunflower protein (SPI) was treated with non-thermal microwave (NMW) processing.•Polar amino acid content decreased, solubility and surface hydrophobicity changed.•Defrost mode (DF) applied SPI had the highest solubility and surface hydrophobicity.•DF treatment improved the emulsion stability of SPI by app. 1.5 fold.•More elastic, less stretchable solid-like layer at the O/W interface was obtained. Sunflower protein isolate obtained from industrially de-oiled press cake was treated with non-thermal microwave, aiming to investigate how structure and emulsifying properties were affected. Our results indicated that the content of polar amino acids was decreased and solubility and surface hydrophobicity were altered upon exposure to non-thermal microwave. Higher solubility and surface hydrophobicity of the samples treated with defrost mode and also 350 W were accompanied by a smaller size and lower uniformity of the oil droplets compared to the control and other samples. Non-thermal microwave treatment improved the emulsion stability by 1.43 times and defrost mode treated sample had the lowest stability index after 120 min. Interfacial dilatational rheology measurements revealed that 70 and 350 W treated samples created higher elastic, less stretchable solid-like layer at the O/W interface in comparison with defrost mode treated and control samples. Consequently, non-thermal microwave treatment could be considered as a promising simple, fast, and “green” protein modification technique.