Effects of physical method and enzymatic hydrolysis on the properties of soybean fiber-rich stabilizer for oil in water emulsions

BACKGROUNDOkara is a by-product from the soybean industry and an abundant resource of insoluble soybean fiber (ISF). ISF with various properties could be obtained by different extraction methods. It is an attractive option to utilize okara by taking advantage of ISF as an emulsifier or stabilizer.RESULTSCompared with the untreated ISF (ISFUT), superfine grinding reduced the particle size and viscosity of ISF (ISFSG). Steam explosion increased the water solubility from 17.5% to 51.7% but decreased the water holding capacity and swelling capacity of ISF (ISFSE) from 15.0 and 14.0 g/g to 4.2 and 3.3 g/g, respectively. Emulsions prepared by ISFUT and ISFSG before or after enzymatic hydrolysis presented large oil droplets and were unstable. Although emulsions prepared by ISFSE after enzymatic hydrolysis (ISFSE-E) showed flocculation, the volume-weighted average diameter (19.7 mu m) were the smallest while the viscosity and viscoelastic modulus were the highest, and exhibited excellent physical stability during storage.CONCLUSIONISF obtained by physical and hydrolysis treatment displayed diverging physicochemical properties while ISF prepared by steam explosion-enzymatic hydrolysis presented the best potential to stabilize emulsions. The present study could provide novel information about the utilization of okara by the application of ISF as an emulsifier or stabilizer. (c) 2023 Society of Chemical Industry. Physical treatment and enzymatic hydrolysis could obtain soybean fiber with different physicochemical properties. Superfine grinding reduced the particle size while steam explosion converted partly the insoluble fiber to soluble fiber. The soybean fiber after steam explosion associated with enzymatic hydrolysis exhibited excellent potential to stabilize oil in water emulsions.