Removal of phytic acid in protein via pretreatment of rapeseed meal

Abstract To obtain rapeseed protein with low phytic acid (PA), soy protein isolate (SPI) was used to investigate the interactions between SPI and PA. The influence of pretreatment (soaking using salt solution and dialysis) of the defatted rapeseed meal on the PA and protein content in the final rapeseed proteins was also studied. The results showed that electrostatic interactions dominated the protein–PA interaction, which was affected by pH and ionic strength. Accordingly, the pH and ionic strength in the soaking medium also influenced the PA remained in the rapeseed proteins. The PA content decreased with the ionic strength (400–800 mM) and relatively low PA was obtained at pH 6.0 (soaking environment). Finally, 52.8 % of the PA have been removed and PA content remained in rapeseed protein isolate (RPI) reached about 0.84 mg/g, at the same time, the protein content was maintained around 86.70 %. Overall, soaking using salt solution and dialysis could be an effective method to achieve high quality rapeseed protein with low PA.