Functional properties of mildly fractionated soy protein as influenced by the processing pH

Peng, Yu; Kersten, Natalie; Kyriakopoulou, Konstantina; Goot, Atze Jan van der


In this study an alternative mild fractionation process for the extraction of soy protein is investigated; aqueous fractionation, in which oil extraction and intensive washing steps are omitted. Moreover, a pH adjustment is proposed instead of the conventional neutralization step. The mildly fractionated soy protein fractions (SPFs) showed higher protein and oil content compared to commercial soy protein isolate. The process retained the proteins’ native state. SPFs adjusted at pH 4.5 and 5.5 (close to pI) formed a powdery texture, resulting in larger size particles after dispersion in water. Despite their low nitrogen solubility index, water holding capacity and viscosity, when mixed with flour these SPFs presented the highest G* values. A flaky texture and reversed properties were observed with SPF adjusted at pH away from the pI. The range of properties achieved exhibits new routes in creating soy protein ingredients with desired functionality, avoiding over-processing due to post-treatment modifications.