Dispersion conditions affect the physico-chemical and technofunctional properties of quinoa protein isolates precipitated with different acids

This study was designed to assess whether the functionality of quinoa protein isolate (QPI) precipitated with acetic acid (QPI-A), citric acid (QPI-C) or HCl (QPI-H) could be further improved or modulated by the dispersion conditions. The soluble protein content, protein profile, secondary structure, thermal properties, gelation behaviour and microstructure of the isolates were evaluated. Dispersion in water for 24 h promoted the solubilisation of QPI-H and improved gel strength. Dispersion in 0.1 M NaCl for 1 h resulted in extensive protein aggregation and hindered gel formation in QPI-A and QPI-C. Dialysis before dispersion impaired the gelation properties for all three types of isolates. The demonstrated ability to improve or modulate the functional properties of QPI not only by choice of precipitation acid but also by dispersion conditions provides a handle for product formulators to broaden the application spectrum for QPI across a range of food textures.