Rheological, structural and functional properties of high-pressure treated quinoa starch in dispersions

Abstract

The impact of high-pressure treatment on the gelatinization of quinoa starch (QS) dispersions was investigated as a function of pressure (300, 450 and 600 MPa for 15 min) and starch to water (S/W) ratio (1:3 and 1:4 w/w). The structural changes of QS were characterized by rheological, DSC, SEM, XRD, and FTIR spectroscopy. The water holding capacity and granules particle size increased significantly with the intensity of pressure. The G' of the QS gradually improved as a function of pressure and S/W ratio. A complete gelatinization of QS occurred at 600 MPa by breaking down of amylopectin crystallites and transformation to the amorphous state, which was confirmed by rheometry, XRD, and DSC. Additional heat-treatment to pressure-treated samples greatly improved the gel rigidity except for the sample treated at 600 MPa. It can be inferred that the functional properties of QS could be significantly modified/improved with the application a pressure-treatment of 600 MPa.

Keywords: Damaged starch; Gelatinization; High-pressure treatment; Mechanical rigidity; Particle size; X-ray diffraction.