Modification of Quinoa Starch by High Hydrostatic Pressure and Ultrasonication and Assessment of Its Physicochemical Properties

Abstract

Quinoa starch was extracted and treated with different technologies to modify its properties. High hydrostatic pressure (HHP) at 250, 350, and 500 MPa at 20 and 40 °C and ultrasonication at 100% power with a constant pulse for 15 min were applied as modification methods. Following the treatments, functional, rheological, morphological, and structural analyses were carried out. Time domain (TD) NMR relaxometry experiments confirmed that HHP treatment caused less granule swelling of starch. NMR relaxation spectra of quinoa starch revealed mainly two distinct proton populations. Results have demonstrated that HHP treatment had a strong modification effect on quinoa starch compared to US and provided a new type of modified quinoa starch that can be used as an instant food product and thickening agent with the feature of retaining the granular shape and reducing swelling. The results were also confirmed by FTIR, XRD, SEM, and DSC analyses.