Effect of Heat Moisture Treatment on the Rheological, in Vitro Digestive Properties and Structure of Quinoa Starch

Heat moisture treatment (HMT) is a widely used method for starch modification due to its safe, green, environmentally friendly, and efficient characteristics. In this study, quinoa starch was modified by HMT with varying moisture contents (20%, 25%, and 30%) at a temperature of 120 °C for 10 hours, and its rheological properties, in vitro digestive properties, and structure were further evaluated. The steady rheology results indicated that all the samples were shear-thinning non-Newtonian fluids. After undergoing HMT, the apparent viscosity of quinoa starch decreased significantly. Additionally, the samples' apparent viscosity decreased as the moisture content of HMT increased. The results of frequency sweep showed that the storage modulus G' of quinoa starch decreased with the increase of moisture content of HMT, while the loss modulus G'', and loss factor increased with the increase of moisture content of HMT. The thixotropic results showed that the thixotropic ring area of quinoa starch decreased with the increase of the moisture content of HMT. Additionally, the results of in vitro digestion showed that the content of rapidly digestible starch in quinoa starch decreased significantly after HMT (P