Effect of Dry Heat Treatment on the Structure of Quinoa Flour and Rheological Properties of Dough

Quinoa flour was subjected to dry heat treatment at room temperature (for control), 110, 130 and 150 ℃ for 1 h, respectively, and different treatments quinoa flour 15% and wheat flour 85% (w/w) were mixed to make bread, the effects of dry heat treatment temperature on the structure of quinoa flour, powder properties and tensile properties of the mixed flour dough as well as textural properties and in vitro digestive activity of the bread were analyzed. The results showed that the dry heat treatment caused the shedding of aggregates on the quinoa flour particles surface and caused defects, meanwhile the shedding degree of aggregates increased with the increase of treatment temperature. While, the crystal type of quinoa flour was not change and remained A-type after dry heat treatment. Compared with control, the water absorption and weakness of the dough that added quinoa flour treated with 110, 130 and 150 ℃ increased by 1.79% and 43.75%, 3.25% and 104.17%, 4.83% and 125.00%, respectively. Elongation, maximum tensile resistance and tensile resistance decreased gradually, and the tensile ratio increased first and then decreased. In addition, the bread hardness decreased by 1.82% and elasticity increased by 4.51% at 110 °C, while the other treatments increased the hardness and decreased the elasticity of quinoa-bread. Meanwhile, the dry heat treatment significantly decreased the RDS content and increased the SDS and RS content of quinoa-bread (P<0.05). This study can provide a theoretical basis for the development of functional foods from quinoa flour.