Changes of components and organizational structure induced by different milling degrees on the physicochemical properties and cooking characteristics of quinoa

Abstract

The pasting characteristics induced by different milling degrees on the cooking quality of quinoa were investigated. The results showed that significant variations were observed in the basic composition of quinoa with different milling degrees, which indicated the existence of effects due to the degree of milling. The combination of starch and water promoted the pasting of quinoa, and with increasing milling, quinoa textural properties tended to produce softer and more viscous. LF NMR results indicated that more water was present in the dense network formed by the starch gelatinization. Rheological properties further demonstrated that milling degree enhanced the interactions between starch molecules and correspondingly increased the energy storage modulus and loss modulus. The microstructures (SEM and CLSM) confirmed that the physical property changes in quinoa were attributed to a dense network structure caused by starch pasting, which was similar to the results of RVA. The higher the amylose/amylopectin ratio (between 0.113 and 0.167), the more pronounced the characteristic peaks. The different degrees of milling of quinoa changed the quinoa crystallinity. Consequently, the degree of milling improved the cooking characteristics and enhanced the physicochemical properties. These results help the quinoa processing industry to develop healthy quinoa products with moderate milling.