Changes in structure, physicochemical properties and in vitro digestibility of quinoa starch during heat moisture treatment with hydrogen-infused and plasma-activated waters.

In this study, comparative effect of heat moisture treatment (HMT) with distilled, hydrogen-infused and plasma-activated waters on the structure, physicochemical properties and in vitro digestibility of quinoa starch (QS) was investigated. To our knowledge, this study is the first to apply hydrogen-infused water to starch modification. The surface of HMT-modified samples was much rougher than that of native QS. HMT did not change the typical "A"-type X-ray diffraction pattern of QS but it increased its relative crystallinity. Meanwhile, amylose content, gelatinization temperature and water absorption capacity of QS significantly increased, whereas viscosity and swelling power markedly decreased. The rapidly digestible starch level of HMT-treated samples was significantly lower than that of native QS, and the resistant starch content markedly increased. These alterations were dependent on treatment moisture level. Furthermore, compared to distilled water, the HMT with hydrogen-infused and plasma-activated waters induced much more extensive effect on above properties, and the sample treated with plasma-activated water had the highest extent due to the acidic or alkaline environment and reactive oxygen and nitrogen species. These results identified that the combination of HMT with hydrogen-infused or plasma-activated water was a novel strategy to improve the thermal stability and functionality of quinoa starch.