Effects of ultra-high pressure combined with cold plasma on structural, physicochemical, and digestive properties of proso millet starch

Abstract

In this study, proso millet starch was isolated and subjected to treatment with ultra-high pressure (UHP), cold plasma (CP), or their combination to modify its functional properties. The changes in structural, physicochemical, and digestive properties of proso millet starch after these treatments were investigated. The proso millet native starch granules showed irregular and polygonal shapes with a smooth surface. Treatments with CP or UHP at low pressures did not change the morphological properties or crystalline structure type of proso millet starch granules, while the treatment with UHP at 600 MPa and CP resulted in a complete gelatinization of starch. Also, UHP treatment at high pressure, followed by CP treatment, destroyed the partial crystalline region and reduced the short-range order of proso millet starch. Besides, a combination of UHP and CP treatment promoted the depolymerization of long chains in proso millet starch. Moreover, the combined treatments could enhance the resistance to high temperature and shearing and improve the pasting stability of starch. Furthermore, the combined treatment could increase the slowly digestible starch content. Therefore, the combination of UHP and CP treatment can be suggested for modifying the functional properties of proso millet starch and promoting its industrial applications.