Exploration of the process and mechanism of magnesium chloride induced starch gelatinization

Abstract

As a new starch gelatinization method, salt induced gelatinization can not only reduce energy consumption but also impart special physicochemical properties to starch gel. In this study, the process and mechanism of MgCl₂ induced starch gelatinization were explored. The results showed that, potato starch could be gelatinized after a treatment of 4 mol/L MgCl₂ for 3 h. The gelatinization started with the slight damage of outer shells, then the internal molecules leached out through the cracks or holes to form gel, finally the outer shells disintegrated. During the gelatinization process, the viscosity and granule size gradually increased after 0.5 h, while the original crystallinity disappeared rapidly in 0.5 h. Besides, MgCl₂ significantly increased the electrostatic interaction, then made starch molecules closer to each other and become denser, which may have close relationship with the appearance of the cracks and the disappearance of crystallization. Moreover, MgCl₂ enhanced the hydration and increased the binding free energy of starch molecules, then promoted starch gelatinization and accelerated the destruction of starch structure, which may be the critical factors of the starch gelatinization induced by MgCl₂. The results will provide reference for the research and application of salt induced gelatinization.

Keywords: Gelatinization mechanism; Gelatinization process; Magnesium chloride; Potato starch.