Effects of inorganic salts on the structural and physicochemical properties of high-hydrostatic-pressure-gelatinized sweet potato starch

Abstract

This study evaluated the effects of inorganic salts (calcium chloride and sodium chloride, 0–1 M) and high hydrostatic pressure (HHP) at 600 MPa on the structural, physicochemical, and gelatinization characteristics of sweet potato starch. The addition of inorganic salts significantly inhibited HHP-induced gelatinization and changed the structural and physicochemical properties of starch in a dose-dependent manner. Compared with sodium chloride, calcium chloride showed stronger inhibitory effects on HHP-induced gelatinization. Scanning electron microscopy, confocal laser scanning microscopy, and polarized light microscopy showed starch gelatinization in HHP-treated sweet potato starch suspensions containing 0.001 M calcium chloride or 0.001–0.01 M sodium chloride. The X-ray diffraction pattern was A-type in native sweet potato starch and C-type in HHP-treated sweet potato starch. For HHP-treated sweet potato starch, the addition of salts increased the gelatinization temperature, the enthalpy change, the crystallinity degree, the swelling power, and the solubility, but decreased the gelatinization degree and viscosity. The physicochemical changes of HHP-treated starch in salts were attributed to the disintegration of starch granules.