Effect of temperature on gelatinization and retrogradation in high hydrostatic pressure treatment of potato starch–water mixtures

The effect of temperature (20–70 °C) on the gelatinization and retrogradation of potato starch–water mixtures (10–70%, w/w) treated with high hydrostatic pressure (HHP) (400–1000 MPa) was investigated. Gelatinization enthalpy change (ΔHgel) and re-gelatinization enthalpy change of retrograded crystalline part (ΔHretro) of the HHP-treated starch were evaluated using differential scanning calorimetry. The value of ΔHgel of 10–20% (w/w) mixtures decreased with increased pressure and temperature, while ΔHgel of 30–50% (w/w) mixtures decreased to certain values with increased pressure and the values depended on treatment temperature. With higher temperature and pressure conditions, ΔHgel of 10–40% (w/w) mixtures reached zero, but ΔHgel of 50–70% (w/w) mixtures did not. Retrogradation was observed with HHP-treated 20–60% (w/w) mixtures and the value of ΔHretro depended on the starch content, pressure, and temperature. The value of ΔHretro trended to increase with increase in starch content. In addition, retrogradation was promoted by HHP treatment at low temperature. Gelatinizaiton and retrogradation behaviors of HHP-treated (400–1000 MPa) potato starch–water mixtures (10–70%, w/w) at 20–70 °C were summerized in a series of state diagrams.