Physicochemical properties, structural properties, and in vitro digestibility of pea starch treated with high hydrostatic pressure

The influence of high hydrostatic pressure (HHP) treatment at 150, 300, 450, and 600 MPa for 25 min on the physicochemical properties, structural properties, and in vitro digestibility of pea starch was studied. Compared to native and pea starch treated at 150-450MPa, the morphology of pea starch at 600MPa was completely destroyed and the particle size became larger, indicating complete gelatinization. The X-ray diffraction results showed that the native pea starch was gradually changed from the C-type into the B-type pattern after 150-600MPa HHP treatment. At 30-70 degrees C, pea starch treated at 600MPa had a higher water absorption index (p<0.05), swelling power, and solubility than other samples did, but opposite results were obtained at 90 degrees C. The rapid visco analyzer (RVA) results indicated that pea starch treated with high pressure at 600MPa showed lower values of peak viscosity, trough, breakdown, final viscosity, and setback (p<0.05), reflecting lower retrogradation. Gelatinization temperatures and enthalpy determined by differential scanning calorimetry (DSC) decreased with the increase of pressure. Furthermore, the in vitro digestibility of HHP treated pea starches was lower than that of native pea starch (p<0.05). Therefore, it is an effective method for HHP treatment to modify the properties of pea starches.