Effect of high hydrostatic pressure and retrogradation treatments on structural and physicochemical properties of waxy wheat starch

In this study, the effects of high hydrostatic pressure and retrogradation (HHPR) treatments on in vitro digestibility, structural and physicochemical properties of waxy wheat starch were investigated. The waxy wheat starch slurries (10%, w/v) were treated with high hydrostatic pressures of 300, 400, 500, 600 MPa at 20 degrees C for 30 min, respectively, and then retrograded at 4 degrees C for 4 d. The results indicated that the content of slowly digestible starch (SDS) in HHPR-treated starch samples increased with increasing pressure level, and it reached the maximum (31.12%) at 600 MPa. HHPR treatment decreased the gelatinization temperatures, the gelatinization enthalpy, the relative crystallinity and the peak viscosity of the starch samples. Moreover, HHPR treatment destroyed the surface and interior structures of starch granules. These results suggest that the in vitro digestibility, physicochemical, and structural properties of waxy wheat starch are effectively modified by HHPR. (C) 2017 Elsevier Ltd. All rights reserved.