High-pressure gelatinization of wheat starch and properties of pressure-induced gels

Wheat starch suspensions of 5% dry matter were treated at 86 degrees C, 15 min, or with pressure at 600 MPa, 25 degrees C, 15 min. Both treatments were found to induce no further melting peak when differential scanning calorimetry was used. Under these previous conditions, starch suspensions subjected to pressure gave original products in terms of swelling index (water binding), amylose release and specific gravity. Pressure induced starch gelatinization with preservation of the granular structure. As a consequence, peculiar properties were expected for pressure-induced gels of 30% dry matter obtained at 600 MPa, 25 degrees C, 15 min. By using Young modulus measurements, calorimetry, X-ray diffraction, and drying kinetics experiments, results showed a limited retrogradation for gels obtained under pressure.