High pressure phase transition kinetics of maize starch

In this paper, the impact of high hydrostatic pressure, temperature and time on the gelatinization of maize starch is reported. Starch transition has been assessed by microscopic inspections of the granule's loss in birefringence which occurs during the first stage of gelatinization in consequence of the water uptake. Experiments have been carried out under combined pressure-temperature treatments in the range of 0.1-650 MPa and 30-75 degrees C. The rate of gelatinization has been determined by an interpolating model and isokineticity lines were plotted in pressure-temperature diagrams. Pressure higher than 300 MPa is necessary to reduce significantly the onset temperature of gelatinization. At those pressures, the isokineticity lines are bended to the left, indicating that the phase transition in birefringence is occurring at lower temperatures. At 30 degrees C, maize starch was gelatinized completely after 30 min at 650 MPa. (c) 2006 Elsevier Ltd. All rights reserved.