Crystallization kinetics of precooked potato starch under different dryingconditions (methods)

Isothermal Differential Scanning Calorimeter investigations of potato starc h, dried using sun, cabinet, fluidised bed, high temperature-short-time or freeze-drying methods were carried out to elucidate on the crystallisation kinetics, i.e. Avrami exponent., half time, degree of crystallisation and g lass transition temperature. Moisture content, resistant starch, rehydratio n percent and volume were also determined and correlated with kinetics of c rystallisation. The freeze-dried and high-temperature short-time-dried pota toes showed high rehydration percentages and volumes. The Avrami exponent r eached values of 1.04-1.05, depending on drying conditions, indicating that the mechanism of crystallisation was the same in all the cases. The bulk d ensity, rehydration percent and volume significantly correlated with glass transition temperature and half time of crystallisation. (C) 2001 Elsevier Science Ltd. All rights reserved.