Publication no. C-1998-1007-06R |  VIEW ARTICLE

Retrogradation of du wx and su2 wx Maize Starches After Different Gelatinization Heat Treatments.

Qiang Liu (1) and Donald B. Thompson (1,2). (1) Department of Food Science, The Pennsylvania State University, 111 Borland Laboratory, University Park, PA 16802. (2) Corresponding author. Phone: 814/863-2950. Fax: 814/863-6132. E-mail: <dbt1@psu.edu> Cereal Chem. 75(6):868-874. Accepted July 28, 1998. Copyright 1998 American Association of Cereal Chemists, Inc.

Retrogradation of du wx and su2 wx starches after different gelatinization heat treatments was studied by differential scanning calorimetry. Suspensions of 30% (w/w) starch were initially heated to final temperatures of 55-180°C. Gelatinized starch was cooled and stored at 4°C. Starch retrogradation in the storage period was influenced by initial heat treatments. Retrogradation of du wx starch was rapid: when initially heated to 80-105°C, retrogradation enthalpy was approximately 10 J/g after one day at 4°C. The retrogradation enthalpy was approximately 15 J/g after 22 days of storage, and reached a maximum of 16.2 J/g after 40 days of storage. For du wx starch, application of the Avrami equation to increases in retrogradation enthalpy suggests retrogradation kinetics vary with initial heating temperature. Furthermore, starch retrogradation may not fit simple Avrami theory for initial heating <=140°C. Retrogradation of su2 wx starch was slow. After 30 days of storage at 4°C, the maximum retrogradation enthalpy for all initial heating temperatures tested was 7.0 J/g, for the initial heating to 80°C. This work indicates that gelatinization heat treatment in these starches is an important factor in amylopectin retrogradation, and that the effect of initial heat treatment varies according to the genotype.