Japonica and indica rice starches (10% w/w) were pregelatinized in a boiling water bath for 5 or 10 min and subsequently heat-treated in a dry state for 0, 1, 2, or 3 h at 130°C to examine the effects of dry heating on pasting viscosity, paste clarity, thermal properties, X-ray diffraction pattern, and gel strength of pregelatinized starches. Heat treatment obviously changed the physicochemical properties of pregelatinized rice starch. The pregelatinized rice starches had higher peak viscosity and final viscosity than the corresponding native rice starches. Heat treatment of pregelatinized rice starch for 1 h increased the peak viscosity, but treatment for 2 or 3 h decreased the peak viscosity compared with the unheated pregelatinized rice starch. The indica rice starch exhibited more substantial changes in pasting viscosity than did japonica rice starch during heat treatment. The melting enthalpy of the endothermic peak occurred at 90-110°C, and the intensity of the X-ray diffraction peak at 20° was increased by dry heating, possibly owing to the enhanced amylose-lipid complexes. The dry heat treatment of pregelatinized starch caused an increase in paste clarity and a decrease in gel strength.
Bibliographical noteFunding Information:
This research was supported by iPET (Korea Institute of Planning and Evaluation for Technology, grant number 311030-03-1-HD120), Ministry for Food, Agriculture, Forestry and Fisheries, Republic of Korea. We also thank Suseong College for financial support.
© 2017 AACC International, Inc.
ASJC Scopus subject areas
- Food Science
- Organic Chemistry