Cereal Chem 66:317-320   |  VIEW ARTICLE

Differential Scanning Calorimetry of Whole Grain Milled Rice and Milled Rice Flour.

F. L. Normand and W. E. Marshall. Copyright 1989 by the American Association of Cereal Chemists, Inc. 

The thermal properties of whole grain milled rice and milled rice flour were investigated by differential scanning calorimetry. Thermal curves were obtained on representative long, medium, short, and very low amylose varieties over the temperature range of 20 to 110 C. All whole grain samples showed two endothermic transitions associated with starch gelatinization whereas comparable flour samples exhibited only one endotherm. The gelatinization temperatures for all long, medium, and short varieties decreased with decreasing grain length. Gelatinization onset temperatures for all samples were similar within each variety, but peak gelatinization temperatures were 13-17 C higher in the whole grain samples. Gelatinization enthalpies were about 40% greater in whole grain rice compared to rice flour for each variety. Heating rate studies conducted on the long-grain variety (Lemont) at rates of 0.17-1.33 C/min (10-80 C/hr) continued to show two gelatinization endotherms although some thermal parameters changed with heating rate. The results show that the thernal curves for whole grain rice are considerably different from comparable flour samples, and these results are discussed in terms of the structural integrity of whole grain rice in determining its thermal properties.