Cereal Chem. 70:512-516   |  VIEW ARTICLE

Thermophysical Properties of Milled Rice Starch as Influenced by Variety and Parboiling Method.

C. G. Biliaderis, J. R. Tonogai, C. M. Perez, and B. O. Juliano. Copyright 1993 by the American Association of Cereal Chemists, Inc. 

Rices differing in amylose content and starch final gelatinization temperatures (GT) were parboiled at 100, 120, and 127 C to determine the formation of amylose-lipid complex I (melting at less than 100 C) and complex II (melting at greater than 100 C), which are observed in model systems. In rices parboiled at 100 C, only the low-GT (less than 70 C) nonwaxy rices exhibited the amylose-lipid complex I melting, without residual (unmelted) starch crystallites. Intermediate-high-GT starches (greater than or equal to 70 C), with residual annealed starch, did not form complex I, nor did waxy IR65. The amylose-lipid complex II melting endotherm was observed in all rices parboiled at 120 and 127 C. It was highest for IR64 parboiled at 120 C. Reduction in hot-water-soluble amylose and increase in X-ray diffraction peak at 2theta = 19.9 degrees for V complex corresponded to maximum DeltaH of amylose-lipid complex II melting for the pressure- parboiled samples of intermediate-high-amylose rices.