Cereal Chem 67:570-574 | VIEW
Effects of Degree of Milling and Lipid Removal on Starch Gelatinization in the Brown Rice Kernel.
E. T. Champagne, W. E. Marshall, and W. R. Goynes. Copyright 1990 by the American Association of Cereal Chemists, Inc.
The effects of the degree of milling (unmilled to 9.1% removal of outer surface) and of surface, nonstarch lipid removal on starch gelatinization in the rice kernel were examined by differential scanning calorimetry. Onset (To) and peak (Tp) gelatinization temperatures of full-fat and defatted kernels were determined to be logarithmic functions of the degree of milling. The removal of the outer 1.3% of the full-fat or defatted rice kernels by milling led to the largest decreases in To and Tp values. The greater the degree of milling, the larger the percentage of lipid solvent extracted from the kernels and the larger the decrease in Tp. Decreases in Tp followed logarithmic and linear functions of the percentage of lipid removed from unmilled and milled rice kernels, respectively. A relatively large decrease in Tp was observed for a small percentage of lipid extracted from unmilled rice kernels compared with the decreases in Tp observed for much larger percentages of lipid extracted from 1.3-9.1% milled rice kernels. Evidence is presented indicating that waxes and nonstarch lipids in the rice kernel have a role affecting starch gelatinization.