Cereal Chem 67:458-463   |  VIEW ARTICLE

Effects of Lipid and Protein Removal on Starch Gelatinization in Whole Grain Milled Rice.

W. E. Marshall, F. L. Normand, and W. R. Goynes. Copyright 1990 by the American Association of Cereal Chemists, Inc. 

Treatment of long-, medium-, and short-grain, and very low amylose varieties of whole grain milled rice with the lipid solvents hexane or chloroform-methanol or the proteolytic enzyme Pronase caused significant changes to occur in starch gelatinization parameters measured by differential scanning calorimetry. Upon examination of the treated kernels by scanning electron microscopy, extensive fissure formation in the kernels was evident. Similar sturctural changes were noted in milled rice soaked in water for 30 min. The starch gelatinization curves for the soaked kernels resembled those for the lipid-solvent-treated kernels but not for the Pronase-treated kernels. However, fissure formation and modification of the kernel surface was more extensive in the Pronase-treated rice. We concluded that the alteration of kernel structure in intact milled rice increased water availability to the starch granules, which produced significant changes in starch gelatinization. Removal of rice lipid or rice protein per se appeared to have only a minor, but measureable, effect on starch gelatinization.