Cereal Chem 56:287 - 294.  |  VIEW ARTICLE
Bleaching Effect of Acid on Pearl Millet.

R. D. Reichert and C. G. Youngs. Copyright 1979 by the American Association of Cereal Chemists, Inc. 

Soaking millet grain (Pennisetum typhoides) overnight in solutions containing sour milk or tamarind pods markedly reduced the color of the grain. This process is traditionally practiced by some Nigerian villagers to improve the appearance of the flour. Decolorization was pH-dependent and was duplicated with 0.2N HCl or citric acid. Acid enetered whole millet very slowly only through areas around the embryo but penetrated scarified millet rapidly through areas where the hull had been broken. The rate of acid bleaching of the grain, monitored by reflectance spectroscopy, increased dramatically with the degree of dehulling. Typically, at a degree of dehulling of 10%, soaking times of 5-10 min in 0.2N HCl were required to bleach millet to a color comparable to the traditional sour milk soaked product. Considerable variation was found in the effectiveness of the acid soaking treatment among different varieties of millet grain.