Cereal Chem 61:232 - 235.  |  VIEW ARTICLE
Basis for Hardness in Pearl Millet, Grain Sorghum, and Corn.

A. A. Abdelrahman and R. C. Hoseney. Copyright 1984 by the American Association of Cereal Chemists, Inc. 

A chemical approach was used to study hardness of pearl millet, grain sorghum, and corn. Grits from the three grains were treated with solvents, and the hardness of the residual material was determined using a particle-size index test. The results indicated that 60% tertiary-butanol was more effective than other solvents in making both millet and corn soft and easy to grind. However, t-butanol was not effective with grain sorghum. A combination of t-butanol and sodium bisulfite or mercaptoethanol was required to soften sorghum grits. When that combination was used with corn, the grits became softer; 78% of the material passed through a 100-mesh (150-microm) sieve. The solubles removed from the grains were added to starch and made into pellets. The pellets were dried and their strength measured with an Instron machine. The solubles extracted with those solvents that were effective in softening the grain produced strong pellets. The force required to break a pellet was directly related to the amount of solubles used to make it. When the solubles were heated before they were added to starch, they lost their ability to hold the starch together. The results show that the substance or substances responsible for hardness in those grains are extractable and sensitive to heat.