Cereal Chem 48:528 - 532.  |  VIEW ARTICLE
Effect of Alkali Dehulling on Composition and Wet-Milling Characteristics of Sorghum Grain.

C. W. Blessin, R. A. Anderson, W. L. Deatherage, and G. E. Inglett. Copyright 1971 by the American Association of Cereal Chemists, Inc. 

Three sorghum grains (RS-626, TE-77, and a commercial sample of U.S. No. 2 yellow) were selected to determine the effectiveness of aqueous solutions of sodium hydroxide (NaOH) as dehulling agents. Various times (2, 4, 6, and 8 min.); temperatures (140, 160, and 180 F.); and concentrations (15, 20, and 25% w./w.) were investigated. A 20% solution of NaOH at 160 F. essentially removed the pericarp in 4 to 8 min. and left the endosperm and germ intact. The treated grain was washed, neutralized with acetic acid, and washed again. Microscopic inspection of stained kernels showed that the major portion of the aleurone layer was not removed with this treatment. Under these conditions, average yield of dehulled sorghum grain was 92%. Ash, ether extract, and protein levels were not significantly affected by alkali dehulling. Fiber contents of the dehulled products were aproximately 50% of the level of the whole grain. When dehulled grain was wet- milled, there was a loss of 5 to 8 percentage points in starch recovery. However, protein content of the starch was about the same as in starch recovered from whole grain. Color of starch from dehulled grain appeared whiter. More and cleaner germ with higher oil content was recovered from dehulled grain. From an overall processing standpoint, 6 min. was an optimum dehulling time with 20% NaOH at 160 F.