Cereal Chem 68:234-238   |  VIEW ARTICLE

Effects of Fiber and Phytate in Sorghum Flour on Iron and Zinc in Weanling Rats: A Pilot Study.

H. I. Ali and B. F. Harland. Copyright 1991 by the American Association of Cereal Chemists, Inc. 

The effects of dietary fiber and phytate (myo-inositol hexaphosphate) in sorghum flours on iron and zinc concentrations in selected tissues of weanling rats were investigated using whole and traditionally decorticated sorghum grains (white durra) grown in Somalia. Two methods were used: the Traditional and the Improved (research) method using fertilizers and pesticides. Total dietary fiber content in the Traditional and Improved whole flours did not differ much (12.84 and 12.58%, respectively). Phytate levels in the Traditional and the Improved whole sorghum flours were 4.03 and 7.26 mg/g, respectively. Iron levels were highest in the Traditional whole and lowest in the Traditional decorticated flour (52 and 39 ppm, respectively). Zinc levels ranged from 39 ppm in the Improved whole to 17 ppm in the Traditional decorticated flour. Results showed that the total weight gain and feed efficiency ratios of rats fed the Improved whole sorghum flour were significantly lower than those of the control rats. The mean tibia iron level of the rats in the control group (119.4 +/- 10 ppm) was significantly higher (P less than 0.05) than those of the rats fed diets containing Improved sorghum flours (76.8 +/- 4 and 86.1 +/- 5 ppm for whole and decorticated flours, respectively). Furthermore, the tibia zinc concentration of the control group was significantly higher (P less than 0.05) than those of any of the four groups fed sorghum-containing diets. This study indicated that consumption of sorghum-containing diets by rats may result in lower mineral concentrations in the bone.