Effect of the Concentration of Wood Ash Extract and Duration of Soaking on the Chemical Composition of High Tannin Sorghum (Sorghum bicolor) Cultivars

A study was conducted to investigate the effect of the concentration of wood ash extract and duration of soaking on the chemical composition of high tannin sorghum cultivars. Ash extract solutions were prepared by mixing hard wood ash and distilled water in plastic buckets at the rate of 1:20, 1:10 and 1:5 (w/v). Two red coloured sorghum cultivars (Kabusiba and Elodir) plus one brown sorghum variety (Sekedo), were soaked in the ash extract solutions at each concentration for 6, 12, 18, and 24 hours. The treated grains were analysed for tannin content, major minerals and amino acid composition. At higher concentrations of ash extract, the reduction in sorghum tannins was correspondingly higher. However, the relationship was not linear and the various sorghum cultivars did not exhibit a similar degree of response to ash extract treatment. Kabusiba sorghum was more responsive to ash treatment than Sekedo and Elodir. Prolonged soaking did not necessarily result into corresponding reductions in tannin content of the grain. The levels of potassium and sodium in the grain were slightly increased as a result of ash extract treatment. At the highest concentration of ash extract, treatment of the grain resulted in slight decreases of some amino acids.