The Effect of Soaking with Wooden Ash and Malting upon Some Nutritional Properties of Sorghum Flour Used for Impeke, a Traditional Burundian Malt-Based Sorghum Beverage

The objective of the present work was to determine the effect of wooden ash extract on anti-nutritional factors and to assess the effect of soaking with malting on nutritional properties of sorghum flour used for impeke. The addition of wooden ash extract during 24 h of soaking resulted in significant decrease in tannin by 50.2% and the decrease was observed to be progressive as malting time increases. 5 d of malting resulted in significant decrease in tannin by 69.3% and in phytic acid by 66.4% with slight decrease in ash, lipid, fiber, and starch. Malting showed an increased percentage of protein, essential amino acids, and then in vitro protein digestibility were markedly improved with increasing malting time. Sugars analysis proved a significant increase in maltose, glucose, fructose, and structural analysis of sorghum starch displayed porosity on granule's surface susceptible to the amylolysis.