Physical and Chemical Properties Characterization of Reduced Tannin Sorghum Flour (Sorghum bicolor L).

Abstract

The aim of this study was to characterize physical and chemical properties of reduced tannin sorghum flour. The physical properties characterized were rheological properties, whiteness, density, swelling volume, solubility and water absorption capacity. The chemical properties characterized were moisture, carbohydrate, protein, fat, ash, tannin, starch, crude fiber, amylose and amylopectin, starch and protein digestibility. The reduced tannin shorgum flour was obtained by polishing and soaking of sorghum grains in 0.3% Na2CO3 solution followed by grinding process. Significant differences were found (p <0.05) among samples for peak viscosity, whiteness, solubility, water absorption capacity. Significant differences were found (p <0.05) in the chemical properties of all samples. The results showed that polishing and soaking of sorghum grains in 0.3% Na2CO3 solution reduced tannin levels by 95% (from 2.9% to 0.12%) and 97% (from 2.39% to 0.08% ). Soaking of sorghum grains in 0.3% Na2CO3 solution reduced protein and starch of sorghum flour, but increased carbohydrate and amylose content and increased digestibility of protein.