Physicochemical and Rheological Characterization of Native and Thermally Silicified Blends of Sweet Potato and Sorghum Starch Granules

The aim of the study was to characterize native and thermally silicified blends of sweet potato and sorghum starch granules using their physicochemical and rheological properties. Sweet potato ( Ipomea batatas L., Family: Convolvulaceae ) and sorghum ( Sorghum bicolor , Family: Poaceae ) starches (PS and SS respectively) were extracted and silicified by dissolving 25%w/w silicon dioxide in ultra-pure water containing 75%w/w starch with continuous stirring at 42 (cid:6) 0.5 o C for 4 mins and subsequently oven-dried (45 (cid:6) 0.5 o C) to form sPS and sSS respectively. Physical blends of sPS and sSS granules in ratios 1:1, 1:2 and 2:1 were made and compared with granule blends of PS and SS at similar ratios. Angle of repose, density measurements, Carr’s index, Hausner’s ratio, morphology, pH, swelling capacity and FTIR spectroscopy were