Preparation and Characterization of Starch Phosphate Obtained from Vigna Subterranean (l.) Verdc (fabaceae) Seeds

Background: Starch phosphate is a chemically modified starch that has been cross-linked with cross-linking agents such as sodium trimethaphosphate (STMP), sodium tripolyphosphate (STPP), or phosphate chloride. Objective: The aim of this study was to prepare and characterize starch phosphate obtained from the native and pregelatinized starches of Vigna subterranean nuts. Methods: Starch phosphate was obtained from native and pregelatinized starches by cross-linking each with di-sodium hydrogen orthophosphate anhydrous and following standards methods. Results: Mean values of the characterization of the starch phosphate was pH (7.06±0.04 and 7.14±0.04), Moisture content (16.50±0.50 and 9.50±1.50%), hydration capacity (293.33±6.67 and 276.67±3.33%), swelling index (250.00±0.00 and 250.00±0.00%), bulk density (0.46±0.00 and 0.48±0.00 g/ml), tapped density (0.55±0.00 and 0.57±0.02 g/ml), Hausner’s ratio (1.19±0.04 and 1.20±0.00), Carr index (15.69±3.00 and 16.36±0.00%), angle of repose (37.35±0.25 and 33.60±0.20°), Particle size (12.91±0.19 and 26.49±1.06µm), particle density (1.70±0.00 and 2.13±0.001 g/ml), porosity (99.41±0.00 and 99.41±0.00%), total ash (0.50±0.00 and 1.25±0.25%), acid soluble ash (1.25±0.25 and 0.50±0.00%), water soluble ash (0.75±0.25 and 1.00±0.00%), sulphated ash (1.75±0.25 and 1.75±0.25%) for native and modified starch phosphate respectively. The water absorption capacity and extractive yield of the starch phosphates ranged from 8.00±0.00 – 26.00±6.00 and 8.00±2.00 – 26.00±0.00, alcohol; 32.00±4.00 and 59.00±1.00% water; 50.00±0.00 and 63.00±17.00% respectively. Conclusion: The findings show that the modification of these starches to starch phosphate greatly enhance the functional properties of the starch and as such can be used as an alternative disintegrant in the formulation of tablets.