Extraction, Characterization and Dextrinization of Starch from Six (6) Varieties of Tubers from Iwo Osun State Nigeria for Application in the Production of Adhesives

Abstract

Tuber crops are widely consumed; they come in various varieties with great nutritional and non- nutritional values. They are very rich in starch. The starch content of each of the six varieties of Nigerian tubers was determined, each of the tubers was wet fractionated in the laboratory and the starch was recovered. The composition of the tubers (dry matter, protein, ash and mineral content) and starch isolation (moisture, starch, protein, phosphorus, fat and carbohydrate) were determined. Substantial differences in the starch content of the tubers were observed. The dry starch recovery ranged from 10.20% to 18.30% and the wet starch recovery ranged from 15.70-32.40%. Moisture content ranged from 13-15.80%, viscosity 275.08 -382.33. The carbohydrate, ash, fat and protein content of the six varieties of the tubers vary from 45% to 53.8%, 1.0 to 2.0%, 19.56 to 21.99% and 10.96-14.29% respectively. All six starches were insoluble in water and ethanol and proved positive to iodine and Fehling’s test. Extracted starch was dextrinated using 0.1M and 0.2M HCl separately at 160 and 100°C to obtain yellow dextrin and white dextrin respectively which were soluble in water. Modified starches were formulated into adhesives. Results obtained indicated satisfactory strength for the adhesives. Thus starches suitable for the production of adhesives were obtained.