A Preliminary Investigation Of Cassava Starch Potentials As Natural Polymer In Bioplastic Production
Starch consists of two types of molecules namely, amylosse and amylopectin .Amylose, a linear chain polymer constitutes about 20% of starch. It is more soluble in water, soluble in hot water but does not form gel while amylopectin is a branched chain polymer that constitutes about 80% of the starch. It is less soluble in water, soluble in hot but forms gel, hence the need for modification. In this study, Cassava starch was modified with distilled water, glycerol and vinegar. The cassava starch, distilled water, vinegar and glycerol were all weighed in required proportions into the beaker. 50g of cassava starch was weighed into a beaker, 10mls of vinegar was added. 20mls of glycerol was also added. The resulting mixture was thoroughly stirred to form a uniform suspension, the suspension was heated, and it was continuously stirred to avoid coagulation with increasing viscosity until gelatinization was achieved at about 100°C. The gel was spread on a smooth, hard surface and mechanically pressed to form sheets. The sheets were air dried to cure for 72hrs to 5% moisture content. The sheet was subjected to tensile test. Water was used as a solvent to first get the biopolymer (starch) into solution. When the solution was heated, the water helped the starch molecules to become disrupted and disordered (denatured). The reduction of starch hydrogen bonding was achieved in the presence of water. Water diffused into the starch granules and hydrogen bonds breaking down the intermolecular bonds of the starch molecules. Water helped the starch molecules to become disrupted and disordered. When the starch was heated with water, water interacted with hydroxyl