Extração e caracterização do amido do Hedychium coronarium e elaboração de filmes biodegradáveis

Abstract

Non biodegradable packing plastics have become an environmental problem and a new way of solving this problem is the use natural polymers in a production of biodegradable materials. Biodegradable films can be mainly produced from polysaccharides, particularty starch. The objectives of this work were to extract and characterizing starch from Hedychium coronarium roots and use it as a starchy source for biodegradable films. The characteristics of starch and films were evaluated according to their physicochemical properties. The films were elaborated according to the casting technique using different concentrations of starch (1, 2, 3 and 4% w/v) and glycerol (10, 20, 30 and 40% v/v, based on starch concentration). Film samples were analyzed concerning its thickness, mechanical tests (traction and compression) and optical properties. Starch presented low content of other constituents and also high amylose content (37.2%). Concerning its morphology, starch granules presented irregular shape with angled edges and average of 38.2 µm size showing crystalline type A. Gelatinization temperature ranged from 73.1 to 78.7°C and high thermal stability and considerable tendency of retrogradation. Film samples presented thickness varying from 0,042 a 0,379 mm according to starch concentration. Deformation at break was influenced by glycerol content and also by starch content, however color, opacity, elastic modulus and force at rupture presented variation related only to starch concentration. In relation to starch crystalinity, films showed a typical amorphous structure, however it was observed a small crystal structure at 29º (2 theta). Starch films were completely degraded in 45 days. The application of the starch films as vehicle for vitamin C showed that loss of active principle and mass depend will the biodegradable films composition.