PREPARATION AND CHARACTERIZATION OF STARCH BASED EDIBLE/ BIODEGRADABLE FILMS

Abstract

To prepare good starch-based films the optimum concentration of high amylose starch was 8%. The various factors affecting the formation of these films were studied by measuring the physical (thickness and surface density), chemical (moisture content and water solubility), optical (light transmission and colour), mechanical (tensile strength and elongation at break) and barrier (water vapour and oxygen permeability) properties and examination of the ultrastructure of the prepared films. The suitable type and level of plasticizers used for preparing such films with good mechanical and barrier properties were glycerol at 40% or sorbitol at 50% level of starch weight. The sorbitol-plasticized starch films were more stable throughout the storage. Addition of glutamic acid as a co-plasticizer improved the different properties. The combination of starch with gelatin, agarose, agar, or PEG1000 were examined. Starch-agar blend films gave best physical, mechanical and barrier properties. Moreover, the IR spectra of these films were obtained and the characteristic IR bands for these spectra were assigned. Addition of glutamic acid and combination of starch with different polymers caused changes in the IR spectrum of starch film.