Edible films based on starch and chitosan. Effect of starch source and concentration, plasticizer, surfactant's hydrophobic tail and mechanical treatment

Edible films based on starch and chitosan were obtained by varying the starch source (potato and cassava starch), starch concentration (0.5 and 1.0%), type of plasticizer (glucose and glycerol), chain length of the surfactant's hydrophobic tail (12 or 18 carbons) and mechanical treatment (0.5 or 4 min stirring time) during the preparation of the film forming solution. A completely randomized design with factorial arrangement 2(4) was utilized. The variables to be determined were film opacity, film thickness, tensile strength, water vapor permeability, elasticity and film solubility. Starch source, starch concentration and type of plasticizer were the most important factors to be consider on formulation of edible films based on starch. Those factors affect to most of the evaluated film properties, except opacity and elasticity. Stirring time may be a valuable and economic tool to improve elasticity, whereas the use of an appropriate surfactant may help to improve the tensile strength of the starch film. (C) 2015 Elsevier Ltd. All rights reserved.