Physical and mechanical properties of composite edible films from sago starch and bulk chitosan

Abstract

The objective of this study was to investigate physical and mechanical properties, such as thickness, water vapor permeability, tensile strength, elongation at break, differential scanning calorimetry (DSC) and microstructure of composite edible films. The film was prepared by casting sago starch from sago palm (Metroxylon sagu ) as film base with 10-50 %w/w glycerol as plasticizer and adding bulk chitosan as a reinforcing material (0.1, 0.3, and 0.5 %w/w). The continuous, homogenous and transparent films were obtained. With regard to mechanical properties, tensile strength decreased when the percentage of glycerol increased. Elongation at break (%E) improved with increasing percentage of glycerol from 10 %w/w to 50 %w/w. However, water vapor permeability properties diminished in all samples when the percentage of chitosan increased. The morphological study of the composite films exhibited rougher surfaces with increasing chitosan in the films. DSC thermograms showed that glycerol incorporated into composite films diminished the onset temperature (T₀) and degradation temperature (T_d). Having these physical and mechanical properties, this edible film has a potential to apply for food packaging purposes. Moreover, this edible film is proved to be more cost-effective and environmentally friendly.