ABSTRACT
The natural polymer Tragacanth Gum is less explored as a supporting matrix, there are very less studies conducted using this polymer in literature. So the present study aims to explore the consequences of different weight percent (wt.%) of gallic acid (GA) on physicochemical properties of Poly (vinyl alcohol)/Tragacanth Gum blend films. The incorporation of GA resulted in more strengthened but less flexible films as confirmed by tensile tests. DSC studies confirmed the miscibility of composite films in the given composition range and TGA studies revealed increased thermal stability. The morphological studies revealed a homogeneous distribution of GA at lower wt.% in the blend system. X-Ray Diffraction study depicted; the added GA lost crystalline structure after incorporating it into the blend. The Water Vapor Transmission Rate (WVTR) was improved after the incorporation of GA into the blend system. Overall migration studies revealed the limited release of GA from the matrix into food simulants. Soil degradation rate increased as the wt.% of GA increased. The composite films presented strong antioxidant activity; therefore, prepared composite films could be used as an alternative to current packaging materials.
ABSTRACT
Ethyl vanillin (EV) incorporated chitosan (CS)/poly(vinyl alcohol)(PVA) blend films of various ratios (1:3, 1:1 and 3:1) were prepared by solvent casting technique. The effect of EV on the mechanical, structural, barrier, optical, food compatibility and antibacterial properties of the CS/PVA films were investigated. Mechanical properties showed that addition of EV increased tensile strength of CPEV-1, CPEV-2 and CPEV-3 films by 39 %, 45 % and 86 %, respectively compared to CS/PVA matrix. The FTIR results confirmed the formation of a Schiff base (CN) and intermolecular hydrogen bonds between CS, PVA, and EV. Incorporation of EV into CS/PVA matrix (i.e. CPEV) showed the marked influence on the water vapor transmission rates (WVTRs) and oxygen transmission rates (OTRs) and exhibited excellent UV barrier capability. Surface morphology of CPEV blend films becomes smooth, homogeneous and dense as visualized through scanning electron microscopy. Contact angle measurements demonstrated the increased hydrophobicity of CPEV blend films with increasing CS content. Strong antibacterial activity was exhibited by CPEV-3 blend films against both E. coli (Escherichia coli) and S. aureus (Staphylococcus aureus) bacteria. The overall migration values of CPEV blend films were 103 times lower than acceptable limits of 10â¯mg/dm2. Therefore, CPEV blends have good potential to be considered as sources of active films for food packaging applications.