Synthesis and Characterization of Chanar Gum Films

Abstract

New polysaccharides are being intensely studied as sources of edible materials, with potential application in food packaging systems, eco-materials and the pharmaceutical industry. This investigation aimed to develop biopolymer films based on the polysaccharides obtained from chañar (CH) fruit (Geoffrea decorticans). The resulting polysaccharides, from hydrothermal extraction (CHT) and acid extraction (CHA) were hydrodynamically characterized, with density, viscosity, and diffusion coefficient measurements to obtain their properties in an aqueous solution (intrinsic viscosity, shape factor, partial specific volume, hydration value, molecular weight, and hydrodynamic radius). The polysaccharides films (CHTF and CHAF) were characterized with SEM/EDX, DSC, TGA-DTG, FTIR, DRX, mechanical tests, water vapor permeation, colorimetry, antioxidant capacity, and biodegradability, to determine potential applications based on these properties. The results indicated that the extraction method affects the hydrodynamic properties of the obtained polysaccharide. They differ in molecular weight, and RH of CHT was greater than CHA. Both gums were quasi-spherical, and the νa/b value of CHT was more than CHA. The films properties did not present significant differences in most cases. SEM micrographs illustrate that CHAF presents a much rougher surface. The results of the mechanical analysis show that CHTF has better mechanical properties, it has higher elongation at break and tensile strength, with a Young Modulus of 2.8 MPa. Thermal analysis indicates good thermal stability of the films until about 150◦ C. The degradation study shows that CH films are biodegradable in a 35 day range. The study of this properties is critical to demonstrate the functionality of biopolymers and their application. The obtained results represent an advantage and evidence that chañar is an interesting source for extract polysaccharides with film forming properties.