Development and characterization of biopolymeric films of galactomannans recovered from spent coffee grounds

The search for new renewable sources for the development of biopolymer packaging has been growing. Among these are galactomannans due to their biodegradability, high availability, and biocompatibility. The objective of this work was to develop biopolymeric film comprised mostly of galactomannans recovered from spent coffee grounds through alkaline and enzymatic treatment. Through the quantification of monosaccharides, it was possible to verify the significant removal of cellulose, maintaining the mannose and galactose monosaccharides. The film was produced by the phase inversion method and characterized in terms of chemical composition, morphology, crystallinity, water vapour permeability and mechanical properties. The results showed that cellulose plays an important role in mechanical properties (tensile strength and deformation), and the water vapour permeability of the film. However, with the partial removal of cellulose, it was possible to obtain a film with different properties since galactomannan molecules form stronger bonds, and consequently generating a more rigid film.