Valorization of agro-industrial wastes for the production of biodegradable products based on collagen

Abstract

Collagen, which can be extracted from livestock and fish processing industry residues, has been widely used in food, cosmetic, pharmaceutical and biomedical applications due to its structural and biological properties as well as its abundance and versatility in forming physical shapes. Furthermore, collagen can be combined with other components to open up new application areas. In this context, the overall objective of this doctoral thesis was to develop products based on collagen, obtained from bovine and porcine skin wastes, with improved properties, incorporating other compounds, some of them also extracted from biowastes, and employing different processing methods. The information about collagen and the materials and characterization methods employed throughout the work are explained in the first two chapters. In chapter 3, citric acid was used to facilitate the processing by laboratory rollers and the functional properties of sheets obtained by compression were investigated. In chapters 4 and 5, aloe vera and chitosan were added in collagen based formulations to evaluate their suitability for biomedical applications. In chapter 6, scaffolds with the same formulation than Chapter 5 was prepared by freeze-drying and material properties and environmental impact were analysed. Moreover, in chapter 7, a syringe-based extrusion 3D printer was used to obtain tetrahydrocurcumin-incorporated porcine collagen scaffolds and their potential as sustained THC delivery systems was analyzed. Then, the electrical properties of collagen films were examined. In chapter 8, ZnO nanoparticles were incorporated into collagen formulations processed by solvent casting in order to obtain materials with induced electro-conductive properties, which could be of great relevance for biomedical applications. In chapter 9, wool and choline dihydrogen phosphate or choline serinate containing collagen formulations were prepared by compression molding to develop next generation advanced functional materials for sustainable electronics.