Due to its unique properties, collagen is used in the growing fields of pharmaceutical and biomedical devices, as well as in the fields of nutraceuticals, cosmeceuticals, food and beverages. Collagen also represents a valid resource for bioplastics and biomaterials, to be used in the emerging health sectors. Recently, marine organisms have been considered as promising sources of collagen, because they do not harbor transmissible disease. In particular, fish biomass as well as by-catch organisms, such as undersized fish, jellyfish, sharks, starfish, and sponges, possess a very high collagen content. The use of discarded and underused biomass could contribute to the development of a sustainable process for collagen extraction, with a significantly reduced environmental impact. This addresses the European zero-waste strategy, which supports all three generally accepted goals of sustainability: sustainable economic well-being, environmental protection, and social well-being. A zero-waste strategy would use far fewer new raw materials and send no waste materials to landfills. In this review, we present an overview of the studies carried out on collagen obtained from by-catch organisms and fish wastes. Additionally, we discuss novel technologies based on thermoplastic processes that could be applied, likewise, as marine collagen treatment.2 of 23 protective colloid functions and film-forming capacity. Also, collagen is a good surface-active agent, with its ability to penetrate lipid-free interfaces [2].Collagen can be utilized in a variety of applications because of its biocompatibility and excellent degradability [3,4]. Furthermore, it is known that collagen is a molecule with weak immunogenicity, which decreases the possibilities of rejection when it is ingested or injected into a different body. Although this molecule has already low antigenicity, this property can be enhanced by modifying it to suppress any immune response [5,6]. Additionally, collagen peptides and gelatin (denatured collagen) have been widely utilized in different fields such as food, medicine, cosmetics, leather and film industries, diagnostic imaging, and therapeutic delivery [7].For many years, most available collagen was extracted from discards from the bovine and porcine processing industries, but during the last few decades the use of collagen from these sources has been limited. The use of porcine and bovine-derived products is occasionally prevented by dietary regimes, due to specific needs or personal choices. It is forbidden by religious constraints, to Muslims, Hindus and Jews who make up 38.4% of the global population [8]. Moreover, the use of bovine-derived products became a concern for a wider section of the population during the bovine spongiform encephalopathy (BSE), transmissible spongiform encephalopathy (TSE) and foot-and-mouth disease (FMD) crises that occurred over the last few decades in all areas of the world, mostly in the United Kingdom and Asia. Bovine-derived products might be a vehicle of transmission of these diseases ...

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The aim of this work was to explore the feasibility of preparing thermoplastic films from commercial zein by film blowing technology. Zein, a cereal protein extracted from maize, was plasticized directly in the extruder, without the time-consuming and expensive solubilization step, usually utilized in literature for this material. Four different batches of zein were investigated, for it has been observed that properties such as the film-forming ability of natural polymers strongly depend on several factors such as sources, extraction, and drying conditions. Thermal, rheological, and macromolecular structural characteristics were evaluated for the different materials to establish a correlation among molecular structure, rheological behavior in uniaxial elongation, and film blowing processability. Results indicate that the best films were made by using thermoplasticized zein characterized with a pronounced strain hardening and a large content of a-helices.

One of the challenges in tissue engineering scaffold design is the realization of structures with a pre-defined multi-scaled porous network. Along this line, this study aimed at the design of porous scaffolds with controlled porosity and pore size distribution from blends of poly(epsilon-caprolactone) (PCL) and thermoplastic gelatin (TG), a thermoplastic natural material obtained by de novo thermoplasticization of gelatin. PCL/TG blends with composition in the range from 40/60 to 60/40 (w/w) were prepared by melt mixing process. The multi-phase microstructures of these blends were analyzed by scanning electron microscopy and dynamic mechanical analysis. Furthermore, in order to prepare open porous scaffolds for cell culture and tissue replacement, the TG and PCL were selectively extracted from the blends by the appropriate combination of solvent and extraction parameters. Finally, with the proposed combination of gas foaming and selective polymer extraction technologies, PCL and TG porous materials with multi-scaled and highly interconnected porosities were designed as novel scaffolds for new-tissue regeneration.

The specific shielding effectiveness of segregated CNT/rubber foams fabricated by the supercritical CO2 method reaches 312.69 dB cm2 g−1.

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The effect of alkaline lignin (AL) and sodium lignosulfonate (LSS) on the structure of thermoplastic zein (TPZ) was studied. Protein structural changes and the nature of the physical interaction between lignin and zein were investigated by means of X-ray diffraction and Fourier transform infrared (FT-IR) spectroscopy and correlated with physical properties. Most relevant protein structural changes were observed at low AL concentration, where strong H-bondings between the functional groups of AL and the amino acids in zein induced a destructuring of inter- and intramolecular interactions in α-helix, β-sheet, and β-turn secondary structures. This destructuring allowed for an extensive protein conformational modification which, in turn, resulted in a strong improvement of the physical properties of the bionanocomposite.

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