Synthesis and manufacturing of customizable β-chitin materials from sea food waste

This thesis explores the valorization of β-chitin, one of the three polymorphic forms of chitin, the second most abundant biopolymer on earth after cellulose. Despite its abundance, β-chitin remains underutilized due to challenges like poor solubility and handling. Derived primarily from squid pens, β-chitin offers advantages over α-chitin, such as higher reactivity and flexibility. The study developed innovative β-chitin-based materials through chemical and physical approaches. Oxidation with ammonium persulfate introduced carboxylic groups at the C6 position, significantly enhancing water solubility and enabling diverse applications. These included hydrogels with tunable mechanical properties at pH 1, 5, and 7.4, and in the presence of ions such as Ca²⁺, Na⁺, and Mg²⁺; chitin-chitosan composite films with improved stability in acidic environments; and encapsulation carriers for carotenoids that preserved their antioxidant activity through digestion. Additionally, physical methods were employed to create β-chitin foams with thermal insulation properties comparable to expanded polystyrene (EPS). Customizable foams with water-repellent and cushioning properties were achieved, expanding potential applications. The final chapter explored the amorphization and re-crystallization of β-chitin, successfully avoiding transformation into the thermodynamically stable α-polymorph through metal-ion treatments. This research underscores the potential of β-chitin as a sustainable and versatile resource for creating customizable materials. By leveraging waste-derived resources and integrating chemical and physical strategies, this study expands the practical applications of this underutilized biopolymer.