Chitin Preparation by Demineralizing Deproteinized Lobster Shells with CO₂ and a Cationite

The inorganic components of crustacean shells are usually removed using HCl solutions. This provokes undesirable modifications in the extracted chitin. In the present procedure, deproteinized lobster shells were demineralized with CO₂ and a cationic resin (cationite). The resulting chitin (CHI-CO₂) is compared in terms of degree of acetylation (DA), crystallinity index (CrI) and thermal stability with chitins obtained by demineralization procedures with HCl (CHI-HCl) and ethylenediaminetetraacetic acid (CHI-EDTA). The ash content of chitins demineralized with CO₂ was similar to that of chitins prepared using HCl or EDTA. However, the resultant DA and CrI of CHI-HCl and CHI-EDTA were lower than those of CHI-CO₂. Thermal stability of CHI-CO₂ was also higher, with maximum decomposition velocity at 360 °C, above those of CHIEDTA (348 °C) and CHI-HCl (332 °C). This indicates that the use of CO₂ and a cationite for demineralizing lobster shells is a promising alternative to conventional HCl and EDTA treatments for obtaining chitin.