The Atlantic blue crab (Callinectes sapidus), an invasive species spreading in the Mediterranean, produces substantial shell by-products. This study examines the impact of thermal pre-treatment (cooking) on the extraction and physicochemical properties of chitin from crab carapaces. Fresh and cooked samples were subjected to a stepwise acid–alkali protocol under mild conditions. The resulting chitins were evaluated through gravimetric yield and multiparametric characterisation, including Fourier-transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and nuclear magnetic resonance. In both samples, the results confirmed the α-chitin allomorph with a high degree of acetylation (≈ 97%), identical molecular features, and a 35% degree of crystallinity. Morphological analysis revealed similar fibrillar architectures with local porosity and a more compact organisation in chitin from cooked carapaces. Chitin in cooked samples had a lower ash content (1.2%) compared to fresh samples (13.4%), indicating higher purity. Chitin recovery was significantly higher for cooked carapace ( 17%) than for fresh carapace ( 14%) (p < 0.05). Overall, thermal pretreatment enhances demineralisation efficiency, enabling effective chitin recovery under diluted acid conditions. This study demonstrates that cooked blue crab carapaces provide a more efficient feedstock for industrial chitin production, supporting circular bioeconomy strategies to valorise invasive species. © 2026