Crustacean shells are rigid and comprise mainly calcium carbonate (CaCO3), chitin and protein. These principal minerals vary with specie and full elimination could influence the physicochemical properties of chitin. In this study a-chitin sourced from crab and shrimp shells was extracted via chemical means using 0.4 M hydrochloric acid (HCl) and sodium hydroxide (NaOH) for demineralization and deproteinization processes respectively. Results from Fourier Transform Infrared Spectroscopy (FTIR) and thermogravimetric analysis (TGA) showed that CaCO3 is more predominant in the crab shell than that of the shrimp. Average hydrogen bond energy (EH) in shrimp chitin was calculated to be 5.25 kCal while that obtained from crab measured 4.71 kCal. Presence of CaCO3 in each exoskeleton is responsible for low thermal stability of embedded chitin, which improves after treatment with both chemicals. (C) 2016 Elsevier B.V. All rights reserved.