Comparative Evaluation of Chitosan Extraction from Mud Crab (Scylla paramamosain) Shells: Yield, FTIR Characterization, and Degree of Deacetylation

Abstract

Crab shell waste is a potential source of chitin and chitosan that can be converted into value-added biopolymers for food applications. This study aimed to compare two extraction methods for producing chitosan from mud crab (Scylla paramamosain) shells and to evaluate the resulting chitosan based on yield, Fourier Transform Infrared (FTIR) characteristics, and degree of deacetylation (DD). Crab shells were subjected to extraction methods modified from Narudin et al. (2020) and Pambudi et al. (2018), involving deproteinization, demineralization, deacetylation, filtration, washing, and drying under different treatment conditions. The chemical composition of the crab shell showed 6.71 ± 0.02% moisture, 9.48 ± 0.08% protein, 0.19 ± 0.00% fat, 70.11 ± 0.01% ash, and 10.40 ± 0.09% dietary fiber. Pambudi et al., 2018 method produced higher chitin and chitosan yields of 94.50 ± 4.10% and 80.20 ± 8.49%, respectively, compared with 87.50 ± 1.41% and 32.30 ± 15.42% obtained using Narudin et al., 2020 method. However, Narudin et al., 2020 method resulted in a higher mean DD of 57.96 ± 15.07%, compared with 29.66 ± 8.04% for Pambudi et al., 2018 method. FTIR spectra showed characteristic hydroxyl, amine, amide, and C–O–C/C–O functional groups in the extracted products. Overall, Pambudi et al., 2018method was more effective for chitosan recovery, whereas Narudin et al., 2020 method produced chitosan with a higher degree of deacetylation. Further optimization is needed to improve DD while maintaining high chitosan recovery.