a modified process for deprotenization of green crab
- 1. A Modified Process For Deprotenization of Green Crab Shells (Carcinus maenas) For Extraction of Chitin/Chitosan Kirubanandan Shanmugam1,2, 1. Visiting Research Assistant, Saint Mary’s University, Halifax, Canada. 2. Graduate Research Student, Department of Process Engineering and Applied Science, Dalhousie University, Halifax, Canada. Email:skirubanandan80@gmail.com Contact No: +91 94446 82247. International Conference on Recent Advancements in Materials (ICRAM-15), 16th – 17th Oct 2015, Anna University, BIT Campus, Trichy, India.
- 2. Introduction Fuyuan Ding et al., Emerging chitin and chitosan nanofibrous materials for biomedical applications Nanoscale, 2014,6, 9477-9493
- 3. Green Crab Shell – A Potential Source for Chitin/Chitosan Proximate Component Green Crab mince (%) Wet Basis Moisture Ash Protein Fiber Fat 67.96±0.46 16.55±0.29 12.27±0.25 02.87±0.15 00.21±0.07 * These value are taken from Beth A. Fulton et al 2013 “Nutritional Analysis of Whole Green Crab, Carcinus maenas, for Application as a Forage Fish Replacement in Agrifeeds”,Sustainable Agriculture Research. Table 1 – Proximate analysis of Green grab shells*
- 4. Chemical Composition of Green Crab Shells Chemical Contents (%) Ash Lipids Nitrogen Protein Chitin 38.00 3.23 5.24 14.08 43.9 1. These values are estimated on the 60 mm carapace width of crab.
- 6. Limitations in Existing & Previous Methods • High concentration of Hydrochloric Acid and Sodium Hydroxide (Harsh Chemicals), • High Temperature. • It would affect the quality of Chitin/Chitosan Polymer – Molecular Weight and Viscosity, • Environmental Problems for Treating Waste Water- TDS and Acidity etc.
- 7. Structure of Crab Shell Fuyuan Ding et al., Emerging chitin and chitosan nanofibrous materials for biomedical applications Nanoscale, 2014,6, 9477-9493
- 8. De-mineralization/De-calcification The demineralization process is carried out in 0.1 M hydrochloric acid and it has taken 6-7 hrs., to neutralize the calcium carbonate or calcite in the crab shells. This process is developed and contributed by Dr.Young, Professor Emeritus, Advanced Inorganic Chemistry, SMU, Halifax, NS, Canada. In my point of view, after completion of demineralization of green crab shells, the crab shells are filmy and lost its brittleness. Therefore, it is confirmed that the de-mineralization of crab shells are completed.
- 9. De-protenization Deprotenization is the crucial step in extraction process. Because it remains obscure about binding of proteins with chitin in the crab shells. As a consequence, the de-proteinization is a complex process and lack of information of about interaction between proteins and chitin and its chemistry in the literature. De-protenization by alkali method such as sodium hydroxide is a common method for removal of proteins from the shrimp shells.
- 11. De-Protenization at 65 °C
- 12. De-Protenization at 65 °C
- 13. De-protenization at 85 °C
- 14. De-protenization at 45 °C
- 17. Limitations and Recommendations Absorption assay at 280nm is a simple method for finding protein releases from the crab shell. BSA (Bovine Serum Albumin) is not a suitable marker for evaluation of crab shell proteins in the solution. But it used to find the total protein content in the solutions. Further, micro syringe is used for preparation of working standard solution of BSA. Active Mixing or stirring is provided for de-protenization process to minimize the treatment time. In addition, sometime there is a fluctuation in temperature in Hot air oven. The complete chemical analysis of grab shell is highly recommended for various analytical purposes. Various scientific approach on deprotenized shell such as SEM (Scanning Electron Microscopy), Nitrogen estimating method should be performed
- 18. Conclusion The performance of de-protenization by chemical method such as sodium hydroxide depends the crab shell thickness, concentration of NaOH, treatment time, temperature and effective mixing. Based on these investigations, 1M concentration of NaOH at temperature of 45 °C is suitable for de-protenization of green crab shells for treatment time of 1-2 hrs. However, the thickness of the shell and its protein content (usually 10%) plays major in performance. The literature reported that de-protenization of shrimp shell is performed with 1M NaOH for treatment time of 24 hrs. But these experiments are performed in 200ml beakers and effective mixing doesn’t influence on the de-protenization process. Moreover, Shrimp shells are flimsy in nature and thinner than crab shell. In our case with thick crab shell, Good contact with NaOH solution is required and it can be provided only by effective mixing
- 19. Reference Chen, P.-Y., et al., Structure and mechanical properties of crab exoskeletons. Acta Biomaterialia, 2008. 4(3): p. 587- 596. Shanmugam, K. (2014). Chemical Based Extraction of Chitosan from Green crabs. Halifax, NS: Biomer Innovations Pvt Ltd. Nwe, N., T. Furuike, and H. Tamura, Chapter One - Isolation and Characterization of Chitin and Chitosan from Marine Origin, in Advances in Food and Nutrition Research, K. Se- Kwon, Editor. 2014, Academic Press. p. 1-15. Percot, A., C. Viton, and A. Domard, Optimization of Chitin Extraction from Shrimp Shells. Biomacromolecules, 2002. 4(1): p. 12-18. Percot, A., C. Viton, and A. Domard, Characterization of Shrimp Shell Deproteinization. Biomacromolecules, 2003. 4(5): p. 1380-1385.
Editor's Notes
- #8: The exoskeleton of the crab shells contains three distinct layers namely Epi cutile, Exocuticle Endo cuticle. Generally, the exoskeleton has a high degree of mineralization, typically calcium carbonate as main constituent, in some case calcium phosphate. In exoskeleton, chitin fibrils are wrapped with proteins forms a form of fibers which is assembled further into a bundle of fibers in the exoskeleton. In addition to that, the calcium carbonate in the form of calcite deposited in the chitin–protein matrix.