Chemical Characterization of Cancer Pagurus, Maja Squinado, Necora Puber and Carcinus Maenas Shells

The present study is a characterization of the chemical composition of crab shells from brown crab, spider crab, velvet crab and green crab. The chitin content of crab shells varied between 9.7 and 16.4% and the protein content was in the range of 13.2 to 20.7%. Ash was the major constituent and accounted for more than 70%. The total carotenoid content ranged between 0.6 and 9.3 μg/g depending on the crab species. Concerning macro elements their content followed the descending order in all species: Ca>P>S>Sr>Cl>K. In the case of trace elements content the descending order in brown crab was: Br>Fe>Rb>Cu>Zn; in spider crab was: Br>Fe>Rb>Zn>Cu and in velvet and green crab was: Br>Fe>Zn>Rb>Cu. The level of contaminants was relatively low and the descending order of their content was the following: As>Pb>Cd>Hg. Crab shells are a potential source of chitin and the levels of macro and trace elements together with the low contaminants concentration make them a raw material for chitin production or utilization as feed ingredients or fertilizers.