Dye Binding Properties of Chitin and Chitosan


  • The author is thankful to L. Kruse, H. Handley and T. Keller for technical assistance and to P.R. Austin, T.E. Furia, W. Weaver and T.R. Watkins for valuable suggestions. This work was supported by a N.I.H. Biomedical Research Support Grant.


Chitin (β (1°4)-N-acetyl-D-glucosamine) and chitosan (deacetylated chitin) are currently available in large quantities as waste products and by-products of the shellfish industry. Their potential as carriers for food additives was studied. Significant correlations were found between dye concentration ranging from 0.2–1.6 mg dye (FD&C Red No. 40) per g chitin or chitosan and dye-binding capacity of chitin or chitosan. Within a pH range of 2.0–7.0, dye-binding capacity of chitin was stable. Chitosan gelled below a pH of 5.5 and could not be evaluated but its dye-binding capacity was constant between pH 7.0 and 5.5. Above pH 7.0 dye-binding capacity decreased for chitin as well as for chitosan but between pH 2.0 and 6.0 no dye was released from dyed chitin containing 0.77 mg dye/g chitin.