Isolation and characterization of chitin from crawfish shell waste

Crawfish shell waste is an excellent source of chitin (23.5% on a dry basis). Procedures for isolation of chitin have been developed, along with investigation of its distinctive physicochemical properties. Optimal conditions for deproteinization of crawfish waste were 3.5% NaOH at 65 degree C for 2 h with a solids to solvent ratio of 1:10 (w/v). Optimal demineralization involved treatment with 1 N HC1 at ambient temperature for 30 min with a solids to solvent ratio of 1:15 (w/v). Removal of the carotenoid astaxanthin from the shell matrix required required extraction with acetone before bleaching with 0.315% sodium hypochlorite solution for 5 min with a solids to solvent ratio of 1:10 (w/v). Proximate and amino acid analyses indicate the potential of the recovered protein fraction in various feed applications. Fractionation of whole crawfish meal has permitted comparison of chemical composition changes with differential particle size, resulting in significant percent increase in protein and reduction in calcium.