Technology of producing chitosan from shell-containing materials
This paper is aimed at developing a technology of producing chitosan from various shell-containing raw materials: shells of crabs, prawns, small Gammarus crustaceans. To achieve this, the researchers were given the tasks to develop a gentle technology of isolating chitin from raw materials and drying it, provide for complete deacetylation of chitin and produce chitosan, and determine the physicochemical properties of chitosan samples. Based on the experiment the product yield was calculated in terms of raw material (about 11% for the shells of crabs and prawns, and 4% for gammarus) and chitin (79%, 78% and 62% respectively). Using the viscometric method the researcher has established the molecular weight of chitosan samples, which amounted to 72444 dalton for chitosan obtained from crab shells, 63200 Dalton for chitosan obtained from prawn shells, and 57300 dalton for chitosan obtained from the shells of Gammarus. These results are consistent with the data described in reference sources. We can state that the selected conditions of chitosan production allow us to obtain the samples with sufficiently high molecular weight. It should be noted that the molecular weight of produced chitosan depends not only on the kind of raw material, on the method of isolating and deacetylating chitin, but also on the storage conditions and time used for collecting the raw material. The researcher has obtained chitosan from three kinds of raw materials with such purity and physico-chemical characteristics which allow us to use these materials not only for industrial purposes, but also as dietary supplements. The author has used potentiometric titration to determine the degree of chitosan deacetylation. The obtained chitosan samples were characterized using IR-spectroscopy. The study of the spectra of obtained chitin samples has confirmed the equivalence of the resulting chitosan to reference samples.