export chitin and chitosan from Asia

hitosan is a biodegradable, non-toxic, linear cationic polymer obtained by the N-deacetylation of chitin. The substance is not soluble in water but becomes soluble in dilute acids when the degree of deacetylation is over 50%. When chitin reaches a nitrogen content of more than 7%, or when the degree of deacetylation exceeds 60% the term chitosan is favoured.  Chitosan has great biological properties but due to his poor aqueous solubility, it is often depolymerized to create low molecular weight chitosans (LMWCs) and Chitooligosaccharides (COSs) , both readily soluble in water due to their shorter chain lengths and free amino groups. By introducing small functional groups such as, alkyl or carboxymethyl groups, we can strongly increase chitosan solubility at neutral and alkaline pH without affecting its cationic character. Chitosan is a versatile polymer with many functional groups available for chemical modification, therefore it displays a lot of potential for commercial applications  such as food, cosmetics , biotechnology, agriculture, environmental protection and wastewater management…

Among characteristics of chitosan greatly influencing the properties of formulations. We have :

  • viscosity and molecular weight
  • degree of deacetylation
  • degree of purety : ash content and protein, turbidity, heavy metal concentration, microbial count
  • source : squid, shrimp

Influence of the preparation method on its physicochemical properties

During chitosan deacetylation, the degradation of the polymer chain takes place. At the same time, the crystallinity of chitosan can be damaged by using harsh reaction conditions. Taking these facts into account, the reaction conditions must be controlled when preparing chitosan. Experience shows that the proper conditions to deacetylate chitin avoiding high degradation involve using heterogeneous conditions with NaOH 75%  and a temperature of 110ºC. The type of crustacean and the chitin isolation process are also factors that affect chitosan quality. Just as chitin, chitosan has a crystalline structure and according to its origin and extraction process, final crystallinity may vary.

Physicochemical characterization of Chitin and Chitosan

Physico Chemical Characteristics Determination methods
Degree of deacetylation (DD) infrared spectroscopy
derivative spectrophotometry
nuclear magnetic resonance spectroscopy
conductometric titration
potentiometric titration
differential calorimetry scanning
Molecular weight viscosimetry
gel permeation chromatography
light scattering method
Crystallinity X-ray diffraction 
Moisture content Gravimetric analysis
Ash content Gravimetric analysis
Protein content Bradford assay