Chitosan is derived from chitin through the process of deacetylation. Its chemical name is poly(beta-(1,4)-2-amino-2-deoxy-D-glucose). In the natural environment, chitosan is an active product with a positive charge, often referred to as “the sixth vital element of the human body” alongside carbohydrates, proteins, fats, vitamins, and minerals.
Due to its molecular structure and pKa (6.2-7.0), chitosan is insoluble in neutral and high pH conditions. However, it can be protonated in acidic solutions. Therefore, when preparing chitosan solutions, acidic solvents like acetic acid and citric acid are typically used. Water-soluble chitosan (WSC) can be directly dissolved in water at neutral pH, simplifying the process and eliminating the need for acidic solvents. WSC is often modified with hydrophilic groups to enhance its suitability for various biological applications, such as antioxidant, antimicrobial, and anticancer properties.
Chitosan oligosaccharide is a derivative of chitin and chitosan, obtained through depolymerization. It possesses unique advantages, including low molecular weight, good water solubility, strong functional effects, easy absorption by the body, and high biological activity.