Chitosan C2

Chitosan

Definition:
Chitosan is a deacetylated derivative of chitin. Chemically, chitin, chitosan, and cellulose share similar structures. In cellulose, the C2 position carries a hydroxyl group, while in chitin and chitosan, it is substituted by an acetylamino group and an amino group respectively. Chitosan is the only basic polysaccharide among natural polysaccharides due to its free amino groups. It is known for its biodegradability, biocompatibility, and bioactivity.

Properties:
The amino groups in chitosans molecular structure are more reactive than the acetylamino groups in chitin, giving chitosan superior biological functions and the potential for chemical modifications. This makes chitosan a highly promising functional biomaterial, even more so than cellulose.

Physiological Functions and Applications

• Biodegradable, Biocompatible, Non-toxic

• Antibacterial, Antitumor, Lipid-lowering, Immune-enhancing

• Widely used in:

  • Food additives

  • Agriculture

  • Environmental protection

  • Cosmetics

  • Healthcare and medicine

  • Antimicrobials

  • Medical fibers and dressings

  • Tissue engineering

  • Drug delivery

  • Gene carriers

  • Absorbable materials

  • And more in daily chemical industries

Antimicrobial Properties

• Antifungal Activity:
  Chitosan is known for strong antifungal effects. In tests against 46 fungal species, it inhibited 32 species including Mucor, Alternaria, and Fusarium. At 100μg/mL, chitosan exhibits noticeable antifungal activity. The effectiveness increases as particle size decreases. Oligomers like heptamers show the strongest activity.

• Antibacterial Effects:
  Effective against E. coli, Pseudomonas fluorescens, Staphylococcus aureus, and Bacillus subtilis.
  Also prevents physiological degradation in fresh food.

• Natural and Non-toxic:
  Ideal for acidic or low-protein food preservation (e.g., 0.1% acetic acid + 0.05–0.1% chitosan solution for fruits).

• Derivatives:
  Modified chitosan derivatives show even stronger antimicrobial properties.

Application Areas

1. Food Industry

• As Additive:
  Used as binder, humectant, clarifier, filler, emulsifier, glaze, and stabilizer.
  Functional oligosaccharides help reduce cholesterol and enhance immunity.
  Typically extracted from shrimp or crab shells using enzymatic or acid hydrolysis.

• As Immobilized Enzyme Carrier:
  Chitosan particles are used as enzyme carriers in sugar production, brewing, vinegar fermentation, and protein hydrolysis.

• As Food Thickener/Stabilizer:
  Microcrystalline chitosan is used in sauces, canned foods, and substitutes like margarine. Prevents sedimentation in vinegar and soy sauce.

• As Edible Film Packaging:
  Mixed with starch to create edible, oil-resistant, biodegradable packaging film for solids, semi-solids, and liquids.

• For Food Preservation:
  Applied in vegetables, meats, seafood, eggs, dairy, soy products.
  Forms a protective film on fruits/vegetables to slow respiration, delay ripening, and retain quality.

  Examples:

  • 1% chitosan in 1% acetic acid extends chilled meat shelf life by 1 week.

  • 50–200 mg/kg chitosan from snow crab controls oxidation in cooked fish.

2. Cosmetics & Daily Chemicals

• Safe & Non-toxic:
  Chitosan has antibacterial and moisturizing effects. Enhances film-forming properties of products.

• Modified Chitosan:
  Hydroxypropyltrimethylammonium chitosan increases hydration, making it ideal for cosmetics.

• Hair Care:
  Added to shampoos and conditioners to improve texture, shine, and manageability, especially for fragile hair. Widely used in Europe, USA, and Japan.

3. Pharmaceutical Applications

• Listed in Chinese Pharmacopoeia (Vol. 4):
  Used as excipient, disintegrant, and thickener.

• Drug Delivery Carrier:
  Enhances drug stability and absorption, controls release rate, targets organs, protects stomach lining.

• Chitosan Microspheres:
  Good adhesion, suitable for mucosal delivery (oral, nasal, GI tract).
  Capable of targeted delivery using functional group modifications.

• Film Forming Material:
  Used in oral films and herbal film formulations. Film properties depend on molecular weight.

• Thickening Agent:
  Viscosity increases with concentration. Exhibits thixotropy at high concentrations and reduced viscosity at higher temperatures.

• Targeted Drug Carrier:
  Functional groups allow ligand binding for targeted therapies. Common forms: nanoparticles and microspheres.

• Other Medical Uses:
  Used as tablet filler, flavoring agent, and surgical absorbable sutures. Biodegradable, non-immunogenic, non-toxic, and body-absorbable.

4. Light Industry Applications

• Formaldehyde-Free Fabric Finishing Agent:
  Converts between chitosan and chitin using acetic anhydride. Non-toxic and safe for textile treatment.

• Chitosan Gels:
  Cross-linked with formaldehyde/acetic acid. Insoluble in water, acids, and most solvents. Good mechanical and chemical stability.

5. Environmental Applications

• Ion Exchange Resin Membranes:
  Cross-linked chitosan with glutaraldehyde absorbs metal ions (Hg⁺, Ni²⁺, Pb²⁺, Cd²⁺, Mg²⁺, Zn²⁺, Cu²⁺, Fe³⁺).

• Wastewater Treatment & Metal Extraction:
  Forms stable chelates with metal ions. Highly effective for treating industrial wastewater.

• High-Viscosity Chitosan for Sludge Treatment:
  Effective, biodegradable, non-polluting. A promising polymer flocculant and metal chelator.