Chitosan

Chitosan

Definition:
Chitosan is a deacetylated derivative of chitin. Chitin, chitosan, and cellulose share similar chemical structures. At the C2 position, cellulose has a hydroxyl group, whereas chitin and chitosan have an acetylamino and amino group, respectively. Chitosan, which contains free amino groups, is the only alkaline polysaccharide found naturally and possesses unique properties such as biodegradability, cell affinity, and bioactivity.

Chemical Properties & Functional Features:

• The amino group in chitosan has higher reactivity than the acetylamino group in chitin.

• Chitosan is a promising functional biomaterial with greater potential applications than cellulose.

• Key attributes include:

  • Biodegradability

  • Biocompatibility

  • Non-toxicity

  • Antibacterial

  • Anti-cancer

  • Lipid-lowering

  • Immune-enhancing properties

Antibacterial Properties:

• Chitosan exhibits strong antifungal effects.

• Effective at 100 µg/mL concentration.

• Inhibits 32 types of fungi including Helminthosporium, Alternaria, and Fusarium.

• Antifungal activity is inversely related to particle size and polymerization degree.

• Demonstrates significant antibacterial effects against:

  • E. coli

  • Pseudomonas fluorescens

  • Staphylococcus aureus

  • Bacillus subtilis

• Effective for fresh produce preservation—commonly used with 0.1% acetic acid + 0.05–0.1% chitosan.

Main Application Areas:

1. Food Industry:

• Used as:

  • Binder

  • Moisturizer

  • Clarifying agent

  • Emulsifier

  • Thickener

  • Coating agent

• Helps:

  • Lower cholesterol

  • Boost immunity

  • Enhance anti-infection and anti-tumor effects

• Extraction: Typically derived from shrimp/crab shells using enzymatic or acid hydrolysis.

Subsections:

• Enzyme Carrier:
  Microcrystalline chitosan used as an immobilized enzyme carrier in sugar, wine, vinegar, and protein hydrolysis.

• Food Additive:
  Enhances mayonnaise, peanut butter, corn paste, and soy sauce stability. Prevents precipitation in vinegar and soy sauce.

• Food Packaging Film:
  Combined with starch to make edible, oil-resistant, biodegradable packaging films.

• Food Preservation:
  Forms a breathable barrier on fruits/vegetables. Retains CO₂, reduces ethylene, and slows ripening.
  Also effective on:

  • Chilled meat (extends shelf life up to 1 week)

  • Seafood (antioxidant and antibacterial, especially with 50–200 mg/kg concentration)

2. Cosmetics & Daily Chemicals:

• Non-toxic, odorless, antibacterial.

• Adds:

  • Film-forming

  • Moisturizing

  • Anti-allergic properties

• Widely used in:

  • Shampoos & hair care products (improves texture and shine)

  • Moisturizers with modified chitosan (e.g., hydroxypropyltrimethylammonium chitosan)

3. Pharmaceutical Applications:

• Listed in China’s Pharmacopoeia for use as:

  • Excipient

  • Disintegrant

  • Thickener

Pharma Subsections:

• Drug Delivery Carrier:
  Improves stability, absorption, and targeted release. Used in oral, nasal, gastrointestinal delivery.

• Film-forming Material:
  For oral and herbal drug films. Molecular weight affects strength and permeability.

• Thickener:
  Viscosity increases with concentration, decreases with temperature.

• Targeted Delivery:
  Functionalized with groups to attach to target ligands or specific cells.

• Other Uses:

  • Tablet filler

  • Flavoring agent

  • Absorbable surgical sutures (biodegradable and biocompatible)

4. Light Industry Applications:

• Used to create formaldehyde-free textile finishing agents.

• Chitosan gels are water- and acid-resistant with high mechanical strength.

• Dual properties of chitosan–chitin interconvertibility are utilized.

5. Environmental Protection:

• Forms stable chelates with metal ions (Hg⁺, Ni²⁺, Pb²⁺, Cd²⁺, etc.)

• Used in:

  • Heavy metal recovery

  • Wastewater treatment

  • Sludge conditioning

• Acts as:

  • Biodegradable flocculant

  • Eco-friendly chelating agent

Storage & Handling Notes:

• Avoid mixing with strong oxidants.

• Store in a cool, dry, and well-ventilated place.