Applications of β-Chitosan
(1) Cholesterol Control
One of the major threats to human health is cholesterol, which contributes to numerous serious diseases. Chitosan reduces cholesterol through two mechanisms: one is inhibiting fat absorption, and the other is promoting the excretion of cholesterol from human blood. Firstly, chitosan suppresses the activity of lipases—enzymes that facilitate fat absorption by breaking down fats to enable their uptake by the body. The second mechanism involves excreting bile acids. Once bile acids are excreted, cholesterol in the blood is utilized to synthesize new bile acids. These two mechanisms make chitosan a potent cholesterol scavenger. As a natural substance, chitosan exhibits strong anionic adsorption capacity, making it suitable for cholesterol reduction without any side effects.
(2) Inhibiting Bacterial Activity
β-Chitosan dissolves easily in weak acidic solvents, and such solutions specifically contain amino groups (NH₂⁺). These amino groups inhibit bacteria by binding to negatively charged molecules on bacterial surfaces. Owing to its bacterial inhibitory activity, β-chitosan finds wide applications in fields such as medicine, textiles, and food industry.
(3) Prevention and Control of Hypertension
One of the most influential factors for hypertension is chloride ions (Cl⁻), which are usually ingested via table salt. In recent years, many people have consumed excessive amounts of salt. Angiotensin-converting enzyme (ACE) produces angiotensin II—a substance that causes blood vessel constriction—and the activity of ACE relies on chloride ions. High-molecular-weight chitosan functions like dietary fiber and is not absorbed in the intestines. It excretes chloride ions through the adsorption interaction between its own chloride ions and ammonium ions. Consequently, chitosan reduces the level of angiotensin II, helping to prevent hypertension—especially in populations with excessive salt intake. In such cases, high-molecular-weight chitosan must be used to enhance the effect.
(4) Adsorption and Excretion of Heavy Metals
A notable characteristic of chitosan is its adsorption capacity. It can adsorb various low-molecular-weight substances, such as metal ions, cholesterol, triglycerides, bile acids, and organic mercury. In particular, chitosan can adsorb not only magnesium and potassium but also zinc, calcium, mercury, and uranium. The adsorption activity of chitosan can exert a selective effect. Excessively high concentrations of these metal ions in the human body are harmful. For example, an abnormally high concentration of copper ions (Cu²⁺) in the blood can lead to copper poisoning and even carcinogenic consequences. It has been proven that chitosan is an efficient chelating medium. The adsorption capacity of chitosan depends on its degree of deacetylation—the higher the degree of deacetylation, the stronger the adsorption capacity.
(5) Moisture Retention
(6) Immune-Boosting Effects
Advantages of β-Chitosan
- β-Chitosan has a higher protein adsorption capacity than α-chitosan.
- Under the action of degrading enzymes (such as lysozyme and chitinase), β-chitosan exhibits a degradation rate several times higher than that of α-chitosan.
- β-Chitosan can be easily processed into threads, making it suitable for manufacturing linear or sheet-like medical materials.
- β-Chitosan has higher affinity and solubility than α-chitosan, which is favorable for the production of various derivatives.
- β-chitin has higher chemical activity than α-chitin, and this property remains unchanged after it is converted into chitosan.
- β-Chitosan has better water retention capacity than α-chitosan.
- In serum, β-chitosan is more easily degraded and absorbed than α-chitosan.
- β-chitin undergoes simple deacetylation, and it is easier to be deacetylated into chitosan compared with α-chitin.
- β-Chitosan has higher biodegradability than α-chitosan.
- β-Chitosan shows a selective and strong inhibitory effect on the growth of oral streptococci, while not affecting the growth of other beneficial bacteria; in contrast, α-chitosan inhibits the growth of all viable bacteria.
