Authors Devlieghere F, Vermeullen A & Debevere J,
Chitosan has recently gained more interest due to its applications in food and pharmaceutics. Among others, the antimicrobial activity of chitosan has been pointed out as one of its most interesting properties of chitosan. Chitosan (poly b-(1-4)N-acetyl-d-glucosamine), a deacetylated form of chitin, is a natural antimicrobial compound. On the one hand it can be obtained from crustacean shells (crabs, shrimp and crayfishes) either by chemical or microbiological processes and on the other hand it can be produced by some fungi (Aspergillus niger, Mucor rouxii, Penecillium notatum) These variations in preparation methods are likely to result in differences in the deacetylation degree, the distribution of acetyl groups, the chain length and the conformational structure of chitosan and will thereby have an influence on the solubility, the antimicrobial activity and other properties. Next to chitosan itself, several chitosan derivatives are known for their antimicrobial activity, e.g., acid-free-water soluble chitosan, quaternary Nalkylchitosan sulfonated chitosan and N-carboxybutyl chitosan. The applications of chitosan and its derivatives are widespread, they are used in agriculture, medicine, environment, food, etc. Apart from its antimicrobial effect, chitosan is also used in food as (1) clarifying agent in apple juice, (2) antioxidant in sausages (3) enzymatic browning inhibitor in apple and pear juices. and in potatoes. Chitosan can also be used as an antimicrobial film to cover fresh fruits and vegetables. Chitosan activates several defense processes in the host tissue acts as a water-binding agent and inhibits various enzymes. The antimicrobial activity of chitosan will depend on several factors such as the kind of chitosan (deacetylation degree, molecular weight) used, the pH of the medium, the temperature, the presence of several food.
