Chitosan is a biocompatible, biodegradable, nontoxic, and cationic polymer. Due to its amino functional groups, chitosan has been extensively investigated in the areas of drug delivery, gene delivery, and biomedicine (Hirano 1999, Thanou et al. 2001, Dang and Leong 2006), and has been reported to enhance drug delivery across the nasal or mucosal layer without damage (Chae et al. 2005a,b). Especially, the cationic properties of chitosan offer valuable properties for drug delivery systems and gene delivery systems. For instance, ion complex formations between chitosan and anionic drug or DNA are available, and these kinds of ion complexes can be prepared simply by mixing into aqueous solutions (Calvo et al. 1997, Chae et al. 2005a,b, Kim et al. 2006).

Until now, wine clarification products came from two basic sources—animal (gelatin, bovine albumin, isinglass, casein), or mineral (bentonite, silica gel). Gelatin has a long history of use as a clarifying agent. Gelatin derives from the collagen contained in animal skin, bones, and cartilage. In Europe, the emergence of Creutzfeld–Jacob disease threw a new suspicion on animal-derived products used as adjutants in the food industry. Blood albumin is, for example, no longer authorized. Some suppliers also now exclusively require wines that have not been treated with animal proteins.
Other recent crises in relation to food safety have caused several winemakers to consider alternative solutions for wine clarification. A consequence is the boost in the search for innovative non animal derived products with equivalent efficiency compared to existing clarification agents and guaranteed non toxicity. From this point of view, the chitinous products derived from fungi appear attractive and promising alternatives to animal derived products such as gelatin. Indeed, chitosan has already been tested as a clarifying agent for beverages and most particularly for fruit juices. Chatterjee (2004) obtained a significant clarification effect by treating 50 mL of grape juice with 0.1 g of soluble chitosan, an effect that was greater than the one obtained with either bentonite or gelatin. Furthermore, it was observed that this treatment had no impact on the chemical characteristics of the wine and that it enhanced sensorial qualities (appearance, color, taste). Another study on apple juice yielded similar results to the Chatterjee study (Soto-paralta 1989).

Chitin and Chitosan are known to have eliciting activities leading to a variety of defense responses in host plants against pathogens, including the accumulation of phytoalexins, pathogenrelated (PR) proteins and proteinase inhibitors, lignin synthesis, and callose formation.
Based on these and other proprieties that help strengthen host plant defenses, interest has been growing in using them in agricultural systems to reduce the negative impact of diseases on yield and quality of crops.

The antidiabetic effect of chitosan has been reported in two types of diabetic models, type 1 and type 2. A number of studies have revealed that chitin and chitosan are effective cholesterol-lowering supplements and fat blockers. When used as a food supplement, chitosan can effectively reduce low-density lipoprotein, cholesterol, and plasma cholesterol. At the same time, it improves the HDL cholesterol & total cholesterol ratio.

Chitosan is known to have immuno enhancing effects, antitumor activities, and increased protective effects against infection caused by certain pathogens.It exhibits anticancer activities and is used as delivery systems for drugs and bioactive agents in cancer treatment. Chitosan-based nanoparticles are also used in cancer diagnosis.