Chitosan as Antimicrobial Agent: Applications and Mode of Action

Chitin is the second most abundant natural biopolymer after cellulose. The chemical structure of chitin is similar to that of cellulose with 2-acetamido-2-deoxy-β- d -glucose (NAG) monomers attached via β(14) linkages. Chitosan is the deacetylated (to varying degrees) form of chitin, which, unlike chitin, is soluble in acidic solutions. Application of chitinous products in foods and pharmaceuticals as well as processing aids has received considerable attention in recent years as exotic synthetic compounds are losing their appeal. This review summarizes some of the important developments related to food applications of chitin, chitosan and their derivatives.

Food applications of chitin and chitosans

Chitosan as a potential natural compound to control pre and postharvest diseases of horticultural commodities

Edible coatings are an environmentally friendly technology that is applied on many products to control moisture transfer, gas exchange or oxidation processes. Edible coatings can provide an additional protective coating to produce and can also give the same effect as modified atmosphere storage in modifying internal gas composition. One major advantage of using edible films and coatings is that several active ingredients can be incorporated into the polymer matrix and consumed with the food, thus enhancing safety or even nutritional and sensory attributes. But, in some cases, edible coatings were not successful. The success of edible coatings for fresh products totally depends on the control of internal gas composition. Quality criteria for fruits and vegetables coated with edible films must be determined carefully and the quality parameters must be monitored throughout the storage period. Color change, firmness loss, ethanol fermentation, decay ratio and weight loss of edible film coated fruits need to b...

Advances in Edible Coatings for Fresh Fruits and Vegetables: A Review

Recent developments in antibacterial and antifungal chitosan and its derivatives.

In in vitro tests, chitosan at 1, 2, and 4% (w/v) significantly reduced the growth of Sclerotinia sclerotiorum on potato dextrose agar plates. The effect of chitosan coating on sclerotinia rot of carrots (Daucus carota L.) held at 22°C was also investigated. Carrot roots were coated with chitosan solutions (2 or 4%) and inoculated with mycelial plugs of S. sclerotiorum culture. After 5 days of storage, chitosan at both rates reduced significantly the incidence of rot (from 88 to c. 28%) and also the lesion size (from 26 to c. 12 mm) of the rot on roots. Microscope studies revealed that fungal mycelium exposed to chitosan appeared to be deformed and dead, whereas untreated mycelium was normal in appearance.

https://www.tandfonline.com/doi/pdf/10.1080/01140671.1997.9513992

B. B. C. Page

Papers

Chitosan coating for inhibition of sclerotinia rot of carrots