Edible films and coatings based on chitosan with essential oils for anti-microbial food packaging application

The purpose of this paper is to provide an updated review of the emerging edible chitosan coatings in combination with essential oils providing an anti-microbial function for the food packaging systems. Chitosan is produced commercially by de-acetylating chitin obtained from shellfish waste, and is bio-degradable, and was approved as a food ingredient in the United States; hence chitosan-films that are clear, tough, and flexible and with good oxygen barriers can be formed by solution casting-method. Recently results from published studies suggested that chitosan films combined with essential oils prevent a broad spectrum of micro-organisms including Gram-positive and Gram-negative bacteria and fungi from growth and proliferation especially when there is a high concentration of the essential oil in the matrix of the natural polymer. Although recent studies showed that some essential oils, including Basil and Thyme essential oils, did not prevent the growth of certain species of fungi including Aspergillus niger, Botrytis cinerea, and Rhizopus stolonifer in an in vitro test. Despite the potentials of essential oils in active food packaging, its economic viability and economic sustainability must be looked into in light of the resource-intensive nature of its production, growing trend of 'green' consumerism, and the decline in the production output of aromatic plants.