A Review: The antibacterial Characteristics of edible coatings in fish meat

Fish, the most perishable food need to be preserved preferably with natural preservatives. Fish consumption has been increasing due to the nutrients it contains and its benefits for human health and the prevention of wide variety of diseases. Due to the poor post-harvest handling, they deteriorate by microbial action. So, the inhibition or microbial growth delay is one of the most frequent actions in the handling and processing of fishery products. In this sense, some alternatives have been sought for its preservation. Active packaging is an area of technology needed to meet the requirements of the contemporary consumer. Active packaging creates additional opportunities in systems for packing goods, as well as offering a solution in which the packaging, the product and surroundings interact. Coating fish products showed that it can prolong their shelf life, reducing thawing loss, cooking loss, weight loss and maintaining the functional properties during frozen storage. Edible films are thin films prepared from materials, which act as a barrier to external factors and thus protect the food product, extend its shelf life and improve its quality. These edible films could form a barrier for quality changes such as dehydration of fresh and frozen meat or microorganism growth on the food surface. Growth of bacteria on the meat surface is a major cause of food spoilage and discoloration. The coatings may serve as carriers for antimicrobial compounds in order to maintain high concentrations of preservatives on the surface of foods. Antimicrobial agents may be incorporated directly into packaging materials for slow release into the food surface or may be used in vapor form. Surface application of antimicrobials represents an alternative to direct application. A few antimicrobial agents have been incorporated into edible coatings to suppress quality changes during storage. Polysaccharides such as chitosan are the most commonly used materials. Chitosan is a polymer derived from chitin, which is obtained from shells of shrimp. Its characteristics make it suitable for use in coatings because it exhibits good gel formation and is not toxic for human consumption. Chitosan is especially of interest for the antimicrobial packaging and biomaterials industry because is cationic and naturally antimicrobial properties. Comparing with other bio-based food packaging materials, chitosan has the advantage of being able to incorporate active and functional substances with antimicrobial activities against Listeria monocytogenes for example. Chitosan because of the positive charge has a better antimicrobial activity than chitin. The exact mechanism of chitosan and its derivatives is still perfectly unknown, but the literature reported different potential explanations. One of the reasons of the antimicrobial character of chitosan is its positively charged amino group, which interacts with negatively chargedmicrobial cell membranes. Chitosan acts as chelating agent that selectively binds trace metals and thus inhibits the production of toxins and microbial growth. The antimicrobial mechanism of chitosan was different from Gram-positive (S. aureus) and Gram negative (E. coli) bacteria. The aim of the present study was to form and determine antioxidant and antimicrobial efficiency of edible coating solutions which contain plant extracts.

کلیدواژه ها:

Antibacterial properties ، fish meat ، edible coating ، shelf life