Study of Antimicrobial Properties of Nano Chitosan with Marjoram Essential Oil in Increasing the Shelf-Life of Shrimp (Nephropidae) at Refrigerated Temperature

The food lasting and its persistence can be increased by adding plant essential oils to the edible films such as chitosan. In the view of the increasing use of nanotechnology in the production of antimicrobial agents and the improvement of the properties of nano-sized compounds in comparison with the primary compounds, the antimicrobial properties of nano-chitosan with marjoram essential oil concentrations to increase the shelf-life of shrimp at refrigeration temperature has been studied. In this study, 1% and 2% concentrations of marjoram essential oil individually and with nano-chitosan with the concentration of 2% was prepared. Six different treated groups were examined for microbial, chemical, and sensory evaluations for 14 days. The results of this study showed that during storage time the total amount of volatile nitrogen increased significantly (P≤0.05), which is the indication of shrimp protein hydrolysis. there was no significant difference between treatments in terms of pH. The amount of malondialdehyde decreased up to day seven and was increased afterward. The coliform bacteria and Staphylococcus aureus count showed a significant difference between the control and other treatments, and with increasing storage time the bacteria count decreased. According to the results, nano-chitosan containing marjoram essential oil is a very suitable substitute for chemical and industrial coatings.