The use of active edible coatings made from a combination of Lepidium sativum gum and Carvacrol to increase shelf life of farmed shrimp kept under refrigerator condition

The aim of this study was to evaluate the effect of edible coating based on Lepidium sativum seed gum containing different levels of carvacrol on microbial, physical quality and shelf life of farmed shrimp (Penaeus semisulcatus) during refrigerated storage (18 days). At first, different concentrations of carvacrol (0, 5, 10 and 15%) were added to edible coating. After that the color indexes, antioxidant and antimicrobial activities of coating samples were studied. Then the shrimp samples were covered with these coating solutions, and were evaluated the effects of them on samples quality and shelf life. The obtained results from edible coating tests showed that by increasing the carvacrol in edible coating, the antioxidant activity and L* values of samples were increased significantly, conversely, the b* value significantly was decreased (p<0.05). Microbial analysis of shrimp samples indicated that edible coating containing 10% and 15% carvacrol had significant effects on reducing microbial load (p<0.05). Correspondence S.A.A Anvar, Department of Food hygiene, Science and Research branch, Islamic Azad University, Tehran, Iran (e-mail: saaa4824@gmail.com). The smallest changes in pH and TBA amounts were seen in the coating samples enriched with 10% and 15% carvacrol. Using of coating containing different levels of carvacrol was increased L* and a* values while the b* significantly was decreased (p<0.05). The results stated that the application of edible coating enriched with carvacrol significantly improved sensory quality of samples (p<0.05). It has been confirmed that coating the shrimps with cress seed coating containing 10% and 15% carvacrol retarded the melanosis in shrimp samples. This study thus clearly indicated the effect of cress seed gum coating containing carvacrol on shrimp samples improved their good quality characteristics and the shelf life during refrigerated storage, which was supported by the results of microbiological, chemical, and sensorial properties. The shrimp treated with cress seed gum coating containing 10% carvacrol gave a good sensory quality.