Effects of nano encapsulation of Rosmarinus officinalis on rainbow trout (Oncorhynchus mykiss) fillet shelf life in 4°c

Rosmarinus officinalis is a natural antimicrobial, which effects on many pathogens and food spoilage organisms. The purpose of this study was using two concentrations of Nano-encapsulation and the ethanolic extract of R. officinalis (0.1% and 0.3%) in order to increase the shelf life of fillets of rainbow trout at fridge temperature. Factors considered included (Proxide value and total volatile base nitrogen) as well as microbial parameters (Total count of bacteria and psychotropic count) in the periods of 0, 3, 6, 9, 12 and 15 days. The changes in TVB-N values during the treatment with nano-encapsulation of 0.3% were lower than the other treatments. The results of microbial parameters in the treatments containing of Nano-encapsulation were less than ordinary extracts. However, on days 9 to 12, all parameters were beyond the standard range (7logCFU/g). In conclusion, based on the results of this study, although Nano encapsulated formed in the concentration of 0.3% compared to the other concentrations had better results, achieving better results and increasing the shelf life of rainbow trout needed thorough evaluation of biological and chemical parameters.