The effect of natural preservative(rosemary and thyme) on minced meat of silver carp

Abstract

The aim of this study to investigate the antioxidant potential of ethanolic extract of Rosmary(Rosmarinusofficinalis) and Thyme (Zatariamultiflora) on fatty acids stability and shelf life of frozen minced silver carp fish( Hypophtalmictysmolitirix ). Treatments include frozen meat in conventional packaging (control), frozen minced fish + 200 ppm thyme(treatment 1), frozen meat + 200 ppm rosemary ( T2), frozen meat + rosemary ( 100 ppm ) and thyme ( 100 ppm )(T3) . Treatments packed in polyethylene bags and were freezed at -36 °C by spiral freezer and IQF method , then were transferred to freezer to keep at -36 °C during the storage. Treatments were analyzed for 10 days intervals in the First month and 15 days intervals in the second month of storage. In the next few months, treatments were analyzed once a month. In this study, various levels of both saturated and unsaturated fatty acids in the three treatments and control treatment were identified. The results showed that Keeping of Minced Fish containing thyme and rosemary extract in freezing conditions led to stability of fatty acids (MUFA, PUFA, omega- 3 and omega-6) and the changes in fatty acid oxidation during storage is not significantly. The profile of fatty acids and their related indicators results as well as statistical tests showed that treatments containing rosemary extract were more stable (-18° C ) in comparison with the control and other treatments during frozen condition. Also these teratmentshad less oleic acid and linoleic acid , ά-linolenic and palmitic acid in compared with others .more According to the results treated minced meat with rosemary extract was kept the quality for six months and more .