Investigation of antioxidant and antimicrobial effects of rozmarinic acid, carnosol and carnosic acid from some aromatic plants on the sardine (Sardina pilchardus Walbaum 1972) fillet

In the current study, the sensorial, chemical(TVB-N,TBA,PV,FFA) and microbiological(TVC,total coliform count) effects of the natural antioxidant extracts (KarA, Kar and RozA) obtained from rosemary (R. officinalis L), sage tea (S. officinalis) and israile oregano (O. syriacum) on vacuum packaged and refrigerated sardine fillets were investigated for 20 days. The chemical and antimicrobial activities of standard herbal extracts together with extracts obtained with different solvents polarities were also determined. KarA standard extract had the highest antioxidant capacity, and the Israile oregano had the highest antimicrobial activity. The result of sensorial analysis indicated that the shelf lives were 13 and 20-days for the control and standardized extract groups, respectively. The TVB-N and FFA values were significantly lower for the standardized extract groups, and the storage TBA and PV levels did not exceed 01.48 mg/MDA and 14.06 meqO2/kg, respectively. All experimental groups had comparatively low microbial counts, the lowest being the RozA group. We conclude that 0.5% standardized extract treatment will increase the shelf life (appx. 7 days) and the quality of sardine fillets.