Quality Assessment of Salted, Modified Atmosphere Packaged Rainbow Trout under Treatment with Oregano Essential Oil

摘要

The present study evaluated the effect of oregano essential oil (EO) on fresh salted, packaged (45%CO_2/5%O_2/50%N2) rainbow trout fillets and stored for a period of 21 d at 4 ℃. Treatments included the following: Ml (control without added EO), M2 (EO 0.2%, v/w), and M3 (0.4%, v/w). Populations of lactic acid bacteria (LAB), H2S-producing bacteria (including Shewanella putrefaciens), Enterobacteriaceae, and Pseudomonas spp. reached higher final numbers in control (Ml) than for M2 and M3 samples. Under treatments M2 and M3, total volatile basic nitrogen (TVBN) and trimethylamine nitrogen (TMAN) values were lower than for Ml samples, whereas lipid oxidation, as judged by determination of thiobarbituric acid values (TBA), did not occur during the refrigerated storage period. Interestingly, treatment M2 resulted in a shelf-life extension of 7 to 8 d for the fresh trout fillets, whereas treatment M3 proved unsuitable (due to strong odor) for trout fillet preservation, as determined by sensory evaluation.