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The changes in chemical, microbial and quality sensory of fillets for silver carp fish treated with black cumin extract during refrigerated storage were investigated. The fish were divided into two groups. First group was dipped in black cumin extract with concentration of 1% and received the highest score in sensory evaluation. Then the fishes were wrapped in polyethylene package. The second group, as the control samples, were wrapped in polyethylene package after dipping in distilled water. All treatments were stored at refrigerator temperature (1±4°C). The microbial tests including total viable count, psychrotrophic count and chemical tests including peroxide index, thiobarbituric acid, free fatty acid value and total volatile basic nitrogen, with sensory evaluation, were done at 4°C over a period of 15 days. The results showed that the black cumin extract delayed lipid oxidation and protein analyses significantly in treated fishes. Psycrotrophic bacteria and total viable count of samples being treated with black cumin extract were maintained lower than the proposed acceptable limit (7 log cfu/g). In comparison to the control samples, microbial spoilage significantly decreased in treated samples. Furthermore, according to sensory analysis, the treatment with black cumin extract led to high quality during storage.The findings indicated that black cumin exerts had strong antioxidant and antibacterial impacts on silver carp fish, such that the shelf life of fillets being treated with black cumin were 2.5 times more than that of control samples during storage in refrigerator.

The present study was conducted to evaluate the effect of different doses of gamma rays on shelf life and fatty acids composition of Rainbow trout fillet (Oncorhynchus mykiss) during refrigerating condition. Quality and shelf life of non-irradiated and irradiated (0, 0.75, 1.5, 2.25, 3, 3.75 and 4.5 kGy) Rainbow trout stored at +4 C was investigated by measurement of microbiological, chemical and sensory analysis .Irradiation of fillets was performed by gamma rays from a Co60 source. Microbial counts for non-irradiated trout fillet samples were higher than respective irradiated fish. Total volatile base nitrogen (TVB-N) values was increased from 7 mg/100 g for non-irradiated to 52.7 mg/100 g after 15 days storage at refrigerator, whereas for irradiated fish lower values of 39.4, 37.6, 28.7, 25.6, 24.8 and 23.2 mg/100 g were recorded at 0.75, 1.5, 2.25, 3, 3.75 and 4.5 kGy, respectively (day 15).initial amount of peroxide value in non irradiated sampleswas 0.8 meq/kg and was increased to 7 meq/kg (7 day).Highest amount of peroxide after irradiation process was belonged to samples irradiated by 4.5 kGy (1.5 meq/kg). Also, total viable count of irradiated samples were decreased significantly (p