Fish Muscle

Aim: The combined effects of oregano extract with vacuum packing (VP) on the quality enhancement of dark and white muscles of frigate tuna (Auxis thazard) stored as intact fillet at refrigerated (3±1°C) conditions were studied.

Materials and Methods: About 35 kg of fish were filleted without skin removal and randomly divided into two groups. One group without treatment (control) and the remaining group were dipped in a sterilized oregano extract solution for 5 min. Chemical, microbiological, sensorial, and textural analyses were carried out in each of dark and white muscles of frigate tuna fillets during storage.

Results: Several quality indexes were higher in dark muscle than white muscle. The sensory assessment indicated that both muscles from control had a shelf life of 12 days. Quality parameters of both muscles had the same tendency and were significantly affected by time and also by the presence of plant extract in VP. Although VP alone was sufficient to delay lipid oxidation on fish fillets, especially on dark muscle but cannot enhance the textural deterioration in both muscles.

Conclusion: Consequently, the employment of such combination had a cumulative effect on preservation, resulting in prolonging the shelf life of both frigate tuna muscles.

The most significant pollutants are the heavy metals in the aquatic network due to their toxicity, accumulation, and bio-magnification. In an attempt to characterize the physical-chemical and demonstrate the potential water impact of the heavy metal content of wastes in two lakes in Sharkia province, Egypt, this study was developed to determine their toxicity and the potential waste impacts in biochemistry and histology of fish muscle. Samples of water and fish muscles were collected and analyzed for heavy metals using atomic absorption of two different fish species (Oreochromis niloticus and Clarias gariepinus) along two canals in Sharkia province in Egypt during the four seasons in 2018. The water samples were also analyzed for the physicochemical parameters. The impact of heavy metal on the enzymatic antioxidant (superoxide dismutase and catalase) as well as the reduced glutathione content, besides the oxidative stress marker presented by lipid peroxidation levels in fish muscles, were evaluated. Results showed the largest amount of chloride (Cl-) and iron (Fe) in the Sharkia water sample, while Faquas water sample had the highest level of HCO3 and iron (Fe). The manganese concentration in the fish muscle was the highest in Sharkia water and the highest level of Fe was detected in the fish muscles collected from Faquas area. These high levels of some of the physicochemical parameters and heavy metals in the two lakes with two different wastes as seen in this study may be a source of water pollution. The highest accumulation of metals in the muscle of the two fish species, suggesting risk for human consumption. There were seasonal variations in the level of LPO in muscle tissue of two types of fishes with a reverse relationship with antioxidant parameters. This accumulation varied seasonal and spatial as well as according to the species of fish. Increasing the level of heavy metals effect on the biochemistry and histology of fish.

Aim: The combined effects of oregano extract with vacuum packing (VP) on the quality enhancement of dark and white muscles of frigate tuna (Auxis thazard) stored as intact fillet at refrigerated (3±1°C) conditions were studied. Materials and Methods: About 35 kg of fish were filleted without skin removal and randomly divided into two groups. One group without treatment (control) and the remaining group were dipped in a sterilized oregano extract solution for 5 min. Chemical, microbiological, sensorial, and textural analyses were carried out in each of dark and white muscles of frigate tuna fillets during storage. Results: Several quality indexes were higher in dark muscle than white muscle. The sensory assessment indicated that both muscles from control had a shelf life of 12 days. Quality parameters of both muscles had the same tendency and were significantly affected by time and also by the presence of plant extract in VP. Although VP alone was sufficient to delay lipid oxidation ...

Seasonal variations of the proximate composition and fatty acid profiles in viscera from Sardinella aurita, Sarpa salpa, and Sepia officinalis were studied. Significant seasonal variations were observed in the amounts of moisture, lipid, protein, and ash between species. Viscera protein content undergoes large fluctuations. This tendency is different from results observed for the edible parts or for the whole body of many marine species. Ash content also showed significant differences. Lipid contents varied with seasons, in a proportionally inverse manner to water contents. Fatty acid composition showed significant differences from October to December. Interestingly, the highest total omega-3 contents were comparable to many commercial marine fish oils.