Effect of essential oils treatment on the frozen storage stability of chub mackerel fillets

The effect of bay leaf (BLO), thyme (TO), rosemary (RO), black seed (BSO), sage (SO), grape seed (GSO), flaxseed (FSO) and lemon (LO) essential oil from vegetable extracted on lipid oxidation and some other quality parameter of frozen chub mackerel during frozen storage at −20°C were examined over a period of 11 months. Taste, odour, texture and overall acceptability of control samples were given ‘unacceptable’ scores by the sixth month. Based primarily on sensory data, the shelf-lives of frozen chub mackerel were found 6 month for samples treated with oil of TO, RO, BSO, SO and LO and 7 month for samples treated with BLO, GSO and FSO. During the 11-months storing process of chub mackerel, the values of pH, total volatile basic nitrogen (TVB-N), trimethylamine nitrogen (TMA-N) both in control group samples and samples treated with oils did not reach to deterioration levels. Thiobarbitüric acid (TBA) and free fatty acid (FFA) values for all treatments remained lower than TBA and FFA values of control samples throughout the 11 month storage period. Particularly, thyme oil treatment is effective in delaying lipid oxidation. Bay leaf, rosemary, sage, lemon, flaxseed and grape seed oils were fallowed.     

Amino Acid and Vitamin Composition of Raw and Cooked Horse Mackerel

Amino acid, vitamin (A, E, B₁, B₂, B₃ and B₆), and proximate composition were determined in raw and cooked horse mackerel. The changes in amino acid, vitamin, and proximate content were found to be significant for all cooking methods (frying, grilling, and steaming). Cooking did in general significantly increase the contents of essential, semi-essential, and other amino acids compared to raw fish species. Amino acid contents of grilled mackerel were significantly higher (p < 0.05) than those found in fried and steamed mackerel. The A, E, B₂, and B₆ vitamin content of fried horse mackerel was found to be significantly (p < 0.05) higher than the grilled and steamed samples. The B₁ content of steamed and B₃ content of grilled were found higher than the other cooked samples. Moisture, protein, fat, ash, and carbohydrate contents of cooked fish ranged between 56.52% to 61.34%, 20.79% and 23.93%, 13.44% and 19.61%, 1.70% and 2.47%, and 1.02% and 4.36 %, respectively. Fried fish had intermediate fat values, while grilled and steamed fishes had a comparatively low value.     

Effect of Mo Addition on Structure and Magnetocaloric Effect in γ-FeNi Nanocrystals

Nanocrystalline powders of (Fe₇₀Ni₃₀)_100?x Mo _x (x = 1 to 4) were produced by high-energy (SPEX) mechanical alloying. Increasing the Mo content was found to stabilize the face-centered cubic phase in mechanically alloyed nanopowders. To obtain a single γ-phase, a powdered sample was solution annealed in the γ-phase field and water quenched. The Curie temperature, T _C, of the alloys was lowered with Mo addition, without decreasing the refrigeration capacity (RC), due to the additional temperature broadening of the magnetic entropy change. Based on previous study on the role of disorder, the additional temperature broadening was attributed to increased positional disorder and changes in the distribution of ferromagnetic exchange bonds introduced by Mo addition into the γ-FeNi system. (Fe₇₀Ni₃₀)₉₇Mo₃ and (Fe₇₀Ni₃₀)₉₆Mo₄ alloys have RC_FWHM values of ～440 J/kg and ～432 J/kg at 5 T, comparable to other prominent magnetic refrigerants operating near room temperature. The economic viability of these alloys, along with their competitive magnetocaloric properties and potential for scalable production, make them good candidate magnetic refrigerants without critical rare-earth materials.