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Showing 3 results for Rashidian


Volume 10, Issue 2 (Spatial Issue on Persian Gulf 2021)
Abstract

In this experiment, head wastes were prepared and enzymatically hydrolyzed using alcalase (2.4 L) enzyme. The hydrolysate was fractionated by ultrafiltration with 10 kDa molecular weight cut-offs and the desired fraction was encapsulated following ion coagulation method (chitosan and triphosphate (TPP)) in nanochitosan capsules. Encapsulation process was optimized based on different ratios of chitosan:TPP and different concentrations (1, 5 and 10 mg/ml) of peptidic fraction. Finally, the degree of hydrolysis and the length of the peptides obtained from enzymatic hydrolysis were determined. The nanocapsules were examined for size, zeta potential and polydispersity index (PDI) using dynamic light scattering (Malvern, England). Structural and surface morphology studies including scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) of capsules produced under favorable conditions were also performed. Particle size was measured in various concentrations and treatments in the range of 30 to 150 nm. The best results were obtained in the treatment of 2: 1 ratio of chitosan to polyphosphate and concentration of 10 mg / ml. The size, dispersion index, zeta potential and size of nanocapsules in the optimal conditions were 0.375, 2020 and 30.13 nm, respectively, and storage conditions at -20 °C had no effect on the quality of nanocapsules. Based on the efficiency study, it was found that fraction with a concentration of 10 mg/ml is well encapsulated by chitosan with an efficiency of 91.04 ± 0.18 percent. The results showed that chitosan-TPP could be used for nanocapsulation of bioactive peptides with an approximate molecular weight of less than 10 kDa.

Volume 21, Issue 156 (February 2025)
Abstract

Current research, has evaluated the efficiency of the membrane process in degumming and neutralization of crude rapeseed oil. Crude rapeseed oil miscellas were prepared using hexane solvent with 20:80 and 30:70 ratios. In order to degumming, the micella passed through the membrane   after adding 0.3% of 85% (w/w) phosphoric acid, under three pressure levels of 2, 3, and 4bar and two flow speed of 0.5 and 1m/s; Then, for neutralization, after adding NaOH aqueous solution in two concentrations of 10% and 30% (w/v) the micella passed through the membrane, under the previous conditions, as well as three temperature levels of 30, 40 and 500C. The results showed that for 20:80 micella, the flux gradually decreased with the passage of time and reached a stable state after about 20 minutes. Surveying the simultaneous effect of conditions throught the neutralization process for 20:80 micella, revealed that the highest flux corresponds to 400C, 4bar, 1.0m/s. Surveying the simultaneous effect of temperature, pressure and flow rate throught the neutralization process for 30:70 micella, has also revealed that the highest flux corresponds to 500C, 2bar, and 1.0m/s. The results of the physicochemical tests also revealed that there is no significant difference in the levels of phosphorus and phosphates in both membrane filtration and conventional rifining methods (p<0.01); But acidity reduction for membrane filtration method was significantly higher than that of classical refining method (p<0.01). The reduction of peroxide index was also significantly higher for classic refining method than membrane filtration method (p<0.01). In terms of color, the results showed that the membrane filtration method was not able to reduce the yellow color in crude oil, while the classic refining method significantly reduced the yellow color (p<0.01). The red color index for the classic method also had a significant decrease compared to the membrane method (p<0.01).
 

Volume 27, Issue 3 (3-2025)
Abstract

This study evaluated the interactive impacts of water temperature and feeding rate on digestive enzymes, intestine histology, growth and stress-related genes, and cultivable intestinal microbiota of Asian seabass (Lates calcarifer). For this purpose, 180 fish (85.0±3.0 g) were reared at three different temperatures (20, 27, and 33°C) and two feeding rates (apparent satiation and 2.5% of biomass) with three replications for 6 weeks. The results revealed no significant differences among different treatments regarding the activity of digestive enzymes (P˃ 0.05) of fish reared under different temperatures and feeding rates. The length, width, and thickness of intestinal villi were unaffected by different temperatures and feeding rates (P˃ 0.05). In addition, no variations were found in the total aerobic bacterial count of fish gut from different experimental groups (P˃ 0.05). At the molecular level, IGF-I and HSP70 coding genes were found to be highly expressed in experimental treatments (P< 0.05). To conclude, the present study showed that temperatures between 27 to 33°C were more optimal for Asian seabass, and the different temperatures and feeding rates did not affect the digestive enzymes, intestine histology, and gut microbiota of juvenile Asian seabass after 6 weeks.

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