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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.

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The volatility of essential oils and their instability against environmental factors limit their use. However, encapsulating these compounds in polymeric nanoparticles can significantly increase their half-life and make their use possible for longer periods. Chitosan, a biodegradable polymer with controlled release and low toxicity, is one of the polymers utilized in the encapsulation of essential oils. As a result, the present study was carried out with the aim of nanoencapsulation of carvacrol and thymol in chitosan using ionic gelation method and the concentration of chitosan (0.1-0.3%), TPP concentration (0.2-0.1%) and concentration of essential oil (0.1-0.2%) as three variables. The mean particle size of chitosan nanoparticles was optimized using response surface methodology and central composite design. The size and polydispersity index (PDI) were determined by DLS, essential oil loading confirmation was evaluated by FTIR, and the spectrophotometric method was used to measure the encapsulation efficiency. Then, the results of the optimization of nanoparticle synthesis were investigated. The optimum conditions for the synthesis of chitosan-thymol nanoparticles and achieving a size of 101 nm and encapsulation efficiency of 72%, a concentration of 0.11% chitosan, 0.19% TPP and 0.14% thymol were determined. In the case of chitosan-carvacrol nanoparticles, a concentration of 0.13% chitosan, 0.19% TPP and 0.15% carvacrol resulted in the formation of nanoparticles with a size of 95 nm and an encapsulation efficiency of 65%. In general, the results demonstrated the ability of the response surface methodology to predict the particle size and PDI of chitosan nano-formulations containing carvacrol and thymol.

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In this study, the antioxidant and antimicrobial effect of nano coating of basil gum with black cumin essential oil (Bunium persicum) was investigated in order to increase the shelf life of rainbow trout fillets. For this purpose, black cumin essential oil was prepared using Clevenger device and the antioxidant activity of different concentrations of it (200, 400, 600, 800 and 1000 ppm) was investigated. According to the results, black cumin essential oil has high antioxidant properties, and as the concentration increased, antioxidant properties were increased too. The cumin essential oil was then nanocapsulated with a basil gum coating. The nano coating, along with the essential oil (according to the electron microscope image), had a spherical and uniform surface with a low porosity percentage. Then, in order to investigate the effect of nano-coating with essential oil on the shelf life of rainbow trout fillet during a 16-day refrigeration period, 4 treatments including control and nano-coating with different concentrations of black cumin essential oil (1, 1.5 and 2 %) produced and periodic chemical parameters (peroxide, thiobarbiotic acid and volatile nitrogen bases) and microbial (total bacterial and total psychrotrophic count) were studied. The results of chemical and microbial analysis showed that, the nano-coating along with the essential oil slowed down the increasing process of oxidation and microbial indices compared to the control treatment. Until the end of the storage period, they had the allowed chemical and microbial range. Therefore, it seems that this treatment can be used as a natural antioxidant and antimicrobial in the meat and fisheries industry.