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In this study, the effect of different amounts of rainbow trout bone micropowder (concentrations of 0.5, 1 and 2%) on the shelf life (the rate of formation of secondary fat oxidation compounds, total volatile nitrogen compounds, water holding capacity, color parameters) and the gel quality (hardness, chewing, cohesiveness and folding characteristics) of the largehead hairtail (Trichiurus lepturus) were examined during 15 days of refrigeration. Addition of bone micropowder to the gels prepared from hairtail fish, affected some of the gels properties. The results showed that with increasing the amount of bone micropowder in surimi gels, the amount of thiobarbituric acid (as the most important indicator of advanced degradation due to fat oxidation) was lower than to control group, which indicates the inhibitory effect of micropowder on lipid oxidation in the prepared surimi. In terms of color parameters, the results showed that horsetail fish gels containing bone micropowder had a darker color than the control. In the Folding Test, the horsetail gel containing bone micropowder with a concentration of 2% received the highest score. In the characteristics of texture profile (hardness, chewiness and cohesion indices), it was found that with increasing the amount of bone micropowder, the texture properties in the prepared surimi were significantly improved (p <0.05). Findings from the present study showed that bone micropowder due to its positive effect on the main indicators can be used to improve the texture properties of horsetail fish surimi gel.

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The aim of this study was to extract astaxanthin from banana shrimp (Fenneropenaeus merguiensis) using ultrasound assisted method and to investigate its antioxidant properties. Extraction with organic acetone solvent was performed by soaking on a magnetic stirrer at room temperature for 5, 10, and 15 minutes, as well as neutralization tests of DPPH and ABTS free radicals. Fe³⁺ ion reduction was carried out. One-way analysis of variance was used for statistical analysis of the data. The best astaxanthin yield was 79.5±0.012 µg/g in the conditions of 20 minutes of magnetic stirrer at ambient temperature with 400 watts of ultrasound for 10 minutes, and the lowest average yield was observed in the condition of 15 minutes of magnetic stirrer at ambient temperature with 400 watts of ultrasound with a time of 15 minutes with a value of 69.3±0.049 µg/g. The findings of all three ABTS, DPPH, and Fe3+ ion reduction tests revealed that the settings were 20 minutes of magnetic stirrer at ambient temperature followed by 10 minutes of 400 watts of ultrasound. In summary, the results of this study demonstrated that using ultrasound for a shorter period of time has a better effect, while increasing the time diminishes the yield and antioxidant qualities.

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 In the current study, fish-isolated protein (FPI) was extracted by alkaline pH method from the wastes of the head and fins of Siberian sturgeon (Acipenser baerii) and Iranian sturgeon (Acipenser persicus) and its composition, functional and structural characteristics were investigated. The results showed that the extraction efficiency according to the wet weight, the protein recovery of FPI, and the dry matter recovery of FPI from the Siberian sturgeon was higher than that of Iranian sturgeon. The results showed 91-94% protein in FPI of two species. The results did not show any significant differences between the proximate analysis and TVB-N (P> 0.05). The water absorption capacity, foaming capacity, and stability of FPI were shown at 30, 50, and 50%, respectively. The whiteness and transparency index of the FPI extracted was low. The results of particle size and zeta potential (P< 0.05) showed that the size of FPI particles in both samples is about a micron and they have a negative charge, so they can be easily used in colloidal systems. FTIR spectroscopy in both samples showed all the absorption peaks related to the main bonds of the protein structure. In general, considering the large amount of sturgeon waste in processing, and the amount of protein, functional properties, and nutritional value of FPI extracted from two species of sturgeon, there is the possibility of using them in human food and sports supplements.

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In the present study, the fish protein isolate (FPI) of wastes of Siberian sturgeon (Acipenser baerii) has been substituted with fish minced (10, 20, 30, and 40%) in preparing fish nuggets. After preparing fish nuggets (88% Silver carp fillet) and initial cooking, the parameters such as approximate analysis, product yield, weight loss, pick-up, microbial growth, and sensory evaluation were investigated. The results showed that the lowest amount of moisture is related to the IP40 Group and no significant difference exists between other treatments. In comparison, the amount of protein in the control sample was the highest (18.00 ± 0.04) and it was decreased with the increase of FPI substitution (P<0.05). The highest amount of weight loss during final cooking was related to the control and IP10 treatments, and the highest product yield was associated with IP20, IP30, and IP40 treatments (P<0.05). The microbial growth results did not show any significant difference among the treatments (P>0.05). Moreover, the sensory evaluation showed the control group, which was only with fish minced, had better taste, smell, texture, etc. than the treatments containing isolated protein. The results of this research showed that the minced fish of silver carp and the FPI by-product can be used to produce fish nuggets, and although in some physical properties, the nuggets containing higher amounts of isolated protein have shown better results, according to the amount of protein and sensory evaluation, the control and the sample containing %10 FPI had better results.