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The effect of the antioxidant extracts on the quality indices of rainbow trout fillet stored at refrigerator (4±1ºC) for 15 days was investigated. The fillets in 3 treatments, including salted in 10% brine, salted in 10% brine plus 1% nettle leaf extract, and salted in 10% brine plus synthetic antioxidant BHT were evaluated at every 3 days interval, using the quality indices including the free fatty acids (FFA), thiobarbituric acid (TBA), peroxide (PV), moisture content, pH levels and sensory characteristics. The results showed that TBA and FFA values increased significantly (p<0/05), but PV significantly decreased in all treatments during the course of storage (p<0/05). Samples containing antioxidants had significantly lower TBA, PV and FFA values in comparison with the control sample throughout the storage. Also, the methanol extract from nettle leaves (at 1% balance) controlled the TBA, PV and FFA indices and entirely replaced the synthetic BHT antioxidants (at 1% balance). Since the sensory evaluation (smell, texture, taste and after taste elements) showed no significant differences between the two antioxidants, both are recommended to preserve the quality of rainbow trout fillet. The nettle leaf extract was found to be more efficient on shelf life extension the fillet.

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Oxidative stability of oils, fats and fatty food products can be affected by many factors such as oxygen, light, heat, metal ions and enzymes used and finally it brings about oxidative corruption. This study has been done to survey the role of Dorema aucheri extract in oxidative stability of fish oil (under microwave heating) and comparising that with BHT synthetic antioxidant. Concentrations of 250 and 500 ppm extracts of Dorema auchri and BHT 200 ppm were added to fish oil and a fish oil sample without the addition of antioxidant was considered as control, Then they were sampled after putting in microwave at time periods 0, 3, 6, 9, and 12 minutes. Chemical oxidative indicators (peroxide, free fatty acids and thiobarbituric acid) were surveyed. According to the results, in all times putting in microwave the amount of peroxide, free fatty acids and thiobarbituric acid  in the treatments that contained extract, were lower than the control treatment, but were higher than the treatment that contained  BHT. A significant difference wasn^'t seen among the treatment that contained 250 ppm of extract and the treatment that contained BHT (p>0/05). According to the results, because of significant difference of samples contained extract with control sample and the lack of significant difference sample containd 250 ppm extract with BHT, it would be expected that Dorema aucheri  extract as antioxidant can be used  in food industry in maintenace of fish oil.

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Protein hydrolysate (PH) from viscera of cultured Siberian sturgeon (Acipenser baerii) was produced. To optimize the production conditions, Response Surface Method (RSM) was employed to examine the effects of three different operating conditions, including time, pH, and enzymatic concentration (Alcalase) on the degree of hydrolysis.The mathematical model showed acceptable fitness of the experimental data as R2 equaled 0.97, which indicated  that   major part of  the  variability  within  the  range  of  values could  be explained  by  the  model. The results showed that the highest degree of hydrolysis (58.21%) was related to the treatment which happened at the enzymatic concentration of 2%, 60 minutes time, and pH=8. Treatment under hydrolysis condition (i.e., E/S = 2%, Time = 45 min, and pH = 8.5) had the highest protein content (42.37g/l), which was used as an alternative to commercial peptone medium (Triptic soy broth) to assess the growth of Salmonella typhi bacteria from 0 to 48 hours. Although there was an upward trend in growth rate of S. typhi both in control and No. 15 (Alcalase) treatments, the log growth of control treatment was found to be better than that of Alcalase treatment. However, there existed no significant difference between the two treatments.

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Aims: Essential oils are a complex of volatile compounds obtained from different parts of plants. Cinnamon (Cinnamomum zeylanicum) essential oil (EO) is known as a suitable source of antibacterial compounds. The aim of present study was to investigate the antibacterial activity of cinnamon EO and ZnO nanoparticles (NPs) against 2 strains of Listeria monocytogenes.
Materials & Methods: In this experimental study, 2 strains of L. monocytogenes (a standard strain and a fish isolated strain) were used. The antibacterial activity of cinnamon EO and ZnO NPs was assessed by well diffusion test. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of cinnamon EO and ZnO NPs were also determined using broth macrodilution method.  Moreover, the antibacterial properties of cinnamon EO and ZnO NPs were investigated in a liquid medium. The data were analyzed by SPSS 19 software, using one-way ANOVA and Tukey's post hoc tests.
Findings: The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of cinnamon EO were 16µl/ml and 64µl/ml, respectively. Furthermore, the MIC and MBC of ZnO NPs were 12.5mg/ml and 25mg/ml, respectively. The bacterial population significantly decreased with increasing the ZnO NPs and the cinnamon EO concentrations (p<0.05) and during cold storage, there were significant differences between the 2 strains.
Conclusion: Cinnamon essential oil and ZnO nanoparticles have strong antimicrobial effects against L. monocytogenes, so that the cinnamon essential oil shows bacteriostatic effects on Listeria, but ZnO nanoparticles show bactericidal effect.

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Aims: The aim of this study was to investigate the effect of cooking (frying and microwave), chitosan additive and freezer storage on the fish fillet in terms of sensory and color evaluation and weight changes.
Methodes: Cultivated fish fillets, frozen at -18 ° C for 4 months. They were then transferred to the Fisheries Processing Laboratory of the Faculty of Fisheries, Gorgan University of Agricultural Sciences and Natural Resources, in the shortest possible time (day 0, day 2 and month 4). The fillets were frozen and cooked in a pan and microwave. The experiment was designed in 4 treatments: T₁ (fried sample without chitosan), T₂ (fried sample containing 1% acid-soluble chitosan), T₃ (microwave cooked sample without chitosan), T₄ (Microwave cooked sample containing 1% acid-soluble chitosan). Fillet weights were measured before and after cooking. Sensory evaluation and colorimetric evaluation of fillets were also performed after cooking.
 
Findings: The use of 1% acid soluble chitosan had no significant effect on sensory parameters and colorimetric factors (p> 0.05). Weight changes in fried fillets increased over time but decreased in microwave-cooked fillets over time.
Conclusion: The use of natural additives such as acid soluble chitosan 1% had no significant effect on the sensory indeces compared to the control group. In terms of colorimetric factors, chitosan had a positive effect on yellowness index. In terms of cooking and having a safe product, it is very important that the weight factor of the microwave cooked fillets is more favorable than the fried fillets.

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Chitosan (Cs) was extracted from shrimp shell and its derivative forms including N-alkyl (AlkCs) and nanoparticles (CsNPs) were prepared. First, the properties of nanoparticles were determined by dynamic light scattering (DLS) and the morphology of nanoparticles and N-alkylated by scanning electron microscopy (SEM). Then their antibacterial activity was evaluated by the test of minimum inhibitory (MIC) and lethal (MBC) concentration, diffusion on agar by disk, permeability of cell membrane by measurement of cytoplasmic beta-galactosidase release (ONPG). The type of apoptosis cell death was also examined by DAPI staining and changes in cell surface integrity by atomic force microscopy (AFM). The results showed that the nanoparticles are spherical with an average hydrodynamic diameter of 240 nm. N-alkyl had a rough surface structure compared to native chitosan. At the least of MIC (78 μg/ml) and MBC (100 μg/ml) points were observed for CsNPs (P < 0.05). Nanoparticles and N-alkyl of chitosan showed the highest diameter of growth inhibition zone at 1250 concentration compared to other disks (p <0.05). Outer membrane permeability of derivative forms of chitosan showed significant differences with native chitosan and cells of control. DAPI staining test showed higher cell death of chitosan-derived forms. DAPI staining test showed higher cell death of derivative of chitosan. The images obtained from AFM showed a change in the membrane integrity of the treated cells compared to spherical and clustered of control cells. Thus, the antibacterial properties of native chitosan improved by physical and chemical modification.
 

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Aims: The aim of the present study is to evaluate the amount of tilapia fish consumption and the relationship between its consumption amount and some demographic characteristics Such as gender, age, occupation, education, marital status, occupation, number of household members and income.
Methods: The statistical population of this research is the whole country. A questionnaire was designed and sent to people electronically through virtual space. Correlation tests were used to evaluate the number of fish purchases per year as well as the amount of each purchase from the output of SPSS software and to investigate the existence of a significant relationship between consumption and demographic characteristics.
Findings: The results showed that Most of the female respondents are married, aged 20 to 35, employed and have bachelor's and master's degrees. Most of them are employees and earn between 3 and 6 million tomans. It was also found that most households (54%) buy fish up to 20 times a year. The average number of times of buying fish per year by the households of the consumption community was 45 times. Most households in the consumer society buy 2 kg of fish each time they buy. The number of households that consume more than 10 kg of fish per purchase was 3.3%. According to the obtained information, the average amount of fish per purchase was calculated to be 8 kg. The per capita consumption of tilapia in households consuming this fish was 4.2 kg.

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Rutilus frisii kutum is one of the most important and economic fish in our country. Since the passage of time and temperature on the quality of fish caught continuous reduced, so decreasing the temperature by ice storage, immediately after fishing, is a good methodto avoid loss of quality fall. Inthisstudy change of some quality parameters of R. frisii kutum during ice storage for 16 days such as expressible moisture, pH, thiobarbituric acid, total volatile nitrogen, free fatty acid, psychrotrophic count and total viable count to assessment the effects of delay of putting ice on fish caught and loss in quality product was measured. According to these results, the chemical and bacterial indicators were increased significantly during the storage in ice. Delayed icing caused the higher degree of oxidation. Furthermore, delayed icing, lack of attention to correct method of storage, and ice storage for a long time can decrease the quality of meat. It is better that fish be ice storage after fishing immediately. Shorten the shelf life of the product on the ice and accelerate cooling, helps to increase the shelf life of the product.  

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Whey protein based edible coating containing 0.5, 1 and 1.5% (w/v) thyme essential oil was used for inhibition of bacterial growth of rainbow trout fillets during cold storage. Microbial analyzes (total viable counts, psychrophilic counts, lactic acid bacteria and Enterobacteriaceaeas) as well as total volatile basic-nitrogen(TVB-N) and pH measuring were performed periodically every four days. Results showed that whey protein coating containing thyme essential oil was able to inhibition of bacterial growth of fish fillets. Also the TVB-N and pH values in the coated samples were significantly (p<0.05) lower than those of non-coated treatment. Among the treatments used in this study, treatment with 1.5% thyme essential oil containing edible coating was the most effective treatment against evaluated bacteria in this study. As could extend the shelf-life of rainbow trout fillets stored at refrigerator for at least 4 days compared to control.  

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 The present study was aimed to investigate the physicomechanical properties of biodegradable ternary films based on chitosan (CH) and starch (ST) at different ratios (100ST/0CH, 75ST/25CH, 50ST/50CH, 25ST/75CH and 0ST/100CH) via a simple casting method.The results showed that adding different ratios of chitosan (25-75%) to the control film (100ST:0CH)significantly reduced the moisture content, and elongation at break (EAB) and water vapor permeability (WVP) of the films, as the 75ST:25CH ratio has the lowest values; also, the solubility, tensile strength, contact angle and whiteness index of the films showed a significant increase compared to the control (p <0.05). FT-IR spectra of different films showed interactions through hydrogen bonding between the hydroxyl moieties of ST and amino moieties of CH in the blends, which enhanced the compatibility between the two polymers. On the other hand, the indicators related to the DSC test indicated that the thermal stability of composite films reduced after the addition of ST. SEM microstructural observations clearly demonstrated a re-organization of the surface of the two-phase films due to the presence of ST.The obtained results suggested the effectiveness of blending approach in improving the compatibility of polymers and overall functionality of films.

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In the present study, in order to identifying the composition of Sargassum sp. Extract, total carotenoid, phenolic and flavonoid compounds were measured by spectrophotometric method. The antioxidant activity of extract was evaluated by free radical inhibitory test (DPPH). Nanoencapsulation of the Sargassum sp. Extract was performed by freeze drying method with composed wall materials of maltodextrin (M) and whey protein concentrate (WPC) and the effects of nanocapsules on oxidation stability Sargassum sp. Extract and subsequently improvement its antioxidant effect on fish oil were assessed by determining of peroxide and para-anisidine during 15 days storage. The evaluations showed the mean values of 0.32 mg/g, 84.19 mg GA/Eg and 4.03 mg GA/Eg of carotenoids, phenols and flavonoids in the Sargassum sp. Extract, respectively. The emulsion prepared from mixture of algae extract and M+WPC was completely stable, and its viscosity and particle size was measured at 670 ± 4 mPa.s and 59.530±62.4 nm, respectively., Fish oil enriched with encapsulated Sargassum sp. Extract and TBHQ showed lowest level of peroxide value and para-anesidine among all treatments during 15 days storage. The highest levels of oxidation indexes were shown in fish oil and pure algae extract, respectively. The results of this study obviously showed that the encapsulation of extract of Sargassum sp. with composed wall materials of maltodextrin (M) and whey protein concentrate (WPC) was effective on improvement of its antioxidant properties stability.

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In this study, effects of Persian gum-chitosan and Persian gum-chitosan incorporated with Garlic (Allium sativum L.) essential oil edible coatings on change in chemical deterioration index (peroxide value (PV), free fatty acids (FFA), thiobarbituric acid index (TBA) and total volatile basic nitrogen (TVB-N)) and sensory properties (Taste, appearance, color, odor and overall acceptability) during 6 months frozen storage (-18 ºC) was investigated. Silver carp fillets were immersed in the Persian gum-chitosan and Persian gum-chitosan incorporated with Garlic essential oil (5%) solutions and then packed and frozen. Experiments were carried out at months 0, 2, 4 and 6 of storage on frozen fillets. Comparing to control, lipid oxidation was significantly delayed in samples treated with Persian gum-chitosan and Persian gum-chitosan incorporated with Garlic essential oil (P ≤0.05). According to the results, application of Persian gum-chitosan incorporated with Garlic essential oil gave the best antioxidative activities and sensory scores. Keywords: Persian gum, chitosan, Allium sativum, silver carp

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In this study, gelatin from common carp scales (Cyprinus carpio) was produced using alkaline, acidic and thermal methods. Then, the physical factors, barrier properties and its appearance characteristics were optimized by changing effective factors in the initial gelatin extraction process. In order to optimize the film, the response surface methodology included a central composite design for extraction process, a series of effective factors in extraction including sodium hydroxide concentration, alkaline pre-treatment, hydrochloric acid concentration and extraction temperature as independent variables were investigated. The dependent variables including tensile properties, water solubility and water vapor permeability were investigated. The results of screening based on mechanical strength and solubility resulted in the selection of 4 factors of 9 factors. In the screening stage, four variables including two factor of the pH of extraction and the duration of the alkaline treatment that had the greatest effect on the tensile strength, and two factor including concentrations of acid treatments and the extraction temperature that had the most effect on the solubility of the films were selected for the the main experiments with gelatin extraction. Other variables that did not have a significant impact on the mechanical properties and film solubility were in their most common form. The main experiments of gelatin extraction included 30 treatments. Solubility showed significant changes (p <0.05). The lowest solubility was 25.08% for treatment No. 9 with alkaline treatment for 195 minutes, acid treatment with 0.3 molar concentration and extraction at 63 ° C. The lowest permeability was for treatment No. 15 with alkaline treatment for 140 minutes, acidic treatment with a concentration of 0.18 molar and extraction at 76 ° C (p <0.05). Finally, it was determined that by changing some of the extraction factors, the properties of gelatin film obtained from common carp scales could be optimized.

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Despite the high nutritional value of shrimp, its per capita consumption in the country is low. Therefore, it is necessary to investigate the reasons for this shortage and to propose ways to increase per capita consumption in order to maintain the health of the population. To this purpose, the behavior of shrimp consumers must first be evaluated. This study was conducted to evaluate the behavior of shrimp consumers in the country by using the general framework of the theory of planned behavior. The statistical population of the study was the whole country which selected 10 cities (Mashhad, Tehran, Gorgan, Bandar Abbas, Yazd, Shiraz, Kermanshah, Ilam, Birjand and Tabriz) by randomized sampling and completed 1000 questionnaires by citizens. Statistical analysis were performed using the Structural Equation Model and Liserl software. The results showed that attitude, subjective norm and perceived behavior control had a positive and significant effect on the intention to shrimp consumption. In addition, the perceived behavior control was also effective on increasing of shrimp consumption. It was found that only two assumptions about the significant effect of convenience of cooking on the attitude and the significant effect of income on the subjective norm were rejected and other assumptions (significant effect of quality, packaging and type of supply and processing on attitude, significant effect of price and positive and negative beliefs on subjective norm, significant effect of consumption time, availability and experimental records on perceived behavior control and significant effect of intention to consumption on increasing of shrimp consumption) were confirmed.

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This study was conducted to evaluate the control efficacy of Pseudomonas chlororaphis, Erwinia herbicola, Bacillus amyloliquefaciens, and Bacillus subtilis, as well as solutions of zinc sulfate, sodium malonate, and oxalic acid against potato white mold caused by Sclerotinia sclerotiorum under field conditions during growing seasons of 2017 and 2018 in Bahar and Lalehjin, Hamedan, Iran. The results showed that strains of Bacillus subtilis as well as zinc sulfate had the highest inhibitory effect against carpogenic germination of sclerotia. The myceliogenic germination of sclerotia was inhibited by solutions of zinc sulfate and sodium malonate with statistically similar results followed by oxalic acid. In addition, activities of resistance-related enzymes including β-N-acetyl hexosaminidase, endochitinase, chitin 1,4-β-chitobiosidase, β-1,3-glucanase, phenylalanine ammonia lyase, polyphenoloxidase, and peroxidase markedly increased in potato leaves due to application of bacteria on plants. The results showed that all treatments were able to reduce significantly (P< 0.05) the number of infected and dead plants in both years. The mixtures of five bacterial biocontrol agents and solution of zinc sulfate were found to be the most effective treatments to control white mold.

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The effect of gum tragacanth (0, and 0.15%) and Fennel (Foeniculum vulgare) (0, 2.5, and 5%) on the chemical and rheological properties, phase separation, Lactic Acid Bacteria (LAB) viability, and sensory characteristics of an Iranian dairy drink "Doogh" was investigated during 20 days of storage. Results cleared the stability of Dooghs prepared with Gum Tragacanth Dispersions (GTD) was significantly higher than samples without this hydrocolloid (P< 0.05). Doogh samples’ viscosity in the presence of Fennel Extract Powder (FEP) was increased significantly (P< 0.05). Power-law and Herschel-Bulkley rheological models were appropriate models for describing the flow behavior of control and treated Doogh samples, respectively. The results showed that by increasing the amounts of FEP, LAB viability increased while the fungi population decreased significantly (P< 0.05). Therefore, this herbal powder could stimulate LAB growth and control the fungi population in treated samples. Finally, adding GTD to the Doogh sample was proper for improving stability, and enrichment with Fennel was suitable for increasing LAB viability and microbial spoilage control.

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Abstract: Demographic discourses in the media or public inform lay people and may impact population planning and policies. Understanding the situation and characteristics of public demographic discourses in Iran helps the government and policy makers to identify experts’ advice to use in effective policymaking and to discern public perceptions and understanding of population policies and promote changes in fertility behavior. The aim of this paper is to examine public demographic discourses which are produced and reproduced in the Iranian media to affect fertility policy and decision making after the announcement of General Population Policies by the Supreme Leader in 2014. This paper uses the critical discourse analysis for analyzing demographic discourses in websites of two influential Iranian newspapers, i.e., Keyhan and Iran, and demographers’ ideas and opinions available online during 21 March 2010 and 21 May 2016. The critical discourse analysis illustrates that the main discourse for public demography is “Conceptual”. Analyzing texts indicates that demographers have tried to reduce the gap between science – policy by disseminating simple and understandable demographic discussions in the media. They argue that demographic issues are specialized topics and require scientific and rigorous research. Therefore, the first step for policymaking and planning is the recognition and understanding of population situation. Public demography intends to facilitate the formulation of an evidence-based policymaking to achieve General Population Policy objectives. Policymakers are recommended to provide favorable social and economic contexts supporting family formation and childbearing towards sustainable population growth outlined in the General Population Policies. Public demography has a vital role in providing a deeper understanding of future population trends and policies.