جستجوی مقالات مرتبط با کلیدواژه « ماهی » در نشریات گروه « کشاورزی »

Edible oils constitutes a chief component of human diets in our daily life to supply essential fatty acids, energy, and nutrients to human. The nutritional value of edible oils varies depending on the type of oil, processing methods, extraction techniques, and storage conditions. Generally, edible oils are high in triacylglycerols with minor compositions. The presence of high amount of unsaturated fatty acids in the structure of triacylglycerol leads to a reduced shelf life of oils. This is associated to the undesired lipid oxidation that occurs when unsaturated fatty acids are exposed to light, oxygen, and heat. This is a major concern in food industry as it might result in undesired food quality deterioration involving reduction of nutritional components and off-flavors. The demand for nutritious and healthy animal and vegetable oils has been increased with a growth in population and economic progress. Therefore, researches for functional and nutritious edible oils has gained world attention on the technology to process edible oils. The use of ultrasound as a new technology in food processes is increasing due to its potential for changing materials and processing speed. This technique displays several advantages over conventional techniques in terms of time, energy consumption, and higher output. Ultrasonic processing is used in the food industry for numerous processes on high lipid containing food products in cutting, cooking, homogenization/emulsification, and microbial inactivation. The aim of this study was to investigate the effect of ultrasound time (0, 20, 40 and 60 min) on physicochemical properties of corn oil, soybean oil and kilka fish oil.

Commercial kilka fish oil, corn oil and soybean oilwere purchased from local market. All of the chemicals and reagents used were analytical reagent grade. Each oil was poured at 250 ml Beaker and then treated with an ultrasonic probe at a frequency of 20 kHz for a specified period of time. Oil chemical and physical properties such as acid value (mg/g), peroxide value (meq O2/kg), oxidative stability index (h), thiobarbituric acid value (mg/kg), conjugated diene value (%), fatty acid composition, fourier transform infrared (FTIR) spectroscopy and color parameters (L*, a*, b* and ∆E) were determined. Data analysis was done using SPSS software and completely random design.

The results of this study showed that with increasing the duration of ultrasound, acid value, peroxide value, TBA value and conjugate diene value, increased and the induction period decreased. On the other hand, ultrasound treatment led to increase palmitic acid, stearic acid, oleic acid, saturated fatty acids (SFA) and monounsaturated fatty acid (MUFA), and decrease linoleic acid, linoleic acid (and palmitoleic acid, eicosapentaenoic acid and docosahexaenoic acid in kilka fish oil), polyunsaturated fatty acid (PUFA), polyunsaturated fatty acid/saturated fatty acids (PUSFA/SFA), unsaturated fatty acid/saturated fatty acids (USFA/SFA), Cox value in corn, soybean, and kilka fish oils. Ultrasound did not change the fourier transform infrared spectroscopy but did change some color parameters. Sonication caused an increase in L* (more lightness) of corn oil, a decrease in a* (more greenness) of soybean oil, an increase in b* (more yellowness) of corn and soybean oils, and a decrease in ∆E compared to control samples. Probably, ultrasound causes destruction and isomerization of the double bands of pigments and as a result changes in color indices. According to the results of this study, ultrasound treatment accelerated the oxidation and degradation of oils and as a result, changed some of the physicochemical properties of the oil, which varied according to the type of oil.

Heavy metals are one of the most important polluting sources of aquatic ecosystems, so the contamination of fishes with heavy metals, such as cadmium, can lead to their bioaccumulation in the body of consumers and ultimately the occurrence of various dangerous diseases. The aim of this research was to evaluate the amount of cadmium concentration in the rainbow trout, marketed in Birjand, Iran. For this purpose, a total of 96 samples of muscle and gill tissues of rainbow trout (48 fresh and frozen fish gill tissue samples and 48 fresh and frozen fish muscle tissue samples) were tested. Samples were prepared by wet digestion method and cadmium concentration was measured using graphite furnace atomic absorption spectrophotometer. After the statistical analysis of the data the mean value of cadmium in all samples was measured 0.007±0.003 ppm. The amount of cadmium in gill tissues was higher than in muscle tissues, but this difference was not statistically significant (p<0.05). In addition, the average concentration of cadmium in muscle and gill tissues were significantly lower than international standards (p>0.05). he results of this research showed that, fortunately the rainbow trout marketed in Birjand city is in a favorable condition in terms of the cadmium concentration.

This study was conducted to survey the consumer’s opinion of Esfahan residents regarding the fish quality. This study was performed for the first time in Iran. The descriptive survey was done randomly using a questionnaire. Studies showed that the residents of Esfahan prefer to spend more time and energy achieving high-quality fish and like not to eat fish at restaurants. They seek an easy way to evaluate the freshness and quality of fish and the value of the high-quality fish and prevent consuming the low-quality fish because of crucial side effects. Consumers do not like to buy packed fish, but they are not assured themselves to select the high-quality fish and they have to trust the salesmen’s comments and rely on promotion and price. Consumers usually believe in crushed ice to preserve the quality of fish (%36). 53.9 percent of consumers rely on their visual ability to choose the correct one, so training and informing them about fish quality indexes can raise the consumption rate.

Vibrio parahmolyticus is a marine and estuarine bacterium that damages the aquatic industry due to food-related outbreaks and is a great threat to food safety and human health. Annually, many reports of food poisoning occur due to consumption. Seafood contaminated with Vibrio bacteria is released. The present study was conducted in order to investigate the frequency of Vibrio parahaemolyticus isolated from Caspian sea fish and to determine the pattern of antibacterial resistance.For five months (June 2021 to October 2021), 220 samples of fish caught from the Caspian Sea were prepared from the Gilan Fisheries Department with full compliance with health conditions. To isolate Vibrio parahemolyticus, after enrichment in buffered peptone water for 24 hours at 37°C, a loop was cultured in thiosulfate citrate bile sucrose agar medium for 24 hours at 37°C. The day after the colony yellow and green suspects are used from standard differential tests. In addition, to determine the pattern of antibiotic resistance according to CLSI guidelines, antibiotic disks of MAST Company were used. Out of a total of 220 fish samples caught from the Caspian Sea, 759% of the fish samples were infected with Vibrio species. Vibrio parahaemolyticus abundance was reported as 19%, which was more than the other species obtained.Also, the results obtained from the antibiotic resistance pattern indicate the sensitivity of this strain to ciprofloxacin antibiotics (98.9%, gentamycin (87.8%), chloramphenicol (92.4%) and their resistance to amoxicillin (96.3%), doxycyclin (94.1%) and tetracycline (92.3%). Our findings showed that the fish studied in the Caspian Sea are infected with Vibrio parahaemolyticus, which can be considered a serious threat to the health of seafood consumers.

The present research was conducted to collect and weigh the criteria affecting the desirability of fish and to provide a coherent and citation ranking for commercial marine fish in Khuzestan province. Semi-structured Delphi interviews with 15 experts were used to identify the criteria. The criteria were prioritized and the sub-criteria were screened using the analytic hierarchy process (AHP) method. A researcher-made questionnaire was used to rank the desirability of fish for consumers and the validity and reliability of the questionnaire were confirmed by conventional methods. Expert Choice and SPSS statistical softwares were used to analyze the data extracted from 181 completed questionnaires. Criteria such as taste and palatability (local weight = 0.209), cooking quality (0.165), thorn density and hardness (0.165), discards ratio (0.153), and price (0.114) are the most striking desirable factors of marine fish in Khuzestan is from the point of view of experts. Fish species including four-finger threadfin (Eleutheronema tetradactylum) (overall weight = 0.379), tiger tooth croaker (Otolithes ruber) (0.368), Sobaity seabream (Sparidentex hasta) (0.364), orange-spotted grouper (Epinephelus coioides) (0.362), silver pomfret (Pampus argenteus) (0.360), Southern meager (Argyrosomus hololepidotus) (0.353), gray sweetlips (Diagramma pictum) (0.353), spangled emperor (Lethrinus nebulosus) (0.351), John’s snapper (Lutjanus johnii) (0.351), and narrow-barred mackerel (Scomberomorus commerson) (0.350) were known as the best options in terms of cooking, preparation, and pre-preparation criteria, respectively, which are more desirable to consumers. The findings of this study can be beneficial for the organizations relevant in the distribution and trade of aquatic animals, such as the Iran Fisheries Organization and it is hoped that the results will be fruitful for production, economic prosperity, and the fishing road map in line with the regulation of domestic markets.

The present research was conducted on Red fish (Carassius auratus, Linnaeus, 1758) in “Gilan Agricultural and Natural Resources Research Center” during Feb 2023-July 2023. In order to prepare a 20% olive leaf extract ointment, 20 g of olive leaf extract was mixed with 100 g of Oserin emulsifier. A total of 30 goldfish weighing 30-25 g were placed in two aquaria of the control and treatment groups with a volume of 1x1x2, m3 of water (25o C , pH= 7/2) with proper aeration and nutritional conditions. After creating wounds on the skin of fish in the control group, no treatment was given, but in the treatment group, 20% olive leaf extract ointment was used on the wounds once per day and continued for 30 days. The healing process of the wounds was measured using calipers at interval days of 5, 10, 15, 20, 25 and 30. The results showed that within 5-10 days after using the extract ointment on fish wounds in the treatment group, the healing process was almost 3 times faster than that of the fish in the control group (p<0/05). After creating a wound in the interval of 15 to 20 days, the process of wound healing and recovery among the fish in treatment group was much faster and the average fish recovery in treatment group was 7 times higher than the wound healing in the control group (p<0/05).

The purpose of this research was to evaluate the behavior of packaged fish buyers and to identify their priorities for purchasing the product in Tehran city. For this purpose, a questionnaire based on research assumptions was designed and completed by the statistical community. The statistical population of the research is the whole of Tehran city, that 12 urban areas were randomly selected for the field study with a sample size of 600 people. In order to test the hypotheses and examine the intensity of the relationship between the items, a proportional conceptual model was designed and analyzed by Lisrel software. Also, In order to evaluate and rank the priorities of the statistical population in relation to some of product characteristics, Friedman's test was used. The results showed that the variables of packaging characteristics, fish species, processing models, types of supply and quality factors were significantly effective on the attitude, while the quality variable with an effect coefficient of 0.31 had the greatest effect on the attitude. The purchase place also had a significant effect on the perceived behavior control and the hypothesis related to it was confirmed. Among the three main elements of the model, attitude towards consumption with an effect coefficient of 0.63 was the most effective element on the intention to buy. In the following, it was found that two variables, price and access, do not have a significant effect on the purchase decision, and the hypotheses related to them were also rejected. The ranking of purchase priorities of Tehrani citizens in relation to fish species, cultured species, types of supply, pack weights, processing models and shopping places showed that the first rank is related to Persian Gulf fish, rainbow trout, whole fish (empty stomach with head), weight of 500 to 700 grams, schnitzel and protein supply stores.

When fish is mechanically processed on a commercial scale, usually between 45 and 55% of its weight is discarded as waste. This amount of waste from aquatic processing contains a large number of nutrients, including protein with high nutritional quality, which, despite its need, is not properly used. In order to optimally use this category of materials and also optimally use underutilization fish, several technologies including the pH shift method were taken into consideration. This method, which is based on the dissolution of the raw material in acid and base (alkali), consists of two stages. In the first stage, the pH of the raw material is reduced or increased by using the corresponding acid or base. This causes the muscle proteins to be charged together and then dissolve in the aqueous medium, and the second stage includes the precipitation of the proteins up to their isoelectric point. The protein obtained from this technique has higher nutritional and functional properties than other conventional techniques for producing protein concentrates such as surimi. This article intends to describe the principles of the pH shift process and the recovery of concentrated protein in this way, the advantages and disadvantages of both acid and alkaline methods and its comparison with the conventional (surimi) processing method, which ultimately the nutritional and functional properties of this process. It is discussed in detail.

Considering the high perishability, quality reduction, and nutritional value of the fish during the storage period, the aim study is to investigate the edible coating based on chicken feet gelatin/green walnut skin extract to preserve the physical characteristics, color, and texture properties of Oncorhynchus mykiss fillet during storage in the refrigerator. After extracting gelatin and green walnut skin extract, the coating solution were prepared. The fillets were coated by immersion method. Physical characteristics (moisture), color indices (L*, a*, and b*) as well as textural properties (hardness, springiness, and Cohesiveness) of the fillets were evaluated during 12 days of storage (on days 0, 4, 8, and 12). Variance analysis was performed by Minitab software (version 18). The mean data comparison by Tukey's test is at a 95% confidence level. The results showed significant moisture retention of coated fillets (p<0.05). The L* and a* index of fillets decreased during 12 days of storage. While, the b* index was increased in all samples (p<0.05). The evaluation of the texture of the fillets showed a decrease in hardness and Cohesiveness, but springiness was increased (p<0.05). The coat had significantly higher hardness, Cohesiveness, and lower springiness than the control sample (p<0.05). Increasing the concentration of green walnut skin extract from 500 to 1000 ppm increased the quality of fillets (p<0.05). In general, It can be concluded that edible coating based on chicken leg gelatin/green walnut skin extract effective to increase shelf- life aquaculture industry.

In the present study, changes in the quality indices and shelf life of fresh fillets of narrow-barred Spanish mackerel (Scomberomorus commerson) and Javelin grunter (Pomadasys kaakan) were investigated over a 12-day storage period in the refrigerator using sensory, chemical (pH, TVB-N, PV, TBARS), and microbiological (mesophilic and psychrotrophic bacterial counts) indices. The sensory scores of both fish fillets reached less than 4 (the acceptable limit for consumer acceptance) on the sixth and eighth days of storage, respectively. The mesophilic and psychrotrophic bacterial counts in the fillets of both fish increased with an increase in storage days, although the rate of increase was different between the two groups, and psychrotrophic bacteria increased to a greater extent with an increase in storage days. The pH of the fresh mackerel and grunter fillets decreased from 6.52 and 6.24, respectively, at the beginning of the storage period to 7.49 and 7.25, respectively, on the final day of storage. The TVB-N level in both fish increased with an increase in storage days and reached 28.36 mg N/100g in mackerel and 36.25 mg N/100g in grunter on the twelfth day of storage. The lipid oxidation indices, namely PV and TBARS, in the fillets of both fish were significantly higher at the end of the storage period than at the beginning. The results of sensory, microbiological, and chemical indices showed that the maximum shelf life of narrow-barred Spanish mackerel and Javelin grunter fillets is 6 and 8 days, respectively.

Microbiological control of food is important to prevent food poisoning in humans. Pathogenic microorganisms are gram-positive or gram-negative pathogens found in food that cause gastroenteritis. The purpose of this study is to investigate the amount of Listeria monocytogenes and Salmonella in fish, shrimp and eggs presented in Shahrekord city. In this study, 300 samples, including 100 fish samples, 100 shrimp samples, and 100 egg samples, were randomly collected from retail stores in Shahrekord city and transferred to the specialized food hygiene laboratory of Shahrekord Islamic Azad University. The samples were enriched in Listeria enrichment culture medium for 48 hours and then on the selected culture medium and the suspected Listeria isolates from Palcam agar culture medium were counted after biochemical confirmation tests and for confirmation Salmonella was used from SS agar, BS agar and then TSI and LIA culture media. Research The results showed that 2 out of 100 fish samples (2 percent), 4 out of 100 shrimp samples (4 percent), and 5 out of 100 egg samples (5 percent) were contaminated. It was Listeria monocytogenes. The amount of Salmonella contamination for fish, shrimp and eggs was 9, 11 and 18 respectively. Due to the prevalence of Listeria, it is recommended to avoid consumption of undercooked seafood by at-risk populations. Strict implementation of sanitary conditions of food contact surfaces and handling areas, and good personal hygiene practices should reduce possible contamination of seafood products by L. monocytogenes.

The effects of dietary aflatoxin B1 (AFB1) and zearalenone (ZEA) co-contamination on goldfish, Carassius auratus, was investigated. Total of 540 C. auratus fingerlings with an average body weight of 6.25±0.12g were randomly distributed in nine different experimental groups with 3 replicates comprised of three dietary levels of AFB1 (0, 50 and 100ppb) and ZEA (0, 500 and 1000ppb). Fish were fed with the experimental diets for 60 days. Then growth and nutritional indicate and pathology of gill and intestinal tissue were investigated. The results showed that dietary AFB1 and/or ZEA contamination depressed the growth performance, and nutritional indices of the experimental groups; the highest and lowest WG, final body weight, TGC and DGC were belonged to control group and AFB50ZEA1000, respectively (P<0.05). Although the nutritional indices, including PER, PPV and LER, were not significantly different among the experimental groups (P>0.05), the fish fed the diet containing 500 ppb ZEA had the lowest value of LPV (P<0.05). The highest intestine tissue inflammation (4.0±0.75) and necrosis (4.0±0.75) scores were observed in AFB100ZEA500 group (P>0.05). Also, the simultaneous presence of AFB1 and ZEA in the diet increased the severity of the gill tissue damage, including hyperplasia, congestion, hemorrhage, and lamellar fusion in almost all treatments containing AFB1 and ZEA (P<0.05). The results revealed that dietary co-contamination of AFB1 and ZEA could negatively affect fish performance at concentration even lower than those indicated in the literature implying that the safe feed mycotoxin thresholds would be revised in terms of fish welfare and performance.

According to the official reports of the Ministry of Health, Treatment and Medical Education, the corona virus or covid-19 was seen in our country (Iran) from the last months of 2018 and quickly turned into an epidemic. The entry of this virus into the country not only involved the country's health system and caused illness and death of many compatriots, but also had a significant impact on the country's economy in the production and trade sectors. Global reports indicate the negative impact of Covid-19 on the fisheries industry, the same as activities of aquatic processing industries in different countries. In this article, the impact of Covid-19 on the country's aquatic processing industry investigated. In order to conduct this research, a questionnaire containing 31 questions on important topics such as the effect of Covid-19 on the volume and price of raw materials, sales volume, type of product, income, labor forces, changes in the marketing method of processed products and other factors were gathered and subjected to the processing. A total of 56 completed answer sheets were received from the processing centers. The results of the analysis of the response letters showed that during the Corona era, 60% of the respondents confirmed a decrease in the supply of raw materials for aquatic products, 72.2% with an increase in the price of raw materials, 67.9% with a decrease in the volume of production, 80% with an increase in the finished product price, 80.8% with decrease in the volume of domestic sales, 81.5% were faced a decrease in the number of customers. Also, 75% of farmers' responses have reported a decrease in the number of seasonal employees during the Corona era. In terms of product exports, 84% of the respondents said a decrease in the volume of exports.

Number of attempts has been made to cryopreserve fish and shellfish gametes. Success has been achieved to establish only sperm banks in case of some commercially important fish. In shellfish, also particularly in shrimps, though the sperm cryopreservation was successful; no attempts were made to develop sperm banks. As far as cryopreservation of egg and embryos of fish and shellfish is concerned, less research efforts were made with limited success. Number of reasons have been given for the failure of egg/embryo cryopreservation and the main barriers speculated are low membrane permeability in the eggs, the large yolk mass of the oocyte, and the presence of compartments in early developing embryos. These factors result in ice crystal formation during the freezing process. In addition, the oocytes and embryos are prone to chilling injuries unrelated to ice crystal damage. There are number of other problems reported by several researchers in the egg/embryo cryobanking protocols which are elaborately discussed in the present paper. There is an urgent need to develop a viable cryobanking technology for fish egg/embryos to enhance fish production in captive condition. Attempts to cryopreserve larvae of aquatic animals are another challenge occurring in the recent past. The aim of the present review is to collect comprehensive information on the efforts so far made on fish and shellfish egg and embryo cryobanking; and to assess the challenges in the development of viable technology and plan for future research for making this technology viable and cost effective.

Due to the rapid spoilage of fish, it is necessary to use new methods of packaging such as coating with natural antioxidants. Chitosan has been well received as a natural preservative due to its renewable properties and similar structure to cellulose. Also, phenolic compounds in tea and cinnamon and its antimicrobial and antioxidant properties have been considered in the packaging of protein substances that are prone to high corruption. In this study extracts of 0.05% tea, 0.5% cinnamon tea, and solution of 2% chitosan-cinnamon tea were prepared. Characteristics of oxidation, chemical changes, microbial analysis and FTIR spectroscopy were examined on trout fillets covered with extracts on 0, 5, 15, 20 days during storage in the refrigerator (4 ). The results showed that coatings containing extracts and chitosan had significant effects at the level of 5% in reduction of microbial load, volatile nitrogen bases and thiobarbiotic acid. Based on FTIR findings, the control sample showed the highest oxidation rate and the sample treated with chitosan extract, tea and cinnamon tea showed the lowest oxidation rate. Covering trout fillets with cinnamon tea and tea extract increased antimicrobial properties, but combining it with a powerful antioxidant such as chitosan has higher effectiveness. Chitosan-cinnamon tea cover can be used to improve the quality of fish fillets and increase its shelf life.

The extensive use of di-ethyl phthalate (DEP) as a plasticizer in plastic products, is a major threat to organisms as it leaches out easily from the plastic matrix into the environment. In this study, we evaluated the hepatotoxicity in goldfish (Carassius auratus) upon treatment with DEP. The 96 hr acute DEP LC50 value was determined as > 4 mg/L, using probit analysis. Three sub-lethal concentrations, 1/5th, 1/10th & 1/20th of DEP LC50 were used for 7 and 14 days. Blood and liver samples were taken out, following liver perfusion with saline, homogenates were made. In this study, the content of lipid peroxidation (LPO/MDA) as a marker for membrane disorders, content of carbonylated proteins (CP), and the levels of ALT and AST (as hepatic necrosis markers) were increased in the liver of DEP-treated fish. Meanwhile, the total antioxidant capacity (TAC) was found to be lowered in liver homogentes. In brief, DEP caused hepatotoxicity in fish through induction of oxidative stress followed by cell membrane instability.

Heavy metals can enter to the aquatic animal's body through dietary or water sources and exert their harmful effects. This study was conducted to compare the toxicity of lead in common carp via diet and water borne conditions. Total number of 135 fish (average weight of 50±10 g) was divided into three groups (each with triplicate) including control, water borne (1 mg/L) and diet borne (1 mg/kg dry diet) lead. Experiment was executed during 21 days and sampling was done at 7, 14 and 21 days after trial initiation. Blood biochemical factors including total protein, albumin, globulin, creatinine, glucose, cholesterol, alkaline phosphatase (ALP), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) were measured in mentioned sampling times. Results showed that lead exposure led to negative effects on blood biochemistry in both groups, but in the case of glucose, LDH and ALP, significant changes were observed between diet and waterborne lead. It may conclud that the diet borne had more toxic effects than waterborne lead and therefore, lead had more potential toxicity through diet in common carp.

Concerns about the negative effects of microplastics on human health have led to increasing attention to the occurrence of microplastics in the aquatic environments. Recent studies have focus from the marine environment to inland waters, particularly the spatio-temporal distribution of microplastics in rivers. Qarasu basin, leading to Gorgan Bay, is the site of many permanent rivers and the levels of microplastic pollution in those rivers are unknown. This study was conducted along 8 different rivers in 2020. Some 9 fish species were identified and the presence of microplastics was confirmed in 87% of fish. The prevalence of microplastic particles among species were Chelon spp.> Carassius gibelio> Gambusia holbrooki> Rutilus rutilus> Neogobius melanostomus> Cyprinus carpio = Vimba persa> Rutilus caspicus> Barbus cyri. The highest type, color and size of fish microplastics were fiber, black, 0.5-0.1mm, respectively. In conclusion the rivers of Qarasu basin have been polluted by microplastics not only in developed areas with intense human activity but also in upstream areas, which can be considered as a source of pollution in Gorgan bay.

Organisms living in frigid environments have evolved different mechanisms to deal with cold air. The emergence of the antifreeze protein gene is one of the most important mechanisms. Antifreeze proteins have critical functional properties for organisms to survive in cold environments. These proteins prevent freezing damage in living organisms such as fish by binding to ice crystals. The variety of species that contain this type of protein and the diversity of the proteins has resulted in the development of a wide range of antifreeze proteins of varying sizes and functions, which has piqued the interest of a variety of companies. Although the development of antifreeze proteins technology is in its infancy, it could have great potential for future performance. Meanwhile, marine resources provide humanity with a unique potential to create such valuable molecules due to their breadth and climatic variability. With this approach, the present study aims to study and introduce antifreeze proteins derived from fish to provide a comprehensive knowledge of the types of antifreeze proteins in them and their potential applications.