Trout Meat Research Articles

MICROBIOLOGICAL QUALITY ASSESSMENT OF RAINBOW TROUT (ONCORHYNCHUS MYKISS) MEAT TREATED WITH ROSEMARY AND THYME DRIED HERBS AND ESSENTIAL OILS

This study investigates the effects of thyme and rosemary dried herbs, as well as thyme and rosemary essential oils (1%, w/v), on the microbiological quality of vacuum-packed rainbow trout meat stored under refrigerated conditions (4 ± 1 °C) for 7 days. The microbiological quality of meat was monitored based on total viable counts, coliform bacteria, and lactic acid bacteria counts over a designated storage period (on the 0th, 1st, 3rd, 5th and 7th day of storage). As expected, the highest total viable counts were observed on the 7th day of storage in the untreated aerobically packed control group reaching 5.723 ± 0.021 CFU.g-1. The tested treatments showed potential in reducing the growth of bacteria in rainbow trout meat samples. Across all bacterial groups under investigation, rosemary essential oil appears to have the most advantageous effect in inhibiting bacterial growth compared to other tested treatments. Cultivated isolates were identified by MALDI-TOF mass spectrometry and assigned to 33 species belonging to 14 families. The most prevalent family was Enterobacteriaceae (18.99%), and the most abundant species found in samples was Hafnia alvei (8.86%). Our findings suggest the potential of using thyme and rosemary in both essential oil and dried forms as natural preservatives to enhance the microbiological quality and longevity of refrigerated rainbow trout meat.

Method for obtaining ecological products from rainbow trout Oncorhynchus mykiss farming

In aquaculture, the period of active development of aquatic organisms is considered one of the most important for the formation of potential in the future. The issue of using natural components when growing aquatic organisms and feeding young fish is given special attention. This research investigated Spirulina (25%) + Vermiculture (50%) + Hermetia illucens (25%) as an additional source of functional active substances and protein that affect the body performance of rainbow trout in early ontogenesis. All objects were cultured in a special bioreactor, which was a component of the recirculating aquaculture model system as well as in the laboratory, where an installation was made for cultivating natural food. The results of the scientific and practical part of the work showed that after the end of the experiment, body weight was higher in the experimental fish by 7.2% than in the control group. This article presents the results of feeding rainbow trout as one of the cases of improving the morpho-functional and biochemical composition of the blood of this species: an increase in the total number of red blood cells by 11.0%, hemoglobin content by 9.7%, total protein at 22.7%, albumin by 24.2%, and creatinine by 15.5%, compared with the control group. The presented positive changes in the functional status of the rainbow trout organism were in harmony with the parameters of body weight, as well as histological indicators. Histological indicators of the liver and muscle tissue of the fish supplemented the obtained positive result of the influence of natural and active components of the feed. Feeding fish according to the scheme in the experimental group promotes the formation of layers of special adipose tissue in the endomysium. The total amount of the stromal component in the muscle tissue of rainbow trout was 25% of the mass of the entire tissue. The control group showed that the muscle fibers were polygonal in cross section, separated from each other within the bundle by delicate layers of endomysium. When using a standard feeding regimen (control group), the stromal component is a moderately expanding structure that replaces the space between the fibers. The experimental group had the most significant indicators. The intensification of individual aspects of homeostasis achieved with the help of feed components (experimental group) promotes the growth of muscle fibers in thickness due to the formation of new fibrils, but not an increase in the proportion of sarcoplasm (watery meat). As a result, neurohumoral regulation and substance synthesis processes improved in the fishes’ body, which helps to improve ontogenesis rates. The presented ingredients in the diet of rainbow trout are natural stimulants of metabolic processes and sources of nutrients. The method allows aquaculture to be defined as being as close as possible to “environmentally safe”. The next stage will be a comprehensive analysis of the qualitative and quantitative characteristics of rainbow trout meat under the influence of the feed factor.

Effectiveness evaluation of the infl uence of protein concentrates on the chemical composition of fish meat

Due to the high demand, cost, growing shortage and low quality of fi sh-meal, there is a constant search for affordable alternative feed raw materials in feeding aquaculture fi shing grounds. The use of high-protein products of plant origin is the most effective option for replacing fi sh-meal in fi sh feed. The purpose of the work was to evaluate the eff ectiveness of the infl uence of protein concentrates on the chemical composition of rainbow trout meat. Testing of compound feed for rainbow trout, the formulation of which included high-protein feed concentrates, was carried out on the basis of IP Kalmykova I. O. and under the conditions of the Research Center “Breeding valuable sturgeon breeds” at the Volgograd State Agrarian University. It was found on base of the results obtained that more intensive growth was observed in the groups in which the mustard protein-containing feed concentrate Gorlinka was introduced into the feed formulation with partial or complete replacement of sunfl ower meal. Here, the increase in the total and average daily live weight gain was noted by 2,83–6,93 % and by 1,62–1,68 %. The use of the Agro-Matic concentrate during the period of the experiment had a positive eff ect on the growth dynamics of rainbow trout, increasing productivity indicators. Thus, live weight indicators increased by 1,29–4,15 %, daily gain indicators increased by 1,44–4,46 % relative to individuals receiving compound feed with fi sh-meal. When studying the chemical composition of trout meat with the addition of Gorlinka concentrate to the feed formulation in the experimental groups, the increase in protein content was revealed by 0,13–0,41 abs.%, inorganic matter by 0,04–0,12 abs.%, also the total amount of amino acids increased by 0,18–0,46 abs.%, while the fat content on the contrary decreased by 0,05–0,17 abs.% compared to the control. In the experimental trout groups, when introducing the Agro-Matic protein concentrate into the diet instead of fi shmeal the protein content increased by 0,03–0,40 abs.%, inorganic matter by 0,08–0,24 abs.%, total amino acids increased by 0,11–0,58 abs.%, there was a slight decrease in the amount of fat by 0,10–0,36 abs.% compared to the 1st control group. The use of protein concentrates has a positive eff ect on the qualitative composition of the muscle tissue of rainbow trout by increasing the protein content and the amount of essential amino acids in the muscle tissue of individuals surpassing the 1st control group in key indicators.

Comparison of Nutritional Composition, Mineral and Heavy Metal Content of Rainbow Trout from Different Aquaculture Systems

In this study, proximate compositions, meat yields, mineral matter (Na, Mg, Ca, K), and heavy metal (As, Fe, Zn, Se, Mn, Co, Cu, Pb, Ni) contents of rainbow trout (Oncorhynchus mykiss) obtained from concrete pond systems and dam lake net cage were examined. Mineral and heavy metal contents were measured by ICP-OES instrumental analyser. According to the results of rainbow trout meat yield and nutritional composition analysis varied between; meat yield were 57.43-66.40%, crude protein were 16.99-19.93%, crude fat were 3.07-4.18%, crude ash were 0.98-1.58%, and moisture contents were 75.10-77.65%. Mineral contents of Ca 2.66-30.58 mg.kg-1, Na 19.53-36.04 mg.kg-1, K 252.79-310.05 mg.kg-1, and Mg 120.75-137.44 mg.kg-1 were detected in the presented ranges. Detected heavy metals were As 0.42-0.56 mg.kg-1, Fe 2.16-3.69 mg.kg-1, Zn 2.67-4.69 mg.kg-1, and Se 0.17-0.77 mg.kg-1. On the other hand, Mn, Co, Cu, Pb, and Ni were not detected. As a result of the study, it was found that the proximate composition, meat yield, mineral matter, and heavy metal contents of rainbow trout vary depending on the location and size of the fish (p<0.05). However, the heavy metal levels detected in muscle tissue did not exceed the consumption limits.

FAT OXIDATION, PROTEIN DEGRADATION AND COLOUR OF RAINBOW TROUT (ONCORHYNCHUS MYKISS) MEAT DURING 3 MONTHS OF FREEZER STORAGE

The aim of the work was to analyze the effect of storage in freezing conditions (-18 ° C) during 3 months of storage on the formation of malondialdehyde MDA, TVB-N (total volatile basic nitrogen), and colour. Rainbow trout up to 500 g (RT) aged 1-1.5 years (n=15) and trout (RT1) up to 3.5 kg aged 2-2.5 years (n=15) were included in the experiment. The stated weight of the fish is already after processing. After slaughtering the fish, samples were taken from each fish for analysis of meat colour in the CIE colour space with a KONICA MINOLTA 2600D (L*, a*, b*) on the 1st day after slaughter and after the 1st, 2nd, 3rd month of storage. The content of TVB-N and MDA was measured parallel. For both weight categories of trout, after three months of freezing, we observed significant (RT1- P≤0.05; RT- P≤0.05) increase in TVB-N compared to the first day of measurement. Malondialdehyde content after three months of freezing was significantly (P≤0.05) higher than at the first measurement in both weight categories of rainbow trout. In the RT experimental group, trout meat after three months of freezing was significantly (P≤0.05) lighter (L*) and less yellow (b*). The meat of the RT1 group after 3 months of freezing storage was significantly (P≤0.05) darker , less red and less yellow.

Study of the effectiveness of using the antioxidant astaxanthin in the composition of feeds for valuable aquaculture objects

The “Enzymsporin” is one of these preparations, which is a probiotic feed additive for optimizing digestion processes, increasing the productivity and safety of fish. Second year rainbow trout grown in cages at the cooling pond of the Smolensk NPP were used as the objects of study. Specialized domestic feed “Trout growth 44/23” was used as the main diet (MD) for feeding the fish. The main diet with the addition of 0,5 g of “Enzymsporin” per 1 kg of feed was used as an experimental variation. An increase of the body girth index (66,7% versus 61,9% at p < 0,05) in the experimental group of the trout was founded. A tendency to increase the coefficient of fatness and the relative length of the stomach and intestines were noted, but the difference was not significant. The relative weight of fish without chyme (gastric and intestinal contents) in the control (without the use of the preparation) was significantly higher by 2,6% (p < 0,05), that indicates its lower nutritional activity. Significant differences in the content of moisture and minerals in the experimental and control groups won’t founded, but the fat content in the body of fish when using a probiotic was 1,5% higher then in control. Therefore, trout meat in this variant was more nutritious. An improvement in rearing results was achieved in the experimental group, especially the average daily growth gain increased by 6,8%, survival — by 6,7%, standing crop of the fish per unit area in a body water — by 9,2%, with a reduction of feed conversion ratio by 10,2%. The trout meat of the experimental group after heat treatment had a more pleasant taste, juiciness and tender texture. The average score of its overall average degustation evaluation significantly exceeded the control (8,0 versus 7,5 at p < 0,05). An economic effect in the experimental variant of feeding was 98257,5 rubles for the 80 m2 cage.

Morphological features and histological structure of the musculature of two trout phenotypic forms when reared in warm water of a power plant

The paper studies the effect of rearing in stocking ponds using the warm discharge water of the Smolensk NPP on the growth and trout meat quality. Some morphological indicators of trout cultivation are presented. The histological studies of the musculature of golden and typically colored trout are presented. It was revealed that the golden trout musculature grows with a predominance of hyperplasia of muscle fibers compared to the typically colored trout. It was shown that trout rearing using NPP cooling ponds does not lead to excessive accumulation internal fat and gives good results.

Atributos sensoriales y preferencia de conserva de trucha arcoíris con salsas de ají amarillo – aguaymanto y rocoto - tomate de árbol mediante mapeo de preferencia

The objective of this study was to evaluate the sensory attributes and the preference of six canned rainbow trout (Oncorhynchus mykiss) with the addition of government liquid based on yellow chili (Capsicum baccatum) – aguaymanto (Physalis peruviana L.) and hot pepper (Capsicum pubescens) – tree tomato (Cyphomandra betacea) sauces through the preference mapping technique (external and internal mapping). The canned rainbow trout were made with the addition of the governing liquid (corresponding to 4% of the formulation) of 3 types of sauces based on yellow chili - aguaymanto in the proportions of 3/1 (AA-3/1), 2/2 (AA-2/2) and 1/3 (AA-1/3) and 3 types of sauces based on hot pepper – tree tomato 3/1 (RT-3/1), 2/2 (RT-2 /2) and 1/3 (RT-1/3). The evaluation of the sensory attributes was carried out by 10 trained descriptive panelists and the preference by 50 regular consumers of canned and trout meat. The preference mapping indicated that the canned with yellow chili - aguaymanto 3/1 (AA-3/1) presented a greater preference of consumers being greater than 80%, it was also represented in a greater amount by three clusters (2, 1 and 3), this canned was characterized by being more spicy, low sensory acidity, less texture and less salty taste.

Proximate and fatty acid composition of meat from rainbow trout (Oncorhynchus mykiss W.) after dietary supplementation with black pepper (Piper nigrum L.) extract

The study was aimed at assessing the effect of dietary supplementation with black pepper (Piper nigrum) on the chemical and fatty acid composition in the meat of rainbow trout (Oncorhynchus mykiss W.), farmed in a recirculating system.
 Rainbow trout were distributed in two groups – experimental fed 1% powdered extract from black pepper (BPE) and control (C) fed without black pepper extract. After the end of the experiment, 6 fish from each group were euthanized, filleted and deboned. The 1% BPE in rainbow trout feed reduced meat water content and increased dry matter percentage and fat content. The fatty acid profile of rainbow trout meat was beneficially influenced by the dietary BPE supplement. The SFA percentage was statistically significantly decreased whereas contents of UFA, MUFA, PUFA and n-3 were considerably higher. No consistent effect was noted with respect to n-6 fatty acids. The improved PUFA/SFA and n-6/n-3 ratios in the supplemented group showed that the tested feed additive had a favourable effect on fatty acid content of rainbow trout meat. Both ratios were within the range, beneficial for human nutrition: > 0.4 and < 5, respectively.

Sensory, Chemical and Microbiological Properties of Trout Sausage (Fermented Sucuk)

This study aimed to produce fish sucuk using rainbow trout (Oncorhynchus mykiss) fillet and investigate its suitability for consumption. Sensory, nutrient composition, fatty acid and amino acid composition analyses were carried out in the sucuk prepared with a commercial spice mix. Total aerobic mesophilic bacteria, total coliform, total Enterobacteriaceae, Lactic acid bacteria, yeast and mould counts were found to be smaller than 1 log cfu g-1. It was found that the ratio of water, protein, fat, ash, total saturated FA, total mono-unsaturated FA and total poly-unsaturated FA were 48.63%, 17.27%, 22.00%, 2.52%, 50.17%, 43.23% and 6.6%, respectively. Glutamic acid (19.1 g 100 g-1), aspartic acid (17.17 g 100g-1), leucine (9.45 g 100 g-1) and lysine (8.05 g 100 g-1) were the main amino acids in fish sucuk. In addition, the sensory analysis results of the sucuk produced entirely from trout meat showed that it was acceptable. This study concluded that a sucuk product suitable for consumption could be produced using trout meat entirely, with the appropriate spice mixture, heat treatment and air conditions. 

Influence of Essential Oils on the Microbiological Quality of Fish Meat during Storage.

Simple SummaryFish meat is highly perishable due to its composition and the naturally present microbiota. The food industry aims to provide healthy, safe, and high-quality products to the market. Several strategies, including the use of natural preservatives, may be used to enhance food shelf life, and they can also be combined with others, such as vacuum packaging. This being the case, essential oils are natural plant components that, due to their composition, possess high antimicrobial and antioxidant effects, and are therefore good candidates to be tested as fish preservatives together with vacuum packaging. In the present study, essential oils from Citrus lemon and Cinnamomum camphora were added to rainbow trout meat for evaluating the microbiological quality (counts of bacteria and identification of present microbiota) of the fish when vacuum packed and stored for 7 days at 4 °C. Our results show that lemon (0.5% and 1%) as well as C. camphora essential oils (0.5% and 1%) had a positive effect on the microbiological quality of fish meat, keeping a high microbial quality of the fish fillets during 7 days of cold storage. The use of these essential oils in combination with vacuum packaging is beneficial in extending the shelf life of rainbow trout meat. All isolated species under the tested conditions are identified in the present study; such information will be useful for the future development of preservation methodologies that target isolated microorganisms, which will enable the food industry to enhance the shelf life and safety of fish.The aim of the present study was to evaluate the microbiological quality of rainbow trout meat treated with essential oils (EOs from Citrus limon and Cinnamomum camphora) at concentrations of 0.5% and 1.0% in combination with vacuum packaging during storage. The composition of the EOs were analyzed by gas chromatography coupled with mass spectrometry, and total viable counts (TVCs), coliform bacteria (CB), and lactic acid bacteria (LAB) were determined on the zeroth, first, third, fifth, and seventh days of storage at 4 °C. Individual species of isolated microorganisms were identified using a MALDI-TOF MS Biotyper. The results show that the major components of the EOs were linalool (98.1%) in C. camphora and α-limonene in C. limon. The highest number of TVCs and CB were 4.49 log CFU/g and 2.65 log CFU/g in aerobically packed samples at the seventh day. The lowest TVCs were those of samples treated with 1% C. camphora EO. For CB the most effective treatment was 1% lemon EO. LAB were only detected in a few samples, and were never present in aerobically packed samples; the highest number of LAB was 1.39 log CFU/g in samples treated with 1% lemon EO at day seven. The most commonly isolated coliform bacteria were Hafnia alvei, Serratia fonticola, Serratia proteamaculans, Pantoea agglomerans, and Yersinia ruckeri. Lactobacillus sakei, Staphylococcus hominis, and Carnobacterium maltaromaticum were the most frequently isolated bacteria from lactic acid bacteria. In conclusion, C. camphora EO at a concentration of 1% showed the highest antimicrobial activity.

Efecto de la inclusión de carne cruda en un paté cocido de carne mecánicamente recuperada de trucha arcoíris

The fishing industry generates large quantities of by-products, most of which are not used and are therefore discarded. The objective of the present research was the elaboration of a pâté-type sausage from mechanically recovered meat of rainbow trout (Oncorhynchus mykiss). The meat was obtained from trout skelons, which were passed through a grinder and sprayed with a mixture of α-tocopherol (0.02%) and ascorbic acid (0.05%). The formulation of the pate was as follows: mechanically recovered trout meat (74.4%), salt (1.3%), sodium tripolyphosphate (0.8%), starch (2%), soy protein isolate (2.4%), margarine (16.7%), soy lecithin (1.9%), onion powder (0.2%), garlic powder (0.2%) and pepper powder (0.1%). Three formulations were prepared: PCR1 (80% cooked meat and 20% raw meat), PCR2 (90% cooked meat and 10% raw meat) and PCR3 (100% cooked meat). For each formulation, the following were evaluated: texture profile, color and sensory evaluation, the latter with the participation of 30 untrained panelists using a 9-point hedonic scale, in which each formulation obtained an average of 6 ("I like it moderately"). The best formulation was PCR3, whose proximate composition was determined: 64% moisture, 16% fat, 12.5% protein, and 3.5% ash. The pâté of mechanically recovered trout meat proved to have a high nutritional value and a good level of sensory acceptance, demonstrating that it is a good alternative for the use of trout fillet by-products.

Insight into acute heat stress on meat qualities of rainbow trout (Oncorhynchus mykiss) during short-time transportation

The objective was to investigate the changes of meat qualities of rainbow trout (Oncorhynchus mykiss) under acute heat stress (T2) during short-time transportation. The antioxidative enzymes, energy substances of metabolism of trout meat were monitored, and the related biological pathway were clarified. Samples without transportation (Control), transported with temperature control (T1), and transported with 30 mg L−1 ascorbic acid (T3) were comparatively studied. The results showed that CAT, SOD and T-AOC activities and T-GSH content of transported fish muscle significantly declined (p < 0.05), especially in T2 group. Significant higher LD, MetMb%, pH, shear force and expressible moisture, lower muscle glycogen and L⁎value were obtained in the transported fish (p < 0.05), and the color and shear force did not recover after 24 h chilling storage. The result of transcriptomic sequences indicated that acute heat stress during transportation changed the meat qualities by inhibiting favored amino acid biosynthesis, while the addition of ascorbic acid reduced the activity intensity and energy demand to relieve acute heat stress.

Biological efficiency of rainbow trout meat lipids depending on the levels of amino acids in fodder

In trout farms of Ukraine, when using compound fodder for their production, the question arises of clarifying the requirement of rainbow trout in energy, protein and amino acids to achieve the maximum realisation of its biological productivity potential. Accordingly, the research explored the effect of using complete fodder with various levels of lysine and methionine on the biological efficiency of rainbow trout meat lipids. The purpose of the experiment was to determine the effect of different levels of amino acid nutrition of commercial rainbow trout on the fatty acid composition of meat lipids and their biological efficiency. For this purpose, five experimental groups were established by the method of analogues. The experiment lasted 210 days and was divided into two periods: equalising (10 days) and main (200 days). During the equalisation period, the feeding diet was the same for the fish of the control and experimental groups. During the main period, the level of lysine and methionine in the experimental fodders for different experimental groups of trout ranged from 2.5 to 2.9% and from 0.8 to 1.0%, respectively. Feeding of rainbow trout during the study period was performed 4-6 times a day, during the daytime at regular intervals. The required amount of fodder was calculated according to the individual weight of the fish and the temperature of the environment during feeding. Cultivation of marketable two-year-olds was performed in ponds with an area of 100 m2 at a planting density of 50 specimens/m2 and a water level of 1 m. The total number of trout in the experimental studies was 25 thousand specimens. It is established that the main share of fatty acids of lipids of rainbow trout meat is saturated fatty acids and monounsaturated fatty acids. As a result of the research, it was determined that using feed with increased levels of lysine and methionine for fish of the 4th experimental group was accompanied by an increase in the content of the sum of saturated fatty acids in meat by 5.84% compared to the control. With the growth of amino acid nutrition of the fodder, there is an increase in the content of linoleic acid in trout m′eat by 0.19-0.24% compared to the control. The practical value of the scientific work is to substantiate approaches to the technological bases of increasing the efficiency of using fodder nutrients in trout farming to ensure high fish productivity, which is of great economic importance

Investigation of dependences of the morphological composition of body and amino acid composition of trout meat proteins (Oncorhynchus mykiss) on levels of the energy value of feeds

The article studies the effect of using complete compound feeds with different energy levels on the morphological composition of the body and the amino acid composition of trout meat proteins. The experiment aimed to establish the influence of different levels of energy nutrition of commercial rainbow trout on the morphological composition of their body and the amino acid composition of meat proteins. For this purpose, five experimental groups were formed using the analog method. The study lasted 210 days and was divided into two periods: comparative (10 days) and main (200 days). During the comparative period, the study fish consumed compound feed of the control group. During the main period, the energy level in experimental compound feeds for different experimental trout groups ranged from 16 to 20 mJ per 1 kg. It was found that with an increase in the mass of two-year-old trout, the mass of muscle tissue and the yield of edible parts probably increases. Feeding fish with an increased amount of metabolic energy (20 mJ.kg-1) resulted in a significant change in the weight of internal organs, including the heart, liver, and kidneys. Increasing the metabolic energy in the compound feeds of fish from 18 mJ.kg-1 to 19 – 20 mJ.kg-1 leads to a significant increase in bowel mass by 13.3 – 5.0%. An increase in the level of metabolic energy in rainbow trout diets from 18 mJ.kg-1 to 19 – 20 mJ.kg-1 contributed to a likely increase in the methionine content in meat. A similar pattern was observed for the tryptophan content. It was found that the content of most essential amino acids in the protein of rainbow trout meat exceeds the corresponding values in the "ideal" protein, except for the content of isoleucine and leucine, which refers them to limiting amino acids.

Dynamics of change of biochemical and functional-technological properties of lake’s trout meat in storage

The leading role in muscle contraction is played by myofibrils, which, from the substances that make up the sarcoplasm, use the necessary energy to perform their functions. The source of energy, in this case, is only the biochemical processes of enzymatic decomposition (hydrolysis, phosphorolysis) of certain substances, in particular, glycogen nucleoside phosphates, located mainly in the sarcoplasm. In the muscle tissue of fish, the bulk of the energy needed to contract muscles is released as a result of ATP breakdown. By the outward manifestation and chemistry of the processes, post mortem rigour Mortis is almost identical to the motor contraction of the living muscle. The molecular mechanism of muscle contraction is based on the interaction of myosin and actin filaments. Studies have shown that the intense breakdown of muscle glycogen leads to a sharp decrease in the pH of muscle tissue in the acidic direction, which in turn affects the chemical composition and physical and colloidal structure of proteins, resulting in increased resistance of fish meat to the action of putrefactive microorganisms; decreased solubility of muscle proteins, their hydration, water-binding ability; swelling of connective tissue collagen; increased activity causing hydrolysis of proteins in the later stages of autolysis; the bicarbonate system of muscle tissue is destroyed with the release of carbon dioxide; precursors of meat taste and aroma are formed; the process of lipid oxidation is activated. As a result of the accumulation of lactic, phosphoric and other acids in fish meat, the concentration of hydrogen ions increases resulting in a decrease in pH.

Eryngium caeruleum essential oil as a promising natural additive: in vitro antioxidant properties and its effect on lipid oxidation of minced rainbow trout meat during storage at refrigeration temperature

Background: One of the most common species of oily fish is rainbow trout. Chemical deterioration of oily fish species is principally caused by lipid oxidation. The adverse effects of various chemical preservatives caused consumer’s attention to shift to natural alternatives. Eryngium caeruleum is an herbaceous plant that is native to the northern areas of Iran and is used in various local foods. The aim of the present study was to investigate the effects of different concentrations of E. caeruleum essential oil (EEO) on the physicochemical and oxidative stability of minced rainbow trout meat for 20 days storage at 4±1°C.Methods: Firstly, the chemical compounds and total phenolic content of EEO were determined by gas chromatography-mass spectrometry and Folin–Ciocalteu reagent, respectively. Then, in vitro antioxidant capacity of EEO was evaluated using 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) methods. Finally, the minced rainbow trout meat was mixed with different concentrations of EEO, and physicochemical and oxidative stability of treatments were investigated for 20 days storage at 4±1°C.Results: According to the results, 0.4% EEO significantly improved the chemical stability of minced fish compared to the control group at the end of storage period with the following scores (P&lt;0.05): pH value (6.3), peroxide value (11.88 meq/kg of lipid) and thiobarbituric acid reactive substance (0.43 mg MDA/kg sample).Conclusions: In order to increase the chemical quality characteristics of minced fish, new ingredient systems that are associated with natural and organic foods are applied. The results of present study indicate that the use of EEO in the meat industry can develop the novel healthy fish products and improve its chemical stability.Keywords: Eryngium caeruleum, Oncorhynchus mykiss, Natural antioxidant, Chemical stability, Lipid oxidation

Efficacy of stinging nettle extract in combination with ε-polylysine on the quality, safety, and shelf life of rainbow trout fillets.

The effects of incorporation of stinging nettle extract (3% and 6%) and ɛ‐polylysine (0.1% and 0.2%) on chemical, microbial properties, and stability of rainbow trout fish fillets wrapped in polyethylene bags (in atmosphere condition) and refrigerated for 12 days at 4°C were evaluated. No remarkable differences regarding the chemical composition of rainbow trout fish (protein, moisture, fat, and ash content) resulting from the treatments were noted. The lowest TBARS (thiobarbituric acid reactive substance) and the highest phenolic compounds were noted in samples treated with 6% SNE + 0.2% ɛ‐PL on day 12, while the highest inhibitory effects against the growth of TVC, psychrotrophic bacteria, coliform, yeast, and molds corresponded to samples treated with 6% SNE (T4 and T5) at day 12. During the storage, the samples' TVB‐N (total volatile base nitrogen) increased, whereas the total phenolic content of the rainbow trout samples declined. The rainbow trout samples treated with 6% SNE + 0.2% ɛ‐PL had the highest amount of redness and the lowest TVB‐N values. Therefore, these natural ingredients could be used to maintain rainbow trout meat quality and shelf life.

Morphological composition of the body and chemical composition of trout meat depending on amino acid levels in feed

Morphological composition of the body and chemical composition of trout meat depending on amino acid levels in feed

Eryngium caeruleum essential oil as a promising natural additive: in vitro antioxidant properties and its effect on lipid oxidation of minced rainbow trout meat during storage at refrigeration temperature

Background: One of the most common species of oily fish is rainbow trout. Chemical deterioration of oily fish species is principally caused by lipid oxidation. The adverse effects of various chemical preservatives caused consumer’s attention to shift to natural alternatives. Eryngium caeruleum is an herbaceous plant that is native to the northern areas of Iran and is used in various local foods. The aim of the present study was to investigate the effects of different concentrations of E. caeruleum essential oil (EEO) on the physicochemical and oxidative stability of minced rainbow trout meat for 20 days storage at 4±1°C. Methods: Firstly, the chemical compounds and total phenolic content of EEO were determined by gas chromatography-mass spectrometry and Folin–Ciocalteu reagent, respectively. Then, in vitro antioxidant capacity of EEO was evaluated using 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2' azino-bis (3- ethylbenzthiazoline-6-sulphonic acid) (ABTS) methods. Finally, the minced rainbow trout meat was mixed with different concentrations of EEO, and physicochemical and oxidative stability of treatments were investigated for 20 days storage at 4±1°C. Results: According to the results, 0.4% EEO significantly improved the chemical stability of minced fish compared to control group at the end of storage period with the following scores (P<0.05): pH value (6.3), peroxide value (11.88 meq/kg of lipid) and thiobarbituric acid reactive substance (0.43 mg MDA/kg sample). Conclusions: In order to increase the chemical quality characteristics of minced fish, new ingredient systems that are associated with natural and organic foods are applied. The results of present study indicate that the use of EEO in the meat industry can develop the novel healthy fish products and improve its chemical stability.