Salmon (Salmo salar) Side Streams as a Bioresource to Obtain Potential Antioxidant Peptides after Applying Pressurized Liquid Extraction (PLE).

The pressurized liquid extraction (PLE) technique was used to obtain protein extracts with antioxidant capacity from salmon muscle remains, heads, viscera, skin, and tailfins. A protein recovery percentage ≈28% was obtained for all samples except for viscera, which was ≈92%. These values represented an increase of 1.5-4.8-fold compared to stirring extraction (control). Different SDS-PAGE profiles in control and PLE extracts revealed that extraction conditions affected the protein molecular weight distribution of the obtained extracts. Both TEAC (Trolox equivalent antioxidant capacity) and ORAC (oxygen radical antioxidant capacity) assays showed an outstanding antioxidant activity for viscera PLE extract. Through liquid chromatography coupled with electrospray ionization triple time-of-flight (nanoESI qQTOF) mass spectrometry, 137 and 67 peptides were identified in control and PLE extracts from salmon viscera, respectively None of these peptides was found among the antioxidant peptides inputted in the BIOPEP-UMP database. However, bioinformatics analysis showed several antioxidant small peptides encrypted in amino acid sequences of viscera extracts, especially GPP (glycine-proline-proline) and GAA (glycine-alanine-alanine) for PLE extracts. Further research on the relationship between antioxidant activity and specific peptides from salmon viscera PLE extracts is required. In addition, the salmon side streams studied presented non-toxic levels of As, Hg, Cd, and Pb, as well as the absence of mycotoxins or related metabolites. Overall, these results confirm the feasible use of farmed salmon processing side streams as alternative sources of protein and bioactive compounds for human consumption.

Changes in the digestion properties and protein conformation of sturgeon myofibrillar protein treated by low temperature vacuum heating during in vitro digestion.

The digestion properties of sturgeon myofibrillar protein (MF) treated by low temperature vacuum heating (LTVH) at different processing temperatures (50, 60 and 70 °C) and times (15 and 30 min) were studied and compared with those of sturgeon MF treated by traditional cooking (TC). The results showed that as the temperature and time increased, the protein digestibility decreased, whereas the particle size and protein aggregation increased. It was observed that the band intensity of myosin heavy chain and myosin heavy chain 7 weakened; however, the band intensity of actin showed little change. MALDI-TOF-MS analysis revealed that the digested products of the samples treated by LTVH had a larger proportion of 750-1000 Da peptides than those treated by TC, which was consistent with the trend of the number of unique peptides identified in each group. Fourier transmission infrared (FT-IR) spectroscopy showed that the contents of α-helices and ß-sheets exhibited negative and positive correlations with the temperature, respectively. Overall, compared to TC, LTVH can relieve the heat stress of protein conformation, reduce protein aggregation to improve the accessibility of the protein to digestive protease, and increase digestibility.

Nutritional evaluation of elongate mudskipper Pseudapocryptes elongatus (Cuvier, 1816) from Diamond Harbor, West Bengal, India.

The mudskipper Pseudapocryptes elongatus (Cuvier, 1816), (Gobiidae) are caught throughout the year and they are considered as most edible mudskipper species in Sundarbans. They are targeted by special gears and sold live in large quantities in the local markets of Diamond Harbor, Namkhana and Kakdweep. The adult P. elongatus (14-18 cm total length) specimens were purchased from the Diamond Harbor landing center for evaluation of its biochemical components such as Protein, carbohydrate, lipid, amino acid, fatty acid, vitamin, and minerals. The percentage composition of protein was high (27.34%) followed by the carbohydrate (4.57%) and lipid (2.72%). The amino acids both essential (47.72%) and non-essential (42.91%) was found adequate. Among fatty acids, polyunsaturated fatty acid (PUFA) was found the maximum (31.55%) followed by saturated fatty acid (SFA; 27.66%) and monounsaturated fatty acid (MUFA; 19.55%). Vitamin A (112.5 IU/100 g) and Ca2+ (62.2 mg/100 g) were found maximum levels. The present finding supports that P. elongatus is valuable for human consumption due to its high-quality protein with well-balanced amino acids.

Utilization of Fish Waste as Fish Feed Material as an Alternative Effort to Reduce and Use Waste.

BACKGROUND AND OBJECTIVE: Waste of fish catching and waste of fish fillet processing will cause environmental pollution, but these materials can still be used as raw material for fish feed. The objective of this research was to change fish wastes to be made as fish powder as raw material of fish feed. MATERIALS AND METHODS: This research employed a completely randomized design with three treatments; Treatment A is artificial feed that uses raw material from trash fish, Treatment B is artificial feed that uses raw material from fish fillet waste and as control is factory-made feed. The silver pompano fish stocking was done with stocking density of 20 fishes m-3. The fishes were cultured for 60 days and they were adapted with formulated feed during 7 days before testing. RESULTS: Fish powder material in Treatment A coming from trash fish waste had good enough protein content by 43.84%, while fish powder material in Treatment B coming from fish fillet waste had lower protein content by 36.3%. The results showed that the control produced better growth activity indicators compared to Treatment A and B. The results of economic analysis showed that Treatment A and B were cheaper to produce compared to control. CONCLUSION: Fisheries waste both fish catch and fish fillet waste can be used as raw material for making silver pompano fish feed. Utilization of the two wastes has two functions namely saving on aquaculture costs and reducing fisheries waste.

Nutritional Characterization of Sea Bass Processing By-Products.

The consumption of functional foods and nutraceuticals is gaining more importance in modern society. The exploration of alternative sources and the utilization of by-products coming from the food industry are gaining more importance. The present study aimed to characterize the nutritional value and potential use of sea bass by-products as a source of high-added-value compounds for the development of supplements. The chemical composition (moisture, protein, fat, and ash contents) and profiles of amino acids (high-performance liquid chromatography coupled to a scanning fluorescence detector), fatty acids (gas chromatography coupled to a flame ionization detector), and minerals (inductively coupled plasma optical emission spectroscopy) were determined for sea bass fillet and its by-products (skin, guts, gills, liver, head, and fish bones). The chemical composition assays revealed that by-products were rich sources of proteins (skin; 25.27 g/100 g), fat (guts and liver; 53.12 and 37.25 g/100 g, respectively), and minerals (gills, head, and fish bones; 5.81, 10.11, and 7.51 g/100 g, respectively). Regarding the amino-acid profile, the skin and liver were the main sources of essential amino acids with an essential amino-acid index of 208.22 and 208.07, respectively. In the case of the fatty-acid profile, all by-products displayed high amounts of unsaturated fatty acids, particularly monounsaturated (from 43.46 to 49.33 g/100 g fatty acids) and omega-3 fatty acids (in the range 10.85-14.10 g/100 g fatty acids). Finally, the evaluation of mineral profile indicated high contents of calcium and phosphorus in gills (1382.62 and 742.60 mg/100 g, respectively), head (2507.15 and 1277.01 mg/100 g, respectively), and fish bone (2093.26 and 1166.36 mg/100 g, respectively). Therefore, the main sources of monounsaturated, unsaturated, and long-chain omega-3 fatty acids were guts and liver. The most relevant source of minerals, particularly calcium, phosphorus, and manganese, were head, fish bones, and gills. The most promising source of proteins and amino acids was the skin of sea bass.

Nutrient and Mineral Profile of Chosen Fresh and Smoked Fish.

In the present study, were determined the basic nutrients (dry matter, crude ash, crude protein, ether extract, and energy) and mineral elements content in chosen species of raw and smoked freshwater and sea fish. The content of dry matter, and basic nutrients and Na+, K+, Ca+2, Mg+2, P+2, Zn+2, and Cu+2 in the fish samples was determined. The dietary intake of several macro- and microconstituents per one serving (150 g fresh or smoked fish) was calculated. The fresh fish contained on average 220.2 to 283.7 g·kg-1 of dry matter, 12.4 to 10.7 g·kg-1 of crude ash, 176.2 to 173.5 g·kg-1 of crude protein, 32.6 to 78.6 g·kg-1 of ether extract, and 104.6 to 119.1 kcal (freshwater and sea fish, respectively). Thermal treatment reduces the water and fat content in fish meat. Reduction of the K, Ca, Mg, P, Zn, and Cu levels was observed most frequently. The one serving of fish covers approximately 23% and 12% of the recommended dietary amount of K, 7.5-5.0% of Ca, ~12% of Mg, 6.8 to 12.5% of Zn, and about covered 6.7% of Cu. The smoking process increased the concentration of some basic nutrients and reduced the fat and mineral content. Whitefish, trout, halibut, mackerel, and herring had the highest levels of the analyzed minerals.

Validation and inter-laboratory study of selective hydride generation for fast screening of inorganic arsenic in seafood.

It is advisable to monitor and regulate inorganic arsenic (iAs) in food and feedstuff. This work describes an update and validation of a method of selective hydride generation (HG) with inductively coupled plasma mass spectrometry (ICP-MS) for high-throughput screening of iAs content in seafood samples after microwave-assisted extraction with diluted nitric acid and hydrogen peroxide. High concentration of HCl (8 M) for HG along with hydrogen peroxide in samples of a same concentration as used for extraction leads to a selective conversion of iAs to volatile arsine that is released and transported to the detector. A minor contribution from methylarsonate (≈20% to iAs) was found, while HG from dimethylarsinate, trimethylarsine oxide is substantially suppressed (less than 1% to iAs). Methodology was applied to Certified Reference Materials (CRMs) TORT-3, DORM-3, DORM-4, DOLT-4, DOLT-5, PRON-1, SQID-1 and ERM-CE278k, in some of them iAs has been determined for the first time, and to various seaweed samples from a local store. The results were always compared with a reference method and selectivity of iAs determination was evaluated. An inter-laboratory reproducibility was tested by comparative analyses of six fish and four seaweed samples in three European laboratories, with good agreement of the results. The method of HG-ICP-MS is sensitive (limit of detection 2 µg kg-1 iAs), well suited for screening of large number of samples and selective at iAs concentration levels at which maximum limits are expected to be set into EU legislation for marine samples.

Fish consumption frequency and lipid peroxidation in the riverside population of Lower Tocantins, Pará / Frecuencia de consumo de pescado y peroxidación lipídica en la población ribereña del Bajo Tocantins, Pará

Introduction: Several studies report the benefits of fish consumption to the prevention of cardiovascular diseases such as atherosclerosis, thrombosis and arrhythmia. On the other hand, regular consumption of fish can induce the accumulation of methylmercury in the body. Objective: To evaluate the relationship between frequency of fish consumption, mercury concentrations and intensity of lipid peroxidation. Methods: A cross - sectional, observational study. It was evaluated riverside in Limoeiro do Ajuru, Pará. Variables were sociodemographic variables, frequency of weekly fish consumption, concentration of total mercury in hair and the dose of malondialdehyde in plasma. The concentrations of total mercury (μg/g) and malondialdehyde (nmol / ml) were respectively 0.63 μg/g and 0.54 nmol/ml for weekly fish consumption less than two meals, 0.51 μg/g 0.42 nmol/ml for consumption in two to four meals and 0.88 μg/g and 0.31 nmol/ml for consumption major than four fish meals. There was a significant difference between groups of two to four and major than four meals, only for the total mercury variable (p = 0.008). Discussion: In this study, low levels exposure and high fish consumption can influencing the bioaccumulation of mercury in this population. Santos et al, found the total mercury concentration (0.09 to 3.79 μg/g) in the rivers and compared the levels according to the intake categories of fish, did not obtain significant statistical difference. This divergent result suggests that deforestation in the Amazon has been increased and is an important vehicle for mercury exposure which affects local survival and subsistence. Conclusion: Riparians in the studied region have high fish consumption and low concentrations of mercury. Although the group with low fish consumption had higher levels of MDA there was no significant difference when compared with other groups

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Effect of high-pressure processing pretreatment on the physical properties and colour assessment of frozen European hake (Merluccius merluccius) during long term storage.

Fish freshness is lost by autolytic degradation produced by endogenous enzymes. Frozen storage is one of the most used methods to preserve fish properties. However, protein denaturation has shown to be a major problem for frozen European hake (Merluccius merluccius), leading to texture losses and off-odour development. The aim of this work was to study the changes produced by high-pressure processing (HPP) before freezing on quality of frozen European hake stored at -21 °C for 12 months. The effect of HPP (150-450 MPa) on mechanical properties and expresible water was evaluated in raw and cooked fish samples. The effect on colour (L*, a* and b*) was assessed only in raw fish. Results showed that HPP before freezing is beneficial to maintain expresible water in good levels up to 6 months. The luminosity significantly increased with pressure level. Textural profile of raw samples showed that HPP increased hardness, adhesiveness and springiness of frozen hake. Cooked samples were also affected by HPP, being the best results obtained at 300 MPa for 6 months of frozen storage. Overall, results showed that HPP improves the quality of frozen hake.

Physico-chemical, colorimetric, rheological parameters and chemometric discrimination of the origin of Mugil cephalus' roes during the manufacturing process of Bottarga.

The aim of this work was to measure the physico-chemical and the colorimetric parameters of ovaries from Mugil cephalus caught in the Tortolì lagoon (South-East coast of Sardinia) along the steps of the manufacturing process of Bottarga, together with the rheological parameters of the final product. A lowering of all CIELab coordinates (lightness, redness and yellowness) was observed during the manufacture process. All CIELab parameters were used to build a Linear Discriminant Analysis (LDA) predictive model able to determine in real time if the roes had been subdued to a freezing process, with a success in prediction of 100%. This model could be used to identify the origin of the roes, since only the imported ones are frozen. The major changes of all the studied parameters (p < 0.05) were noted in the drying step rather than in the salting step. After processing, Bottarga was characterized by a pH value of 5.46 (CV = 2.8) and a moisture content of 25% (CV = 8), whereas the typical per cent amounts of proteins, fat and NaCl, calculated as a percentage on the dried weight, were 56 (CV = 2), 34 (CV = 3) and 3.6 (CV = 17), respectively. The physical chemical changes of the roes during the manufacturing process were consistent for moisture, which decreased by 28%, whereas the protein and the fat contents on the dried weight got respectively lower of 3% and 2%. NaCl content increased by 3.1%. Principal Component Analyses (PCA) were also performed on all data to establish trends and relationships among all parameters. Hardness and consistency of Bottarga were negatively correlated with the moisture content (r = -0.87 and r = -0.88, respectively), while its adhesiveness was negatively correlated with the fat content (r = -0.68).

Combined effect of pH and heating conditions on the physical properties of Alaska pollock surimi gels.

Physical properties of Alaska pollock surimi paste were investigated as affected by pH (4.0 and 6.0-10.0) and heating conditions (slow and fast). The highest values of gel strength and deformability, as shown by breaking force and penetration distance, were obtained at pH 7.5-8.0, while the lowest values were at pH 10.0 followed by pH 6.0 and pH 6.5, respectively. Two-step slow heating process increased the breaking strength value nearly two times higher than one-step fast heating. The effect of pH was strikingly high at pH 7.5 when gels were prepared using 2-step heating, indicating the pH dependence of endogenous transglutaminase. However, the highest gel strength was obtained at pH 8.0 when gels were prepared in fast heating. Whiteness value (L - 3b*) increased significantly (p < .05) as pH increased from 6.0 to 6.5, but thereafter decreased significantly (p < .05) as pH increased. L* value (lightness) and b* value (yellowness) continuously decreased as the pH is shifted from 6.0 to 10. Fast heated gels showed the lowest yellowness, resulting in whiter appearance, probably due to the effect of reduced browning reaction. PRACTICAL APPLICATIONS: The uniqueness of this study was to measure the combined effect of pH and heating conditions on the gel texture and color. There were various studies dealing with pH or heating conditions independently. As the primary character for surimi seafood is gel texture and color. The highest values of gel strength and deformability, as shown by breaking force and penetration distance, were obtained at pH 7.5-8.0, while the lowest values were at pH 10.0 followed by pH 6.0 and pH 6.5, respectively. Two-step slow heating process increased the breaking strength value nearly two times higher than one-step fast heating. Whiteness value (L - 3b*) increased significantly as pH increased from 6.0 to 6.5, but thereafter decreased significantly as pH increased. L* value (lightness) and b* value (yellowness) continuously decreased as the pH is shifted from 6.0 to 10. Fast heated gels showed the lowest yellowness, resulting in whiter appearance.

Effect of curry leaf and clove bud essential oils on textural and oxidative stability of chill stored sutchi catfish fillets.

Effect of coating with curry leaf and clove essential oils (EO) on oxidative and textural stability of sutchi catfish fillets were evaluated during chilled storage. The changes in parameters associated with textural and lipid degradation was also evaluated to ascertain the interactive effect of polyphenols with muscle proteins. Further, the results were compared against vacuum and conventional polyethylene packaging practices. Prior to coating, the properties of antioxidants were evaluated in vitro based on total phenolic and flavonoid contents, 2, 2-diphenyl-1- picrylhydrazyl radical scavenging activity, inhibition of linoleic acid peroxidation, iron reducing power, and metal chelating ability. Coating with clove bud EO was found to be more effective in protecting the textural quality and retarding lipid oxidation of the fillets during chilled storage. Curry leaf EO was found to have only moderate effect. PRACTICAL APPLICATIONS: In addition to the well-studied antibacterial and antioxidant properties, plant polyphenols have become an intense focus of research for their ability to cross-link proteins that widens their applications for textural and functional modification of food and beverages. Currently, a number of carcinogenic chemicals such as ammonia and formalin are hazardously used to prevent texture deterioration in chilled fish associated with post-rigor changes and microbial reactions. This study evaluates the efficacy of polyphenols present in culinary herbs such as clove bud and curry leaf EO, in stabilising the texture of fish meat during chilled storage. From the results, it could be inferred that both the EO at 0.25% level mediated protein cross-linking/complexation and maintained textural integrity during chilled storage apart from exhibiting antioxidant activities.