Salmon Fillets Research Articles

A comparative study of organic- versus conventional Atlantic salmon. II. Fillet color, carotenoid- and fatty acid composition as affected by dry salting, cold smoking and storage

The aim of the present study was to investigate the effect of dry salting, cold smoking and 14days refrigerated storage at 4°C on the stability of carotenoids, color and fatty acids in commercially reared organic Atlantic salmon (Salmo salar L.). As reference, conventionally reared Atlantic salmon was used. Pigment sources in feeds for the organic and conventional salmon were Panaferd-AX® (PAN) and Carophyll Pink® (CP), respectively. The dry salting process was found to be the main cause for losses of carotenoids throughout salting, smoking and storage, whereas no differences were found in stability of the different flesh carotenoids. The diverse composition of flesh carotenoids in organic salmon seems however to have minor influence on the color of the cold smoked product. Colorimetric characteristics of the fillet surface and liquid loss during storage of cold smoke fillets were found to be mostly affected by the fatty acid composition of the flesh which differed between the organic and conventional raw material. Moreover, dry salting and cold smoking were found to alter colorimetric differences between raw organically and conventionally reared salmon, resulting in an equal colorimetric perception of cold smoked organic and conventional salmon fillets after 14days refrigerated vacuum storage. Statement of relevance•This paper investigates the stability of carotenoids, color and fatty acids throughout processing and storage of cold smoked organic farmed Atlantic salmon.•This paper focuses on the diversity of carotenoids presented in organic salmon fed a feed containing Panaferd-AX and how these carotenoids affect the color of the smoked product.•This paper investigates the suitability of the presented organic salmon as raw material for the smoking industry.

Occurrence of Mislabelling in Prepared Fishery Products in Southern Italy.

Fish authentication is a major concern not only for the prevention of commercial fraud, but also for the assessment of safety risks deriving from the undeclared introduction of potentially dangerous toxic or allergenic substances or environmentally damaging fish where endangered species are involved. Moreover, food authentication might affect the diet of certain groups of consumers, such as followers of religious practices. Considering the authentication of fish products is one of the key issues in food safety, quality and sustainability, the aim of this work was to investigate the prevalence of mislabelling in sole (Solea solea), plaice (Pleuronectes platessa), Atlantic salmon (Salmo salar), and hake (Merluccius merluccius) fillets from markets and supermarkets located in Apulia (Southern Italy) using DNA barcoding. The results of the molecular investigations reveal that 42/98 (42.8%) fillet samples were not correctly labelled. In particular, 12/27 (44.4%) fillets of sole (Solea solea) were identified as belonging to Solea senegalensis. In addition, 13/28 (46.4%) plaice (Pleuronectes platessa) samples were identified as Pangasius hypophtalmus. All Atlantic salmon (Salmo salar) samples were correctly labelled. Post-sequencing data analysis revealed that 17/30 (56.6%) hake fillets (Merluccius merluccius) were not correctly labelled, of which 8/30 samples identified as Merluccius hubbsi, 5/30 samples as Merluccius products and 4/30 as Merluccius capensis. The study reveals a high occurrence of species mislabelling in the prepared fish fillet products, further evidence of the need for increased traceability and assessment of the authenticity of food products.

Protective Effect of Fish Gelatin‐Based Natural Antimicrobial Coatings on Quality of Indian Salmon Fillets during Refrigerated Storage

AbstractThe present study was carried out to examine the effect of gelatin‐based coating solutions enriched with natural preservative agents like chitosan, garlic (Allium sativum) and lime (Citrus aurantifolia) on quality and shelf life of refrigerated fresh Indian salmon (Eleutheronema tetradactylum) fillets. Three different coating solutions were prepared (T1: 10% gelatin; T2: 10% gelatin + 1.5% chitosan + 30% lime juice; T3: 10% gelatin + 1.5% chitosan + 30% garlic extract) and evaluated for antimicrobial activity. The antimicrobial activity of coating solutions was evaluated against eight fishborne pathogens and spoilage bacteria by agar well diffusion and micro broth dilution methods. The coating formula was found to be highly efficient in extending the shelf life of Indian salmon fillets up to 16 days in refrigerated storage by dip treatment. Among the three different treatments, garlic containing coating solution (T3) was found to be the best in extending the shelf life of fish fillets.Practical ApplicationsThe need for natural edible coatings in food industry is of great demand and it is challenging to have natural compounds exhibiting better preservative role as comparable with chemical preservatives. The present study evidenced that edible coatings made of gelatin, chitosan and garlic/lime extracts exhibit preservative action and extend the shelf life of fish fillets.

Gaping and loss of fillet firmness in farmed salmon (Salmo salarL.) closely correlated with post-slaughter cleaning of the abdominal cavity

This study analysed the effect of cleaning intensity of the abdominal cavity and storage temperature from slaughter to the end of processing on the quality of farmed salmon (Salmo salar L.) fillets. These two parameters were manipulated in an experimental setup using in total thirty salmon with an average weight of 4.2 kg. The experiment was designed to imitate realistic scenarios in a normal production process in the Faroe Islands. The salmon stored at low temperatures had an average muscle temperature of 4.65°C, whereas the salmon stored at ambient temperature had an average muscle temperature of 11.27°C. After the salmon were gutted to remove all viscera except the kidney, the abdominal cavity was either rinsed lightly or meticulously cleansed of kidneys, all blood and bodily fluids. A wide range of quality and production parameters were measured either straight after cleaning or after the salmon had been stored in chipped ice at 1.5°C for 7 days. All measured parameters were analysed for possible correlations by principal component analysis (PCA). Blood and remains left in the abdominal cavity were shown to have a significant negative effect on fillet firmness (P < 0.01) and gaping (P < 0.01). The different storage temperatures between slaughter and gutting, tested in this experiment, did not significantly affect fillet firmness or gaping. However, the fillet colour showed significant negative correlation (P < 0.01) with the storage temperatures applied.

Efficient integration of particle analysis in hyperspectral imaging for rapid assessment of oxidative degradation in salmon fillet

This study investigated the potential of using hyperspectral imaging technology (900–1700 nm) to determine the thiobarbituric acid (TBA) value and pH for evaluation of lipid oxidation in Atlantic salmon (Salmo salar) fillets during cold storage for 0, 3, 6, 9 and 12 days at 1 ± 1 °C. Good results were achieved for both parameters by using partial least square regression (PLSR) calibration models with full spectral region. Two simplified models were then built by using forward stepwise-multiple linear regression (MLR) variable selection method to select 18 and 10 most important wavelengths for TBA value and pH, respectively. The optimised stepwise-MLR model for TBA value yielded satisfactory results with correlation coefficient (rC) of 0.921 and root mean square error of calibration (RMSEC) of 1.840 μmol MDA/kg fish. This model was used to visualise the TBA value distributions during different storage days. Further improvements were achieved by applying particle analysis on the images to extract only the spectra from white stripes in salmon fillet. When in tandem with detrend pre-processing technique, the calibration model based on particle analysis demonstrated the best performance for TBA value prediction (rC = 0.957 and RMSEC = 1.449 μmol MDA/kg). In addition, a novel chemometric strategy accomplished by the use of hyperspectrograms was also proposed in this work and satisfactory results were obtained. The overall results confirmed the capability of near-infrared hyperspectral imaging as a rapid and non-invasive technique to monitor lipid oxidation in salmon fillets.

Efficacy of electrolyzed oxidizing water as a pretreatment method for reducing Listeria monocytogenes contamination in cold-smoked Atlantic salmon (Salmo salar)

Listeria monocytogenes contamination in ready-to-eat (RTE) fish products, in particular in cold-smoked salmon is an important food safety concern. This study evaluated the antimicrobial activity of electrolyzed oxidizing (EO) water as a pretreatment method during the process of cold-smoked salmon to inactivate L. monocytogenes. In addition, the effect of EO water treatment on the sensory and textural quality of the final product was also evaluated. Raw Atlantic salmon (Salmo salar) fillets were inoculated with L. monocytogenes (with an approximately cell number of 6 × 105 CFU/g L. monocytogenes ATCC 19114) and treated with EO water at three different temperatures (20, 30, and 40 °C) and at three different exposure time of 2, 6, and 10 min before the cold-smoking process. A combination of EO water and a mild temperature (40 °C) had reduced L. monocytogenes populations by 2.85 log10 CFU/g. The sensory as evaluated by a consumer panel (N = 71) and texture, which was measured by texture analysis showed no significant changes between EO and mild temperature treated samples and the control.

Changes of proteins during superchilled storage of Atlantic salmon muscle (Salmo salar).

Changes in protein stability in relation to ice crystals development in salmon fillets during superchilled storage were studied. Due to the significant differences in ice crystal sizes observed in our previous studies, the protein solubility was analysed separately, at the surfaces and centres of the superchilled samples. The water-soluble proteins were stable for the entire storage time. The salt-soluble proteins in the superchilled samples were stable for 1week of storage. The salt-soluble proteins were significantly decreased at day 7 and 14 of the centre and surface of the superchilled samples, respectively. In contrast, the salt-soluble proteins were significantly increased at day 21 both at the centre and surface of the superchilled samples. These findings are significant for the industry because it provides valuable information on the quality of food in relation to ice crystallization/recrystallization during superchilled storage.

Positional Distribution of Fatty Acids in Triacylglycerols and Phospholipids from Fillets of Atlantic Salmon (Salmo Salar) Fed Vegetable and Fish Oil Blends.

The nutritional and functional characteristics of dietary fat are related to the fatty acid (FA) composition and its positional distribution in the triacylglycerol (TAG) fraction. Atlantic salmon is an important source of healthy long chain omega 3 FA (particularly, eicosapentaenoic (EPA) and docoxahexaenoic (DHA) acids). However, the impact of lipid sources in salmon feeds on the regiospecificity of FA in the fish TAG remains to be explored. The present study determines the effect of feeding salmon with blends of palm, rapeseed, and fish oil, providing two different EPA + DHA concentrations (high: H-ED 10.3% and low: L-ED 4.6%) on the fillet lipid class composition and the positional distribution of FA in TAG and phospholipids. The regiospecific analysis of fillet TAG showed that around 50% of the EPA and around 80% of DHA was located in the sn-2 position. The positional distribution of FA in phosphatidylcholine (PC), showed that around 80% of the EPA and around 90% of DHA were located in the sn-2. Fish fed the vegetable-rich diets showed higher EPA in the sn-2 position in PC (77% vs. 83% in the H-ED and L-ED diets, respectively) but similar DHA concentrations. It is concluded that feeding salmon with different EPA + DHA concentrations does not affect their positional distribution in the fillet TAG.

Utilisation of feed resources in production of Atlantic salmon (Salmo salar) in Norway

In 1990, 90% of the ingredients in Norwegian salmon feed were of marine origin, whereas in 2013 only around 30%. The contents of fish meal and fish oil in the salmon feed were 18% and 11%, respectively, in 2013. Between 2010 and 2013, salmon production in Norway increased by 30%, but due to a lower inclusion of marine ingredients in the diet, the total amount of marine ingredients used for salmon feed production was reduced from 544,000 to 466,000tonnes. Norwegian salmon farming consumed 1.63milliontonnes of feed ingredients in 2012, containing close to 40 million GJ of energy, 580,000tonnes of protein and 530,000tonnes of lipid. 1.26milliontonnes of salmon was produced. Assuming an edible yield of 65%, 820,000tonnes of salmon fillet, containing 9.44 million GJ, and 156,000tonnes of protein were produced. The retentions of protein and energy in the edible product in 2012 were 27% and 24%, respectively. Of the 43,000tonnes of EPA and DHA in the salmon feed in 2012, around 11,000tonnes were retained in the edible part of salmon. The retentions of EPA and DHA were 46% in whole salmon and 26% in fillets, respectively. The fish in/fish out ratio (FIFO) measures the amount of fish meal and fish oil that is used to produce one weight equivalent of farmed fish back to wild fish weight equivalents, and the forage fish dependency ratio (FFDR) is the amount of wild caught fish used to produce the amount of fish meal and fish oil required to produce 1kg of salmon. From 1990 to 2013, the forage fish dependency ratio for fish meal decreased from 4.4 to 0.7 in Norwegian salmon farming. However, weight-to-weight ratios such as FIFO and FFDR do not account for the different nutrient contents in the salmon product and in the forage fish used for fish meal and fish oil production. Marine nutrient dependency ratios express the amount of marine oil and protein required to produce 1kg of salmon oil and protein. In 2013, 0.7kg of marine protein was used to produce 1kg of salmon protein, so the Norwegian farmed salmon is thus a net producer of marine protein.Statement of relevanceThis manuscript shows the retention efficiency of nutrients from feed resources to final product in the Norwegian salmon production, including limiting resources such as the omega-3 fatty acids EPA and DHA and phosphorous. It is highly relevant to compare the efficiency in commercial scale with experimental data, and this is to our knowledge the first attempt to make such calculations for an entire commercial aquaculture production.

Bacteriophage cocktail significantly reduces or eliminates Listeria monocytogenes contamination on lettuce, apples, cheese, smoked salmon and frozen foods

ListShield™, a commercially available bacteriophage cocktail that specifically targets Listeria monocytogenes, was evaluated as a bio-control agent for L. monocytogenes in various Ready-To-Eat foods. ListShield™ treatment of experimentally contaminated lettuce, cheese, smoked salmon, and frozen entrèes significantly reduced (p < 0.05) L. monocytogenes contamination by 91% (1.1 log), 82% (0.7 log), 90% (1.0 log), and 99% (2.2 log), respectively. ListShield™ application, alone or combined with an antioxidant/anti-browning solution, resulted in a statistically significant (p < 0.001) 93% (1.1 log) reduction of L. monocytogenes contamination on apple slices after 24 h at 4 °C. Treatment of smoked salmon from a commercial processing facility with ListShield™ eliminated L. monocytogenes (no detectable L. monocytogenes) in both the naturally contaminated and experimentally contaminated salmon fillets. The organoleptic quality of foods was not affected by application of ListShield™, as no differences in the color, taste, or appearance were detectable. Bio-control of L. monocytogenes with lytic bacteriophage preparations such as ListShield™ can offer an environmentally-friendly, green approach for reducing the risk of listeriosis associated with the consumption of various foods that may be contaminated with L. monocytogenes.

Dehydration kinetics of salmon and trout fillets using ultrasonic vacuum drying as a novel technique

In this study, a novel ultrasonic vacuum (USV) drying technique was used to shorten the drying time of fish fillets. For this purpose, ultrasonic treatment and vacuum-drying were simultaneously performed to dehydrate salmon and trout fillets at 55°C, 65°C, and 75°C. In addition, the USV technique was compared with vacuum-drying and oven-drying techniques. The dehydration kinetics of the fillets was successfully described by seven thin-layer drying models with R2 range between 0.944 and 1.000. Depending on drying temperatures and fish species, the drying times could be shortened using the USV technique between 7.4% and 27.4% compared with vacuum-drying. The highest effective moisture diffusivity was determined in the fillets dried with the USV technique and they increased with increasing drying temperatures. Ultrasonic treatment accelerated the vacuum drying process for the fillets; therefore, this technique could be used to improve the efficiency of vacuum-drying for the fillets.

Effect of selective breeding on collagen properties of Atlantic salmon (Salmo salar L.)

Collagen content and properties of skeletal muscle were studied among selected (FP) and unselected (WP) Atlantic salmon lines that were reared together to avoid any environmental effects. The FP group had significantly higher body weight at harvesting, softer texture and lower connective tissue yield compared with the WP group. The relative collagen fractions (acid, pepsin, insoluble) were similar, but the FP group had a greater abundance of amino acids involved in collagen triple helix conformation and stabilisation (Gly, Pro, Hyp and Hyl), whilst the Lys content was greater for the WP group, indicating a more aggregated collagen. The connective tissue denaturation temperature was lower for the FP group, coinciding with a lower degree of collagen self-assembly and intermolecular-crosslinks. It is concluded that selective breeding has resulted in lower connective tissue stability of Atlantic salmon fillets.

Multi-contaminant analysis of organophosphate and halogenated flame retardants in food matrices using ultrasonication and vacuum assisted extraction, multi-stage cleanup and gas chromatography–mass spectrometry

A multi-residue analytical method was developed for the determination of a range of flame retardants (FRs), including polybrominated diphenyl ethers (PBDEs), emerging halogenated FRs (EFRs) and organophosphate FRs (PFRs), in food matrices. An ultrasonication and vacuum assisted extraction (UVAE), followed by a multi-stage clean-up procedure, enabled the removal of up to 1g of lipid from 2.5g of freeze–dried food samples and significantly reduce matrix effects. UVAE achieves a waste factor (WF) of about 10%, while the WFs of classical QuEChERS methods range usually between 50 and 90%. The low WF of UVAE leads to a dramatic improvement in the sensitivity along with saving up to 90% of spiking (internal) standards. Moreover, a two-stage clean-up on Florisil and aminopropyl silica was introduced after UVAE, for an efficient removal of pigments and residual lipids, which led to cleaner extracts than normally achieved by dispersive solid phase extraction (d-SPE). In this way, the extracts could be concentrated to low volumes, e.g. <100μL and the equivalent matrix concentrations were up to 100g ww/mL. The final analysis of PFRs was performed on GC–EI-MS, while PBDEs and EFRs were measured by GC–ECNI-MS. Validation tests were performed with three food matrices (lean beef, whole chicken egg and salmon filet), obtaining acceptable recoveries (66–135%) with good repeatability (RSD 1–24%, mean 7%). Method LOQs ranged between 0.008 and 0.04ng/g dw for PBDEs, between 0.08 and 0.20ng/g dw for EFRs, and between 1.4 and 3.6ng/g dw for PFRs. The method was further applied to eight types of food samples (including meat, eggs, fish, and seafood) with lipid contents ranging from 0.1 to 22%. Various FRs were detected above MLOQ levels, demonstrating the wide-range applicability of our method. To the best of our knowledge, this is the first method reported for simultaneous analysis of brominated and organophosphate FRs in food matrices.

A Feasibility Study on the Use of Near Infrared Spectroscopy for the Authentication of Depurated Salmon Fillets

Some species of actinomycetes, fungi, and blue-green algae produce semivolatile off-flavor compounds responsible for earthy-musty odorants in water from aquaculture facilities and tend to bioaccumulate within fish flesh. Although these off-flavor compounds are harmless to human health, high levels within fish tissue lead to an undesirable taste leading to an unmarketable consumption quality. Preharvest processes such as depuration can be used to eliminate most of these off-flavor compounds and ultimately enhance salmon quality. This study examined the potential of near infrared spectroscopy (NIRS) to discriminate depurated from nondepurated salmon fillets (n = 62). Partial least squares discriminant analysis based on NIR spectra correctly classified 100 % of non-depurated and depurated salmon fillets. The successful classification was likely a consequence of statistically significant differences in the content of off-flavor compounds between both samples, which could have been detected by NIR spectra. Thus, NIRS is a fast, inexpensive, solvent-free, and non-destructive technology that can be used for the authentication of salmon with enhanced quality for marketing purposes.

The Culture of Pediococcus pentosaceus T1 Inhibits Listeria Proliferation in Salmon Fillets and Controls Maturation of Kimchi.

The objective of this study is to evaluate the antilisterial effect of Pediococcus pentosaceus T1, which was isolated from kimchi, and to assess its potential for extending the shelf life of salmon and kimchi. Pediococcus pentosaceus T1 culture effectively inhibited proliferation of Listeria monocytogenes in a dose-dependent manner in a salmon-based medium. Antilisterial effect of the culture was stronger than that of nisin, an antibacterial peptide, as evidenced by lower minimum inhibitory concentration value (20 mg/mL) compared to nisin (over 20 mg/mL). P. pentosaceus T1 culture also effectively inhibited the growth of Listeria in salmon fillet. In particular, the culture (6 g per 100 mL) showed a stronger inhibitory effect than sodium hypochlorite (0.2 mg/mL), a disinfectant used in food processing. In kimchi fermentation, the treatment with P. pentosaceus T1 culture suppressed changes of acidity and pH during maturation. The inhibitory effect of the culture on kimchi lactic acid bacteria, which include Leuconostoc mesenteroides and Lactobacillus sakei, led to a drastic decrease in maturation rates of kimchi. Moreover, sensory test on kimchi treated with P. pentosaceus T1 showed that the culture improved overall acceptability of kimchi, which can be observed in higher scores of sourness, texture, off-flavour and mouthfeel compared with untreated kimchi. The results of this study suggest that kimchi-derived P. pentosaceus T1 could be a potential antilisterial agent in fish products as well as a starter to control overmaturation of kimchi.

NMR approach for monitoring post-mortem changes in Atlantic salmon fillets stored at 0 and 4 °C

High resolution NMR technique has been used to monitor post-mortem changes in salmon (Salmo salar) fillets upon storage at 4 and 0°C. Thirty-one different fish metabolites influencing freshness and taste properties have been unequivocally assigned by NMR using either available standard compounds or ad hoc acquired 2D 1H–1H TOCSY and 1H–13С HSQC spectra. The monitored fish metabolites include amino acids, dipeptides, sugars, vitamins, biogenic amines, as well as different products of the ATP degradation. The detection and monitoring of biogenic amines by NMR, upon fish storage, is information of interest for consumers, since some of these compounds are toxic. The data from this study shows that NMR spectroscopy also provides the amount of all metabolites necessary for the calculation of the K-index used to express fish freshness. A good correlation was found between the K-index increase and the formation of the undesired biogenic amines. The metabolite concentrations and the K-index found in this work were compared and found coherent with literature data. The performed study reveals the strengths and the suitability of the NMR approach to monitor different biochemical processes occurring during fish storage and qualitatively and quantitatively characterise fish metabolites determining fish quality.

Efficacy of Acidified sodium chlorite in controlling Listeria monocytogenes in salmon fillet

The purpose of this study was planned out to evaluate the effectiveness of Acidified SodiumChlorite (ASC) on the viability of L. monocytogenes by contaminating Salmon fish sampleswith 1x108 cfu/g of L. monocytogenes, followed by dipping the contaminated samples indifferent concentrations of ASC 250, 500 and 1000 ppm. The samples were stored inrefrigerator at ° 4c to be examined for L. monocytogenes count at Zero day ,First, third, fifthand seventh day of refrigeration storage. The results revealed that the counts ofL.monocytogenes in salmon fish samples dipped in different ASC concentrations of 250, 500and 1000 ppm in zero (treatment day), were 1x107,3.8x106 and 1x106 cfu/g respectively, andin the first day after storage the counts were 8x106,1x106 and 1x105 cfu/g respectively while inthe third ,fifth and seventh day the counts were reduced to be <10 cfu/g.

Kinetics of protein and textural changes in Atlantic salmon under frozen storage

Fish proteins are highly susceptible to changes during frozen storage, leading to modifications in protein solubility, functionality, and structure, which affect the rheological properties, which, in turn, contribute to changes in techno-functional properties. Under frozen storage, these changes are the result of many physical and chemical modifications, especially structural and functional protein changes. The aim of this study was to evaluate and quantify protein and textural changes during frozen storage of Atlantic salmon (Salmo salar) fillets at four temperatures (268K, 264K, 260K and 255K). The Weibullian model was applied in order to understand the quality changes. Results for all frozen storage temperatures showed that total volatile basic nitrogen (TVB-N) did not reach the regulated limits (30–35mg/100g muscle), salt-soluble protein (SSP) decreased systematically and total nitrogen (TN) was constant. Hardness, adhesiveness, gumminess and chewiness levels decreased systematically at all temperatures, but cohesiveness and springiness values were relatively constant over time, at the same given temperature. A comparison between different temperatures showed an increase in the measurements observed. A kinetic analysis for TVBN, SSP, hardness, adhesiveness and chewiness, was performed. All quality indicators, except TVBN, showed reaction rates inversely proportional to the temperature, and fractional shape factors or orders of reaction. Using the Weibullian model, this study demonstrates that, in complex biological processes, quality indicators do not have an integer kinetic order and reaction rates are strongly temperature-dependent. Thus, this kind of model can be used to improve understanding, prediction, and control of the frozen storage process.

Effect of omega-3 fatty acid oxidation products on the cellular and mitochondrial toxicity of BDE 47

High levels of the flame retardant 2,2′,4,4′-tetrabromodiphenyl ether (BDE 47) have been detected in Pacific salmon sampled near urban areas, raising concern over the safety of salmon consumption. However, salmon fillets also contain the antioxidants eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), whose oxidation products induce cellular antioxidant responses. Because oxidative stress is a mechanism of BDE 47 toxicity, we hypothesized that oxidized EPA and DHA can ameliorate the cellular and mitochondrial toxicity of BDE 47. HepG2 cells were treated with a mixture of oxidized EPA and DHA (oxEPA/oxDHA) at a ratio relevant to salmon consumption (1.5/1 oxEPA/oxDHA) followed by exposure to 100μM BDE 47. Pretreatment with oxEPA/oxDHA for 12h prior to BDE 47 exposure prevented BDE 47-mediated depletion of glutathione, and increased expression of antioxidant response genes. oxEPA/oxDHA also reduced the level of reactive oxygen species production by BDE 47. The oxEPA/oxDHA antioxidant responses were associated with partial protection against BDE 47-induced loss of viability and also mitochondrial membrane potential. Mitochondrial electron transport system functional analysis revealed extensive inhibition of State 3 respiration and maximum respiratory capacity by BDE 47 were partially reversed by oxEPA/oxDHA. Our findings indicate that the antioxidant effects of oxEPA/oxDHA protect against short exposures to BDE 47, including a protective role of these compounds on maintaining cellular and mitochondrial function.

Toward enhancement in prediction of Pseudomonas counts distribution in salmon fillets using NIR hyperspectral imaging

Pseudomonas spp. counts (PC) is a good indicator for spoilage evaluation, but its detection with traditional techniques is time-consuming, destructive and inefficient. The aim of this study was to evaluate the potential of near-infrared (NIR) hyperspectral imaging to predict PC distribution in salmon fillets. Full wavelength data were related to PC values by partial least square regression (PLSR), resulting in coefficient of determination (RP2) of 0.90 and root mean square error of prediction (RMSEP) of 0.52. Most effective wavelengths (MEW) were selected by regression coefficients (RC), successive projections algorithm (SPA) and competitive adaptive reweighted sampling (CARS) algorithm, respectively, to optimise the PLSR model. CARS-PLSR model built with ten MEWs of 941, 1105, 1161, 1178, 1222, 1242, 1359, 1366, 1628 and 1652 nm performed better with RP2 of 0.91 and RMSEP of 0.49. Colour maps were finally generated and PC distribution was visualised. NIR-HIS shows a great promise for evaluating PC distribution of salmon flesh during cold storage.