Peer-reviewed articles

Complete genome sequence of the hyperthermophilic piezophilic, heterotrophic and carboxydotrophic archaeon Thermococcus barophilus MP

Thermococcus barophilus is a hyperthermophilic, anaerobic, mixed heterotrophic, and carboxydotrophic euryarchaeon isolated from the deep sea hydrothermal vent Snakepit site on the mid-Atlantic ridge at a depth of 3,550 m. T. barophilus is the first true piezophilic, hyperthermophilic archaeon isolated, having an optimal growth at 40 MPa. Here we report the complete genome sequence of strain MP, the type strain of T. barophilus. The genome data reveal a close proximity with Thermococcus sibiricus, another Thermococcus isolated from the deep biosphere and a possible connection to life in the depths.

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Peer-reviewed articles

Low field Nuclear Magnetic Resonance on the effect of salt and modified atmosphere packaging on cod (Gadus morhua) during superchilled storage

Low field Nuclear Magnetic Resonance was used to evaluate the effect of salt and modified atmosphere packaging (MAP) on cod loins during superchilled storage. Transversal and longitudinal proton relaxation times of the cod loins were measured with Carr – Purcell – Meiboom – Gill (CPMG) and Inversion Recovery (IR) pulse sequences respectively. The relaxation parameters reflected the observed differences in muscle caused by variation in salt concentration, the choice of salting method (brining or brine injection) and packaging (air or MAP), as well as superchilled storage temperature and storage time. Significant correlations were found between the NMR parameters and parameters describing the water dynamics of the muscle (moisture and salt content, water holding capacity, drip and cooking yield), as well as muscle pH and counts of H2S-producing bacteria in chosen sample groups. The study showed the possibility of using low field NMR to indicate fish quality deterioration, when the spoilage mechanisms affect the water properties and muscle structure.

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Peer-reviewed articles

Continuous quality and shelf life monitoring of retail-packed fresh cod loins in comparison with conventional methods

This study investigated the applicability of a new photochromic time-temperature indicator (TTI) to monitor the quality and shelf life of fresh cod loins in retail packs at different storage conditions; also compared this automatic monitoring method with other methods of quality control, such as sensory, chemical and microbiological analyzes; and with a shelf life prediction model. TTI placed on the bottom of the packs effectively reflected the temperature condition of the product. TTI with the initial square value of 61 was suitable for continuous monitoring of the quality and shelf life of the product repacked on day 6 after processing. The estimated product shelf lives based on TTI and on the square-root model for relative rate of spoilage of fresh seafood were well correlated.

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Peer-reviewed articles

Chemical properties and sensory quality of ice cream fortified with fish protein

BACKGROUND: Fish protein powder is a functional ingredient that can be used for enhancing the nutritional value of food products. In this study the effect of fortification with different levels of fish protein powder (FP) on chemical properties and sensory quality of Persian ice cream with 0, 30 and 50 g kg−1 FP during storage at - 18 ° C for 4 months was investigated.

RESULTS: Ice creams fortified with 50 and 30 g kg−1 FP had significantly higher protein and solid-non-fat content than ice cream with 0% FP or 83, 69 and 51 g kg−1 protein and 215, 204 and 181 g kg−1 solid non-fat, respectively. All products had the same levels of fat, lactose, acidity and pH. They had similar sensory quality after production except for color, but sensory properties of fortified samples changed significantly after 2 months of storage. Color faded, cohesiveness decreased, sandiness / coarseness increased, sweetness decreased and fish flavor and off-odor increased. The control ice cream scored highest for additives odor and flavor.

CONCLUSION: Development of ice cream fortified with fish protein powder could be an effective way to enhance nutritional and functional value of ice cream. But studies on storage stability, consumers' acceptance and attitudes are recommended if companies are planning to do so.

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Peer-reviewed articles

Flavor and quality characteristics of salted and desalted cod (Gadus morhua) produced by different salting methods

Flavor characterization and quality of salt-cured and desalted cod (Gadus morhua) products was studied using sensory analysis and gas chromatography techniques. The products were produced in Iceland using two different processing methods (filleting and splitting) and three different salting procedures, ie, the old single-step kench salting or a multistep procedure, and presalting (injection and brine salting or only brine salting), which was followed by kench salting. The main difference observed was between fillets and split fish, where the split fish was darker and had stronger flavor characteristics. Comparison of different salting procedures showed that the use of presalting improved the appearance of the salted products, which can be described as increased lightness and reduced yellowness of the products. In the same products, the intensity of curing flavors was milder, as described by sensory analysis and key aroma compounds. Derivatives from lipid and protein degradation contribute to the characteristic flavor of the salted products.

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Peer-reviewed articles

Isolation and characterization of an antigen from the fish pathogen Moritella viscosa

Aims: Moritella viscosa is a Gram-negative psychrophilic bacterium that causes winter ulcer disease in farmed fish. The aim of the study was to describe an outer membrane protein of roughly 20 kDa in pathogenic M. viscosa and to compare the coincident protein of strains isolated from different fish species and geographical locations.

Methods and Results: The protein was isolated from a pathogenic strain of M. viscosa. An oligopeptide sequence obtained with MS / MS analysis showed homology to Escherichia coli OmpA and Neisseria surface protein A. The protein was named Moritella viscosa outer membrane protein 1 (MvOmp1), and sequence analysis confirmed that it is an integral membrane protein consisting of eight antiparallel β-strands, three short periplasmic turns and four long hydrophilic extracellular loops. The encoding gene, mvomp1, was fully sequenced in nine strains representing different serotypes and phenotypes. The results revealed some differences in the extracellular loops between strains. The mvomp1 gene was cloned and expressed in E. coli, and the recombinant product was recognized by anti-M. viscosa polyclonal antisera.

Conclusions: The results indicate that MvOmp1 is a major protective antigen of M. viscosa.

Significance and Impact of the Study: The results open up possibilities for use of the protein as a part of a subunit vaccine in the future.

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Peer-reviewed articles

Identification and Quantification of Arsenolipids Using Reversed-Phase HPLC Coupled Simultaneously to High-Resolution ICPMS and High-Resolution Electrospray MS without Species-Specific Standards

Although it has been known for decades that arsenic forms fat-soluble arsenic compounds, only recent attempts to identify the compounds have been successful by using a combination of fractionation and elemental and molecular mass spectrometry. Here we show that arsenolipids can be directly identified and quantified in biological extracts using reversed-phase high-performance liquid chromatography (RP-HPLC) simultaneously online-coupled to high-resolution inductively coupled plasma mass spectrometry (ICPMS) and high-resolution electrospray mass spectrometry (ES-MS) without having a lipophilic arsenic standard available. Using a methanol gradient for the separation made it necessary to use a gradient-dependent arsenic response factor for the quantification of the fat-soluble arsenic species in the extract. The response factor was obtained by using the ICPMS signal of known concentration of arsenic. The arsenic response was used to determine species-specific response factors for the different arsenic species. The retention time for the arsenic species was utilized to mine the ES-MS data for accurate mass and their tandem mass spectrometry (MS / MS) fragmentation pattern to give information of molecular formula and structure information. The majority of arsenolipids, found in the hexane phase of fish meal from capelin (Mallotus villosus) was in the form of three dimethylarsinoyl hydrocarbons (C23H38AsO, C17H38AsO, C19H42AsO) with minor amounts of dimethylarsinoyl fatty acids (C17H36AsO3, C23H38AsO3, C24H38AsO3). One of the dimethylarsinoyl fatty acids (C24H38AsO3), with an even number of carbon in the fatty acid chain, was identified for the first time in this work. This molecular formula is unusual and in contrast to all previously identified arsenic-containing fatty acids with odd numbers of carbon.

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News

The EcoFishMan project is once again attracting attention

The EcoFishMan European Union project, led by Matís, will be on "Seas the Future” conference in the Faroe Islands on June 7 and 8.

The purpose of "Seas the Future" is to promote continued work, through Nordic cooperation, and thus promote joint actions and regional coordination for sustainable development, both between the Nordic countries and their neighbors in the adjacent areas of the North Atlantic, the Arctic and in the European Union.

As has been stated in Matís news and websites, the European Union expects the EcoFishMan project to develop a new methodology that will be useful for changes and improvements to its fisheries management system. Emphasis is placed on co-operation with fishermen, fishing and processing and on the utilization of information from electronic catch diaries. The aim of the project is to promote environmentally friendly, sustainable and economic management with a special emphasis on traceability and to minimize discards.

That EcoFishMan The project involves a total of 13 institutions, companies and universities in eight European countries, including the University of Iceland and the University of Tromsø in Norway. The project is expected to cost 3.7 million euros over three years and the EU's grant is 3.0 million euros.

Peer-reviewed articles

Following the kinetics: Iron-oxidizing microbial mats in cold Icelandic volcanic habitats and their rock-associated biomarkers

Icelandic streams with mean annual temperatures of less than 5 ° C, which receive the cationic products of basaltic rock weathering, were found to host mats of iron-cycling microorganisms. We investigated two representative sites. Iron-oxidizing Gallionella and iron-reducing Geobacter species were present. The mats host a high bacterial diversity as determined by culture-independent methods. β-Proteobacteria, Actinobacteria, α-Proteobacteria, and Bacteroidetes were abundant microbial taxa. The mat contained a high number of phototroph sequences. The carbon compounds in the mat displayed broad G and D bands with Raman spectroscopy. This signature becomes incorporated into the weathered oxidized surface layer of the basaltic rocks and was observed on rocks that no longer host mats. The presence of iron-oxidizing taxa in the stream microbial mats, and the lack of them in previously studied volcanic rocks in Iceland that have intermittently been exposed to surface water flows, can be explained by the kinetic limitations to the extraction of reduced iron from rocks . This type of ecosystem illustrates key factors that control the distribution of chemolithotrophs in cold volcanic environments. The data show that one promising sample type for which the hypothesis of the existence of past life on Mars can be tested is the surface of volcanic rocks that, previously, were situated within channels carved by flowing water. Our results also show that the carbonaceous signatures of life, if life had occurred, could be found in or on these rocks.

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Peer-reviewed articles

Quality characteristics and consumer acceptance of a high fish protein puffed corn-fish snack

Corn snack fortified with 7% fish protein powder made from saithe (Pollachius Virens) surimi was selected by expert panel from industry for consumer studies in Iran and Iceland. They hedonically screened products with 3%, 5%, 7% and 9% fish protein powder. Snack containing 9% fish protein powder (FP) had significantly lower liking for odor, texture, flavor, and overall acceptability than the other three prototypes. Snacks fortified with 3%, 5%, and 7% FP had similar sensory attributes. Therefore, snack with the highest level of FP (7%) was selected for acceptance tests. It was seasoned with cheese powder, vegetable oil, salt, and colorant. The amount of protein, moisture, fat, ash and salt in fortified corn snack (FCS) was 12%, 2%, 31%, 3%, and 2% respectively. Consumers' acceptance was studied using a central location test method. Consumers were 6–16 years old children in two communities (Iceland and Iran). They liked FCS but Iranian children favored it more than Icelandic children. Majority of parents of the participants expressed their willingness to choose this product when buying snacks.

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