Peer-reviewed articles

Determination of inorganic arsenic in seafood: Emphasizing the need for certified reference materials

o evaluate the accuracy and robustness of an extraction method, utilizing an alkaline-ethanolic solution and microwave heating, the certified reference material (CRM) TORT-2 was subjected to three different instrumental methodologies: high-performance liq-uid chromatography (HPLC), coupled with and without post-column hydride generation; inductively coupled plasma-mass spectrometry (ICP-MS); and HPLC-hydride generation-atomic fluorescence spectrometry (HPLC-HG-AFS). The three methods gave a consistentvalue of inorganic arsenic (As) which is near the mean value of the reported values in the lit-erature, which, however, range by a factor of 10. Inorganic As, defined here as all As speciesthat do not have an As – C bond, that is, the sum of arsenite and arsenate and any thiol-boundAs, was found to be less than 4 % of total As concentration in 12 samples of fish meal whensubjected to this extraction method followed by HPLC-ICP -MS. To date, there is no certifiedvalue of inorganic As in a seafood-based reference material to compare to in order to vali-date the findings. This illustrates the difficulties in quantitative determination of inorganic Asin seafood and the need for a reference material for inorganic As and proficiency tests inorder to introduce legislation for a maximum level of inorganic As in seafood and feed.

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Peer-reviewed articles

A model of fish consumption among young consumers

Purpose

The purpose of this study is to examine attitudes towards fish consumption, social pressure, fish preparation and cooking skills, sensory beliefs, health involvement and fish consumption in childhood as predictors of fish consumption among consumers in their early adulthood. While the impact of these factors on fish consumption has been examined to some extent among adult consumers, this is believed to be the first study where the focus is on people in their late teens and their early 20s.

Design / methodology / approach

A cross sectional sample of Icelanders between 17 and 26 years old (n= 1,735) responded to a questionnaire. Structural equation modeling was used to estimate the direction and strength of relationships between variables.

Findings

The paper finds that attitude towards fish consumption, social pressure and fish preparation and cooking skills were correlated to fish consumption. Sensory beliefs and health involvement were also correlated to fish consumption, but this relationship was mediated by attitudes. Finally, there was a relationship between fish consumption in childhood and fish consumption but that relationship was mediated by sensory beliefs and attitude.

Research limitations / implications

The number of external variables included in the model is limited and correlational methods were used to estimate the relationship between factors.

Originality / value

The decrease in fish consumption among young consumers is of concern. Understanding the role different variables play in their fish consumption habits can provide health authorities and managers in the fish industry with useful insights for strategies for increasing the intake of fish among young consumers.

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Peer-reviewed articles

Characteristics of freeze-dried fish protein isolated from saithe (Pollachius virens)

Fish proteins isolated from by-products or low commercial / underutilized species using pH-shift process is a new source of proteins that may be used as wet or dried ingredients to develop value-added convenience foods. This paper reports the effects of freeze-drying on characteristics of fish protein isolates (FPI) from saithe (Pollachius virens) with or without lyoprotectants. Freeze-dried saithe mince from the same lot and without additives was used as a control. The resulting fish protein powders contained 71-93% protein, 1.5-3% moisture, 0-21% carbohydrate and 0.5-2% fat. Lipid oxidation (assessed by TBARS) of FPI powder groups was higher than that of fish mince powder. The results revealed that oxidation started during the pH-shift process and was increased by freeze-drying. Functional properties and sensory attributes were influenced by the advanced oxidation. However, the mince powder was less oxidized and had higher functional properties such as water binding capacity, gel forming ability, emulsification, foaming properties and color and lower sensory scores for rancid odor and flavor than the FPI powders. Further studies on how to prevent oxidation of fish flesh during pH-shift and drying processes are recommended.

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Peer-reviewed articles

Numerical modeling of temperature fluctuations in superchilled fish loins packaged in expanded polystyrene and stored at dynamic temperature conditions

An appropriate thermal insulation of fresh fish packaging can substantially reduce negative effects of poor temperature management in chill chains. The aim of the current study is to experimentally and numerically investigate the performance of two types of EPS (expanded polystyrene) boxes in protecting superchilled fresh fish products subject to temperature fluctuations, simulating conditions during transport. One EPS box type is a new improved version designed by utilizing numerical heat transfer modeling for minimizing the maximum product temperature during thermal load. This box weighed 11% less than the older box type. The performance of the boxes was evaluated by means of temperature monitoring and sensory evaluation. The thermal insulation of the new boxes was significantly better compared to the old boxes. According to sensory evaluation, storage in the new boxes resulted in approximately 2 days longer storage life. A satisfactory agreement between numerical results and experimental results was obtained.

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News

A big step in improving the nation's health?

Krónan and Matís are collaborating to help Icelanders reduce their excessive consumption of sweets at so-called candy bars.

The companies have jointly had a poster made that has been erected in several Króna stores. The poster contains information on the moderate amount of Saturday sweets and the amount is based on average values for the daily energy needs of several age groups. The average values from the chemical analyzes can be found in the Icelandic database on the chemical content of food (ÍSGEM).

As most people know, Icelanders eat too much added sugar. This is not least due to the high consumption of sweets from so-called candy bars in stores, which are mostly picked up on Saturdays. Although it is not necessary to consume sweets, it is possible to make a sweet day "fit" into a healthy lifestyle as long as a certain moderation is observed when it comes to the amount consumed. Most people eat too much candy on Saturdays and the instructions found on the poster are presented to help consumers choose a moderate amount.

A healthy lifestyle with a varied diet and moderate exercise is the basis of mental and physical well-being. Matís has a role to play in the nation's public health and also manages ÍSGEM.

The króna has advocated for Icelanders to choose a healthy lifestyle and, for example, they cultivate fruit bars in the króna store. In addition, the ISK often offers healthy and good food to encourage consumers to choose healthier products.

The collaboration is an experiment that is being launched in several Króna stores. It is the reactions of Króna's customers and other consumers that will determine whether instructions will be installed in more stores. It will be possible to compare the total weight of sweets that have been sold before the posters were installed and then the total weight after the posters were installed. In this way, it will be possible to see if the poster matters when it comes to the quantity sold in each store every Saturday.

The poster can be seen here.

For further information Steinar B. Aðalbjörnsson, marketing director of Matís and Berglind Ósk Ólafsdóttir, marketing director of Kaupás.

Peer-reviewed articles

HPLC-HG-ICP-MS: a sensitive and selective method for inorganic arsenic in seafood

The addition of an online post-column hydride generation (HG) step to the commonly used high-performance liquid chromatography inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) setup for arsenic speciation proved to significantly improve the detection limits for the determination of inorganic arsenic (iAs) as arsenate in seafood samples, where the limit of detection and limit of quantification were found to be 0.0004 and 0.0014 mg kg−1, respectively with HG. HG as an additional step further added to the selectivity of the determination of the iAs species and increased the detection and quantification of low levels of iAs (<0.002 mg kg−1) in samples with complicated matrices.

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Peer-reviewed articles

Evaluation of Seafood Product Concepts by Young Adults and Families with Young Children from Denmark, Norway, and Iceland

This article describes the results of a study that tested the responses to 14 seafood concepts among young adults and families with young children in Denmark, Norway, and Iceland. This study was aimed at gaining insight into the evaluation of new seafood product concepts by individuals with low seafood consumption. Based on consumer-reported values and previous concept-testing, 14 seafood product concepts were tested by 296 consumers in a web-based experiment. Consumers' preferences depended on the size of fish, the presence of information, and the fish species offered. Young adult consumers evaluated the product concepts differently than parents of young children. Three consumer clusters, based on attitudinal variables, were identified explaining the differences in the evaluation of the product concepts. The outcome of this study will be used to develop a product for realistic in-home testing.

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Peer-reviewed articles

Marchantin A, a macrocyclic bisbibenzyl ether, isolated from the liverwort Marchantia polymorpha, inhibits protozoal growth in vitro

In vitro anti-plasmodial activity-guided fractionation of a diethyl ether extract of the liverwort species Marchantia polymorpha, collected in Iceland, led to isolation of the bisbibenzyl ether, marchantin A. The structure of marchantin A (1) was confirmed by NMR and HREIMS. Marchantin A inhibited proliferation of the Plasmodium falciparum strains, NF54 (IC50 = 3.41 μM) and K1 (IC50 = 2.02 μM) and showed activity against others protozoan species Trypanosoma brucei rhodesianT. cruzi and Leishmania donovani with IC50 values 2.09, 14.90 and 1.59 μM, respectively. Marchantin A was tested against three recombinant enzymes (PfFabI, PfFabG and PfFabZ) of the PfFAS-II pathway of P. falciparum for malaria prophylactic potential and showed moderate inhibitory activity against PfFabZ (IC50 = 18.18 μM). In addition, the cytotoxic effect of marchantin A was evaluated. This is the first report describing the inhibitory effects of the liverwort metabolite marchantin A against these parasites in vitro.

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Peer-reviewed articles

Synergistic cytotoxic effect of the microtubule inhibitor Marchantin A from Marchantia polymorpha and the Aurora Kinase Inhibitor MLN8237 on breast cancer cells In Vitro

Macrocyclic bisbibenzyls are a class of characteristic compounds, exclusively produced by liverworts. They are attracting increasing attention due to their wide range of biological activities, including antibacterial, antifungal, and antioxidant properties as well as cytotoxicity. Marchantin A is a cyclic bisbibenzyl that has previously been isolated from Marchantia polymorpha and other liverwort species and has been shown to exert cytotoxic effects. In the present study we found that the Icelandic M. polymorpha species produces marchantin A and through an in vitro cell growth inhibition assay, marchantin A was shown to induce a reduction in cell viability of breast cancer cell lines A256 (IC50= 5.5 µM), MCF7 (IC50= 11.5 µM), and T47D (IC50= 15.3 µM). The effect was considerably increased in all cell lines in a synergistic manner when the Aurora-A kinase inhibitor MLN8237 was added simultaneously. Fluorescence microscopy confirmed the antimicrotubular effect of marchantin A, and cell cycle analysis indicated enhanced cell division failure when combining this mitotic-spindle inhibitor with the checkpoint modulator.

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Peer-reviewed articles

Bacterial succession during curing process of a skate (Dipturus batis) and isolation of novel strains

Aims

To study the succession of cultivated and uncultivated microbes during the traditional curing process of skate.

Methods and Results

The microbial diversity was evaluated by sequencing 16Sr RNA clone libraries and cultivation in variety of media from skate samples taken periodically during a 9-day curing process. A pH shift was observed (pH 6 · 64–9 · 27) with increasing trimethylamine (2 · 6 up to 75 · 6 mg N per 100 g) and total volatile nitrogen (TVN) (from 58 · 5 to 705 · 8 mg N per 100 g) but with relatively slow bacterial growth. Uncured skate was dominated by Oceanisphaera and Pseudoalteromonas genera but was substituted after curing by Photobacterium and Aliivibrio in the flesh and Pseudomonas on the skin. Almost 50% of the clone library is derived from putative undiscovered species. Cultivation and enrichment strategies resulted in isolation of putatively new species belonging to the genera Idiomarina, Rheinheimera, Oceanisphaera, Providencia and Pseudomonas. The most abundant genera able to hydrolyze urea to ammonia were Oceanisphaera, Psychrobacter, Pseudoalteromonas and isolates within the Pseudomonas genus.

Conclusions

The curing process of skate is controlled and achieved by a dynamic bacterial community where the key players belong to Oceanisphaera, Pseudoalteromonas, Photobacterium, Aliivibrio and Pseudomonas.

Significance and Impact of the Study

For the first time, the bacterial population developments in the curing process of skate are presented and demonstrate a reservoir of many yet undiscovered bacterial species.

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EN