The marine environment, contains abundant renewable resources, eg macroalgae with unique polysaccharides, motivating the search for enzymes from marine microorganisms to explore conversion possibilities of the polysaccharides. In this study, the first GH17 glucanosyltransglycosylase, MlGH17B, from a marine bacterium (Muricauda lutaonensis), was characterized. The enzyme was moderately thermostable with Tm at 64.4 °C and 73.2 °C, but an activity optimum at 20 °C, indicating temperature sensitive active site interactions. MlGH17B uses β-1,3 laminari-oligosaccharides with a degree of polymerization (DP) of 4 or higher as donors. Two glucose moieties (bound in the aglycone +1 and +2 subsites) are cleaved off from the reducing end of the donor while the remaining part (bound in the glycone subsites) is transferred to an incoming β-1,3 glucan acceptor, making a β-1,6-linkage, thereby synthesizing branched or kinked oligosaccharides. Synthesized oligosaccharides up to DP26 were detected by mass spectrometry analysis, showing that repeated transfer reactions occurred, resulting in several β-1,6-linked branches. The modeled structure revealed an active site comprising five subsites: three glycone (−3, −2 and −1) and two aglycone (+1 and +2) subsites, with significant conservation of substrate interactions compared to the only crystallized 1,3- β-glucanosyltransferase from GH17 (RmBgt17A from the compost thriving fungus Rhizomucor miehei), suggesting a common catalytic mechanism, despite different phylogenetic origin, growth environment, and natural substrate. Both enzymes lacked the subdomain extending the aglycone subsites, found in GH17 endo-β-glucanases from plants, but this extension was also missing in bacterial endoglucanases (modeled here), showing that this feature does not distinguish transglycosylation from hydrolysis, but may rather relate to phylogeny.
Author: Kristín Edda Gylfadóttir
This study was undertaken to evaluate the effects of liquid smoked flavorings and wood smoke on the sensory, color, texture, and lipid stability of smoked mackerel fillets for four weeks chilled storage. Fish fillets were smoked by two methods: (1) immersed in brine (1:1) containing 100 g/L NaCl at 0-5 °C for 3 hours, allowed to drain at room temperature (~20 °C) for 2 hours and smoked directly with wood smoke in a smoking chamber at 25 °C for 3 hours; (2) immersed in brine (1:1) containing 5 mL/L commercial liquid smoke flavorings and 60 g/L NaCl for 16 hours at 0-5 °C then dried at 25 °C for 2 hours in an oven. Smoked samples were then vacuum packed and stored chilled at -1 °C for one week, followed by 4±1 °C for three weeks. The quality changes in sensory, color, texture, and lipid stability were observed after 0, 1, 2, 3 and 4 weeks of storage. The results showed that, smoked mackerel using commercial liquid smoked flavorings was higher in rancid flavor, lightness, redness, and yellowness but had less bitter odor and was softer than the wood smoked mackerel. The lipid oxidation was higher after the wood smoke process but was however rather stable during the chilled storage. In contrast, lipid oxidation in the liquid smoked products increased significantly during chilled storage.
Abstract
Background
Health authorities are increasingly integrating environmental sustainability considerations into food-based dietary guidelines. However, concerns persist about the accuracy of the data used to assess environmental impacts, as well as the extent to which these guidelines are followed in practice.
Aim
To compare dietary greenhouse gas (GHG) emissions estimates using different top-down and bottom-up life cycle assessment (LCA) databases; and to estimate GHG emissions of food consumption within the ranges set for meat and dairy in recently proposed environmentally sustainable diets.
Methods
Dietary GHG emissions were estimated for participants in the 2019–2021 Icelandic National Dietary Survey (n = 822) using three publicly available LCA databases from Denmark, the US, and France. GHG emissions among participants whose consumption was aligned with the EAT-Lancet diet, the 2021 Danish food-based dietary guidelines and the 2023 Nordic Nutrition Recommendations were also quantified.
Results
The mean dietary GHG emissions among participants were 6.3, 6.1, and 6.1 kg CO2-eq/day based on the Danish (top-down), US (bottom-up), and French (bottom-up) databases, respectively. The relative ranking of foods was also consistent across all three databases. For example, the relative contribution of total CO2-eq (% range for the three databases) was highest for red meat (39–51%), followed by dairy (10–17%) and beverages (9–13%). The contribution from plant-based foods (6–10%), seafood (4–11%), and poultry/eggs (<5%) was modest. The dietary habits of most participants (86%) were outside the ranges for meat and dairy consumption as set by the three sustainable diets. However, participants reporting consumption within the ranges for meat and dairy had mean GHG emissions ranging between 4.2 and 4.7 kg CO2-eq/day, depending on the diet. In comparison, the mean for participants not adhering to the sustainable diets was 7.7 kg CO2-eq/day. These results are higher than those reported in other Nordic and European studies, likely due to high consumption of lamb, beef, and dairy, and low consumption of plant-based food.
Conclusion
All three LCA databases provided similar estimates for total dietary GHG emissions and relative ranking of different food groups. Based on current dietary habits in Iceland, adherence to environmentally sustainable diets would lead to a substantial reduction in dietary GHG emissions.
The study aimed to evaluate the effects of onboard refrigerated seawater (RSW) storage of whole ungutted cod on the quality parameters of fillets. The reference group was directly gutted, bled, and stored in ice, while three experimental groups were gill-cut, bled, and stored ungutted in an onboard RSW tub at −1.5°C for 24, 60, and 84 hours. The results showed a difference between groups with extended RSW storage leading to negative effects such as increased gaping, bile spots, TVB-N levels, and bacterial growth after 60 hours. Conversely, the 24-hour RSW group closely resembled the quality parameters of the reference group.
Seaweed is becoming a popular food source due to its high nutritional content, but may also contain potentially toxic elements (PTEs). This study investigates trends in PTEs in several species of seaweed collected in Iceland, and variations between thallus section, location, and season. As (3.8-265 mg kg-1), Cd (0.06-18 mg kg-1) and U (0.03-1.9 mg kg-1) were highest in Phaeophyta collected in February, whilst certain Chlorophyta contained the highest levels of Pb ( 0.02-1.8 mg kg-1) and Fe (25-13607 mg kg-1). Samples contained high levels of essential trace elements but elevated levels of Cd – 19 samples exceeded the maximum level (3 mg kg-1) in food supplements. As levels were also high where over half of samples exceeded the 40 mg kg-1 ML for As in seaweed-derived animal feed. Certain species grown in Iceland may be prone to high levels of Cd and not be suitable for consumption in large quantities.
The short harvesting period of cultivated brown seaweed in Europe can make it difficult for cultivators to produce high quality seaweed biomass all year round. Hence there is a need for novel processing and preservation methods. Acid preservation is a well-known method to preserve food, where the aim is to reduce the pH below 4.5 to inhibit microbial growth. To evaluate the effectiveness of acid preservation, a shelf-life experiment was conducted with Saccharina latissima and Alaria esculenta. The biomass was either treated with lactic or citric acid and stored for approximately seven months. Physicochemical (including proximate composition, trace minerals, total phenolic content (TPC), texture and pH), microbial-, sensory attributes, and antioxidant (ORAC, DPPH) analyzes were performed on the preserved biomass during storage. The proximate composition, color, pH, and texture of the acid-preserved seaweed were relatively stable throughout the storage. However, a decrease was observed in TPC and antioxidant properties (assessed by DPPH) with the acid treatments. Acid preservation is, thus, a good method to stabilize the studied biomass for food and feed applications, but less applicable if intended for antioxidant purposes. However, the acid treated biomass might be suitable as an ingredient for a wide range of value-added products.
Atlantic herring Clupea harengus feeding in the Norwegian Sea are assumed to consist of Norwegian spring spawners (NSSH), Icelandic summer spawners (ISSH) and North Sea autumn spawners (NSAH). Putative Norwegian autumn spawners (NASH), Faroese autumn (FASH) and spring (FSSH) spawners also feed in the area.
However, until there is a method to discriminate between populations in mixed samples, fishery and survey data from the Norwegian Sea will be solely attributed to the predominating NSSH, ultimately causing biased stock assessments.
Hence, we evaluated if a panel of 120 single nucleotide polymorphisms (SNPs) associated with spawning characteristics and salinity preferences would be an effective discrimination tool. The overall observed levels of genetic differentiation were high (FST = 0.57, p < 0.001, 95% CI: 0.51−0.62). Spawners from stocks under current management (NSSH, NSAH and ISSH) were well separated, but the putative populations were not. Discriminant analysis of principal component as well as Structure runs confirmed the differentiation observed with FST. When the SNP panels were tested on commercial fishery samples of NSSH east of Iceland, up to 16% were assigned to ISSH.
This implies that catch data are seriously biased and demonstrates the potential of SNP panels as a tool to solve the problem. However, work is needed to develop improved SNP panels that effectively separate the putative populations from the managed stocks. We recommend that such a tool should be established in regular sampling of fisheries and surveys in the Norwegian Sea and accounted for in future stock assessments, advice and management.
Dietary vitamin B12 deficiency is one of the most common micronutrient deficiencies worldwide, with over a billion individuals suffering from low levels of the vitamin. While ruminant-derived meat and dairy products play a crucial role in providing the recommended B12 dietary allowance (2.4 μg/day), increasing the production and consumption of meat and milk entails substantial environmental ramifications.
Spirulina blue-green algae (Arthrospira platensis) has been widely proposed as healthier and more sustainable substitutes for meat, milk, and dairy products (also known as meat and milk analogues). However, previous research has shown that while Spirulina contains desirable macro- and micro-nutrients (eg, essential amino acids, calcium, potassium, magnesium, iron), the majority of vitamin B12 found in so-called traditional Spirulina is a non-active , pseudo-form (cobamide), unavailable to humans, referred to as pseudo-vitamin B12. This renders traditional Spirulina a limited alternative to animal-source foods. As a response, in this exploratory in vitro study, we ask whether light conditions may enhance active vitamin B12 production in Spirulina.
We describe the use of scalable photobioreactors, artificially illuminated, located in the Hengill area of Iceland. These systems are used to cultivate Photosynthetically Controlled Spirulina (PCS), to produce carbon–neutral and nutritious biomass containing unopposed, biologically active vitamin B12, in levels comparable to beef (1.64 μg/100g in PCS with a standard deviation of 5% versus 0.7– 1.5 μg/100g in beef). In terms of mitigating global vitamin B12 deficiency, we explore production scale up scenarios.
In one scenario, by re-allocating the electricity currently consumed by heavy industry, Iceland could produce 277,950 tonnes of Spirulina biomass per year, which translates into approximately 4555 g per year of active vitamin B12, able to meet the recommended dietary allowance ( RDA) of over 13.8 million children aged 1–3. More ambitious production scenarios could see Iceland providing the RDA for over 26.5 million children aged 1–3, and over 50 million children aged 0–6 months.
Matís and RISE from Sweden will bring together experts in the field of bioeconomy in a workshop called "BIO2REG expert workshop on research infrastructure and living labs" on September 5th and 6th next in Matís' house in Reykjavík.
In the workshop, projects related to bioeconomies, the development of the last decades and the importance of green energy will be reviewed. National and foreign experts will speak, as well as field visits to selected companies in the capital area and the surrounding area.
The workshop is open to everyone and free of charge.
A registration link along with further information and program drafts can be found here:
At Matís, we work on diverse research and development projects on meat in collaboration with producers and various stakeholders. The goal is to strengthen domestic meat production and promote value creation. Recently, a project funded by the Food Fund and entitled Discection yields and nutrient value of Icelandic lamb meat and organs and was won by Matís and the Icelandic lamb marketing agency.
The project was carried out in close cooperation with the production centers Kjarnafæð-Norðlenska /SAH Afurðir in Blönduós, Sláturfélag Suðurlands and the meat production center of Kaupfélag Skagfirðinga. The project was launched so that it would be possible to provide new and reliable data to replace the 20-30-year-old data that was always relied on and had become obsolete. The lack of new and up-to-date data on utilization and nutritional value led to high marketing efforts for lamb meat and side products both on the domestic and export markets.
In the project, an assessment was made of utilization rates within the meat assessment categories of lamb, but lamb meat is generally classified into 40 categories at the slaughterhouse, and farmers are paid accordingly. In recent years, farmers have carried out extensive breeding work based on data they have collected in a central database, thereby increasing the productivity of meat per sheep by approx. 30%. This means that the types of meat that are most common today in terms of the ratio of muscle and fat to bone are completely different from those that were most common 20-30 years ago. The data that was used on the Icelandic market did not reflect the actual situation of Icelandic lamb meat well enough before this study was started. In addition, there was a lack of new data on nutrient values, as that data was also about 20-30 years old. Such measurements are useful for those who want to justify that the product is wholesome, tasty, has some uniqueness, etc. The third starting point of the study was an examination of whether the meat assessment carried out in Iceland was fair and adequate.
It was considered important that the quantity and quality of the research material would reflect the population well so that the results obtained would be significant and durable. Therefore, 63 carcasses from seven meat grade categories were selected, covering the 92% production based on the division into meat grade categories in 2021. Carcases were selected on three different slaughter days, in two slaughterhouses, in the north and in the south, and the head of the meat grading department at the Food Agency confirmed that each carcass was a traditional carcass in own rating category and not on the category's boundaries.
The proportion of meat, fat and bones in different quality categories confirmed that meat food in Iceland is realistic and in accordance with the definitions behind the food according to the European model. Here you can read the report in its entirety and view a detailed description of the measurements.
Measurements were then made of nutrients and heavy metals and updated figures were entered The ÍSGEM nutrient database. The measurements were made on lamb pieces and lamb meat products, lamb offal and other by-products such as liver, kidneys, hearts, lungs, testicles, esophagus, pancreas, spleen, and blood.
It turned out that the lamb meat was so rich in vitamin B12, vitamin folate, potassium and zinc that it is permissible to label these substances as part of the meat's nutrition labeling on packaging. The heavy metals mercury, cadmium, lead and arsenic were not measurable in the meat, i.e. were below the limits that could be safely measured. This limit is very low and therefore the possible concentration of heavy metals is extremely low.
The lamb offal and by-products are rich in iron and selenium, but these substances are important nutrients. In the case of significant quantities, labeling of food packaging is permitted according to the labeling regulations. The heavy metal cadmium was detectable in liver and kidney but not in other samples. Mercury, lead and arsenic were not measurable in the samples, although with the exception that mercury in the kidneys was measurable.
These results from the chemical measurements are truly interesting and give ample reason for improving the labeling of these products and providing information to stakeholders and the public..
Hafliði Halldórsson, manager of the Icelandic lamb marketing agency, and Óli Þór Hilmarsson, project manager at Matís, discussed the implementation and results of the project in new episode of Matvælin, Matís' podcast about research and innovation in food production. It is both fun and informative to listen to these professionals talk about the issue that is clearly dear to them. The podcast is available on all major podcasts and also in the player below.
Important results made available
A large number of people will be able to benefit from the results of this project. For example, all production centers in sheep slaughter as well as processing companies, innovative companies, retailers, farmers who practice home processing and other small producers will receive accurate data that increases efficiency in planning, cost and margin calculations during processing and product price estimation.
Small producers in innovation have a great need for up-to-date and accurate data on the chemical content of raw materials, to confirm the nutritional content and healthiness of their products. The weight of side products in the industry's income base is one of the biggest opportunities of the future, and all data that confirms claims about the purity of products and the high value of essential nutrients are therefore extremely important.
Retail stores, specialty stores, restaurants, institutions and canteens will also be able to use the data to benefit their operations and re-evaluate nutritional content labels. The results are also useful for teaching and research in agriculture, meat industry and cooking.
Sigurgeir Höskuldsson product development manager at Kjarnafæð Norðlenska and Benedikt Benediktsson production manager at SS agree that research on the chemical content of lamb meat is useful when it comes to calculating the nutritional value of meat products produced. For obvious reasons, it is not possible to measure every single product, but it is important to have access to a nutrient database that is up-to-date and with the best possible information. The results will be useful both for packaging labeling and also for marketing purposes.
Ægir Friðriksson, Head of Culinary Arts at the College of Education in Kópavogur mentions that in the chef's world not much attention is paid to meat evaluation because production centers and distributors classify the meat, but it is all the more important that chefs are aware of the difference in terms of utilization rate and meat quality. This report provides a good insight into how meat consumption and utilization go together.
María Guðjónsdóttir, professor at the Faculty of Food and Nutrition, University of Iceland mentions that a life cycle analysis of the lamb value chain is currently under review at the university. Higher utilization from lamb meat production means a relatively lower environmental impact per edible piece, especially when considering the environmental impact of the proteins, which are the main consumption component. The analysis shows that the production of Icelandic lamb is on a similar path environmentally as production in other countries. The lamb also has a particularly strong effect on the country's food security, as the sheep need less imported feed and fertilizer than many other animals. Detailed analyzes like those presented in Matís' lamb report are necessary for continued research into both the quality, utilization, and environmental impact of our value chains. In addition, it can be mentioned that HÍ and Matís are part of a pan-Nordic research network that focuses on meat research in the Nordic countries. The results of the report are used in comparative research on the quality and utilization of lamb meat between countries.