• Comparing the primary energy and phosphorus consumption of soybean and seaweed-based aquafeed proteins – A material and substance flow analysis

    Authors:  Gaspard Phillis (NTNU), Erik Gracey (Møreforsking Ålesund), Lars Christian Gansel (NTNU), Annik Magerholm Fet (NTNU), Céline Rebours (Møreforsking Ålesund)

    Publisher: Journal of Cleaner Production

    Year: 2018

    Abstract

    This study compares the environmental performances of two protein sources for aquafeed production: Brazilian soy protein and Norwegian seaweed protein concentrates. The efficiency and sustainability of these two production systems are assessed using a comparative material and substance flow analysis accounting for the transfers of primary energy and phosphorus. The primary energy and phosphorus demand of 1 t of soy protein concentrate is compared to 2 t seaweed protein concentrate to assess commodities with similar protein contents. The primary energy consumption of the latter protein source (172,133 MJ) is found 11.68 times larger than for the soy-based concentrate (14,733 MJ). However, the seaweed protein energy requirement can be reduced to 34,010 MJ if secondary heat from a local waste incineration plant is used to dry the biomass during the late-spring harvest. The seaweed system outperformed the soy system regarding mineral phosphorus consumption since 1 t of soy protein requires 25.75 kg mineral phosphorus while 2 t of seaweed protein require as little as 0.008 kg input. These results indicate that substituting soy protein with seaweed protein in aquafeed leads to an environmental trade-off. The seaweed value chain produces proteins with near zero mineral phosphorus consumption by using naturally occurring marine phosphorus while the soy value-chain produces proteins for roughly 1/12th of the primary energy required by seaweed. Based on the current production technology, the seaweed value-chain will require extensive innovation and economies of scale to become energy competitive. Further research should investigate the predictive environmental impacts of a fully developed seaweed protein concentrate value-chain and account for the background emissions and multi-functionality in each system.

    Link to publication: https://www.sciencedirect.com/science/article/pii/S0959652618322364

  • Variations in polyphenol and heavy metal contents of wild-harvested and cultivated seaweed bulk biomass: Health risk assessment and implication for food applications

    Authors: Michael Roleda (Nibio, Norway), Hèléne Marfaing (CEVA, France), Natasa Desnica (Matis, Iceland), Rosa Jónsdottir (Matis, Iceland), Jorunn Skjermo (SINTEF Ocean, Norway), Céline Rebours (Møreforsking, Norway),   Udo Nitscke (Skidmore College, United States)

    Publisher: Food Control

    Year: 2019

    Abstract

    Seaweeds are increasingly used in European cuisines due to their nutritional value. Many algal constituents, such as polyphenols, are important antioxidants and thus considered beneficial to humans. However, many seaweed species can accumulate heavy metals and exhibit potential health risks upon ingestion. We investigated temporal and spatial variations in polyphenol and heavy metal (As, Cd, Hg, Pb) concentrations of three edible seaweed species. The brown algae Saccharina latissima and Alaria esculenta, and the red alga Palmaria palmata were sourced from natural populations and aquaculture in the NE Atlantic and processed as bulk biomass mimicking industrial scales. The mean polyphenol content was species-specific (Alaria > Saccharina > Palmaria), and highest in winter (for Alaria and Saccharina) and spring (for Palmaria); inter-annual and spatial variations were marginal. Heavy metal concentrations varied between species and depended on collection site, but seasonal variations were minimal. Our data suggest that all three species are good sources of antioxidants, and the heavy metal concentrations are below the upper limits set by the French recommendation and the EU Commission Regulation on contaminants in foodstuffs. A health risk assessment indicated that consumption of these seaweed species poses a low risk for humans with regard to heavy metals. However, an EU-wide regulation on maximal concentration of heavy metals in seaweeds should be established.

    Link to publication: https://www.sciencedirect.com/science/article/pii/S0956713518303694?via%3Dihub

  • Biomass soaking treatments to reduce potentially undesirable compounds in the edible seaweeds sugar kelp (Saccharina latissima) and winged kelp (Alaria esculenta) and health risk estimation for human consumption

    Authors:  Pierrick Stévant (Møreforsking), Hélène Marfaing (CEVA), Arne Duinker (Nifes), Joël Fleurence (Mer Molécule Santé), Turid Rustad (NTNU), Ingrid Sandbakken (SINTEF Industry), Annelise Chapman (TANGO Seaweed AS)

    Publisher: Journal of Applied Phycology

    Year: 2018

    Abstract

    Samples of cultivated edible kelps Alaria esculenta and Saccharina latissima were analysed for their cadmium, iodine and inorganic arsenic contents. The inorganic arsenic levels were low in both species but samples of A. esculenta had relatively high cadmium contents (up to 2.01 mg kg−1 dry weight (DW)), and iodine levels were high in S. latissima samples (up to 6568 mg kg−1 DW), exceeding the limits established by the French food safety authority for both elements. Simple soaking treatments in warm fresh water (32 °C) reduced the iodine in S. latissima and treatment of A. esculenta in hypersaline solution (2.0 M NaCl) reduced the relative cadmium content. However, both treatments affected the nutrient content of the biomass, illustrated by considerable variations in DW and the content of bioactive compounds (e.g. minerals, polyphenols, fucoxanthin). Health risks associated with the consumption of these seaweed species were estimated using risk factors based on established tolerable intake levels. The contribution of A. esculenta to dietary cadmium intake does not appear to pose a threat to the consumer while the daily consumption of S. latissima leads to excessive iodine intakes. The moderate consumption of these kelps will, on the other hand, improve the iodine status in iodine-deficient populations.

    Link to publication: https://link.springer.com/article/10.1007%2Fs10811-017-1343-8

  • Iodine content in bulk biomass of wild-harvested and cultivated edible seaweeds: Inherent variations determine species-specific daily allowable consumption

    Authors: Michael Roleda (Nibio, Norway), Jorunn Skjermo (SINTEF Ocean, Norway), Hèléne Marfaing (CEVA, France), Rosa Jónsdottir (Matis, Iceland), Céline Rebours (Møreforsking, Norway), Anne Gietl (National University of Ireland Galway, Ireland), Dagmar B. Stengel (National University of Ireland Galway, Ireland), Udo Nitscke (Skidmore College, United States)

    Publisher: Food Chemistry

    Year: 2018

    Abstract

    This study represents a large-scale investigation into iodine contents in three commercially important and edible seaweed species from the North Atlantic: the brown algae Saccharina lattisima and Alaria esculenta, and the red algae Palmaria palmata. Variability among and within species were explored in terms of temporal and spatial variations in addition to biomass source. Mean iodine concentration in bulk seaweed biomass was speciesspecific: Saccharina > Alaria > Palmaria. Iodine contents of Saccharina biomass were similar between years and seasons, but varied significantly between sampling locations and biomass sources. In Alaria and Palmaria, none of the independent variables examined contributed significantly to the small variations observed. Our data suggest that all three species are rich sources of iodine, and only 32, 283, or 2149 mg dry weight of unprocessed dry biomass of Saccharina, Alaria, or Palmaria, respectively, meets the recommended daily intake levels for most healthy humans.

    Link to publication: https://doi.org/10.1016/j.foodchem.2018.02.024

  • Nutritional value of the kelps Alaria esculenta and Saccharina latissima and effects of short-term storage on biomass quality

    Authors: Pierrick Stévant (Møreforsking), Hélène Marfaing (CEVA), Turid Rustad (NTNU), Ingrid Sandbakken (SINTEF Industry), Joël Fleurence (Mer Molécule Santé), Annelise Chapman (TANGO Seaweed AS)

    Publisher: Journal of Applied Phycology

    Year: 2017

    Abstract

    Storage of macroalgae in seawater, prior to further processing, is a standard initial pre-treatment step after harvest to avoid rapid degradation of the biomass. In the context of using seaweeds in human food and animal feed products, such practice may affect the nutritional value and the overall quality of the biomass. The effects of seawater storage on the chemical composition (i.e., mineral fraction, carbohydrates, proteins, polyphenols, and fucoxanthin) and surface color of two cultivated kelps (Phaeophyceae), Alaria esculenta and Saccharina latissima, were investigated over a 22-h period. Storage treatments resulted in a rapid decrease in dry weight during the first 2 h (−21.4 and −20.4% in Aesculenta and Slatissima, respectively) with subsequent stabilization. Although it is not clear whether the reduction of dry weight was caused by the release of nutritional compounds from seaweed biomass or water uptake during storage treatment, the results from chemical analyses suggest the combined effect of both mechanisms. Seawater storage increased the ash and sodium contents and reduced carbohydrate and polyphenol levels in both species. Among carbohydrates, the levels of mannitol and glucose (laminaran) were particularly reduced in Slatissima samples while the fucose level, reflecting fucoidans, was reduced in Aesculenta. The protein content remained relatively stable in both species. These results provide evidence of the effect of seawater storage on the quality of the edible kelps Aesculenta and Slatissima. The results will contribute to selecting postharvest strategies adequate for maintaining biomass quality, minimizing losses of valuable compounds and increasing profitability for industrial

    Link to publication: https://link.springer.com/article/10.1007/s10811-017-1126-2

  • Palmaria palmata as an alternative protein source: enzymatic protein extraction, amino acid composition, and nitrogen-to-protein conversion factor

    Authors: Málfríður Bjarnadóttir, Björn Viðar Aðalbjörnsson,  Anna Nilsson, Rasa Slizyte, Michael Y. Roleda, Guðmundur Óli Hreggviðsson,  Ólafur H. Friðjónsson, Rósa Jónsdóttir

    Publisher: Journal of Applied Phycology

    Year:2017

    Abstract

    The red seaweed Palmaria palmata has previously been reported to have high protein content high in essential amino acids. To extract the proteins a rigid cell wall consisting mainly of β-(1→4)/β-(1→3)-D-xylans must be disrupted. Different methods have been used to overcome this problem along with various methods used for protein evaluation. In this study, the effect of enzymatic pre-treatment on protein extraction was examined. Both enzymatic hydrolysis with xylanase and protease were tested. The amino acid content of the fractions was examined after extraction. The amino acid composition was similar to what has previously been reported; P. palmata was high in essential amino acids. Accordingly, a nitrogen-to-protein conversion factor was calculated for each fraction individually and protein results were compared with calculation using the proximate 6.25 conversion factor. The nitrogen-to-protein conversion factor varied between fractions but all factors were significantly lower than the popularly used 6.25 indicating that this conversion factor for processed P. palmata is effectively and considerably overestimating the protein content. Enzymatic pre-treatment with xylanase resulted in enhanced amino acid content and successful protein extraction. Enzymatic hydrolysis using protease resulted in higher protein content in the liquid extract compared to hydrolysis with xylanase, due to the release of proteins, peptides, and amino acids. Therefore, hydrolysis with protease is not suitable to extract proteins from P. palmata with the method described within this study but might be an optimal method to examine the bioactivity by extracting the protein hydrolysates. However, the result from this study confirm that hydrolysis with xylanase is a feasible choice to extract proteins of good quality from P. palmata.

    Link to publication: https://doi.org/10.1007/s10811-017-1351-8

  • Seaweed aquaculture in Norway: recent industrial developments and future perspectives

    Authors: Pierrick Stévant (Møreforsking), Céline Rebous (Møreforsking), Annelise Chapman (TANGO Seaweed AS)

    Publisher: Aquaculture International

    Year: 2017

    Abstract

    The use of cultivated seaweeds as a feedstock for multiple industrial applications has gained increasing interest in the Western World over the past decades. Norway has an extensive coastline and a well-established aquaculture sector offering suitable preconditions for developing large-scale cultivation of seaweed biomass both in monoculture and in Integrated Multi-Trophic Aquaculture (IMTA) systems. Recent efforts from research, industry and public authorities have been committed to develop a Norwegian bio-economy based on cultivated seaweed, focusing on cultivation and processing of the biomass. This review reports on the status of seaweed aquaculture in Norway, supported by production data collected since the delivery of the first commercial cultivation permits at sea in 2014. Although novel product developments are currently limited, future industrial perspectives based on cultivated biomass are being discussed. Upscaling from experimental cultivation schemes to commercial production requires a thorough assessment of the risks and benefits associated with seaweed aquaculture, as well as the development of a regulative framework adapted to this industry. Issues associated with upscaling the macroalgal production that needs to be addressed includes (i) genetic interactions between cultivated and wild crops, (ii) impacts of seaweed cultivation on surrounding ecosystems, (iii) epiphytes and diseases, (iv) area utilization and (v) threats from climate change. Addressing these issues and adapting production practices will ensure the environmental and economic sustainability of an emerging industry based on cultivated seaweed biomass in Norway.

    Link to publication: https://link.springer.com/article/10.1007/s10499-017-0120-7