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BIONÆR-Bionæringsprogram

Safe kelp for food and feed – controlling the transfer of iodine and arsenic through the value chain

Alternative title: Trygg tare til mat og fôr - kontroll med jod og arsen gjennom verdikjeden

Awarded: NOK 5.0 mill.

Project Number:

320687

Project Period:

2021 - 2024

Funding received from:

Location:

Partner countries:

Aquacultural production of kelp (a group of brown macroalgae) is on the rise worldwide and has great potential as both food and feed. Kelps contain several essential micronutrients but can also contain undesirably high levels of certain elements. In this project we study the content and fate of iodine and arsenic throughout value chains from cultivation to human food consumption, with the aim to facilitate management of food safety of this important resource. The project is a collaboration between Norwegian and Chinese partners. We are focusing on the species Saccharina latissima (sugar kelp) and Alaria esculenta (winged kelp), which are cultivated in Norway, and S. japonica, which is cultivated in China. We will characterize environmental and genetic variation in content of iodine and arsenic, reveal relationships between iodine content and stress tolerance in kelp, study how iodine content in kelp is a function of irradiance and temperature, including genes involved in this. Fresh kelp has a very short shelf life, and post-harvest treatments can greatly affect the shelf life and quality (sensory, microbial, chemical and physical) of sugar kelp. We will study how processing affects content of iodine and arsenic in kelp-based food and feed, and how iodine and arsenic from kelp is taken up, transformed and accumulating in humans and in farmed animals. We will determine availability, uptake and allocation in cereals fertilized with kelp processing residues and manure from kelp-fed animals. We will compare critical levels and food regulations of macroalgal iodine and arsenic in China and Europe and relate our results to critical levels for these elements. Communication of results to food safety authorities, kelp, food and feed industry and other stakeholders is an important part of the project. Results per November 2023: To reveal the relationship between stress, iodine content and gene expression in cultivated sugar kelp, two experiments was performed where the kelp was exposed to different light intensities or temperatures. The effect on elemental composition and gene expression has been analysed. We have done a small-scale preservation experiment with sugar kelp using ensiling techniques. A range of different ensiling additives such as organic acids, chemical stabilizers and a range of different microbes have been added to the kelp, and sealed bags have been incubated in ambient temperature for 2.5 months. The differently preserved kelp have been processed and are ready to be analyzed for iodine, total arsenic and inorganic arsenic. Kelp residues after extraction of different fractions, are tested as a fertilizer in a pilot experiment with cereals. The purpose is to assess the fertilizer and soil amendment potential, as well as to produce samples for development of analytical methods for inorganic arsenic in soil and plant material. We have published a review paper where we describe and compare legislation, limits and recommendations for iodine and arsenic in macroalgae used as food and feed from Europe and China. We have also performed a survey of people’s use and knowledge about algae as food in Norway, China and Chile.

Aquacultural production of kelp (a group of brown macroalgae) is on the rise worldwide and has great potential as both food and feed. However, kelps can contain high levels of potentially harmful elements, such as iodine and arsenic. The main objective of this Sino-Norwegian collaborative project is to obtain knowledge about the content and fate of iodine and arsenic throughout various value chains from cultivation of kelp to human food consumption, thereby facilitating management of food safety in the utilization of this important resource. The project has the following sub-goals: (1) Describe environmental and genetic variation in?content of iodine and arsenic in?Saccharina japonica; (2) Reveal?relationships between?iodine?content, stress, stress tolerance and?function of vanadium-dependent haloperoxidases in S. japonica, S. latissima and Alaria esculenta; (3) Develop a dynamical model for iodine content in?S.?latissima?as a function of irradiance and temperature; (4) Describe how processing affects content of iodine and arsenic in kelp in food and feed; (5) Develop models for uptake, bioaccumulation and transformation of iodine and arsenic from kelp in humans; (6) Describe uptake, bioaccumulation, transformation and allocation of iodine and arsenic in farmed animals given kelp-based feed; (7) Determine arsenic availability, and iodine and arsenic uptake and allocation in cereals fertilized with kelp processing residues and manure from kelp-fed hens; (8) Compare critical levels and food regulations of macroalgal iodine and arsenic in China and Europe; (9) Synthesize the results from the project and relate this to critical levels for iodine and arsenic; (10) Communicate results to food safety authorities, kelp, food and feed industry and other stakeholders.

Funding scheme:

BIONÆR-Bionæringsprogram