Seaweed and kelp are macroalgae that grow along mountain sides under the sea and on rocky bottoms. In large parts of Asia, algae have long been used as an ingredient in dishes. Norway and other European countries are less accustomed to the use of algae, but still move in the same direction. In Europe, the largest populations of algae are found along the Norwegian coast.
On this occasion, Spire Trondheim has interviewed Elin Njåstad, researcher on macroalgae at NTNU and Diogo Raposo from Trondheim-based company Seaweed Energy Solutions AS, which grows kelp outside Frøya.
Among the many varieties of algae found in Norway, sugar kelp and butare are among the most common to use in food. These contain important vitamins such as vitamins A and C, proteins, antioxidants, as well as the mineral iodine. Due to the good conditions for the growth of algae in Norway, it is believed that macroalgae can become a much larger industry than it is today (Johansen & Rogne 2020; Skoglund 2020; Helledal 2020). Norway has a long coastline that receives a natural supply of nutrient-rich water. This enables kelp cultivation without artificial fertilization. In 2018, 169 tonnes were cultivated in Norway, and the annual production is estimated to increase to 20 million tonnes in 2050 (Broch et al., 2019).
Seaweed and kelp have a wide range of uses. It can be used, for example, as fish and animal feed, spices, flavor enhancers, snacks and accessories for main courses. In January, two Norwegian students, Frida van der Drift Breivik and Frøya Thue, received DOGA's award for innovative design for their edible packaging of kelp that replaces plastic packaging (Nordbø 2020).
The interest in blue growth is promising for the kelp industry, says Diogo Raposo, who works as production coordinator for Seaweed Energy Solutions. Projects such as SINTEF's PlastiSea and ProSeaFood, on bioplastics and processing for food consumption, respectively, can provide us with increased knowledge and new areas of use for brown algae.
Seaweed and kelp in the diet - how much is healthy?
As the intake of seaweed and kelp has increased in Norway, the Norwegian Food Safety Authority has been particularly concerned about the iodine content in these (Norwegian Food Safety Authority, 2019a). Although Norwegians are generally low in iodine, neither too high an intake nor an abrupt increase in iodine intake is recommended (Folkehelseinstituttet, 2018). Untreated, some kelp species can exceed the recommended daily intake for iodine, and the Norwegian Food Safety Authority therefore recommends that people do not eat large amounts of kelp and kelp in anticipation of more knowledge (Norwegian Food Safety Authority, 2019b). However, this may be within reach - the Institute of Marine Research is conducting a five-year research project on seafood and feed resources that, among other things, looks at food safety in macroalgae for human consumption (Institute of Marine Research, 2020). Raposo points out that we can learn from Asia, which bleaches most of the kelp that is eaten.
We can reduce the iodine content by blanching seaweed and kelp in hot water. Blanching can reduce the iodine content of kelp by up to 90 percent (Nielsen et al., 2020). The heat treatment causes the seaweed and kelp to change color from brown to green, and it still tastes very good.
How to produce sustainably?
Seaweed cultivation has several properties that facilitate a sustainable blue industry. It requires minimal land and fresh water, and neither pesticides nor fertilizers are applied. Macroalgae absorb nitrogen and phosphorus that are naturally available in the water column. In addition, the macroalgae bind CO2, which according to Njåstad counteracts ocean acidification. One of the challenges facing the kelp industry is the presence of moss animals ("pests" that grow on seaweed and kelp), which stop kelp harvesting in the spring. Raposo confirms that this is a challenge for the industry; "We are planning the harvest with the moss animals in mind, since we cannot sell kelp for food with animals growing on it." The mosses appear in the spring, possibly as a result of the spring sun and increased temperatures. Increased sea temperatures due to climate change can start this natural process earlier, and potentially become a future problem for the industry, says Njåstad.
What effect increased biomass in the form of macroalgae can have on marine ecosystems is something Njåstad is researching in the Kelppro project, at NTNU. If Norway is to start large-scale production, it is important to have increased knowledge about ecosystem impacts. Among other things, this artificial kelp forest - the production facilities - can form new habitats for species that live along the coast, and function as a food container, hiding place and rearing area for small fish and other marine fauna.
Diogo Raposo also says that the industry on its own initiative has developed guidelines to take into account adaptations and genetics of the species that naturally grow along the coast. As members of the Norwegian Kelp Farmers' Association, they follow the recommendations to use many mother plants found within 100 km from the cultivation facility. This is a measure to take into account the local adaptations stored in the genotypes of macroalgae. "We are also involved in developing guidelines for good practice in other European countries," he says.
Tips for seaweed and kelp collection
To get started, the two recommend taking a reconnaissance trip in the local area, picking up some species home and reading a bit about them. Finger kelp, for example, is good for chips (!) And should be picked at low tide. Boots, waders or swimwear may be needed to reach some species. There are many good resources online if you want to try to harvest yourself, for example tingmedtang.no, which has a number of tips, recipes and information about different species of kelp and kelp. Some of these are:
- Choose a place with good water flow, and not near spills and quays.
- Think sustainably: Leave the attachment, and do not take too much from any one area.
- Take from seaweed that grows attached, not that which floats ashore.
Translated from original article.