Laminaria seaweed, raw (kelp, organic?)

Seaweed from the brown algae genus Laminaria ( Laminaria spp.), also known as seaweed or kelp , is popular raw and cooked in both Asian and Nordic cuisine. Organic?

Use in the kitchen

A Laminaria algae is an algae from the genus Laminaria within the phylum of brown algae (Phaeophyceae). In German-speaking countries, it is colloquially known as seaweed or kelp, as are other macroscopic brown algae, red algae and green algae. What is kelp? Kelp, the English term for seaweed, is also a common name for Laminaria algae or other brown algae species. Kelp also refers to extensive seaweed forests, which often consist of kombu algae, especially Japanese leaf kelp, which is why the term kelp is also used for this species.

In 2016, there were 33 taxonomically recognized species from the genus Laminaria , including Fingerkelp ( Laminaria digitata ) and palm kelp ( Laminaria hyperborea ). ¹ Numerous species that were previously classified as Laminaria were separated into a separate genus Saccharina in 2006 following molecular genetic studies. For example, the correct Latin name for Japanese leaf kelp (kombu) is now Saccharina japonica . Laminaria japonica is still considered a synonym, or basionym. ² However, this article focuses on other Laminaria species. Read more about Japanese leaf kelp in the article " Kombu seaweed, dried (raw?, organic?) ".

Laminaria algae have a slightly different taste depending on their origin. The leaves taste either sweet and mild or salty and smoky and typically like algae. The algae are suitable for consumption fresh, pickled in vinegar and dried. Whether the kelp algae, which is usually dried in Europe, is of raw food quality depends largely on the drying process and processing used.

The dried leaves must be soaked in water for about 10 minutes before further processing and allowed to swell. If you want to eat the algae raw or prepare it afterwards, you should increase the soaking time to at least 30 minutes or heat the algae in a pot of water on a stove. Before the water starts to boil, you should scoop out the algae again.

How can you eat kelp? Raw, kelp tastes great in salads (e.g. in a cabbage salad with white cabbage ) and smoothies (e.g. with kale , banana , oat milk , orange juice and linseed ). Cooked, they go particularly well in vegan rice and vegetable stir-fries (including with mushrooms, carrots , edamame and chili flakes ) and soups (e.g. miso soup). Marinated (e.g. with sesame oil , soy sauce , mirin or lemon juice ) and briefly seared or crispy fried, they also taste excellent. They also spice up vegan pancakes and omelettes, and made into noodles, they are a good alternative to glass noodles. In Scandinavia, kelp and beetroot are served with flatkökur (flatbread), and kelp (e.g. fingerweed) is used together with coriander , star anise ,pepper , chili and dried mushrooms to make a Nordic dashi broth.

When cooking legumes such as lentils and beans, you can add a piece of brown seaweed. The glutamic acid it contains, which creates the famous umami taste, makes the legumes more tender and shortens the cooking time.

By the way: The color of brown algae changes from brown to green when heated. The carotenoid fucoxanthin gives brown algae their brown color. But brown algae also contain chlorophyll, which gives many plants a green color. When cooked, the unstable fucoxanthin breaks down, causing the brown color to disappear and the green color of the existing chlorophyll to appear. ²¹

Vegan recipe for pickled finger kelp

Ingredients (for 1 jar): 175 g fresh finger kelp (or another kelp algae; preferably organic), 250 ml water, 125 ml apple cider vinegar , 1 tbsp sea salt , 35 g sugar , ginger (approx. 3 cm), 4 cloves of garlic , 1 red chili pepper.

Preparation: Sterilize the jar. If you are using dried finger kelp, first place it in water and let it soak and swell for about 30 minutes. Cut the swollen or fresh finger kelp into thin strips. Mix apple cider vinegar, salt and sugar in a saucepan with 250 ml of water and bring to the boil. Cut the ginger and chili into thin slices and peel the garlic cloves. Put the finger kelp with the ginger, chili and garlic in the jar and then pour the hot brine over it. The seaweed should be completely covered. Close the jar tightly with the lid and leave to marinate for a few weeks. The pickled finger kelp can be eaten as a side dish with vegan dishes, as an ingredient in salads or used as part of a filling for sandwiches or wraps. The opened jar will keep in the fridge for weeks.

Vegan recipes with laminaria can be found under the note: " Recipes that have the most of this ingredient ".

Purchasing - Storage

Supermarkets (e.g. Coop , Migros , Denner , Volg , Spar , Aldi , Lidl , Rewe , Edeka , Hofer , Billa ) and organic supermarkets (e.g. Denn's Biomarkt , Alnatura ) generally do not stock Laminaria algae. You will have more luck in Asian shops or online shops, which sell dried kelp and rarely fresh. Organic quality is well represented in online offers. Kelp algae can also be found processed into powder as a dietary supplement.

The availability of Laminaria algae varies depending on the size of the store, catchment area, etc. If you are interested, click on our recorded food prices for the DA-CH countries (above under the ingredient image). There you will find current prices from various supermarkets and their price development.

Storage tips

Dried Laminaria algae are best stored in an airtight container in a dry place protected from light. This way they will last for several years. Fresh algae should be kept in the refrigerator and used within a few days.

Ingredients - Nutritional values - Calories

The energy content of Laminaria algae (raw) is 43 kcal and is therefore low. With 0.56 g fat per 100g, they are also low in fat. They contain 9.6 g carbohydrates/100g and 1.7 g proteins/100g. The salt content is relatively high and covers 24.7% of the daily requirement at 592 mg/100g. ³

Raw Laminaria seaweed is particularly rich in folate . Its content of 180 µg/100g (90% of the daily requirement) is similar to that of arame seaweed (180 µg/100g) and bladderwrack (180 µg/100g). Slightly less is found in red algae seaweed (146 µg/100g), slightly more in wakame (196 µg/100g). Dried seaweed naturally has much more of it: with 1269 µg/100g, dried dulse (ragweed) has about seven times the vitamin. ³

Vitamin K is also present in a considerable amount at around 66 µg/100g (88% of the daily requirement). Bladderwrack (66 µg/100g) and Arame algae (66 µg/100g) again contain a similar amount. Swiss chard contains even more vitamin K (830 µg/100g). ³

121 mg of magnesium are found in 100 g of raw kelp (32% of the daily requirement). Again, the content of bladderwrack and arame algae is comparably similar. Raw horseradish has a lot of this element at 628 mg/100g. Dried red algae leaves (nori) also have a considerable value at 741 mg/100g. ³

The iodine content of raw Laminaria algae is very high, averaging 38,000 µg/100g. ⁴ Algae are generally rich in iodine, for example dried dulsen has 7,500 µg/100g, arame algae (raw) 70,000 µg/100g and dried kombu algae 295,400 µg/100g. The content can vary considerably depending on the region of cultivation, storage, processing, etc. Read more about iodine in the chapter "Danger - Intolerances - Side Effects".

The complete ingredients of Laminaria algae (raw), the coverage of the daily requirement and comparison values with other ingredients can be found in our nutrient tables. In the article Nutrients explained you will get a detailed insight into the topic.

Health effects

Laminaria algae are rich in phenolic compounds and the polysaccharide laminarin. Laminarin and its derivatives have beneficial effects on health. Some in vitro and in vivo studies have shown that this substance has immunomodulatory properties by activating interleukins and signaling pathways and increasing the microbicidal potential of phagocytes, among other things. In addition, extracts rich in laminarin have antimicrobial and antioxidant activity. Recent research also reports on the ability of the polysaccharide to induce apoptosis in cancer cells without being cytotoxic to normal cells. ^5,6

Dangers - Intolerances - Side effects

Kelp algae and seaweed in general are a source of the essential trace element iodine . This plays an important role in thyroid function, as it is required for the synthesis of thyroid hormones. However, long-term, high intake of iodine is problematic and can lead to thyroid dysfunctions such as hyperthyroidism or hypothyroidism.

The genus Laminaria , in particular the species Laminaria digitata , contains the strongest iodine stores. Species of this genus of brown algae that are of interest to the food industry have iodine contents of around 170,000 to 3,100,000 μg/100g dry matter. The bioavailability of iodine from brown algae is high and, according to in vivo studies, varies between 31% and 90%. ^7,8

The recommended iodine intake is 150 μg/day for adults. The Scientific Committee on Food ( SCF ) has set a maximum tolerable amount of 600 μg/day. The amount of brown algae biomass that corresponds to a certain amount of iodine varies greatly. Processing processes (e.g. drying) can significantly reduce the iodine content of brown algae, but the iodine content is still high afterwards. The stated maximum daily iodine intake for adults (600 μg) can be achieved by consuming 0.2-11 g of processed, dry brown algae. ⁸

Therefore, only consume brown algae in small quantities and when buying algae products, make sure that the iodine content and a maximum recommended daily intake are stated. This way, you can estimate how high your iodine intake is and avoid consuming too much.

Folk medicine - natural healing

Due to the similarity between finger kelp ( Laminaria digitata ) and palm kelp ( Laminaria hyperborea ), they were most likely used for the same folk medicinal purposes. The records found come exclusively from the Scottish West Isles. Martin Martin found kelp there in 1695, which was valued as a remedy for loss of appetite when cooked with butter. On South Uist it was chewed and swallowed to treat constipation and on Skye it was eaten to purify the blood. ⁹

Ecological footprint - animal welfare

Seaweed farms appear to be more sustainable than agriculture on land. The cultivation of seaweed does not require fresh water (keyword: water footprint ), chemical fertilizers or soil - which are major negative factors of farming on land. ¹⁰ In contrast to seaweed (macroalgae), microalgae (e.g. Chlorella vulgaris ) are often grown on land in artificial ponds, which requires more input. ^22,23

In general, algae remove CO₂ from the atmosphere, which is good for the climate. According to researchers at the Max Planck Institute for Marine Microbiology in Bremen, brown algae absorb large amounts of carbon dioxide from the air and release some of the carbon it contains back into the environment in the form of mucus. Since the algae mucus, called 'fucoidan', is difficult for other marine creatures to break down, the carbon bound in it is out of the atmosphere for a long time. The researchers estimate that brown algae could remove up to 550 million tons of carbon dioxide from the air every year. ¹¹

Brown algae also influence the atmosphere and climate by emitting large amounts of iodine as they store large amounts of iodine, particularly algae of the genus Laminaria . Iodine emissions have been shown to have an impact on aerosol formation, the formation of coastal clouds and climate warming. Increasing global iodine emissions could trigger an acceleration in the melting of Arctic sea ice. ^7,12

China is the largest producer of macroalgae. A life cycle analysis (LCA) of a Chinese seaweed farm showed a CO₂ footprint of 0.0575 kg CO ₂ eq/kg of fresh kelp algae. The researchers compared this value with five other LCA analyses of plants in Europe. This revealed large differences. ²⁴ Seaweed is sometimes referred to as a CO₂ sink: because seaweed absorbs more CO₂ than is released during cultivation. However, this negative CO₂ footprint (CO₂ sequestration) is only short-term if the seaweed is used as food. ²⁶

Animal protection - species protection

Kelp algae are essential elements of coastal ecosystems in temperate latitudes and the northern polar seas. They form unique ecosystems with other large algae, so-called kelp forests. They not only serve as a source of food or habitat for many marine animals such as fish, crabs, sea urchins, snails and sea lice, but also provide a substrate for smaller algae that grow on them (epiphytes) and in them (endophytes). ^13,14

The warming of the oceans has led and may continue to lead to a decline in laminaria populations, as they thrive mainly in cool seas. ¹⁴

Worldwide distribution - cultivation

Algae of the genus Laminaria occur in temperate to polar rocky coastal ecosystems, especially in the Northern Hemisphere. ¹⁵

While Laminaria algae is mainly harvested from natural sites in Western countries, it has been cultivated in Asian countries since the early 1950s. ¹⁵ The three main producers in 2012 were China, Korea and Japan, with China's market share being 4.35 million tonnes, which was 23% of total world production. At that time, Denmark was the only European country to cultivate Laminaria . ¹⁶

Found in the wild

Laminaria algae grow mainly in the cool seas of the northern hemisphere. ¹⁴ Finger kelp ( Laminaria digitata ) is found on the Atlantic coasts of northern Europe and East America - from Brittany to northern Norway, from Newfoundland through the Canadian Maritime Provinces to Maine. Palm kelp ( Laminaria hyperborea ) is found mainly on the coasts of Norway, Scotland and Ireland. ^{6, 7, 16} Both species are found in the North Sea and the Baltic Sea. ¹⁴ On beaches in these regions, you can often find specimens cast out. They are often found with a piece of substrate, as they have clung firmly to the surface with their adhesive organ. ¹⁷

Finger kelp and palm kelp are easily confused. However, finger kelp has a shorter, smooth, oval stem, while palm kelp's stem is long, round, and rough.

Other Laminaria species include Laminaria rodriguezii , Laminaria ochroleuca and Laminaria brasiliensis . Laminaria rodriguezii is a deep-sea brown algae endemic to the Mediterranean Sea. ¹⁸ Laminaria ochroleuca is distributed in the Mediterranean Sea, the Northeast Atlantic and the Southeast Atlantic. ¹⁹ Laminaria brasiliensis occurs off the coast of Brazil. ²⁰

Cultivation - Harvest

There are a number of technical variations in the cultivation of seaweed, even if one only considers Laminaria . The cultivation methods include single culture and co-culture. Basically, the meiospores of Laminaria are "seeded" onto ropes. These are then attached to various hanging or floating culture devices on which the seaweed grows. Currently, the so-called "forced cultivation technique" successfully accelerates seaweed cultivation. However, this technique is labor-intensive and costly, as the development of the zygotes and the attachment of the young sporophytes to the ropes require land-based indoor tank facilities before the culture ropes are released into the sea. This method shortens the culture time from 2 years to 12 months. ¹⁵

Further information

Algae from the genus Laminaria belong to the family Laminariaceae within the brown algae order Laminariales. Since the genus Laminaria was established by Lamouroux in 1813, more than 200 species, subspecies and forms have been described. During the 20th century, Canadian researchers recognized that the genus Laminaria exhibits great morphological plasticity and that there are only a few reliable characteristics for distinguishing the species. They proposed transferring some species that had previously belonged to the genus Laminaria to a new genus ( Saccharina ). ^{2, 15}

Laminaria are among the most complex and largest brown algae and are considered one of the most important algal genera due to their high species number, biomass, dominance and economic importance. ¹

Read also our articles on other brown seaweeds such as bladderwrack , kombu seaweed (dried) , arame seaweed and wakame and also on red seaweeds (kelp) such as kelp , dulse (dry seaweed) and nori sheet .

Alternative names

Algae of the genus Laminaria are colloquially called seaweed, kelp or seaweed. However, other macroscopic brown algae, red algae and green algae are also referred to as seaweed or seaweed, and other brown algae species are referred to as kelp.

Incorrect spellings of the genus name Laminaria (e.g. Laminara, Laminatia, Laminira, Lamenaria, Lamineria, Laminarie, Laninaria, Laminria, Lamnaria, Lamonaria, Leminaria) occasionally creep in.

In English, Laminaria algae are called Laminaria seaweed or kelp.

Other uses

Laminaria seaweed contains alginic acid (alginate). Because this substance can form a gel, it is used as a stabilizer in many foods, cosmetics and pharmaceutical products. ¹⁴ The use of finger kelp in the development of processes for bioethanol production is also being investigated. ¹⁶