Table of contents
Dried wakame is a versatile brown seaweed popular in Asian cuisine. This iodine-rich seaweed can be used sparingly in salads, soups, and many other dishes.
Uses in the kitchen
Wakame (Undaria pinnatifida) is a brown seaweed that can be used fresh or dried. Freshly harvested wakame is brownish-olive. Unless explicitly stated, industrial post-harvest treatment involves blanching at 65°C, which changes the color from brown to green. Such wakame is no longer considered raw. Whether dried wakame is considered raw also depends on the drying process and processing. Conventionally processed wakame is often exposed to high temperatures.11,12 Dried wakame products are considered raw if the maximum temperature during drying did not exceed 42°C. However, there are also traditional drying methods for fresh, wild-grown wakame (Su-boshi) that dry in the sun or with hot air without prior blanching. Ash drying (Hai-boshi) is another traditional method, in which the high pH of the ash inactivates enzymes.
Dried seaweed strips appear dark to blackish-green, thin, slightly wavy, and look hard and brittle. In Europe, only dried wakame or fresh wakame processed into a marinated salad is usually available in stores.
Before using dried wakame, rinse it first in cold water, then soak it in lukewarm water for about 10-15 minutes, and finally squeeze out the excess water. Soaking allows the dried wakame to absorb water and significantly increase its volume. The amount of soaked seaweed is approximately five to ten times the amount of dried seaweed.
Dried wakame can be eaten raw or unprocessed, but it is also suitable for cooking. Overcooking will cause the color to turn brown again.12
Traditional dishes featuring wakame include Japanese miso soups (e.g., Japanese miso soup with zucchini and carrots). The wakame salad 'Goma Wakame' is a popular side dish in American and European sushi restaurants. Literally translated, 'Goma Wakame' means sesame seaweed, as the recipe typically includes sesame seeds. It also contains, among other things, lime juice, rice vinegar, sesame oil, fresh ginger, garlic, coriander leaves, and chili. Soaked wakame also tastes wonderful in other salads, for example, with cucumber, leafy greens (such aslettuce ), or tofu. Crushed dried wakame seaweed makes a mineral-rich seasoning. Soy sauce and rice vinegar complement Asian dishes with wakame perfectly.
Dried wakame serves as a source of iodine, for example in Erb-Lycopene soup with tomatoes. Like many other seaweeds, dried wakame contains a lot of iodine. Adding seaweed to dishes adequately covers the daily iodine requirement. If you use little or no iodized table salt, but live in an iodine-deficient area (many parts of Europe), you should ensure sufficient intake. 1 g of dried wakame per day is enough to meet the iodine requirement.
Vegan recipe for rice noodle and wakame salad with cucumber
Ingredients (for 4 people): 100g rice noodles (alternatively shirataki noodles, glass noodles), 50g dried wakame seaweed, 1 organic salad cucumber, 2 organic limes, 1 clove of garlic, 1 tbsp sesame oil, 1 tbsp soy sauce, 1 tbsp rice vinegar, 2 tbsp black or white sesame seeds.
Preparation: Rinse dried wakame under cold water and soak in lukewarm water for 10-15 minutes. Place rice noodles (or glass noodles) in a bowl, pour boiling water over them, and let them soak for about 10 minutes.* Once the rice noodles have a slightly firm texture, drain them through a sieve and rinse them with cold water. Remove the wakame from the water, squeeze out the excess water, and add it to the rice noodles. Wash the cucumber, trim the ends, halve it lengthwise, and use a vegetable peeler to slice it into thin strips. Add the cucumber strips to the rice noodles and wakame.
For the marinade, halve the limes and squeeze their juice into a small bowl. Peel the garlic and press it using a garlic press. Add the garlic to the lime juice and mix with sesame oil, soy sauce, and rice vinegar. Toss the marinade and sesame seeds with the salad and serve immediately.
* If you prefer shirataki noodles instead of rice noodles, proceed as follows: drain the liquid in which the noodles are packed. Rinse the noodles with cold water using a sieve. Then drain well.
Vegan recipes with dried wakame can be found under the note: "Recipes that have the most of this ingredient".
| This is not just for vegans or vegetarians: Vegans often eat unhealthily. Avoidable nutritional mistakes . |
Shopping - Storage
Dried wakame is usually not part of the standard product range at major retailers such as Coop, Migros, Denner, Volg, Spar, Aldi, Lidl, Rewe, Edeka, Hofer, and Billa. Some large supermarkets sell marinated wakame salad ('Goma Wakame'). You'll have more luck in Asian grocery stores or online shops. There, you can buy dried wakame cut into strips, as flakes, or as an instant product to stir in (no soaking required). Organic quality is readily available online. Dried seaweed in raw food quality (gently dried below 42 °C) is also available. However, since raw food products are not licensed, there is no clear guarantee of this. With traditional methods like sub-boshi, the color appears more brownish, indicating that it hasn't been blanched. Hai-boshi is also traditionally done without blanching. These algae are primarily available in the countries where they are grown.
The availability of dried wakame varies depending on the size of the store, its catchment area, etc. Our recorded food prices for the German-speaking countries (Germany, Austria, Switzerland) can be found above under the ingredient image – and by clicking, you can see how these prices have changed across different suppliers.
Storage Tips
Dried wakame should be stored like other dried foods in a dark, cool, and dry place. Stored this way, it will keep for several months. After opening the packaging, reseal it airtight or transfer the dried seaweed to a sealable container.
Ingredients - Nutritional Values - Calories
The composition and quantity of ingredients, including secondary plant compounds, vary extremely depending on the variety, growing conditions, processing methods, etc.
100 g of dried wakame has an energy content of 178 kcal. Adding water reduces this to 45 kcal/100 g (see Wakame, raw). Dried wakame is low in fat. Carbohydrates make up the largest proportion at 41 g/100 g, of which approximately 33 g are fiber. The protein content is lower at 14 g/100 g.
The iodine content of wakame can vary greatly and depends heavily on the harvest region. We show a calculated value of 21,842 µg/100g for dried wakame from Japan, which is 14,561 % of the daily requirement! Therefore, you should only use one gram of dried wakame to meet your daily iodine needs. Seaweed is generally high in iodine; for example, dried kombu seaweed has an extremely high value of 295,400 µg/100g, while dried dulse (sea lettuce) has a much lower value of 7,500 µg/100g. Raw arame seaweed contains 8,750 µg/100g and raw laminaria seaweed 38,000 µg/100g.2 You can find more information about iodine in algae in the chapter "Dangers - Intolerances - Side effects" or generally in the article on iodine.
Dried wakame is also high in vitamin K. 100 g contains 660 µg.22 This is comparable to dried oregano or marjoram (622 µg/100 g). Dried wild garlic (2625 µg/100 g), dried basil, and thyme (1714 µg/100 g) are particularly rich in vitamin K. Since only small amounts of dried wakame and spices are typically consumed, the actual intake is negligible. However, 1 g of dried wakame still covers 8 % of the daily requirement.2
Magnesium is present at 1100 mg/100g, which is 293 % of the daily requirement.22 This is a very high magnesium content. For comparison, dried nori seaweed shows a value of 741 mg/100g, kombu seaweed 510 mg/100g, and dulse only 168 mg/100g.2
The complete list of ingredients in dried wakame, its coverage of daily requirements, and comparison values with other ingredients can be found in our nutrient tables below the ingredient image.
Effects on Health
Numerous studies demonstrate the important role of wakame (Undaria pinnatifida) polysaccharides in their nutritional and medicinal value. Wakame contains fucoidans, which are found only in brown algae. They possess numerous biological activities, including antioxidant, anti-obesity, anti-diabetic, anti-aging, antimicrobial, anticoagulant, antihypertensive, antithrombotic, immunomodulatory, and anti-inflammatory properties.1,3,4,5
Results from cancer research demonstrate an inhibition of malignant cell proliferation by up to 52 %. Hydrolyzed fucoidans, in particular, exhibit anti-cancer effects in lung and stomach cancers. Fucoidan also inhibits the formation of new blood vessels, thus slowing the spread and growth of tumors in liver and prostate cancer. Furthermore, various peptides in wakame exhibit effective activity on enzymes that regulate blood pressure and play a role in cardiovascular diseases.4
Secondary plant compounds
Many of the health benefits of wakame can be attributed to its secondary plant compounds. Our article on secondary plant compounds provides an overview of the classification of these compound groups, their occurrence in foods, and their potential effects on humans.
Wakame contains, among other things, the following secondary plant compounds:4,20,21
- Isoprenoids: Triterpenes: Steroids (Fucosterol), Saponins; Tetraterpenes: Carotenoids: Carotenes (Beta-carotene), Xanthophylls (Zeaxanthin, Fucoxanthin, Fucoxanthinol)
- Polyphenols: Phenolic acids: Hydroxybenzoic acids (4-hydroxybenzoic acid, protocatechin acid, syringic acid), Hydroxycinnamic acids (caffeic acid, ferulic acid); Flavonoids: Flavonols (quercetin, quercitrin), flavanones (naringenin, naringin), flavones (cacticin); Tannins: Phlorotannins (fucole, phloroeckol, eckol, carmalol)
- Other plant compounds (including protease inhibitors): Chlorophyll a and c
Gentle drying at 40 °C preserves the metabolites in wakame better than drying at 80 °C, researchers found. Furthermore, freeze-drying preserved the metabolites better than oven drying.25
Studies report on the antioxidant effect of steroids, carotenoids, phenolic acids, flavonoids and phlorotannins in wakame extracts. Oxidative stress occurs in the human body when there is an imbalance between the production of reactive oxygen species (ROS), also known as free radicals, and the body's own antioxidants during metabolic processes. An excess of reactive oxygen leads to cell damage to DNA, proteins, lipids, and cellular membrane systems. Antioxidants stabilize free radicals and thus help prevent microbial inflammation, tumor formation, obesity, diabetes, high blood pressure, and cardiovascular disease. Research is increasingly focusing on the discovery of natural antioxidants, particularly for the development of therapeutic or functional foods.4
Specifically, fucoxanthin and fucoxanthinol improve inflammation caused by obesity. Fucosterol prevents acute lung damage by inhibiting pro-inflammatory signaling pathways. Phlorotannins occur as complexes in the cell wall components of algae and exhibit diverse bioactive properties, especially with regard to their wound-healing power. In particular, eckols and phloroeckol suppress pro-inflammatory enzymes and thereby inhibit infections caused by bacteria such as Staphylococcus aureus, Pseudomonas aeruginosa, or Escherichia coli.
A study shows how different cooking methods affect the fucoxanthin content in dried Undaria pinnatifida. While the fresh seaweed contained 20.70 mg/100g dry weight (DW) of fucoxanthin, all four tested cooking methods led to an increase. The content rose particularly sharply with boiling (24.49 mg/100g DW) and blanching (22.98 mg/100g DW). This could be because heat releases bound fucoxanthin, alters the cell structure, and facilitates extraction. Furthermore, heat inactivates oxidizing enzymes that prevent further degradation.24
The cooking method negatively affects the chlorophyll a content. Values decreased to 6.29 mg/100g fresh weight after blanching, steaming, boiling, and baking, respectively – 4.23 mg/100g, 5.13 mg/100g, and 2.70 mg/100g – each significantly below the value of fresh algae (8.34 mg/100g). The loss followed the following pattern: blanching (24.50 %) < boiling (38.45 %) < steaming (49.32 %) < baking (67.59 %). Presumably, heat breaks down chlorophyll into pheophytins, while cell contents leach into the cooking water. The loss was particularly pronounced during baking at 160 °C, which is attributed to thermal degradation. These results are consistent with previous studies on other algae and vegetables.24
Dangers - Intolerances - Side Effects
The brown seaweed wakame, and seaweed in general, is a source of the essential trace element iodine. Iodine plays an important role in thyroid function, as it is required for the synthesis of thyroid hormones. However, long-term, high iodine intake is problematic and can lead to thyroid dysfunction (e.g., hyperthyroidism).
The recommended daily intake of iodine is 150 µg/day for adults. The Scientific Committee on Food (SCF) has established a tolerable upper intake of 600 µg/day. The amount of brown algae biomass that corresponds to a given amount of iodine varies considerably. While processing methods (e.g., drying) significantly reduce the iodine content of brown algae, it remains high even after processing. The stated maximum daily intake of iodine for adults (600 µg) can be achieved by consuming 0.2 to 11 g of processed, dried brown algae.
Therefore, consume brown algae, including wakame, only in small quantities (max. 1 g/day) and ensure that the iodine content and a maximum recommended daily intake are indicated when purchasing algae products. This allows you to estimate your iodine intake and avoid excessive consumption. A healthy body stores 10-20 mg of iodine and has a reserve that lasts for several weeks without additional intake. People with thyroid dysfunction should avoid consuming wakame.
Algae products may contain traces of crustaceans, so caution is advised for people with a crustacean allergy.
Folk medicine - Natural medicine
Traditional medicine in Asia has used wakame for more than 2000 years as an active ingredient for edema, mucus elimination, diuresis, and detoxification.5
Ecological Footprint - Animal Welfare
The primary indicator for assessing the climate-friendliness of a food product is its CO2 footprint . This depends on various factors, such as cultivation method (conventional/organic), seasonality, country of origin, processing, transport, different packaging types, and whether the product is fresh or frozen. Organic seafood, as with land products, is preferable.
While we did not find specific values for the ecological footprint of wakame, we did find data for other seaweed species: dried sugar kelp (S. latissima) has a carbon footprint of 6.12 kg CO2 eq/kg, and fresh, even wetter, 0.16 kg CO2 eq/kg. One red algae species (Gracilaria lemaneiformis) used for agar production even had a negative carbon footprint (-7.21 kg CO2 eq/kg), meaning the algae were able to store more CO2 than they released during production. On average, seaweed is a very climate-friendly food.
Algae farms appear to be more sustainable compared to land cultivation. This is because the cultivation of seaweed requires no fresh water (keyword: water footprint), no chemical fertilizers, and no soil – which are significant negative factors of land-based farming.13 In contrast to seaweed (macroalgae), the cultivation of microalgae (e.g., Chlorella vulgaris) often takes place on land in artificial ponds, which requires more input.14,15
Algae remove CO2 from the atmosphere, which benefits the climate. According to researchers at the Max Planck Institute for Marine Microbiology in Bremen, brown algae absorb large quantities of carbon dioxide from the air and release some of the carbon it contains back into the environment in the form of mucus. Because this algal mucus, called fucoidan, is difficult for other marine organisms to break down, the carbon remains bound within it and does not return to the atmosphere for a long time. Researchers estimate that brown algae could thus absorb up to 550 million tons of carbon dioxide from the air annually.
Brown algae also influence the atmosphere and climate by emitting large amounts of iodine, particularly algae of the genus Laminaria, as they are strong iodine sinks. These iodine emissions have been shown to affect aerosol formation, coastal cloud formation, and climate warming. Rising global iodine emissions could accelerate the melting of Arctic sea ice.18,19
Detailed explanations of various sustainability indicators (such as ecological footprint, CO2 footprint, water footprint) can be found in our article: What does the ecological footprint mean?
Animal welfare – Species conservation
Wakame is often considered one of the worst invasive species in the world. Although wakame prefers cold water (5–20 °C), it exhibits a high tolerance for sunlight and temperature. It is able to withstand high waves, salinity, and other harsh environmental conditions. High population densities result in a dramatic appearance in highly invasive locations due to its large and conspicuous sporophyte stage. However, the situation in Australia shows that while wakame can very successfully invade a wide range of coastal areas, there is little evidence of direct harmful effects.3,8,9
The commercial cultivation of seaweed in ever-larger areas leads to the uptake of essential nutrients by algae. This can have harmful consequences for the marine ecosystem, including a reduction in phytoplankton growth, disruption of marine food webs, increased noise pollution from harvesting machinery, an increase in algal diseases that threaten wild seaweed populations, and sedimentary anoxia and hypoxia (oxygen depletion) in groundwater. It is therefore essential to analyze the environmental impact on the surrounding ecosystem before commercial seaweed cultivation is established in new areas.
Global Distribution - Cultivation
The brown algae species wakame (Undaria pinnatifida) is native to the cold temperate seas of China, Japan, and Korea. Intentionally and unintentionally, it has spread to many other locations, including the European Atlantic, the French Mediterranean, Australia, and New Zealand. As an invasive species, it exhibits a high tolerance for light, temperature, and salinity (see chapter "Ecological Footprint - Animal Welfare"). Wakame has a long history of large-scale cultivation in China, Japan, and Korea.1,3,8
In the EU, 99 % of algae production comes from wild stocks. Globally, the opposite trend exists, with 99 % of algae coming from cultivation. Although large parts of European marine regions, such as the Mediterranean and the Black Sea, are unsuitable for algae cultivation, the untapped potential for this purpose remains substantial. Atlantic waters are suitable for cultivating cold-water algae, such as wakame. Parts of the Baltic Sea are also usable. However, the areas used must be sufficiently cold and have a sufficiently high salinity for cold-water algae.
The consumption of and demand for algae is increasing among the European population. However, the calculated harvest volume from potentially usable European areas is smaller than the projected demand in European markets. Therefore, in addition to expanding algae cultivation, it is important to conduct research to optimize algae farming. This includes identifying the most suitable species for cultivation, developing innovative cultivation techniques, and improving harvesting methods.
Wakame is native to the cold-temperate regions of the northwestern Pacific Ocean (along the coasts of Japan, Korea, Russia, and China). It is non-native, or invasive, almost worldwide.8
In Northeast Asia, wakame is an annual winter species that inhabits rocky substrates from the low intertidal zone down to 18 m depth and is widespread at depths of 1 to 3 m. The algae grow up to 1–1.7 cm per day, reach a length of 1.3 to 2 m, and have a maximum lifespan of about 6 to 8 months. The thallus (vegetative body) of wakame is anchored by a fibrous peduncle that functions as a root, while the midrib is connected at the end to rolled-up, wing-like leaves. Sporophylls (spore-bearing leaves) are present only in mature plants.
Cultivation - Harvesting
Information on the cultivation of wakame seaweed can be found under Wakame, raw.
Industrial Production
To achieve the desired color and quality, blanching wakame seaweed after harvesting is common practice. This changes its original brownish color to green. The color change is due to a modification of the enzymes associated with chlorophyll and occurs above 65 °C. Salting is common in industrial products, as it preserves the seaweed. Prolonged heating at excessively high temperatures degrades the chlorophyll to pheophytin, and the color reverts to brown. Improper cooking can also cause wakame to regain its brown color during storage.
The drying process involves several steps: washing, shredding, desalting, and drying. Large quantities of wakame often pass through a roller dryer.12 Sun-dried wakame seaweed is also available.11 Gentle drying below 42 °C results in raw food-quality products.
Further information
The macro-brown alga Wakame (Undaria pinnatifida) belongs to the family Alariaceae within the order Laminariales.
Also read our articles on other brown algae such as arame, bladderwrack, kombu (dried) and laminaria, and on red algae (seaweed) such as cartilaginous kelp, dulse (dried) and nori sheets.
Alternative names
What is wakame called in German? The Japanese name wakame is also common in German, often also wakame seaweed. In English, it is known not only as wakame but also as sea mustard or Japanese kelp.
Bibliography - 19 Sources (Link to the evidence)
| 1. | * "Wakame blades are green when cooked and have a subtly sweet flavor and satiny texture. The blades are normally cut into small pieces as they tend to expand during cooking." "In Japan and Europe, wakame is consumed either dried or salted. It is mainly used in soups (particularly miso soup) and salads (tofu salad), or simply used as a side dish. These dishes are typically dressed with soy sauce and vinegar/rice vinegar. In addition, Goma wakame, also known as seaweed salad, is a popular side dish at American and European sushi restaurants. Literally translated, it means “sesame seaweed”, as sesame seeds and oil are usually included in the recipe." "Fucoidan is usually extracted from brown seaweeds, including Undaria pinnatifida. Fucoidan exhibits beneficial bio-activity and has antioxidant, anticancer, and anticoagulant properties." "The brown seaweed species U. pinnatifida (Figure 2) is native to the cold temperate seas of China, Japan, and Korea, and has been introduced in many other places including the Europe Atlantic, French Mediterranean, Australia, and New Zealand (Figure 3). It is regarded as a highly invasive species with a high tolerance for light, temperature, and salinity [5,6]. It is also highly fertile with high growth rate and large reproductive output, releasing spores all year round [6,7]. It is farmed extensively in Japan, Korea, and Japan and as such, it is an abundant source from which fucoidan could be extracted and used." Narratives Review DOI: 10.3390/md16090321 Study: weak evidence | Zhao Y, Zheng Y, Wang J, et al. Fucoidan Extracted from Undaria pinnatifida: Source for Nutraceuticals/Functional Foods. Mar Drugs. 2018;16(9):321. |
| 2. | ● Website | USDA United States Department of Agriculture. |
| 3. | * "Extracts of U. pinnatifida possess exceptional bioactivities such as antioxidant, anticancer, anti-coagulant, anti-inflammatory, anti-diabetes and anti-microbial properties which are mainly exerted by polysaccharides, carotenoids, tocopherols, phycobilins, phycocyanins, vitamins, fatty acids and sterols (Wang et al. 2018), as well as amino acids, peptides and proteins (Zhang, Pang, and Han 2014)." "According to the findings of a number of studies, excellent bioactivities possessed in proteins of U. pinnatifida may lead to the utilisationof these proteins in various nutraceutical applications, as antioxidant, antihypertensive, anticancer, anticoagulant, antidiabetic and antimicrobial agents. Similar studies done on nutraceutical applications of proteins of other seaweed species warrant these potential applications." "It was first found in China, Japan and Korea and has spread to more than twelve countries comprising Spain, Australia, France, Italy, North and South America, Argentina and New Zealand (Mak et al. 2014)." "The quantity of U. pinnatifida production in 2014 from China, the major producer in the world, was 203,099 tonnes dry weight from 7693 production sites. It corresponded to 2,030,990 tonnes of wet weight and the total global production was 2,359,000 tonnes of wet weight in the same year (FAO 2016). The total global productions of U. pinnatifida in past 50 years are illustrated in Figure 2. China, Japan and Republic of Korea mainly contribute to the global production of U. pinnatifida and the extensive commercial cultivations have been developed in these countries due to growing demand for U. pinnatifida as food and feed ingredient, especially after 2002." "Though U. pinnatifida favors cold water (5–20 C), it shows greater tolerance to sunlight and temperature. It is capable of withstanding high wave exposure, salinity and other harsh environmental conditions (Hewitt et al. 2005). Generally, they are 60–120 cm long seaweeds which reach to 2–3 m length at maturity. Thallus of U. pinnatifida is fixed with fibrous holdfast which acts as the root of plant while the midrib of pant is attached to rolled wing-like blades at the end. Sporophyll is only present in mature plants and stipe extents sway from holdfast becoming the midrib (Figure 1)." Narratives Review DOI: 10.1080/10408398.2021.1898334 Study: weak evidence | Nadeeshani H, Hassouna A, Lu J. Proteins extracted from seaweed Undaria pinnatifida and their potential uses as foods and nutraceuticals. Crit Rev Food Sci Nutr. 2022;62(22):6187-6203. |
| 4. | * "U. pinnatifida is edible seaweed and rich in carbohydrates, unsaturated fatty acids, protein composition, vitamins, and minerals, as well as natural bioactive compounds such as polyphenols, pigments, and phytosterols. Because of these components, U. pinnatifida possesses various bioactivities such as antioxidant, anti-inflammatory, anticancer, anti-obesity, anti-diabetes, and anti-hypertensive activity." Narratives Review DOI: 10.1016/j.aquaculture.2018.06.079 Study: weak evidence | Wang L, Park YJ et al. Bioactivities of the edible brown seaweed, Undaria pinnatifida: A review. Aquaculture. 2018;495:873-880. |
| 5. | * "The water extraction and alcohol precipitation method are the most used method. More than 40 U. pinnatifida polysaccharides (UPPs) were successfully isolated and purified from U. pinnatifida, whereas only few of them were well characterized. Pharmacological studies have shown that UPPs have high-order structural features and multiple biological activities, including anti-tumor, antidiabetic, immunomodulatory, antiviral, anti-inflammatory, antioxidant, anticoagulating, antithrombosis, antihypertension, antibacterial, and renoprotection." "Numerous studies have found that polysaccharides of U. pinnatifida play an indispensable role in the nutritional and medicinal value." "Undaria pinnatifida, one of the most widespread seafood consumed in China and many other nations, has been traditionally utilized as an effective therapeutically active substance for edema, phlegm elimination and diuresis, and detumescence for more than 2000 years." Narratives Review DOI: 10.1016/j.ijbiomac.2022.02.138 Study: weak evidence | Zeng J, Luan F et al. Recent research advances in polysaccharides from Undaria pinnatifida: Isolation, structures, bioactivities, and applications. Int J Biol Macromol. 2022;206:325-354. |
| 8. | * "The kelp Undaria pinnatifida, or “Wakame,” has a global non‐native range and is considered one of the world's “worst” invasive species. Since its first recorded introduction in 1971, numerous studies have been conducted on its ecology, invasive characteristics, and impacts, yet a general consensus on the best approach to its management has not yet been reached." "Native to cold‐temperate areas of the northwest Pacific (the coastlines of Japan, Korea, Russia, and China), the adventive kelp Undaria pinnatifida (Harvey) Suringar, 1873 (Phaecophycae, Laminariales), or “Wakame,” has a worldwide non‐native range (Figure 2). First identified as an invasive species on the Mediterranean coast of France in the 1970s (Perez, Lee, & Juge, 1981), Undaria pinnatifida (hereafter referred to as Undaria) is now established on the coastlines of 13 countries across four continents (James, Kibele, & Shears, 2015)." "It is also a major species for seaweed mariculture in China, Japan, and Korea (Yamanaka & Akiyama, 1993), with total world yield in 2013 exceeding 2 million tonnes fresh weight (FAO FishStat)." "In its native northeast Asia, Undaria is a winter annual species that inhabits rocky substrates from the low intertidal to 18 m depth, and is widespread at depths of 1–3 m (Koh & Shin, 1990; Saito, 1975; Skriptsova, Khomenko, & Isakov, 2004). ... Sporophytes can grow up to 1–1.7 cm per day, reach 1.3–2 m in length, and have a maximum life span of around 6–8 months (Castric‐Fey, Beaupoil, Bouchain, Pradier, & L'Hardy‐Halos, 1999; Choi, Kim, Lee, & Nam, 2007; Dean & Hurd, 2007)." Narratives Review DOI: 10.1002/ece3.3430 Study: weak evidence | Epstein G, Smale DA. Undaria pinnatifida: A case study to highlight challenges in marine invasion ecology and management. Ecol Evol. 2017;7(20):8624-8642. |
| 9. | * Undaria is often considered to be one of the world's worst Narratives Review DOI: 10.1016/j.marenvres.2017.09.015 Study: weak evidence | South PM, Floerl O et al. A review of three decades of research on the invasive kelp Undaria pinnatifida in Australasia: An assessment of its success, impacts and status as one of the world’s worst invaders. Marine Environmental Research. 2017;131:243-257. |
| 11. | ● "Parental plants that are used for yearly sporeling production come from the farmed population. Parental plants are usually reserved on lone-lines until end of June after commercial harvest at the end of April. The plants are cultured under relatively deep water to elongate the time at sea until seeding process (hatchery) starts." "At the end of June, when seawater temperature rises to 18–19 °C, well-matured sporophylls are cut off from the sporophytes, brought to land and dried in ambient temperature for 1–2 hours in a shaded place. Sporophylls are then put into filtered seawater for releasing spores, again at ambient temperature (16–18 °C). When the concentration of spores in the water reaches 100 000–150 000 per millilitre, the sporophylls are removed from the water, and collectors are inserted. Collectors are constructed by wrapping 2 mm thick nylon string around a plastic frame made of polyvinyl chloride (PVC) pipes. Collectors are removed from the seeding tank once the string are seeded with sufficient spores (50–100 spores within a 100× microscopic field), and are then transported in tanks of filtered seawater for the next step of the hatchery process. In the northern hemisphere, the hatchery starts in June when seeding spore onto collector is performed and ends in late of September when the seawater temperature drops to 22 °C, which is optimal for 200 µm long sporophytes to grow rapidly. The collectors are then transported to open sea and further grown at a water depth where the irradiance is about 200–300 µmol photons m-2 s-1. The sporeling string is cut into 5 cm long pieces for insertion onto the main cultivation ropes when open sea cultivation starts." "Cultivation of U. pinnatifida starts at sea by laying the longline horizontally and inserting sporeling strings at intervals of 35–40 cm. These strings will hang in the water, usually within 1 m of the surface. The interval between the horizontal longlines is 2 m. Each individual longline is 8 m in length. The initial sporeling is roughly 1 cm long. They will reach 2–3 m between outplanting in October and harvesting in April. Each individual longline can produce approximately 80–130 kg fresh Undaria biomass. The main variables to final production weight are the location, water current (strong current is favoured) and water depth where they are farmed." "Harvesting starts in February when the sporophyte thalli reach approximately 1.5–2 m, and ends in late April. Plants are harvested manually by cutting the plants off the main cultivation rope. Sporophylls and thalli are packed separately and transported to the processing facility on the same day." "Sporophylls are frozen immediately, while the remaining parts are bathed in hot water (85–95 °C) for approximately 20–60 seconds. The cooked plants are then thoroughly salted. The salted plants are packed in bags and pressed with heavy objects overnight to remove the excess salt water. Thereafter, the midribs and blades are separated manually by hand, packed into boxes and stored between -5 and -5 °C." "In Japan, there are various kinds of commercial wakame products, including: dehydrated or dried, seasoned and instant wakame food. Most of the dehydrated products are of the traditional type, such as Suboshi and Haiboshi wakame. Compared with Suboshi wakame that is dried under the sun without ash treatment, Haiboshi wakame can keep its vivid green colour during storage at 35 °C for 50 days in the dark." Website | |
| 12. | * "The tops and bottoms of the Undaria are trimmed at harvest, and the thallus is briefly blanched in sea water (rarely in fresh water); this changes its color from brown to bright green. The color change results from a change in chlorophyllrelated enzymes, and is regulated by time and temperature of blanching. The color change occurs above 65 C, but if the wakame is heated at too high a temperature for too long, chlorophyll is degraded to phaeophytin and the color changes to brown. Failure in the boiling process frequently leads to Undaria turning brown during storage. After blanching, Undaria is cooled, mixed with salt and preserved overnight in a highly-saturated salt water solution. The salted blades are then drained and allowed to dehydrate for several days, after which the mid-ribs are removed. The blade portions are further dehydrated before being checked for quality and packed into polyvinyl packages, which are stored at -20 C." "In this process, the boiled and salted product is washed, chopped, desalted and dried at the factory. We use mechanical drying because the final product rehydrates quickly. However, large quantities of Undaria are processed through a rolling dryer, as this results in an end product comprised of small, easily-packed pieces (Iwasaki & Sato 1984). Less than 10% of the moisture is retained, which is good for product-stability during storage." Narratives Review DOI: 10.1007/BF00004026 Study: weak evidence | Yamanaka R, Akiyama K. Cultivation and utilization of Undaria pinnatifida (Wakame) as food. J Appl Phycol. 1993;5(2):249-253. |
| 13. | ● "Ocean farms are seemingly more sustainable compared to land-based agriculture because cultivation of seaweeds requires no fresh water, chemical fertilizer, or land, which are the significant negative factors to land-based cultivation." DOI: 10.1016/B978-0-12-418697-2.00001-5 Book: weak evidence | Tiwari BK, Troy DJ. Seaweed sustainability – food and nonfood applications. In: Tiwari BK, Troy DJ. (Ed.) Seaweed Sustainability. Academic Press. 2015;1–6. |
| 14. | * A 2014 study found Narratives Review DOI: 10.3389/fnut.2022.1029841 Study: weak evidence | Diaz CJ, Douglas KJ et al. Developing algae as a sustainable food source. Front Nutr. 2023;9:1029841. |
| 15. | ● Numerous studies have assessed the environmental impacts of full-scale algae cultivation in recent years (Richardson et al., 2012; Lardon et al., 2009; Gallagher, 2011). The impacts most commonly considered in these assessments include energy use, water consumption, land use, and greenhouse gases emissions: First, energy expenditure can be required for mixing to prevent biomass settling during cultivation for gas transfer to supply CO2 and remove excessive oxygen (Keymer et al., 2013) and for temperature control if overheating is a critical issue (Bechet et al., 2014). This energy consumption can generate indirect CO2 emissions depending on the source of energy ultimately used. Second, water is consumed during harvesting (efficient recycling can be challenging), leaks, and free-surface evaporation in open ponds, causing a level of water demand that can stress local water resources (Yang et al., 2011; Wigmosta et al., 2011; Guieysse et al., 2013b). Third, generating large quantities of algal biomass requires large land areas (Bechet et al., 2013b), which may cause a range of economic, social, and ecological impacts even if “marginal” land is used. Finally, microalgae were recently shown to produce significant amounts of nitrous oxide N2O (Alca´ntara et al., 2015; Guieysse et al., 2013a), which is a potent greenhouse gas and ozone-depleting pollutant (Myhre et al., 2013). DOI: 10.1016/B978-0-08-101023-5.00021-2 Book: weak evidence | Béchet Q, Plouviez M et al. Chapter 21 - Environmental impacts of full-scale algae cultivation. In: Gonzalez-Fernandez C, Munoz R. Microalgae-Based Biofuels and Bioproducts [Internet]. Elsevier; 2017:505–525. |
| 18. | * "The genus Laminaria comprises the strongest accumulators of iodine currently known and are major emitters of both molecular iodine and iodinated organics into the atmosphere. These latter species are important contributors to the surface destruction of tropospheric ozone, contributing to coastal cloud formation and are an important link between ocean biology, atmospheric composition, and climate." "It (Laminaria digita) is the strongest iodine accumulator among all living systems that is currently known, and its iodine emissions have an established impact on aerosol formation." "Finally Laminaria digitata (Oarweed), is the major kelp species on North Atlantic rocky shores, including Maine and the Canadian Maritimes, Newfoundland and the European Atlantic coast from Brittany (France) to northern Norway." Narratives Review DOI: 10.1039/c8mt00327k Study: weak evidence | Küpper FJ. Carrano CJ. Key aspects of the iodine metabolism in brown algae: a brief critical Review. Metallomics. 2019;11(4):756–764. |
| 19. | ● "Die steigenden globalen Jod-Emissionen könnten demnach in der Arktis das Abschmelzen des Meereises weiter beschleunigen." Website | Universität Innsbruck. Jod aus den Weltmeeren beeinflusst das Klima. 2021. |
| 20. | * Brown seaweeds are recognized sources of compounds with a wide range of properties and applications. Within these compounds, phlorotannins are known to possess several bioactivities (e.g., antioxidant, anti-inflammatory, and antimicrobial) with potential to improve wound healing. To obtain phlorotannins enriched extracts from Undaria pinnatifida, a biorefinery was set using low-cost industry-friendly methodologies, such as sequential solid–liquid extraction and liquid–liquid extraction. The obtained extracts were screened for their antioxidant and antimicrobial activity against five common wound pathogens and for their anti-inflammatory potential. The ethanolic wash fraction (wE100) had the highest antioxidant activity (114.61 ± 10.04 mmol·mg−1 extract by Diphenyl-1-picrylhydrazyl (DPPH) and 6.56 ± 1.13 mM eq. Fe II·mg−1 extract by and Ferric Reducing Antioxidant Power (FRAP)), acting efficiently against Gram-negative (Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria, and showing a nitric oxide production inhibition over 47% when used at 0.01 µg·mL−1. NMR and FTIR chemical characterization suggested that phlorotannins are present. Obtained fraction wE100 proved to be a promising candidate for further inclusion as wound healing agents, while the remaining fractions analyzed are potential sources for other biotechnological applications, giving emphasis to a biorefinery and circular economy framework to add value to this seaweed and the industry. In Vitro Laborstudie DOI: 10.3390/biom11030461 Study: weak evidence | Ferreira CAM, Félix R et al. A biorefinery approach to the biomass of the seaweed undaria pinnatifida (Harvey Suringar, 1873): obtaining phlorotannins-enriched extracts for wound healing. Biomolecules. 2021;11(3):461. |
| 21. | * The alga Undaria pinnatifda is able to synthesize a great variety of bioactive metabolites of pharmaceutical and other industrial interest. However, this species has not yet been comprehensively studied in the Golfo San Jorge region (Chubut, Patagonia Argentina). Thus, in the present study, U. pinnatifda was collected at Golfo San Jorge, seasonally extracted and the chemical profle and biological activity evaluated by diferent techniques. The results showed that U. pinnatifda fundamentally biosynthesizes phenolic acids (cafeic and ferulic acids), favonols and favanol glycosides (quercetin, cacticin, quercitrin), carbohydrates, tannins, lipids, saponins, quinones, steroids, triterpenes and cardiotonic glycosides (of the k-strophanthoside, sciloriside, adynerin and convalatoxin types), with diferences according to the season. The extracts also showed moderate antioxidant activity by the DPPH method and outstanding cytotoxic activity by the Artemia salina test. Based on the results obtained, U. pinnatifda can be considered as a potential source of bioactive molecules. Variations in the metabolites were observed throughout the seasons; particularly in the winter season, favonoids were present in hexane and chloroform extracts, but not in methanol; tannins and other phenolic derivatives in the three winter extracts. This shows the importance of conducting seasonal studies to determine the best season for collection based on the metabolites to be studied. In vitro Laborstudie DOI: 10.1007/s10811-023-03058-0 Study: weak evidence | Quezada DP, Flores ML, Córdoba OL. Seasonal chemical screening and biological activity of Undaria pinnatifida (Harvey) suringar (Alariaceae, laminariales, phaeophyta), collected at golfo san jorge (Patagonia argentina). J Appl Phycol. 2023;35(5):2413–2429. |
| 22. | ● Website | ÖNWT - Die österreichische Nährwerttabelle: Wakame getrocknet (ÖNWT-TCM G015410). |
| 24. | * Undaria pinnatifida (U. pinnatifida) is an edible brown seaweed with high health value. The objective of this study was to evaluate the effect of traditional cooking methods (i.e., blanching, steaming, boiling and baking) on the color, texture and bioactive nutrients of U. pinnatifida, so as to screen out the traditional cooking methods more suitable for U. pinnatifida. In this study, methods of blanching and boiling resulted in better reduction in total color difference (0.91 ± 0.58 and 0.79 ± 0.34, respectively) and retention of chlorophyll A (62.99 ± 1.27 µg/g FW and 51.35 ± 1.69 µg/g FW), along with better elevation of fucoxanthin content (increased by 11.05% and 18.32%, respectively). Baking method got the best retention of total phenol content (1.62 ± 0.11 mg GAE/g DW), followed by methods of boiling and blanching (1.51 ± 0.07 mg GAE/g DW and 1.43 ± 0.05 mg GAE/g DW). Among these cooking methods, blanching and boiling seemed to be the more suitable for U. pinnatifida compared to other methods. These results could help to determine the better cooking methods for U. pinnatifida products and provide a scientific and theoretical basis for improving human dietary health. Experimentelle Laborstudie DOI: 10.3390/foods11081078 Study: weak evidence | Jiang S, Yu M et al. Traditional cooking methods affect color, texture and bioactive nutrients of Undaria pinnatifida. Foods. 2022;11(8):1078. |
| 25. | * Metabolomics is often used to comprehensively elucidate the metabolites in organisms like seaweed. Amino acids hydrolysed from proteins and certain targeted metabolites in seaweed have been investigated. However, water-soluble metabolites like free amino acids, organic acids, and sugars have seldom been comprehensively analysed. Metabolomics are valuable tools for these studies, but they require optimisation of pre-treatment methodology. Here, we evaluated various pre-treatment drying and extraction methods for brown seaweed metabolomics. Three edible brown seaweeds (Cladosiphon okamuranus [Mozuku], Saccharina japonica [Kombu], and Undaria pinnatifida [Wakame]) were used. Freeze-drying and oven-drying at both 40 and 80 °C were investigated. Methanol-water extracts with and without chloroform were compared. Metabolites were evaluated and quantified using liquid chromatography-mass spectrometry and capillary electrophoresis-mass spectrometry. The results showed that metabolite profiling was determined mainly by seaweed species identity rather than pre-treatment method. Freeze-drying yielded higher metabolite concentrations than oven-drying at either 40 or 80 °C. The effects of extraction with and without chloroform on metabolite concentration varied with seaweed species. Experimentelle Laborstudie DOI: 10.1007/s10811-018-1614-z Study: weak evidence | Hamid SS, Wakayama M et al. Drying and extraction effects on three edible brown seaweeds for metabolomics. J Appl Phycol. 2018;30(6):3335–3350. |
| We have categorized studies and books on nutrition and health according to the following 3 evidence categories: green = strong evidence, yellow = medium evidence, purple = weak evidence. The remaining sources are marked ingray . You can find a detailed explanation in our article: Science or Belief? How to evaluate publications.. | ||
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