Algae (food)

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Dried kombu seaweed
Dried nori seaweed

Algae , especially seaweed , are mainly consumed as food in East Asia , Polynesia and in coastal regions of Europe and America. Depending on the type, they are almost tasteless or have a spicy-salty taste. The varieties known in Europe today through Japanese cuisine include kombu , wakame and the nori used for sushi . In Asia, algae grow in seawater for up to a year. Algae from European breeding (for example off Sylt ) are harvested after three to four months.

Algae contain carbohydrates and proteins that can only be partially digested, i.e. fiber . Because of this and because of their low fat content , algae have only a low quantitative nutritional value . They contain a high proportion of minerals and vitamins . Due to their sometimes very high iodine content , algae should only be consumed in moderation and should be avoided if the thyroid is overactive . A high iodine content is predominantly found in algae imported from Asia.

tradition

The use of algae by humans is difficult to prove archaeologically, so most of the evidence goes back to written sources. The consumption of algae has a long tradition - at least in Asia. He has been from China since around 2500 BC. Chr. Handed down; from there it was adopted in Japan , Korea and the Pacific Islands.

In Japan, remains of seaweed of the genera Eisenia and Sargassum were found together with fish bones and mussel shells in settlements from the Jōmon and Yayoi times ; this points to the consumption of algae as early as prehistoric times . An early written testimony is the Taihō Code from the year 701 AD, which lists algae such as Laminaria , Undaria , Porphyra and Gelidium among the marine products that are paid as tax to the imperial court. In the early Heian period , 21 types of seaweed were used as food, as evidenced by the oldest Sino-Japanese dictionary in Japan, called Wamyōshō and compiled by order of Emperor Daigo . During the Heian period, nori algae were reserved for the nobility. At the time of the Warring States , edible algae such as Hizikia , Laminaria , Eisenia , Undaria , Nemacystus and Porphyra, along with seafood and fish, were used to feed the armies. It was not until the Edo period that nori became an essential part of Makizushi, and the feudal government ordered that brown algae of the genera Laminaria , Undaria , Ecklonia and Hizikia be stored as well as grain to prevent famine. Laminaria species were also used to make confectionery at the beginning of the Edo period. In addition, the processing of algae into agar began in the Edo period .

Economic importance and use

Today, between eight and eleven million tons of algae are harvested from farms around the world, some of which is processed into animal feed, fertilizer or cosmetics. In Japan, around 300,000 tons are sold as food every year. In China, around three million tons are consumed annually as cooked vegetables or soup.

The Asian cuisine uses algae frequently and in many ways. You can, fried, steamed or cooked in vinegar are inserted serve as spice or tea . Algae are processed into salads or added to soups , eaten as a vegetable side dish or dried as a snack . In Japan, algae account for up to 20% of the daily consumption.

Algae still play a subordinate role in European cuisine to this day. The consumption of algae has a long tradition in Wales , among others . Under the name “Laver Bread”, the black bread from the sea used to be a food for Welsh farmers, today it can be found in various forms in Welsh cuisine. The algae of the genus Porphyra umbilicalis used for this are also exported to France , Holland and Luxembourg . In France and Ireland , up to 1,000 tons of seaweed are consumed each year. Algae products for the delicatessen market come from Spain. In the 1990s, an ecologically compatible algae production was established on the Galician coast as part of the “Porto Muinos” project.

As a raw material for food additives such as agar , alginate and carrageenan , algae are of great importance for the food industry . Algae and algae products like agar are also used in molecular cuisine.

composition

100 grams of fresh algae contain on average:

ingredient salary
water 90.5 g
protein 5.9 g
carbohydrates 2.1 g
fat 0.4 g
Iodine 50.0 µg

The calorific value of 100 g of algae is 153.3 kJ (36.5 kcal). Dried seaweed consists of 25 to 75% fiber , which is predominantly water-soluble.

Risks

Iodine content

The iodine content of 50.0 μg / 100 g given above is an average value that relates to fresh algae. Above all, algae imported from Asia can contain significantly more iodine, as algae in Asia grow longer in seawater and accumulate more iodine until harvest. In dried algae products, the proportion of around 90 percent water is missing in fresh algae, the iodine content per 100 g is accordingly around ten times higher in dried algae products. The German Nutrition Society (DGE) recommends a maximum daily intake of 200 micrograms iodine. If the iodine content of algae products is unknown and the amount consumed is handled uncritically, there is a risk of iodine oversupply .

The Federal Institute for Consumer Health Protection and Veterinary Medicine (BgVV) and the Federal Institute for Risk Assessment (BfR) issued warnings about dried algae products with excessive iodine content in 2001 and 2004 (updated in 2007). In 2017, the German consumer advice centers pointed out that the problem is still topical. Above all, they warn of products that do not contain any information on the iodine content or the maximum consumption. The consumer advice centers refer to frequent reports on the Internet portal www.lebensmittelwarnung.de as well as in the European rapid warning system RASFF , which warn of products with a high iodine content.

Toxins in AFA algae

The AFA algae (green span algae ), which are also popularly known as blue or blue-green ancient algae, are cyanobacteria , which are often offered as a dietary supplement . Certain strains produce toxins that can damage the nervous system and liver. The BfArM issued a warning in 2002 and issued a notice to counter misleading and scientifically unsubstantiated advertising claims on the health-promoting effects of food supplements made from AFA algae.

Types of algae used

Around 220 species of algae are grown worldwide. The following types of food are mainly used:

See also

literature

  • Éric Coisel: Enjoyment from the sea: Algae - simply delicious & healthy . Hädecke Verlag, Weil der Stadt 2004 (224 pages).
  • Ole G. Mouritsen: Seaweeds: edible, available & sustainable . The University of Chicago Press, Chicago, London 2013 (English, 287 pages, limited preview in Google Book Search).

Web links

Commons : algae as food ( Edible seaweed )  - collection of pictures, videos and audio files

Individual evidence

  1. ↑ A. Jiménez-Escrig, FJ Sánchez-Muniz: Dietary fiber from edible seaweeds: Chemical structure, physicochemical properties and effects on cholesterol metabolism . In: Nutrition Research . tape 20 , no. 4 , 2000, pp. 585-598 , doi : 10.1016 / S0271-5317 (00) 00149-4 (English).
  2. ↑ Ole G. Mouritsen, Prannie Rhatigan, José Lucas Pérez-Lloréns: World cuisine of seaweeds: Science meets gastronomy give an incorrect year (701 BC) for the “Tahio Codex” (correct: Taihō Codex ) . In: International Journal of Gastronomy and Food Science . tape 14 , 2018, p. 56 , doi : 10.1016 / j.ijgfs.2018.09.002 (English). Correct and more detailed: Kazutosi Nisizawa, Hiroyuki Noda, Ryo Kikuchi, Tadaharu Watanabe: The main seaweed foods in Japan . In: Hydrobiologia . tape 151 , no. 1 , 1987, pp. 5 , doi : 10.1007 / BF00046102 (English).
  3. ↑ Thierry Chopin, Manav Sawhney: Seaweeds and their Mariculture estimate 11.3 million tons of algae from aquaculture . In: John H. Steele (Ed.): Encyclopedia of Ocean Sciences . 3. Edition. tape 2 . Academic Press, 2009, pp. 493-502 , doi : 10.1016 / B978-0-12-813081-0.00757-6 (English).
  4. ↑ Ole G. Mouritsen, Prannie Rhatigan, José Lucas Pérez-Lloréns: World cuisine of seaweeds: Science meets gastronomy . In: International Journal of Gastronomy and Food Science . tape 14 , 2018, p. 56 , doi : 10.1016 / j.ijgfs.2018.09.002 (English).
  5. ↑ aid: Focus on nutrition . 9th year, August 2009, p. 322 .
  6. ↑ A. Jiménez-Escrig, FJ Sánchez-Muniz: Dietary fiber from edible seaweeds: Chemical structure, physicochemical properties and effects on cholesterol metabolism . In: Nutrition Research . tape 20 , no. 4 , 2000, pp. 585 , doi : 10.1016 / S0271-5317 (00) 00149-4 (English).
  7. ↑ BgVV warns of health risks from iodine-rich algae products. Press release. April 3, 2001, Retrieved September 4, 2019 .
  8. ↑ BfR: Health risks from excessive iodine content in dried algae. Updated BfR Opinion No. 026/2007 dated June 22, 2004 ( PDF ; 189 kB ) Retrieved on September 4, 2019 .
  9. ↑ Consumer advice center : Often too much iodine in seaweed. July 13, 2018, accessed September 4, 2019 .
  10. ↑ BgVV and BfArM warn: Food supplements made from AFA algae cannot replace medical therapy. August 2002, accessed September 4, 2019 .
  11. ↑ Thierry Chopin, Manav Sawhney: Seaweeds and their Mariculture . In: John H. Steele (Ed.): Encyclopedia of Ocean Sciences . 3. Edition. tape 2 . Academic Press, 2009, pp. 493-502 , doi : 10.1016 / B978-0-12-813081-0.00757-6 (English).
  12. ↑ ( Page no longer available , search in web archives: M. Harrison: Edible Seaweeds around the British Isles . Wild Food School, 2008. )@1@ 2Template: Dead Link / www.countrylovers.co.uk
  13. ↑ Michael Guiry: Himanthalia elongata (Linnaeus) SF Gray. In: The Seaweed Site: information on marine algae. Retrieved September 4, 2019 .