1) Green and blue-green seaweeds include: Enteromorpha sp. and Ulva lactuca;
2) Brown seaweeds include: Laminaria sp. and Undaria pinnatifida;
3) Red seaweeds include: Porphyra sp., Chondrus crispus, Palmaria palmata, Gelidium amansii.
kanten (Japan), dai choy goh (China), gulaman (Philippines)
Agar-agar is the Malay name for a gum discovered in Japan that had been extracted from a red seaweed of the genus Eucheuma and only locally used. Now, the name applies to a type of Japanese agar-agar, important both in Japanese cooking and worldwide consumption, which comes from red algae of the genus Gelidium. The gum is known in Japan as “kanten”, but is referred to by many names including ‘grass jelly’, ‘seaweed jelly’, and ‘vegetable gelatin’ since true gelatin is an animal product. Agar-agar is the most powerful gel-forming of all gums because of the unusual length of its carboyhydrate molecules. It is also unique in its ability to withstand near boiling-point temperatures, making it ideal for use in jellied confections in tropical countries.
The marine plant, from which this gum is extracted, is gathered and left on the beach to dry and bleach before being sold to a factory where it is beaten, washed, and boiled to extract the gum. Then, it is frozen and thawed. As the water runs out of it, so do any of the impurities, leaving the purified gum to be dried. This method of purifying (freezing and thawing) is said to have been discovered accidentally by a Japanese innkeeper during a frosty winter of 1658. Since then, the product has gained in popularity in Japanese cuisine, not only for making jellies, but also as a general thickener for soups and sauces.
During the 19th century, agar-agar was imported by western countries, not only for making desserts, but as a growth medium for bacteria experiments. During the WWII, when trade was suspended with Japan, western countries began looking at their own seaweed, but found the yield to be substantially inferior until they found that other seaweeds could give such other useful gums as alginates, carrageenan, and furcellaran. Since then, agar-agar has been less dominant in the market although it remains important to Japan. The seaweed in Japan called ‘ogo’ is another source of a similar product. Alginates is a general name for various gums extracted from brown algae, including Californian kelp, Macrocystis pyrifera, several Ascophyllum species, and oarweeds of the genus Laminaria, which grow along the British coast. The US and Britain are the chief producers. The use of alginates increased along with the growth of processed food and are now among the most widely used making excellent thickenings, emulsifiers, and stabilizers which can be dispersed in both hot and cold water. Although extensively used by the food industry, it is not used in domestic cooking.
Arame (Eisenia bicyclis) is a brown alga or kelp that is also known as sea oak because of the shape of its leaves. It grows wild on solid rock a few yards under the water’s surface on many Pacific coasts, and is one of the most nutritious of all plants.
dillosk (Scotland) (Palmaria palmata or Rhodymenia palmata) flourishes in the cold coastal waters of both the Atlantic and the Pacific, and is probably the most widely distributed of the edible red seaweeds. Today, this species is successfully cultivated along the coast of Brittany, in France. Dulse is a red seaweed that was prized by the Celts and the Vikings and has been harvested on beaches at low tide, air-dried, and boiled in soups from Ireland to Iceland well into the 20th century. The people of Scotland, Ireland, and Iceland have been using dulse for centuries, and collect it off their coasts with considerable difficulty. Many consider it to be the most delectable of all seaweeds. Dilsea carnosa is another type of edible seaweed, unrelated to the regular dulse, but identical in taste, appearance, and nutritional value. Dried dulse is a popular food in Canada, where much of the world’s supply is harvested in New Brunswick and Nova Scotia. From there, it is exported to Scotland, Ireland, and the US. There is a type that is processed in the US state of Maine; but, so far, it has proven inferior to the Canadian dulse. Dulse is extremely rich in iodine, phosphorus, calcium, and contains more potassium than any other food. In Canada, dulse is available in most major food outlets, but not so in the US, where there seems to exist an almost psychopathic horror to any seaweed. Dulse can be served in a variety of ways: as a side dish, in soups and salads, as a sandwhich ingredient or in powdered form to be used as a spice or flavouring.
Haricot vert de mer, sea spaghetti (Himanthalia elongata) is long, dark, and rich in trace elements and vitamins. It is successfully cultivated in Brittany, France, and increasingly exported fresh for the Japanese restaurant trade. The long strands must first have its furry layer removed by hand under cold running water before it is prepared for eating.
Hijiki, hiziki (Hizikia fusiformis) is among the most mineral-rich of plants, containing fourteen times as much calcium as cow’s milk. It is a highly branched black seaweed and so tough that after its first drying, it must be cooked for up to four hours under pressure before being allowed to dry again. It has a uniquely astringent, but nutty, flavour.
Irish moss, carrageen, Iberian moss (Chondrus crispus – Family Gigartinaceae) is actually a seaweed and not a moss. It is found along the coasts of the North Atlantic in both Europe and North America. It can either be reddish-purple or green in colour. Ireland is a major source of the world’s supply and where this vegetable is steamed and eaten with potatoes or cabbage. Its most common use outside of Ireland is in the making of rennet-free gelatin (carrageen), preferred by vegetarians since true gelatin is an animal product. This gelatin is extensively used in making various soft cheeses, ice cream, aspics, and jellies. Carrageen is a gum extracted from Chondrus crispus; and, although found on both sides of the Atlantic, it is especially associated with Ireland, where it is called ‘carrigin’ in Gaelic. These beautiful fan-like fronds have properties similar to Agar-agar and are used in a similar manner. A tea made from Irish moss is used as a tonic, being widely used in Irish folk medicine as a trusted cure for coughs and colds. The name carrageen is also applied to a related plant, Gigartina stellata, found growing in the Southern Hemisphere and used in New Zealand.
Kelp, kombu, konbu, laminaria (Laminaria japonica) is the best known species of kelp. It has broad, shiny leaves and flourishes in cool waters off the coasts of Japan, Korea, Siberia, and Brittany in Northwest France. It has been cultivated in Japan for about 300 years and elsewhere on a large scale for about forty years. A rich stock (dashi) can be prepared from kelp because of its concentration of the flavour-enhancer glutamic acid. The best varieties of kombu grow in the cool precoastal waters of the northern-most Japanese island of Hokkaido. Their broad, sweet-tasting, thalli (leaves) grow up to thirty-three feet long.
Laver (Porphyralaciniata) is a reddish purple, crinkly seaweed that is gathered off the shores of the British Isles. This ancient food has been valued for centuries by the Scots, Welsh, and Irish. When cooked, it turns a greenish brown. In Scotland, it is dipped in oatmeal and fried or made into a purée. The Welsh marinate it in oil and lemon juice and serve it with black pepper on toast. The water in which laver is cooked turns into a thick jelly that, when combined with potatoes and other vegetables, makes a delicious and healthy soup. Laver is not generally available outside of Great Britain and Ireland; but, with an increased interest in sea vegetables, it may not be long before it is also offered to North Americans. The Maritime Provinces of Canada have made an attempt in this direction to harvest and process a type of laver called “wild nort”.
Nori is the edible seaweed belonging to entirely different families of algae. There are about thirty different red and green seaweeds, mostly of the genus Porphyra and sold under the name of “nori”. The most important of these are Porphyra umbilicalis, P. tenera, P. yezoensis, and P. haitanensis. Nori is important from a culinary and an economic standpoint in Japan, where some 300,000 metric tons of fresh weight is harvested each year. Cultivation takes place on raft-like screens. The widely distributed species P. umbilicalis is native not only to Japan but also to the coasts of the Atlantic, the North Sea, the Baltic Sea, and the Pacific coasts of North and South America, and the beaches of Hawaii. In Ireland, it is called sloke; and, in Wales, laver, and eaten as a fresh vegetable. To obtain nori, fresh seaweed is chopped, pressed between bamboo mats, and dried either in drying rooms or in the sun. Good quality nori is mild-tasting and black in colour, but having a purple sheen. It should be packed airtight.
Sea lettuce, sea laver, lettuce laver, laitue de mer (Ulva lactuca) is quite a different plant altogether and not related at all to the seakale, a member of the cabbage family. Its thin, crinkled, lettuce-like leaves pass from pale to bright to dark green as they grow and age. It is a mild in flavour and exported fresh from France. When dried, it is reminiscent of spinach in smell and appearance. It has a worldwide distribution, and is possibly the most widespread of the edible green seaweeds. It can be used raw or cooked.
Red algae, red laver, edible seaweed (Porphyra abbottae, formerly P. perforata – Family Rhodophyta)
Seaweeds, marine algae, giant kelp, brown algae (Macrocystis integrifolia – Family Phaeophyta) Giant kelp is one of the largest marine algae with its deep, greenish brown, stem-forms or stipes that are only one or two cell-layers thick. Their large, flat leaf-like blades can be over a foot long and almost as wide, and mature blades can reach heights of five feet. They are found near rocks in the upper subtidal zone to a depth of about twenty feet. They are usually in large bed areas close to the open ocean, but not directly exposed to heavy surf. Red algae has a thin membranous blade that is broad and irregularly-shaped. When fresh, it is reddish-purple or greenish, having the consistency of cellophane; but, when dry, it becomes black and brittle. It is extremely rich in iodine and other minerals, especially calcium, iron, and fluorine and is especially beneficial to thyroid function. It is also known to lower blood cholesterol, alkalize the blood, remove radioactive residues from the body, help with weight loss, and act as an important aid in bone mineralization and density. Sea vegetables are also used to treat such conditions as goiter, water retention, and swollen lymph glands.
Spirulina is a spiral-shaped, blue-green, single-celled alga. It thrives in warm alkaline lakes around the world, including Lake Chad in Africa and Lake Texcoco in Mexico. Appearing like floating green scum, spirulina is collected and dried. It was such a highly valued, life-sustaining food by the Aztecs, that it was used as a form of currency. Spirulina is over 65% complete, predigested protein, making it much easier to digest in the human body. Spirulina also absorbs and retains many minerals from the water: potassium, calcium, zinc, magnesium, manganese, selenium, iron, and phosphorus. In addition, it is also rich in B vitamins, including usable amounts of B12, Vitamin E, beta carotene and chlorophyll. Spirulina has toning and cleansing properties, and is used to detoxify the liver and kidneys, cleanse the arteries, build and enrich the blood, and promote beneficial intestinal flora. It also contains high amounts of phenylalanine, an amino acid which curbs the appetite. Spirulina has been used to treat various ailments, including anemia, malnutrition, hepatitis, inner inflammations, diabetes, hypoglycemia, and poor skin tone. It also strengthens the immune system and helps prevent cancer because of its blue pigment called phycocyanin, a known cancer inhibitor.
Susabi nori (Porphyra yezoensis) flourishes best on coasts with a cold current, and now predominates in all regions of Japan.
Wakame (Undaria pinnatifida) is one of the most important species of seaweed, next to nori, on the Japanese menu, and is eaten both dried and fresh. The nutritional value is high, as the leaves consist of 13% protein, as well as containing substantial amounts of calcium. Wakame is a brown alga or kelp, and grows in water twenty to thirty feet deep. It is usually harvested from boats by means of long hooks and then sold fresh or sun dried. Since this seaweed is salted for transport, certain cleansing must take place before eating. Wakame must be thoroughly rinsed under running water, then placed in boiling water and boiled for thirty seconds, then rinsed in ice water. The leaves are then spread out and the hard midrib removed.