For hundreds of years, people living near the oceans consume algae that are edible, tasty and beneficial to health. However, historically, it is the Asians who have developed a real culinary tradition with seaweed. The interest that Westerners have shown in it really became apparent when they realized that they brought exceptional and rare nutrients (antioxidants, mineral salts, trace elements, vitamins, proteins in the form of amino acids).
Origins of sea lettuce
Sea lettuce (Ulva lactuca) belongs to the family of Ulvaceae and is one of the many existing species of marine green algae. It looks a little like lettuce in the garden, it is 20 cm high but can extend more. It is characterized by a fine texture and very flexible, elastic, allowing it not to tear at the slightest snap. Its green color is due to the chlorophyll it contains.
She lives only a few months but she can pick herself up all year knowing that the periods of renewal are the most suitable, namely spring and autumn, because they are still young. Attention to areas where it is highly developed, which is an indicator of eutrophication of water that is to say that water contains a lot of nitrogen and phosphorus, phenomenon due to agricultural pollution (slurry, pesticides...) but also to urban wastewater discharges. As sea lettuce is nitrophilous, it appreciates the abundant presence of nitrogen and when it tends to become invasive, it becomes a good bioindicator "nitrogen pointer", but also indicating the presence of metals such as manganese, nickel, iron, copper, zinc, cadmium, lead. It is therefore important to ensure that sea lettuce comes from A zones, classified by the Ministry of Agriculture after analysis of the absence of bacteriological or chemical pollution.
Sea lettuce is found in the Atlantic Ocean, many on the coasts of Brittany, but also in the North Sea, Channel and Mediterranean, on the supralittoral part, that is to say the nearest part of the land that is submerged only by high tides, storms and spray. She picks up young, hung on the ground, on the dyke, the jetty or the rocks: what allows it to fix itself to its support, it is a small disk of fixation on which one finds a mini stipe. It can also grow up to 10 meters under water.
The nutritional benefits of sea lettuce
Sea lettuce is eaten raw or cooked (10 to 15 minutes in water) and is cooked in different ways, added in a salad, an omelette or with fish for example. It is appreciated for its firm and tender consistency as well as its fresh but pronounced taste that can recall that of sorrel.
The consumption of sea lettuce (30 to 45 kcal / 100 g) provides little iodine compared to other algae, but it allows to provide large intakes of vitamin C since it contains 8 times more than orange, calcium, iron and magnesium with a quantity 10 times higher than milk, spinach and wheat germ, without forgetting that sea lettuce is also a source of vitamin A, chlorophyll, while being rich in protein, fiber, mineral salts and low in fat. Curiously, it also has a low sodium content. Its high content of antioxidants makes it particularly attractive especially to prevent the appearance of certain cancers and cardiovascular diseases.
Conservation and use of sea lettuce
Apart from its fresh food consumption, sea lettuce may be frozen or dried away from sunlight which may discolour it. Once dehydrated, in the form of flakes, it will stay dry, cool and dark, until you use it as a condiment or rehydrating it.
Sea lettuce can be gathered for other purposes than culinary, especially when it has developed a lot on a coastal area, since seaweed is a fertilizer for the garden.