Pour the egg mixture into the pan a little at a time over low heat. Place the nori sheet on the wooden surface and, using chopsticks or a wooden spatula, fold the set egg mixture together on itself several times to create a flat, layered omelette tamago. Remove the omelette from the pan and press itinto shape with a bamboo rolling mat, which will imprint a nice surface texture on it.
Different species of seaweeds avail themselves of a variety of strategies in order to grow. In sea lettuce Ulva lactuca , the cells all undergo division more or less randomly throughout the organism. Other species, among them several types of brown algae, have a growth zone at the end of the stipe and at the bottom of the blade; this is where an existing blade grows and new blades are formed.
The oldest blades are outermost, eventually wearing down and falling off as the seaweed ages. As a result, the stipe can be several years old, while the blades are annuals. This growth mechanism allows the seaweed to protect itself from becoming overgrown by smaller algae, called epiphytes, which fasten on to it. On certain seaweed species, the epiphytes are found overwhelmingly on the stipes, which can become covered with them, while the blades retain a smooth surface as long as they are young and still growing.
Finally, some types of seaweeds, such as bladder wrack Fucus vesiculosus and the majority of the red algae, grow at the extremities of the blades. The overall effect of seaweeds on the global ecosystem is enormous.
It is estimated that all algae, including the phytoplankton, are jointly responsible for producing 90 percent of the oxygen in the atmosphere and up to 80 percent of the organic matter on Earth. We can compare their output with that of plants by looking at the amount of organic carbon generated per square meter on an annual basis. Macroalgae can produce between 2 and 14 kilograms, whereas terrestrial plants, such as trees and grasses in temperate climates, and microalgae can generate only about 1 kilogram.
The vast productive capacity of macroalgae can possibly be best illustrated by the fact that the largest brown algae can grow up to half a meter a day.
That amounts to a couple of centimeters an hour! Seaweeds are made up of a special combination of substances, which are very different from the ones typically found in terrestrial plants and which allow them to play a distinctive role in human nutrition. Most notably, the mineral content of seaweeds is 10 times as great as that found in plants grown in soil; as a consequence, people who regularly eat seaweeds seldom suffer from mineral deficiencies.
In addition, marine algae are endowed with a wide range of trace elements and vitamins. Because they contain a large volume of soluble and insoluble dietary fiber, which are either slightly, or else completely, indigestible, seaweeds also have a low calorie count. A wild strain of Chondrus crispus , or Hana-Tsunomata in Japanese, appeals to both the eye and the palate.
This seaweed has a distinct crunchy texture and a milder taste than most other sea vegetables. Its flamboyant colors—pink, green, and yellow—are completely natural. Marine algae possess a fantastic ability to take up and concentrate certain substances from seawater. For example, the iodine concentration in konbu and other types of kelp is up to , times as great in the cells of the seaweeds as in the surrounding water, and the potassium concentration is 20—30 times greater.
On the other hand, the sodium content is appreciably lower than that of salt water. Depending on the species, fresh seaweeds are 70—90 percent water by weight. The composition of the dry ingredients in the different types of seaweeds can vary a great deal, but the approximate proportions are about 45—75 percent carbohydrates and fiber, 7—35 percent proteins, less than 5 percent fats, and a large number of different minerals and vitamins.
Broadly speaking, the proteins in seaweeds contain all the important amino acids, especially the essential ones that cannot be synthesized by our bodies and that we therefore have to ingest in our food. Porphyra has the greatest protein content 35 percent and members of the order Laminariales the lowest 7 percent.
Three groups of carbohydrates are found in seaweeds: sugars, soluble dietary fiber, and insoluble dietary fiber. Many of these carbohydrates are different from those that make up terrestrial plants and, furthermore, they vary among the red, the green, and the brown species of algae.
The sugars, in which we include sugar alcohols such as mannitol in brown algae and sorbitol in red algae, can constitute up to 20 percent of the seaweeds. The seaweed cells make use of several types of starch-like carbohydrates for internal energy storage; again, these vary according to species. For example, the brown algae contain laminarin, which is of industrial importance as it can be fermented to make alcohol. Norwegian winged kelp Alaria esculenta is appearing on the menus of top restaurants.
Soluble dietary fiber, which is situated in between the seaweed cells and binds them together, constitutes up to 50 percent of the organism. Composed of three distinct groups of carbohydrates, namely, agar, carrageenan, and alginate, fiber can absorb water in the human stomach and intestines and form gelatinous substances that aid in the digestive process. Insoluble dietary fiber derived from the stiff cell walls of the seaweeds is present in lesser quantities, typically amounting to between 2 percent and 8 percent of the dry weight.
Cellulose is found in all three types of algae and xylan another type of complex carbohydrate in the red and green ones.
The primary mineral components in seaweeds are iodine, calcium, phosphorous, magnesium, iron, sodium, potassium, and chlorine. Added to these are many important trace elements such as zinc, copper, manganese, selenium, molybdenum, and chromium. The mineral composition, especially, varies significantly from one seaweed species to another. Konbu contains more than —1, times as much iodine as nori.
On average, dulse—a widely eaten red seaweed—is the poorest choice in terms of mineral and vitamin content but, on the other hand, it is far richer in potassium salts than in sodium salts. In general, marine algae are a much better source of iron than foods such as spinach and egg yolks. Seaweeds contain iodine, although the exact quantities again vary greatly by species.
The iodine content is dependent on where the seaweed grew and how it has been handled after harvest. Furthermore, the iodine is not evenly distributed, being most abundant in the growing parts and least plentiful in the blades.
In particular, the brown seaweeds contain large amounts of iodine. It is not known for certain why brown seaweeds contain so much iodine, but this is probably linked to their capacity for rapid growth. Iodide was found to act as the main antioxidant for this tissue. In addition, the study showed that the action of iodide was not accompanied by an accumulation of organically bound iodine. The history of the discovery of iodine as an element actually begins with seaweeds.
He noticed that his chemical experiments with the seaweed ash gave rise to a violet-colored vapor that condensed as crystals on his copper vessels and, unfortunately, caused them to corrode. Courtois convinced first his French, and later his English, fellow chemists that his discovery had important dimensions. Their work then rapidly led to the identification of the substance that was the source of the vapors. It turned out to be a previously unknown element and, as the color violet is called iodes in Greek, the new element was given the name iodine.
Terrestrial plants are a poor source of iodine, which can result in iodine deficiency in vegetarians and vegans. The accidental discovery of iodine in seaweeds is a wonderful example of how research and an open mind on the part of the researcher can lead to results that have a major significance for the economy and for human health. Despite their importance to human diet, seaweeds have often been regarded with disdain.
That unpleasant smell is due to a number of gases that are not dangerous, but are the source of odors that we consider offensive. In a bowl mix together the oats, seeds, seaweeds, salt, and baking powder.
Add water and mix well until the dough becomes sticky. Divide the dough into two and place one part on a piece of baking paper. On top of the dough add another piece of baking paper and roll the dough out as thinly as possible between the two.
With a knife or pizza wheel cut the top baking paper and divide the dough into squares without cutting through the bottom paper. Remove the top baking paper and place the dough and the bottom paper on a baking sheet. Repeat the procedure with the other part of the dough. The multicellular algae just have a stalk to support its filaments. Gordon T. Taylor via Commons Wikimedia public domain. Now, what about underwater plants? Are all of those green things in the aquarium algae?
An example of an aquatic plant is Elodea, a common waterweed which is widely used to decorate aquariums and artificial aquatic environments. This plant belongs to the group of Angiosperms, of the Kingdom Plantae. This kingdom is comprised of vascular and avascular photosynthetic organisms, that is, with or without the presence of vessels that are responsible for the conduction of mineral salts and water. Vascularization is also responsible for the presence or absence of the reproductive parts; in the case of Angiosperms these reproductive parts generate flowers, leaves and fruit.
The leaves of the submerged aquatic plants are generally very thin and stubby, allowing them to support turbulence and oscillations of the water, without tearing.
The leaves of the aquatic plants also have a permeable surface, which aids in internal circulation of the air. Cifonauta- Banco de Imagens de Biologia Marinha.
Acesso em: 06 dez. Algae: Protists with Chloroplasts. Each type of seaweed has its own habitat, and many red seaweeds grow in places where they can attach themselves to other organisms.
Brown seaweeds grow in colder waters, and there are about 1, species in this group. Giant kelp is one type of brown seaweed. Often growing in towering groups, kelp form dense clusters in shallow waters, creating communities that are like underground forests.
Giant kelp can grow over 33 meters long, and scientists have recorded ten to twelve inches of growth a day in giant kelp that live in Monterey Bay off the coast of California. Besides being an important food source in parts of the world, seaweeds also contain anti-inflammatory, anti-microbial and cancer-fighting compounds that are used for medical purposes, according to the National Ocean Service.
Seaweeds have been used for thousands of years for their health-promoting properties. Seaweeds also play an important role in underwater ecosystems. They provide food and shelter for fish and other marine animals like sea urchins and crustaceans.
Living at the base of the food chain, they support many other life forms in aquatic communities. Just like other photosynthetic organisms, seaweeds produce oxygen as a byproduct of photosynthesis. It is estimated that algae produces 30 to 50 percent of Earth's oxygen, which sustains humans and other species that live on land and in the sea. As it captures carbon, seaweed also helps to reduce the acidity of the ocean.
Seaweeds reduce pollution by absorbing excess nutrients and toxins — like organic chemicals and heavy metals — from the water. They also soak up micronutrients and antioxidants from clean water, making them an excellent fertilizer for farms.
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