Mining

English name: laver, seaweed

Rhodophyta: the general name of Porphyra. Porphyra contains up to 29 ~ 35% of protein, iodine, vitamins and inorganic salts. It tastes delicious and can be used to treat goiter and lower cholesterol. It is an important economic seaweed. Widely distributed all over the world, but mainly distributed in temperate zones. About 70 species have been found. The natural growth of laver is limited, and the output mainly comes from artificial breeding. Porphyra haitanensis, Porphyra yezoensis and Porphyra tender are the main cultured varieties.

Japanese name is laver. Porphyra is a marine red algae. The thallus is composed of a layer of cells embedded in a thin layer of colloid, which is dark brown, red or purple. The sexual reproductive structure is at the edge of the thallus. It is distributed in the northern and southern hemispheres, grows at the high tide line of intertidal zone, and grows best in nitrogen-rich waters (such as near the outlet of sewage pipes). After harvesting and drying, it can be used as food, and its consumption exceeds that of other algae. Artificial farming is an important food in eastern countries. It can be used as the main ingredient of soup, other food and meat seasoning. In the British Isles, laver is baked on bread and tastes like oysters.

[Edit this paragraph] A brief history

As early as 1400 years ago, Yao Min's Book of the Northern Wei and Qi Dynasties in China mentioned that "all of them are in the seaside mountains of Wudu, and they know how to eat laver". According to Meng E's Herbal Medicine for Dietotherapy in the Tang Dynasty, laver was "born in the South China Sea, blue in color, with stones attached and dried purple". During the Northern Song Dynasty, laver has become a precious tribute. In the book Compendium of Materia Medica in Ming Dynasty, Li Shizhen not only described the morphology and collection method of laver, but also pointed out that laver was mainly used for "hot air disturbing the throat" and "scabies and lumps, so it is appropriate to eat laver often". Breeding has a long history. Japanese fishermen may have collected natural seedlings with bamboo branches and branches in the first half of the17th century, and then cultivated them with bamboo curtains and natural fiber cross-net curtains. For a long time, laver seedlings can only rely on natural growth, with limited sources and small-scale breeding activities. 1949, K.M. Drew of Britain discovered for the first time that the important fruiting spore growth period of laver was spent in shells, which opened the way for studying the source of natural seedlings. Then in 1953 and 1955, China Zeng Chengkui revealed the whole life history of laver, which laid a theoretical foundation for artificial breeding. Since then, laver culture has entered the period of full artificial production, and the output has been greatly improved.

[Edit this paragraph] Biometrics

Porphyra is simple in shape and consists of three parts: a disc-shaped fixer, a handle and a blade. Leaves are single or branched membranous bodies composed of 1 layer cells (a few species have 2 or 3 layers), and their length varies from several centimeters to several meters according to different species. Contains chlorophyll, carotene, lutein, phycoerythrin, phycocyanin and other pigments. Different kinds of laver show purple, blue-green, reddish brown, green brown and other colors because of their different content ratios, but most of them are purple, so they are named laver.

The life of laver includes two distinct stages: the larger thallus (gametophyte generation) and the smaller filamentous body (sporophyte generation). The thallus is sexually propagated, and the vegetative cells are transformed into female and male cells respectively. After fertilization, female cells divide many times to form fruit spores, which are released from algae after maturity, attach to calcareous shells and other substrates with the flow of seawater, germinate and grow in the shells. Grow into filaments. Filaments grow to a certain extent to produce cyst branches of conchospores, and then divide to form conchospores. After release, the shell spores attach to rocks or artificial stakes or net curtains and germinate directly into phyllodes. In addition, some kinds of bacteria can also reproduce asexually, from vegetative cells to monospores, and grow directly into bacteria after spreading and attaching. Monospore is also one of the important seed sources in aquaculture production.

Porphyra thallus mostly grows in intertidal zone, and likes the sea area with strong wind and waves, gentle tidal current and rich nutrition. Strong anti-drying ability; The suitable light intensity is 5000 ~ 6000 lux, which has the characteristics of high light saturation point and low light compensation point and belongs to high-yield crops. The adaptability to low temperature varies with the water content of algae. When it is quickly dried to a water content of 20%, it can still recover its vitality at a low temperature of about -20℃ for several months to 1 year. It has a wide range of application to the specific gravity of seawater, but 1.020 ~ 1.025 is suitable. Filaments have poor dry resistance and low requirements for light, and are naturally distributed below the low tide line. Under the condition that the temperature begins to drop and the sea water flows, conchospores are often released in large quantities at 9 ~ 1 1 every morning, showing obvious diurnal periodicity.

[Edit this paragraph] Breeding

The whole process can be divided into two stages: filamentous culture and leaflike culture.

Filamentous culture is a process of collecting fruit spores artificially, forming cyst branches of conchospores by cultivating filaments, and finally forming conchospores. Usually in the nursery. There are two ways to cultivate sea screw and free silk. Filamentous culture is carried out from February to March to September. Nurseries are mostly east-west, with skylights and side windows for lighting, or artificial light sources are added. Breeding ponds can be divided into two types: plane and three-dimensional. The former is 20 ~ 30 cm deep, and the culture medium-shells (mostly mussels) are laid flat on the bottom of the pool; The latter pool is 50 ~ 70cm deep, and shells are hung in the pool. When cultivating in spring, the fruiting spores of excellent laver are selected to make mushroom spore water, which is evenly sprayed on the shell and drilled into the shell, and shell spores can be formed after 4-5 months. The main management measures include: ① adjusting the light intensity. At first, it was 3000 lux, and gradually decreased to about 500 lux after the formation of shell sporangium branches; ② Apply nutrition. Potassium nitrate and potassium dihydrogen phosphate can be applied in a certain proportion according to different growth periods; ③ Control the water temperature. Therefore, the whole culture period of filamentous fungi is not affected by high temperature in summer and early cooling in autumn, and seedlings are harvested on schedule.

Free filamentous culture is to cultivate fruit spores in glass bottles and make them grow naturally into filaments. The ecological conditions during culture are basically the same as those of the same kind of laver. Free filament is mostly used as a breeding method for secondary seedling collection and application, but as a production method, it is still limited to individual areas.

The cultivation of Phyllostachys pubescens mainly includes several processes, such as collecting conchospores (also called seedling selection), seedling emergence management and vegetable cultivation. In autumn, the conchospores can be cooled to a certain temperature, and collected when the conchospores on Porphyra haitanensis (below 27℃) and Porphyra yezoensis (below 20℃) mature and begin to spread. Cultured filaments can be collected indoors or in the ocean. When picking seedlings indoors, synthetic fibers or brown ropes are woven into a net curtain as an attachment substrate and placed in a culture pool to naturally attach the shell spores to the net curtain; After a few hours, hang the net curtain in the sea. When collecting seedlings in the sea area, both the net curtain and the artificially cultured filamentous body should be placed in a preset device in the sea, so that shell spores can naturally attach to the net curtain. Due to the diurnal periodicity of the release of conchospores, the peak of the release is mostly between 10 ~ 1 1, so the seedlings are generally harvested in the morning. In addition, free silk can be used to collect conchospores.

The seedling stage is the time when the net curtain enters the sea and the seedlings are seen by the naked eye. In order to grow strong seedlings and full seedlings early, it is necessary to put net curtains at suitable tidal levels, remove weeds and fertilize in time. Rational fertilization, disease prevention and timely harvesting should be carried out in the leaf forming stage. The cold storage net technology adopted in Japan, that is, when the seedling grows to 1 ~ 3cm, it is quickly dried to a water content of 20%, then stored in the cold storage at -20℃ for several days to 1 year, and then put back into the sea to continue growing, which not only helps to avoid the occurrence of diseases, but also can replace the net curtain with the decreased quality of laver with cold storage net curtain to keep the produced laver young and tender.

The culture of bacteria can be divided into semi-floating raft and full floating raft according to the arrangement of net curtains in the sea area (see algae culture). The former is suitable for shallow sea beaches, while the latter is mainly used in deep sea areas. Both of these methods now use artificial culture of filaments and artificial seedling collection to provide seedling sources, which occupy a major position in production. In addition, there is a vegetable tank culture method in China, which mainly uses natural shell spores to culture on rocks. The unit output is high, but it is greatly influenced by natural conditions and the production is unstable. China also successfully attached the somatic cells of Porphyra yezoensis and Porphyra haitanensis to the screen by cell engineering technology.

The most common diseases in diseased silk culture are macular disease and mud red disease, both of which are caused by microorganisms. Can avoid purifying water quality and stabilize culture conditions. The common diseases of leaves are red rot and pitcher plant disease, which are mainly prevented by reasonable close planting and reasonable harvesting. In severe cases, the aforementioned cold storage net technology can be used.

After harvesting and processing the thallus for about half a year, fresh vegetables can be harvested several times regularly by machinery or hand until the next spring. Fresh vegetables are cut, washed, made into cakes and dried to make commercial laver for sale. Dried products can be used as cooking materials, and can also be processed into canned food for direct consumption.

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[Edit this paragraph] Chinese medicine-laver

Porphyra haitanensis Porphyra yezoensis Ueda. Dianthus suborbiculata Tenera Kelm. Other wild algae are algae. The algae body is purple, generally 12-30 cm high, and the longest cultured Porphyra haitanensis is more than 4 meters. Distributed in coastal areas from Liaoning to Guangdong.

The edible part of laver contains10.3g of water, 28.2g of protein, 0.2g of fat, 48.3g of carbohydrate, 343mg of calcium, 457mg of phosphorus, 33.2mg of iron,10.23mg of carotene,10.44mg of vitamin B and 22.07mg of vitamin.

Porphyra is sweet, salty and cold, and has the effects of resolving phlegm, softening hardness, clearing away heat and promoting diuresis, tonifying kidney and nourishing heart. Used for goiter, edema, chronic bronchitis, cough, beriberi, hypertension, etc.

[Edit this paragraph] Nutritional analysis

1. is rich in nutrition and high in iodine, and can be used to treat goiter caused by iodine deficiency. Porphyra has the function of softening and resolving hard mass, and is also useful for other blood clots;

2. Rich in choline, calcium and iron, it can enhance memory, treat anemia of women and children, promote the growth of bones and teeth, and promote health care; Contains a certain amount of mannitol, which can be used as an auxiliary food to treat edema;

3. Polysaccharides contained in laver can obviously enhance cellular immunity and humoral immunity, promote lymphocyte transformation and improve immunity; Can significantly reduce the total cholesterol content in serum;

4. The inhibitory rate of effective components of laver on Ehrlich cancer is 53.2%, which is helpful for the prevention and treatment of brain tumor, breast cancer, thyroid cancer, malignant lymphoma and other tumors.

[Edit this paragraph] Suitable for the crowd

Suitable for everyone.

1. It is especially suitable for patients with goiter, edema, chronic bronchitis, cough, swelling and pain, gonorrhea, beriberi, hypertension, early lung disease, cardiovascular disease, various lumps and hyperplasia.

2. It is not advisable to eat more, and people with poor digestive function and vegetarian spleen deficiency eat less, which can cause diarrhea; Abdominal pain loose stool fasted; Breast lobular hyperplasia and various tumors patients eat; It is not suitable for people with spleen and stomach deficiency and cold.

[Edit this paragraph] Cooking instructions

Generally speaking, hotels and families in Chinese mainland often use washed laver as soup. In fact, there are many ways to eat laver, such as cold salad, deep frying, stuffing, fried meatballs, crispy fried, cooked with eggs, meat, mushrooms, pea tips, carrots and so on as side dishes or main courses.

Soak the hair with clear water before eating, and change the water 1 ~ 2 times to remove pollution and toxins.

[Edit this paragraph] Therapeutic effect

Porphyra is sweet, salty and cold, and enters the lung meridian;

Has the effects of resolving phlegm, softening hard mass, clearing away heat, promoting diuresis, tonifying kidney and nourishing heart;

Used for goiter, edema, chronic bronchitis, cough, swelling and pain, gonorrhea, beriberi, hypertension, etc.

1. Used for resolving phlegm due to lung heat: laver 30g, radish 1, boiled soup. The method of treating all kinds of purulent sputum cough with laver is: grinding laver into powder, refining honey into pills, taking 6 grams after each meal, twice a day, or chewing laver dry.

2. The method of treating iodine deficiency goiter with laver is: take 30 grams of laver, 3 grams of dried tangerine peel and white radish 1 piece as soup every day. Or decocting Porphyra, Gynostemma pentaphyllum, Prunellae Spica and Scutellariae Radix in water.

3. Treatment of hypertension and blurred vision: laver and cassia seed can be decocted in water.

4. Treatment of chronic tracheitis: Porphyra, oyster and polygala can be decocted in water.

[Edit this paragraph] Other related

Porphyra was eaten in ancient China. What I first saw was the "purple color of nylon stratum" in Zuo Si's Five Degrees of Fu in the Jin Dynasty. According to Lu Yanji's note, the "purple" is "grass of the North Sea". There is a record of collecting laver in Ji Jie Ji in Tang Dynasty. By the Yuan Dynasty, "South Australia Porphyra" had been exported. Five Magazines in the Ming Dynasty pointed out that litchi, oyster house, roe fish and laver were regarded as the "four beauties" in Fujian, while the Spectrum of Sexy Diet contained the content of "nourishing the heart with blood".

About 300 years ago, laver was cultivated in Fujian, China by spraying lime water or putting bamboo curtains, which was also widely eaten in mainland China. In 1950s, scientists in China studied the source of Porphyra spores, which created conditions for artificial propagation.

[Edit this paragraph] Remarks

1. If the laver soaked in cold water is blue-purple, it means that the dish has been polluted by toxic substances before drying and packaging, and this laver is harmful to human body and cannot be eaten;

2. Porphyra is seafood, which is easy to regain moisture and deteriorate. It should be packed in black food bags, placed in a low-temperature dry place, or placed in a refrigerator to maintain its taste and nutrition.

[Edit this paragraph] Dietotherapy value

The thallus of Porphyra yezoensis and Porphyra rotundifolia. Also known as Zi Ying and Suocai. Liaoning, Shandong, Jiangsu, Zhejiang, Fujian, Guangdong and other coastal areas of China are all distributed. Some people also carry out artificial cultivation. Take it in autumn and winter, and dry it for later use (not too much sun or exposure).

[Sexual taste] Sweet, salty and cool. It can soften hard mass, clear away heat and phlegm, and promote diuresis and dampness.

[reference] contains protein, fat, carotene, vitamin B 1, B2, B 12, c, nicotinic acid, choline, amino acids (alanine, glutamic acid, aspartic acid, etc. ), iodine, calcium, phosphorus, iron.

[Purpose] Used for scrofula; Cough with thick phlegm; Drinking too much is annoying and hot; Beriberi, edema and dysuria.

[Usage] Decocting, boiling, grinding, etc.

[Note] "Supplement to Materia Medica" says: "Eating more makes people have abdominal pain, get angry and foam, and it will disappear with a little heating vinegar." Therefore, this product should not be used for a long time.

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1, laver soup: laver 15g, decocted in water; Or cook soup with pork and seaweed and season with oil and salt.

This prescription only works on the softening and hard mass of laver. Can be used for treating swelling and pain, scrofula, and phlegm-core lump.

2. Porphyra powder: Porphyra 15g, ground into fine powder. 5g each time, honey mixed with boiling water.

This prescription takes laver to clear away heat and phlegm, and honey moistens the lungs to relieve cough. Modern used for lung abscess, bronchiectasis, cough with thick phlegm or foul smell.