In the early spring, seasonal vegetables have been listed, in the spring shoots, cabbage, cress and other vegetables "compete for the glory", toon but with the Shanghai Pudong market 90 yuan a pound of "sky-high price" rushed to the hot search, netizens directly called "can't afford to eat"!
According to the merchant quotation of the Guangzhou takeaway platform, the price of toon in Guangzhou is about 15 yuan / 100 grams, and the freshly picked toon can reach 20 yuan / 100 grams, which is comparable to the price of the Shanghai Pudong market. Even from this quotation model, we can see the "golden price" of toon: other vegetables are sold by the pound, and it is sold by two.
Why is the value of toon still high? It is understood that one is because toon is a very seasonal vegetable; the other is that toon is only young buds for consumption, and the initial production is small.
It's time to eat toon, so let's take a comprehensive look at the history of toon, explore the special taste of toon and the health knowledge contained in it.
01
The past and present lives of toon
Toon was first published in the ancient book of Mountains and Seas of the Pre-Qin Dynasty, "the mountain of waiting, its mountain has many trees", which has been cultivated in China for more than 2,000 years. Modern research has found that toon may not have originated in China. The report in Plant Research speculates that toon should have originated in tropical Asia in northeastern India and Myanmar and its neighbors.
Although toon may have come from overseas, in China, the history of eating toon is particularly long, and the folk saying "March 8, eat Tsubaki buds" is still circulating. As early as the Han Dynasty, folk tsubaki eating habits have spread all over the north and south of the river, and the Ming Dynasty's "Imperial Capital Scenery and Material Strategy" said, "New Year's Day into chun buds, cucumbers, one bud and one melon, a few thousand thousand dollars", obviously has been promoted to the palace tribute.
There are many ways to eat toon, raw and cooked salt, oil and salt, stir-fry gluten, blanch soup into tea, mix tofu... They are all popular dishes.
Just as pine cypress is proud of snow bucket frost, willow soft and long stay, toon also has its own unique cultural imagery in the long river of ancient Chinese culture. "Xuantang" is the ancient mother's name, "椿" and "萱" together called "椿萱", referring to the parents. Tang Yin of the Ming Dynasty has a poem "Chun Xuan Tu", "Lacquer Garden Tsubaki Tree Millennium Color, Tangbei Xuan Root MarchFlower." Skillfully painting and dancing in pairs, the parents will never live forever", which expresses the admiration of Tsubaki and Mao.
02
Why is toon so "fragrant"
Some researchers analyzed the volatile chemical components contained in toon, and finally detected 53 compounds from its volatile oils, the composition is mainly alkenes, olefins, terpenes and enols account for 73.98% of the identified substances, and alcohol compounds account for 7.69%. Other components include aldehydes, ketones, esters, ethers, furans and sulfur-containing and nitrogen compounds, accounting for about 10.67%.
The special aroma of toon comes from thiophenes, lipids, aldehydes, hydrocarbons and other substances, and the content of these ingredients will also vary.
Studies have shown that the characteristic aroma components of toon are mainly trans-2-hexenal (trans-2-hexenal), 2,5-dimethylthiophene (2,5-dimethylthiophene) and 3,4-dimethylthiophene (3,4-dimethylthiophene).
Toon leaves are rich in 16 kinds of amino acids, with a total content of up to 27.43%, of which glutamic acid content is the highest. Glutamic acid, aspartic acid and sodium chloride react to produce sodium glutamate and sodium aspartate, these two compounds are important umami substances in food, of which sodium glutamate is the main component of our common monosodium glutamate. The glutamic acid and aspartic acid contained in toon are 42.33% of the total amino acids, ranking first among wild vegetables such as cabbage and bracken. This explains why toon is so delicious after cooking.
It is worth noting that there are often Ailanthus in the market who mistakenly enter the team of Toon. Although the two are very similar in appearance, they are two very different plants. Toon contains special aromatic volatile substances, which have a unique aroma when smelled, while ailanthus, although similar in appearance to toon, has a strange odor and has a certain toxicity. When shopping for toon, it can be distinguished by slightly twisting the leaves to smell the smell.
03
Toon has exquisite medicinal uses
Toon is not only delicious, but also has medicinal value.
More than 1,300 years ago, the "Tang Materia Medica" first recorded the medicinal value of toon, calling it "the main treatment of scabies, wind scabies"; Li Shizhen of the Ming Dynasty also recorded in the "Compendium of Materia Medica" that "toon leaves are bitter, warm boiled water washes scabies, young buds are eaten, wind and detoxification; white skin and root bark, bitter, warm and non-toxic" effects.
As a famous medicinal and edible woody plant in China, toon has a medicinal history of thousands of years, and its roots, bark, buds, leaves, and fruits can be used as traditional Chinese medicine, and modern pharmacology has also scientifically explained and analyzed the chemical active ingredients and pharmacological effects of toon.
Pharmacologists have found that the young leaves of toon contain flavonoids, terpenes, anthraquinones, saponins, tannins, alkaloids and other important medicinal components through material extraction and animal experiments, which have the effects of sterilization, anti-inflammatory, analgesic, anti-cancer, inhibition of platelet aggregation, antioxidant and hypoglycemia.
(1) Antibacterial, anti-inflammatory, analgesic effect
Pharmacologists conducted in vitro antibacterial experiments on the aqueous extract and alcohol extract of toon bark, and found that they had a strong inhibitory effect on Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, etc.; preliminary pharmacodynamic experiments found that the two compounds isolated from toon had the effect of dissolving phlegm, anti-inflammatory and enhancing immunity; and animal experiments also found that oral water extracts from toon leaves slowed the pain of mice and showed analgesic effect.
(2) Hypoglycemic effect
Animal experiments have shown that toon leaves will and only lower the blood sugar of diabetic mice, and will not affect the blood sugar of normal mice. Clinical studies have shown that toon leaf water extract can reduce the blood glucose value of diabetic patients, even for patients with hyperglycemia that cannot be improved by general hypoglycemic drugs, and can also alleviate chronic complications such as numbness in the limbs, body aches and unstable blood pressure caused by diabetes.
(3) Hypotensive effect
Vascular smooth muscle cells are the main cellular components that make up the tissue structure of the blood vessel wall and maintain blood vessel tone, and the changes in their mechanism and function are the cytopathological basis for various cardiovascular diseases such as hypertension and atherosclerosis. Changes in the concentration of calcium in the blood affect the function of many cells, including the contractile function of vascular smooth muscle cells, which play an important role in the formation of vascular resistance. A substance in toon can reduce the concentration of calcium ions in vascular smooth muscle cells, which plays a role in relaxing blood vessels and lowering blood pressure.
(4) Anti-cancer effect
Studies have found that toon young leaves can inhibit the growth of certain cancer cells, such as A549, H226 lung cancer cells, Co10205 rectal cancer cells, U-20S monster cells, and HepG2 and C3A liver cancer cells. At present, the inhibitory effect of toon on cancer has been carried out to the stage of animal experiments, and the results have found that the anti-cancer effect is obvious, which may be related to alkaloids and other substances in the leaves of toon.
04
Toon is eaten with care
Although toon has a good health effect, its nitrate and nitrite content is also higher than that of ordinary vegetables, and many people are worried that eating too much will cause cancer.
Nitrates and nitrites are widely present in the water and soil of nature, and some nitrite substances are formed by plants absorbing nitrogen in the soil during growth, which is one of the natural substances of plants. Therefore, most vegetables will contain a certain amount of nitrate and nitrite substances, but the content will be different.
Nitrate itself is not toxic, but after entering the human body, bacteria in the mouth and intestines will reduce it to nitrite with a certain degree of toxicity. Nitrite is not carcinogenic, and after entering the body, it will react with the decomposition product of the protein under acidic conditions to generate nitrosamines, and "nitrosamines" are the carcinogens that have been identified.
In 2002, the United Nations Who's Joint Committee of Experts on Food Additives (JECFA) set the intake of nitrite at 0.07 mg/kg (calculated as nitrite ions), which was later changed to 0.13 mg/kg.
Throughout the growth cycle, the content of nitrite varies between about 1.475 and 2.778 μg/g. If an adult weighing 60 kg wants to eat toon and eat nitrite poisoning, he needs to eat nearly 2 kg or so of toon.
In addition to avoiding ingestion of nitrite directly from plant species, it is relatively important to reduce the uptake of nitrite in the body to convert to nitrite. It is worth noting that the nitrate content in toon buds ranges from 500 mg/kg to 3000 mg/kg, so eating 100 g of toon buds may reach the upper limit of nitrate intake.
It is time to taste "Tsubaki" in early spring, and toon is delicious but not gluttonous, and eating too much toon or the wrong way of eating it will increase the health risk. We can reduce this risk by taking the right way to eat:
1. It is recommended to eat toon with a relatively tender texture, or fresh toon buds;
2, should be blanched before eating the buds of toon that are not fresh or about to be refrigerated;
3. It is most appropriate to control the time of pickled toon buds in 2 weeks;
4. Supplemented by eating foods with high vitamin C content.
Liu Jia, attending physician of the Department of Clinical Nutrition of the Third Affiliated Hospital of Guangzhou Medical University, said: "(Toon) contains a lot of carotene, which is very good for the eyes. Toon is a photosensitive food, and some patients with chronic diseases, eye diseases, and skin diseases are not recommended to eat toon. ”
This article was first published on Healthnews21
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