Common and Russian Dandelions: Nutrition, Latex, and Rubber
Edible and Useful Weeds
Dandelions are often considered to be annoying weeds, especially when they grow on lawns. Some people deliberately cultivate common dandelions in order to experience their nutritional and culinary benefits, however. The plants have another interesting benefit in addition to their edibility. They produce a thick liquid called latex, which can be turned into rubber. The Russian dandelion has the potential to become an excellent source of commercial rubber.
The use of Russian dandelions to produce rubber could soon become very important. Natural rubber is a valuable commodity because it has useful properties that synthetic rubber lacks. Unfortunately, there's a problem with the current supply of natural rubber from the para rubber tree. The Russian dandelion could be the answer to this problem.
Dandelions belong to the plant family known as the Asteraceae. This family was previously known as the Compositae. The latter term refers to the composite nature of the flower, which is really an inflorescence made of many smaller flowers, or florets.
Nutritional and Culinary Benefits of the Common Dandelion
The scientific name of the common dandelion is Taraxacum officinale. The plant has bright yellow flowers that are made of many tiny florets. The dandelion’s name comes from the French phrase “dent de lion”, which means "lion's tooth". The phrase refers to the deeply divided leaves of the plant.
The leaves make a nutritious but bitter salad green. Cooking the leaves reduces their bitterness. They are a good source of vitamin A (in the form of beta-carotene) as well as vitamin C. Vitamin C is destroyed by heat, however. The leaves are also rich in potassium, calcium, and iron. They are a diuretic, a substance that increases urine production and fluid removal from the body.
Dandelion flower heads are sometimes used to make a wine. The flowers are mixed with oranges, lemons, sugar, water, and yeast (natural or purchased) and then fermented. Raisins and cloves are sometimes added to the mixture. The flowers are also dipped in a flour mixture and fried to make fritters. Some people make an infusion or tea from the flower heads or from the leaves. The roots can be cooked like a root vegetable or roasted and ground to make a coffee extender.
As is the case with any wild plant, it's important to be absolutely certain of a dandelion's identification before using it as food. In addition, dandelions picked for food should be grown in an area free of pesticides and pollution.
Common dandelions are edible and are often used as food. Some other species of Taraxacum are also eaten. It's unknown if all dandelion species are edible, however, or if all parts of every species are edible. This is one reason why plant identification is essential when foraging for food.
Common Dandelion Latex
If the flower head of a common dandelion is removed or if the flower stem is broken, a milky white fluid exudes from the wound and coagulates after being exposed to air. The fluid is known as latex.
A dandelion’s latex is made by specialized cells called laticifers, which form long chains inside the plant. The laticifers are perforated to form latex vessels, through which the latex travels.
Latex is a complex, sticky mixture made of polymers and other substances dispersed in water. A polymer is a long molecule made of smaller molecules joined together. The components of latex include proteins, carbohydrates, oils, resins, and gums. It’s thought that the function of the material is to seal wounds and to protect the plant from insect attack and infection by microbes.
Latex is produced by other flowering plants besides the common dandelion, including the rubber tree. Most rubber today is made from the latex of the para rubber tree. The population of this plant is decreasing, however, along with the world's rubber supply. In several countries there are plans to make rubber from the latex of the Russian dandelion, which is a relative of the common dandelion.
A Time Lapse Video: Flower to Seed Head
Researchers say that about ten percent of flowering plants produce latex. The exudate is generally white in colour but is sometimes colourless, yellow, orange, or red.
Producing Rubber from Common Dandelions
It’s possible to make rubber from the common dandelion. The process is sometimes carried out as a science experiment in schools. The experiment should be avoided by people who are allergic to latex. It’s thought that since dandelions are very different plants from rubber trees it’s unlikely that anyone with rubber latex allergies will also be allergic to dandelion latex. In fact, dandelion latex is believed to be hypoallergenic. It's probably best to wait until this is absolutely certain if someone knows that they have a latex allergy, however.
To make the rubber, part of a finger is coated with dandelion latex. Several dandelions are needed to collect enough latex. The latex is allowed to coagulate to form rubber and is then carefully rolled off the finger. (Body heat helps the rubber to form.) The dandelion rubber is stretchy but quite delicate. It's fun to play with common dandelion rubber. The product isn't good enough to use commercially, however. Luckily, the rubber from Russian dandelions is suitable for commercial use.
Natural Rubber Production
The para rubber tree is also known as the Brazilian rubber tree and has the scientific name Hevea brasiliensis. In traditional rubber production, a para rubber tree is wounded with a diagonal cut and the dripping latex is collected. (The tree recovers to be tapped again in the future.) The coagulation process is sped up by the addition of formic acid. The moist chunks of rubber are pressed into sheets and dried. The drying process often involves the rubber being placed in a smokehouse.
In commercial rubber production, liquid latex is collected from the rubber tree and is shipped in air-tight containers to factories. Placing ammonia in the collection tanks prevents coagulation. In the factories, the latex is shaped into sheets or placed in molds and solidified.
Sulphur and heat are often used to "vulcanize" rubber. The chemical reaction between the rubber and the sulphur makes the rubber stronger and resistant to temperature changes. Without vulcanization, rubber tends to melt in hot weather and become brittle in cold weather.
How Natural Rubber Is Made
The World's Rubber Supply
Most of the South American population of the para rubber tree has been destroyed by fungus. The tree now grows mainly in Southeast Asia. The Asian population of the tree is decreasing too, however, due to a combination of factors. These include fungal infection, political instability, loss of habitat, and possibly climate change.
Rubber is used to form thousands of different products, but the majority is used to make tires. As the number of cars and other vehicles in the world is increasing, the demand for rubber is also increasing. Another problem is that natural rubber is becoming more expensive. Synthetic rubber can be produced, but vehicles require at least some natural rubber in their tires to provide elasticity. Some types of tires must be made entirely of natural rubber.
Some people grow a plant called Ficus elastica in their home or garden. The plant is sometimes known as a rubber plant or a rubber tree. It does produce a latex that can be turned into rubber. However, it's not the same "rubber tree" that's used to produce commercial rubber.
History of Russian Dandelion Rubber
A high-quality rubber can be produced from Taraxacum kok-saghyz, the Russian dandelion. Some researchers say that Russian dandelion rubber is as good as the rubber produced from the para rubber tree. Russian dandelions look much like common dandelions and are native to Kazakhstan and Uzbekistan, two republics that were once part of the Soviet Union.
During the second world war, the rubber supply to parts of Europe and the United States was blocked. Russian dandelions were used to make rubber instead. The extraction of latex from the dandelions was an expensive process, however. Another problem was that the latex coagulated very soon after its release from the plant. Once the para rubber supply was restored, the process of making rubber from dandelions ended.
Extracting Latex from Russian Dandelions Today
Recently researchers have once again become interested in making rubber from Russian dandelions. The cultivation of the Russian dandelion, and perhaps of other latex-producing plants, may be the solution to the world's rubber supply problem. The roots of the dandelion produce most of its latex.
Improved methods of latex removal have been created to tackle the problem of rapid coagulation after a dandelion is wounded. Researchers are also trying to increase the yield of latex and to decrease the cost of rubber production.
The latex is removed from sliced roots by solvent extraction and/or the use of a centrifuge and then processed into rubber. The exact details of the process are being kept secret by the companies involved, however. There could be a lot of money at stake in the production of dandelion rubber.
Increasing the Latex Yield
Scientists have found a way to block the quick coagulation of Russian dandelion latex, increasing the amount of latex that can be removed. The latex coagulates when exposed to air due to the rapid production of polymers, a process called polymerization. An enzyme called polyphenoloxidase (or polyphenol oxidase) is responsible for the polymerization.
Scientist can stop the action of polyphenoloxidase by infecting the dandelion with a genetically engineered virus. The virus removes the section of genetic code in the dandelion's DNA that is responsible for the production of the polymerization enzyme. The genetically altered plants provide four to five times as much liquid latex as the plants that are not genetically altered. The scientists are breeding the altered plants and are trying to create large populations of dandelions that lack the problematic segment of DNA.
Some researchers are trying to improve the yield of latex from Russian dandelions in a different way. They look for natural strains of dandelion that produce slightly more latex than other strains and then selectively breed the high-latex producers with other high-latex producers. They repeat this process in each generation of dandelion plants.
Natural Rubber from Russian Dandelions
The video above describes Russian dandelion rubber production by a German company. People in other countries are also growing the dandelions on an experimental basis, including people in the United States and Canada.
Inulin Production from Russian Dandelions
Russian dandelions are being cultivated for other reasons besides their ability to make latex. They contain a large amount of inulin, a carbohydrate that is being added to a growing number of processed foods. Some people confuse inulin with insulin, but they are different substances. Inulin is a carbohydrate while insulin is a hormone that regulates the blood sugar level. At the moment, most commercial inulin is produced from chicory, a relative of dandelions.
Inulin is a type of fibre. It isn't digested in our stomach and small intestine, but it is digested by some of the helpful bacteria in our large intestine. It's classified as a "prebiotic" rather than a probiotic. Probiotics contain useful bacteria; prebiotics support their growth.
Inulin is mildly sweet but doesn't raise the blood sugar level. This makes it useful for diabetics. It can improve the taste and texture of foods and is sometimes used as a sugar or fat substitute. Inulin also promotes calcium absorption and is used in a medical test that assesses kidney function. In addition, it can be fermented to make ethanol, which can then be used as a fuel.
Most people don’t think about dandelions very much, except when they’re annoyed when the plants appear where they’re not wanted. This is a shame. Dandelions have many uses, both for individuals and for society. The Russian dandelion and possibly other types of dandelions as well may become very economically important in the next few years.
- Nutrients in raw dandelion leaves from the USDA (United States Department of Agriculture)
- Latex in plants from the USDA Forest Service
- Natural rubber production from dandelions from the phys.org news service
- Rubber from Russian dandelions from Wageningen University
- Inulin from Russian dandelions from Wageningen University
- Wahler D, Gronover CS, Richter C, et al. Polyphenoloxidase Silencing Affects Latex Coagulation in Taraxacum Species. Plant Physiology. 2009;151(1):334-346. doi:10.1104/pp.109.138743.
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© 2011 Linda Crampton