Is rhubarb a fruit or a vegetable? In fact, due to its origin, it is classified as a vegetable. However, due to the way it is prepared, it is often mistakenly classified as a fruit. It is quite funny in the USA - there it is officially assigned to the fruit. Rhubarb owes its popularity to the combination of its fruity and sour taste. It is particularly popular in desserts. Especially famous is the delicious rhubarb pie. But also the strawberry-rhubarb jam is not to be neglected.
The origin, properties and history of rhubarb
Rhubarb originates from Asia and has existed for a very long time. Already 2,700 years BC, the vegetable was mentioned in a Chinese herbal book. At that time, however, it was considered a medicinal plant and the roots were used instead of the stalk. These were processed into powder, which was then used against constipation and constipation, as well as to fight the plague.
From England, rhubarb spread to Europe relatively late, to be more precise in the 18th century. Since then, rhubarb has been considered a popular vegetable and is grown worldwide in temperate climates. In Germany, it has been cultivated for just 150 years. Its peak season is from mid-April to the end of June.
The rhubarb stalk can grow 70 cm long, but the plant itself grows up to 2 m high. It comes in different varieties, which have different characteristics. First, there is the green rhubarb, which has a green skin and green flesh. This variety tastes quite sour and is rather unpopular. Since the green rhubarb has a high concentration of oxalic acid, it should be avoided from people with gout and kidney problems. Red rhubarb, on the other hand, is the milder and therefore more popular variety. It has a reddish skin but also a greenish to reddish flesh. Basically, the greener the flesh, the more acidic the vegetable. Therefore, the sweetest variety, is the one with red stalk and red flesh. Incorrectly, rhubarb is often mistaken for fruit. This is mainly due to the fact that it is prepared like fruit. However, since it belongs to the knotweed family, rhubarb is clearly a vegetable. In the USA, however, the vegetable is actually classified as a fruit.
The ingredients of rhubarb
The main component of rhubarb is water. The water content is 95 %, which is why 100 g of the vegetable contain just 13 kcal. However, besides a lot of water, rhubarb also contains a lot of healthy nutrients such as vitamin A, vitamin B1, vitamin B2, vitamin C and niacin, which is also known as vitamin B3. In addition to vitamins, minerals such as potassium, calcium, phosphorus, magnesium and iron are also found. Particularly noteworthy here is the calcium, which occurs at 50 mg per 100 g.
As already mentioned, rhubarb also contains oxalic acid. This is a dicarboxylic acid, which is mainly found in plant food or is formed in the body through metabolism. There are 460 mg of oxalic acid per 100 g of rhubarb. This high concentration makes the vegetable one of the frontrunners among foods with a high content of oxalic acid.
The effect of rhubarb on our body
Rhubarb strengthens our immune system and defenses through the vitamin C. The contained potassium has a dehydrating effect on us and promotes the transport of nutrients into the body cells. The sodium, on the other hand, supports our digestion.
Besides all the positive effects on our body, rhubarb can also be poisonous if prepared incorrectly or consumed in excess. This is due to the oxalic acid, as it can cause symptoms of poisoning in excessive amounts. A particularly high concentration of the acid is found mainly in the leaves and in the raw state of the vegetable. The concentration of oxalic acid also increases with the age of rhubarb. A particularly negative effect of oxalic acid is that it binds calcium. This can lead to the condition of teeth and bones being affected, especially if consumed in excess.
However, in normal amounts and when properly prepared, rhubarb is safe for most people.
Rhubarb in the kitchen
The most popular or probably the best known is the use of rhubarb for the rhubarb pie. However, also very popular is the strawberry-rhubarb jam. But the vegetable can also be processed into juices.
To be able to process the rhubarb properly, the stalks must be washed and the leaf base and the stalk end must be removed. If the stalks are fibrous or very thick, it is recommended to peel them beforehand. After that, the rhubarb stalks are cut into pieces. Subsequently, the rhubarb must be cooked, as this reduces the content of oxalic acid. Only after it is cooked, it should be further processed.
Buying and storing rhubarb
When buying, you should make sure that the stalks are firm, have a slight sheen and the ends look juicy. These are criteria that show the freshness of the vegetable. If rhubarb stalks look wavy, it means that they are not yet ripe.
It is best to store rhubarb wrapped in a damp cloth in the vegetable compartment of the refrigerator. This way it stays fresh for a few days. It can also be frozen very well.
Note: Do not store rhubarb in metal containers or aluminum foil under any circumstances, as the oxalic acid can cause chemical reactions.