The potato, botanically Solanum tuberosum, is a species of the nightshade family (Solanaceae). In addition to the potato, the genus Solanum (Solanum) also includes other popular crops such as the eggplant (Solanum melongena) and the tomato (Solanum lycopersicum). The genus itself includes around 1,400 species. Many have parts that are poisonous to humans or are even completely poisonous. The toxins in the nightshade plants are the so-called alkaloids. The best known are morphine, strychnine and solanine.
Solanine
Solanine is a mildly toxic chemical compound found in potatoes. It is often referred to as “tomatine,” which is present in tomatoes, but has a different chemical composition. Solanine is heat-resistant, fat-insoluble and water-soluble at high temperatures, i.e. it passes into the cooking water. The lethal dose is 400 milligrams. The first signs of poisoning occur at a dose of 200 milligrams.
In adults, the first signs include:
- Daziness
- Touch sensitivity
- difficulty breathing
If you continue to take solanine, you will experience nausea and vomiting. These symptoms are often referred to as solanism.
Solanine in potatoes
Solanine is basically contained in every potato. 30 to 80 percent are
- in the bowl
- directly under the bowl
Tip:
Solanine and other alkaloids are also found in the green parts of potatoes. That is why the above-ground parts of the plant are poisonous to humans.
The solanine content in the tubers has been drastically reduced through breeding. While a study from 1943 occasionally found almost 40 milligrams of solanine per 100 grams in a non-green potato, the solanine content in the peel of new varieties is around 3 - 7 milligrams per 100 grams of potatoes. The proportion in the potato body is significantly lower. The solanine content of all new varieties is considered to be harmless to he alth. The first symptoms of poisoning with new varieties only appear when a few kilos are consumed raw and unpeeled.
Tip:
In older varieties, the solanine content can therefore be higher than in new potato varieties.
In nature, the bitter tasting solanine protects the potato from pathogens, rot pathogens and predators. That's why the solanine content increases slightly in bruised or peeled raw potatoes. The proportion of solanine also increases if potatoes have been exposed to light for a long time.
Tip:
Store potatoes in a dark place. The ideal storage temperature is 10 degrees Celsius.
Green spots
Green spots on potatoes or green potatoes contain more solanine than brown potatoes. The green spots on potatoes arise after the formation of solanine and actually come from chlorophyll production. However, the intensity of the green color is an indication of the potato's increased solanine content. The following applies: the greener, the more solanine there is in the tuber. Solanine production is stimulated by:
- Warmth
- Daylight
- Injuries to the tuber (frost or bruises)
Discard or peel?
If parts of the potato have turned green, the entire potato does not have to be thrown away immediately. However, you should cut out the green areas generously. If the potato has turned completely green, it is not advisable to consume it, even if the solanine content is reduced during preparation.
Tip:
The potato should also be cut out generously if it has sprouted.
In addition to solanine, chaconine and leptins are also found in potatoes with green spots. The effect of these substances on the human body has not yet been extensively researched. Therefore, eating green potatoes is not recommended for
- people with weak he alth
- Children
- Potato water
Since solanine is released into the water when potatoes are cooked, it must not be used for cooking. It's also better not to drink it. However, it can be used as a fertilizer or weed killer.
