Solanine belongs to the group of alkaloids. Alkaloids are substances found in many plants and also occur in varying concentrations. The best-known alkaloids are caffeine and theophylline, which are found, for example, in coffee and tea.
The alkaloids in potatoes are often referred to as Solanine This is a mixture of various glycoalkaloids, consisting mainly of solanine and chaconine.
When does the risk of poisoning begin?
In addition to the toxic alkaloid solanine, potato plants also contain small amounts of choline and acetylcholine. We find these toxins, for example, in
- flowers,
- berries,
- unripe, green potatoes, as well as
- in sprouts or also eyes of sprouting potatoes
again.
However, the cultivated varieties that we buy today generally contain hardly any concerning amounts of glycoalkaloids. We are talking here about a general value between 1.8 and 9.4 mg per 100 g of fresh potatoes. This value can vary between the different potato varieties. Some varieties show values of 10-13 mg, while others reach more than 20 mg per 100 g of fresh potatoes.
Important: initial symptoms of poisoning generally occur only from about 40 mg per 100 g of potatoes.
Symptoms of poisoning include
- a burning and scratchy feeling in the throat,
- headaches,
- vomiting,
- diarrhea.
In severe cases, it can even lead to cerebral edema, drowsiness progressing to coma, and severe convulsions.
What can you do if poisoning is present?
As a first medical countermeasure, doctors advise inducing vomiting in those affected. Afterwards, a doctor should be consulted to clarify further measures.
Particular caution should be exercised with children, since small children in particular can die from solanine poisoning. In adults, a fatal case has not yet become known. (Source: Toxikologie der Nahrungsmittel, Stuttgart 1990)
How can I avoid solanine?
Just because potatoes contain solanine does not mean that you can no longer enjoy them. The alkaloid content can be detected especially in the sprouts as well as around the eyes and in the potato skin Thus, the concentration of solanine decreases significantly from the outer skin layer through to the pith layer.
Furthermore, various criteria can be observed to reduce the occurrence of solanine:
- There is a significant difference between the individual varieties in terms of alkaloid content.
- For the varieties that we currently obtain in the supermarket or at the weekly market, one cannot speak of a health-relevant threshold value.
- Weather conditions, such as hail or frost damage, as well as very cold growing phases, can significantly influence the level of alkaloid content.
- Unripe potatoes clearly contain more solanine than more mature tubers.
- Potatoes that were damaged to a greater or lesser extent during harvesting, transport, and storage, and therefore show injuries, indisputably contain more solanine than comparable undamaged potatoes.
- Light on potatoes not only causes the tubers to turn green, but also increases the formation of solanine. Green potatoes always contain higher levels of alkaloids than non-green tubers.
- Potatoes that are ideally stored at a temperature of up to 10° and have not been exposed to serious temperature differences form fewer alkaloids than potatoes that are stored too warm, receive too much light, and are therefore stimulated to sprout.
- Cooked potatoes should be used up quickly, preferably within 24 hours.
Tip: in potatoes that are peeled, the alkaloid content is reduced many times over. Ultimately, the tubers contain only 5-10% of the original solanine content. Green and damaged potatoes should definitely be discarded.
Read also: Potato gratin recipe
Photo by Janine, meinhaushalt.at
