Green potatoes are the ricochet in the culinary potato paradise. Our grandmothers already warned against eating green-skinned tubers because of the risk of bad stomach upset. This guide is dedicated to all potato lovers who are worried about green potatoes. Read here whether green potatoes are edible or poisonous?
Are green potatoes poisonous and how to avoid them?
Green potatoes contain the toxic solanine, which is produced in high concentrations under the peel when exposed to light. Consuming larger quantities can lead to symptoms of poisoning. Remove green spots and sprouts before preparing potatoes and always store them in a dark, cool and dry place.
Are green potatoes poisonous?
Green means negative side effects for potatoes, such as toxic ingredients and bitter taste. A naturally he althy food, green potatoes do not belong on the table. The culinary spoilsport is solanine, a natural poison that helps the nightshade plant protect itself from predators. Solanine is a glycoalkaloid that forms in high concentrations beneath the shell under the influence of light. Chlorophyll is responsible for the green color. The non-toxic, green plant substance acts as an alarm signal for the existence of harmful solanine in the potato in question.
Intentional or unintentional consumption of large quantities of green, solanine-contaminated potatoes causes moderate to severe symptoms of poisoning. Since glycoalkaloids are associated with a very bitter taste, the palate usually warns in good time before ingesting a number of green potatoes that are harmful to he alth.
Grüne Kartoffeln - Voll bio oder voll giftig?
Where is the most solanine lurking?
A bowl of steaming potatoes has been a staple on every table for generations. As a rule, consumption results in a full sense of well-being for young and old. The reason for culinary enjoyment without regret is to pay attention to different solanine concentrations in different parts of a potato. Before the potatoes end up in the cooking pot, any questionable components are removed. The more familiar the cook is with these contexts, the more perfect he althy, harmless preparation will be. We wanted to know exactly and consulted the scientific publications of Ms. Dipl. oec. troph. Claudia White. The following table demonstrates where high concentrations of solanine lurk in potatoes:
| Parts of a potato | Total Alkaloids |
|---|---|
| whole tuber | 10-150 mg/kg |
| Skin (2-3% of a potato) | 300-640 mg/kg |
| Peel (10-12% of a tuber) | 150-1070 mg/kg |
| pulp | 12-100 mg/kg |
| Germs/Eyes | 2000-7000 mg/kg |
Experts define the consumption of 2-5 milligrams of potato alkaloids per kilogram of body weight as an acute toxic dose. The smallest lethal dose is an intake of around 6 milligrams per kilogram of body weight, although significant individual fluctuations must be taken into account. In self-cultivated, ecologically managed vegetable patches, home gardeners usually harvest potatoes with an alkaloid content of well under 100 milligrams per kilogram of harvested quantity. Eating 300 grams of potatoes leads to an adult intake of around 1 milligram per kilogram of body weight. This safe value applies to peeled, properly treated tubers without green spots or sprouting eyes.
Eaten green potatoes – what to do?
Eating green potatoes initially causes stomach pain and vomiting
The good news first: serious poisoning from eating green potatoes is rare. Of around 2,000 clinically known cases of potato alkaloid poisoning across Europe, 30 were fatal. Experts assume that mild solanine poisoning is usually not diagnosed as such. The reason is the non-specific symptoms. The following indications indicate the consumption of green potatoes:
- first symptoms: after 2 to 20 hours
- slight scratchy throat
- Headache, fever, low blood pressure, fast pulse
- Gastrointestinal complaints
- Vomiting and diarrhea
- Severe symptoms of poisoning: drowsiness, muscle tremors, restlessness, fainting
The symptoms of poisoning can last up to a week. The symptoms are often interpreted as a simple upset stomach and are treated with self-medication. In robust adults, the symptoms improve quickly and are not associated with eating green, solanine-contaminated potatoes.
If severe symptoms of poisoning occur, a doctor should be consulted immediately. Children and sensitive seniors with suspicious, non-specific symptoms should be in the hands of knowledgeable doctors to clarify the cause and prevent worse consequences.
Tip
Popular recipes for this great tuber contain the word “green”. Green beans with potatoes or green sauce with eggs and potatoes make our mouths water. This does not mean that green potatoes should be added to the cooking pot as an ingredient. Always use ripe potatoes with creamy yellow flesh. Cut off any suspicious green areas generously before preparation.
Green spots on potatoes – edible or poisonous?
For the he alth risk situation,no all-clearcan be given if potatoes are partially green. Green spots on potatoes often contain a high concentration of undesirable alkaloids, making consumption a risky balancing act for the whole family. You should generously cut out any isolated green spots. This precaution also applies to one or the other eye. However, potatoes with a large green color on the skin as well as several green spots, eyes and sprouts arenot suitable for consumption.
Prevention tips – this is how potatoes don’t turn green
Proper storage is the best prevention against green potatoes and the resulting he alth risks. The rule of thumb applies: light and heat are pure poison for stored potatoes. To enjoy premium quality potato dishes, you should store the tubers like this:
- Always store potatoes in a dark and dry place
- ideally spread out loosely on a shelf or stacked in an airy potato box
- maximum temperature at storage location: 8°-10° Celsius
- minimum temperature: 4°-6° Celsius
If fresh potatoes boasted a he althy, brown skin without eyes when they were purchased, this can quickly change in an unsuitable storage space. The influence of light and excessively high temperatures stimulate the production of toxic alkaloids and turn every great tuber into a bitter, green evil. All potatoes that are not prepared and eaten immediately should therefore be stored in a dark, cool and dry place, even if the waiting time before consumption is only a few days.
Excursus
Frying destroys solanine
Food experts explicitly point out that toxic solanine and other harmful alkaloids only decompose at a temperature of 240° Celsius. As a result, cooking green potatoes makes them unpalatable. Proud owners of a deep fryer do not throw away potatoes with green skins. Frying in hot fat causes a significant reduction in solanine. It is important to note that you do not leave the food to be fried in the hot oil for an unnecessarily long time. There is a risk that the toxins will be transferred back into the finished fried fries or fried potatoes. For this reason, regular replacement of frying fat is essential.
Green potatoes as seed potatoes – is that possible?
Green potatoes are ideal as seed potatoes
Ingenious home gardeners do not throw away green potatoes, but rather give the tubers a second life as seed potatoes. In this case, the solanine content cannot be high enough because it stimulates germination. Green-skinned potatoes are ideal for pre-germinating on the windowsill. When planting time begins in the bed, pre-sown potatoes start the gardening season with a vital growth lead. This is how it works:
- Plant green potatoes behind glass 4 to 6 weeks before the outdoor planting season begins
- Pour peat-free vegetable soil or a mix of compost and sand into a wooden box, used egg cardboard or seed tray
- Spray the soil with soft water, diluted valerian tea or field horsetail decoction
- Insert green seed potatoes up to half the height of the tubers
- Set up in a bright location with temperatures between 12° and 15° Celsius
Warmth and light cause the shell to turn green further and allow strong germs to sprout from the eyes. The growth engine is glycoalkaloids, which are now showing their good side.
Harvesting ripe potatoes – this is how it works
If potatoes come out of the ground with a green skin, you will be very disappointed. Unripe, green potatoes contain a concentrated load of toxic alkaloids. The tubers are non-climacteric fruits and do not ripen. Knowledgeable home gardeners avoid the hassle of a premature harvest of green apples by applying a simple rule of thumb: 2-3 weeks after the potato weed has died, potatoes are ready for harvest.
The point at which the herbaceous parts of the plant take root depends primarily on the type of potato grown. Early varieties require a growing season of 90 to 110 days, whereas late varieties take up to 160 days to mature. Furthermore, weather, soil quality and nutrient supply contribute to when, deep in the soil, unripe, green potatoes transform into ripe, brown-skinned tuber treasures.
Peeling potatoes and cutting out individual green spots and germs reduces the poison content by up to 90 percent.
Frequently asked questions
What is solanine?
Solanine is the most common alkaloid found in potatoes. This is a secondary plant ingredient that is contained in nightshade plants and acts as a defense against predators and pathogens. The highest concentration of the toxin is in the peel as well as in the eyes and sprouts. An important identifying feature for solanine are green spots on the tuber or a completely green shell. The alkaloid is extremely heat-resistant and partially water-soluble. Solanine is released into the water when cooking.
What is the risk of solanine poisoning after eating green potatoes?
In the past 100 years, only a few cases of poisoning due to solanine have been known and documented. Experts interpret this as an indication that the distinctively bitter taste of glycoalkaloids usually prevents dangerous poisoning. However, it is also conceivable that there is a significant number of unreported cases due to non-specific symptoms. On this basis, the risk of solanine poisoning from eating green potatoes is considered to be low.
What does the Federal Institute for Risk Assessment recommend with regard to the solanine content in potatoes?
The Federal Institute for Risk Assessment (BfR) recommends consumers to always store potatoes in a dark, cool and dry place. Tubers with green skin, green spots and germs are not suitable for consumption. Isolated green areas can be cut out. Children should only eat peeled potatoes. Potato dishes with a bitter taste belong in the trash can. Potato cooking water should not be reused. It is also advisable to change the frying fat for potato dishes regularly.
Are green potatoes still poisonous when cooked?
Unfortunately, cooking does not make green potatoes edible. Solanine and other toxic glycoalkaloids are tough. Boiling hot water has no or minimal influence on the high concentration of harmful substances in the peel, green areas and germs. Only at a temperature of more than 240° Celsius does a gradual dissolution process begin.
I often find tubers with green skins in the potato sack. Can I peel and eat these potatoes or should I throw them away?
For the good of you and your family, we recommend throwing away potatoes with large green skins. The green color signals prolonged, unfavorable contact with light and heat. As a result, a high concentration of potato alkaloids has built up in the tubers. You can generously peel and cut out specimens with isolated green spots. You should deep-fry slightly green potatoes after the pretreatment because the hot fat dissolves most of the remaining toxins.
Can green potatoes ripen?
If bad weather forces the home gardener to harvest potatoes early, green tubers are in between. Understandably, the gardener's heart bleeds to dispose of green, solanine-contaminated potatoes after all the effort spent growing and caring for them. Unfortunately, you won't be spared the grief because potatoes cannot ripen like apples, plums or pumpkin. On the contrary, the poison content increases the longer the tubers are exposed to light and heat.
Do other edible nightshades also contain toxic solanine if the fruits are green?
Characteristic of all edible nightshades is a worrying concentration of solanine in green fruits. In addition to potatoes, these include tomatoes, peppers, eggplants, chilies and goji berries. In completely green tomatoes, for example, the average solanine content is a whopping 32 milligrams per 100 grams, which is clearly in the dangerous range. The preparation usually doesn't change much. More than 90 percent of the solanine concentration is retained in sweet and sour pickled green tomatoes.
Tip
It belongs in the realm of fables that small potatoes contain fewer toxins than voluminous tubers. In fact, the concentration of poisons contained is inversely proportional to size. The smaller a potato, the higher the proportion of solanine and other toxins. When buying potatoes, always give preference to larger specimens and ignore mini-sized tubers.
