Is it okay to eat greenish potatoes?

Delicious potatoes in summer are rich in nutrients such as vitamin C, potassium, phosphorus, and iron. They are also highly versatile and used as ingredients in various dishes. Sometimes, when preparing potatoes, you may notice that the skin has turned green. In such cases, you're worried about whether it's safe to eat the potatoes. Is it okay?

Potatoes usually turn green when exposed to sunlight for a long period because chlorophyll synthesis occurs. This phenomenon of potatoes turning green is called 'greening.'

Potatoes are crops that develop from thickened underground stems. These stems form potatoes when they are underground, but when exposed to sunlight, they do not form potatoes and instead turn directly into stems. This is due to chlorophyll synthesis.

Potatoes turn green even when exposed to light for a long time, not just sunlight. The reason why potatoes are covered with newspaper at supermarkets or markets is also for this reason. Usually, greening occurs immediately after harvest or during storage and distribution.

The problem is that when potatoes are stored for a long time, the content of the toxic substance solanine increases. In particular, the glycoalkaloid compounds of solanine cause a bitter taste. The bitterness varies depending on the degree of storage, and high concentrations of glycoalkaloids can cause nausea and allergic reactions. According to the 'Washing and Packaging Technology to Reduce Storage and Decay of Potatoes' by the National Institute of Food and Drug Safety, glycoalkaloid components produce the characteristic aroma and bitter taste of potatoes at low levels (below 15 mg/100g FW), but at high concentrations, they can lead to nausea, coma, and even death. The U.S. Food and Drug Administration strictly limits the glycoalkaloid content to 20 mg/100g FW or less. The same applies to sprouted potatoes. It is known that sprouted and discolored potatoes have solanine levels more than ten times higher than regular potatoes.

It is safer not to eat potatoes that have turned green or sprouted.

Solanine is heat-resistant and does not easily disappear even after cutting away discolored areas or sprouts and cooking in hot water. When storing potatoes, they should be kept away from prolonged exposure to sunlight or light.

After purchasing potatoes, store them in a black bag, newspaper, or box to keep them from spoiling for a longer period. The appropriate storage temperature is between 7 to 10 degrees Celsius, and when stored at room temperature above 10 degrees, do not keep them for more than a week.