Ever Wonder: Why Do Potatoes Turn Green? ~ The Garden of Eating - a sinfully good blog about food

Tuesday, December 15, 2009

Ever Wonder: Why Do Potatoes Turn Green?

Although I've known for many years that you're not supposed to eat the skin of potatoes that have turned green, I did not know why the skin turns green or why it's bad for you.

Thanks to Google, I am now well-informed about this "greening" phenomenon (what on earth did we all do before Google?!)

It appears that potatoes naturally contain two alkaloids called solanine and chaconine. These alkaloids can cause digestive and neurological problems in concentrated amounts. But don't get too freaked out, one green potato is not going to kill you.


Photo of a green potato courtesy of Elise at Simply RecipesI have not had a chance to take a photo of a green potato lately but Elise of Simply Recipes graciously gave me permission to use this photo from her own post on green potatoes. Thanks again, Elise!

There are a few things that increase the amount of these two alkaloids present in a potato -- poor growing conditions are one and exposure to sunlight is another. The alkaloids are actually colorless -- the green color of a potato's skin is actually caused by the development of chlorophyll which is a direct result of exposure to sunlight (think back to elementary school science class.) This is why potatoes do best stored in total darkness (though that is, unfortunately, not a condition those of us without root cellars can easily provide for the little tubers.)

So the green color of the skin is more of a helpful warning that higher levels of these nasty alkaloids may also be present in the potato even though it is actually caused by chlorophyll and not by the alkaloids.

But it's safest just to peel the skin and any flesh that has turned green off before cooking, regardless. In addition, the alkaloids, particularly solanine, have an unpleasant bitter taste so the potatoes will taste better without that.

1 comment:

Anonymous said...

Thanks for the info- I read that I shouldn't eat/cook green potatoes but was not sure why. I thought potatoes were an indestructible food- who knew!