Solanine question: Just need some quick info

[toadstool]

Muddled through a few things online but can't find what I want. I noticed this topic in another thread and had a few questions.

It's my understanding that I shouldn't eat the skins of potatoes. I'm not really concerned about regular potatoes, but about other types.

What about the skins of new potatoes? Or the small red ones? Any safer?

How about sweet potatoes? Are their skins okay?

I understand that potato skins have lots of nutrients. So I'd like to eat the skins, if possible.

Thanks!

[Lothar M Kirsch]

You can eat the skins of new potatoes as they didn´t have the time to develop solanine. The potatoe produces solanine if the skin is hurt, but also with time. The longer out of the earth the more solanine it contains. This doesn´t apply to sweet potatoes as they belong to a different botanical family. So their skins should be o.K. Other nightshade plants as tomatoes and eggplant also may contain solanine. The skin itself doesn´t contain lots of nutrients but the part that lies directly under the skin. If you boil them with the skin on and peel them off afterward you´ll have all the nutrients, but you shouldn´t do this with very old potatoes.

[Lothar M Kirsch]

1Vegan supplied an intersting link in another thread and I hope it´s o.K. to copy it into this thread:

http://www.panhandle.unl.edu/potato...ms/greening.htm

Quote:
The green indicates an increase in the presence of glycoalkaloids, especially, in potato, the substance "solanine" (see structure). When the potato greens, solanine increases to potentially dangerous levels. Increased solanine levels are responsible for the bitter taste in potatoes after being cooked. Solanine biosynthesis occurs parallel but independent of chlorophyll biosynthesis; each can occur without the other. Unlike chlorophyll, light is not needed for solanine formation but is substantially promoted by it. The formation of solanine in potato is localized to the skin, usually no deeper than an eight of an inch (3 mm). In processed potatoes such as chips and fries, there is little hazard since peels are removed. It also needs to be strongly emphasized that potato breeding programs have resulted in the commercial release of only potato lines with very low levels of solanine.

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Light contains ultra-violet radiation as well as visible rays. Ultra-violet and visible light in the blue-violet region promotes the formation of glycoalkaloids, steriod-like compounds, and, for potatoes, most notably "solanine" in tubers. When tubers are exposed, the solanin content in the peel may increase as much as ten times. Toxic levels for people are about one-hundredth of an ounce for 200-pound person. This 200-lb person would need to eat about 20 lb of normal potatoes in a day to reach this level. But, with UV light-exposed tubers in which solanin had increased ten-fold, only 2 lb could be dangerous. A large baked potato frequently weighs close to a pound but common sizes are six to 11 ounces in restaurants. Potatoes containing more than 0.1% solanine (.01 oz/10 oz potato) are considered unfit for eating. Cooked potatoes cannot turn green nor produce solanine because the enzyme mechanism for their production is destroyed by heating at cooking temperatures. But, note the chlorophyll and solanine already produced before cooking will remain after cooking.


note: I like new potato's. I eat them with peel.

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[Christy]

I usually peel potatoes, unless baking them whole. If it's green underneath the skin, I peel until it's gone. Is this okay?

[Lothar M Kirsch]

I pondered about this problem. The skin is very thin, but the peel is different. If you cook the potatoes with the skin, the nutrients as well as the solanine stay inside. If you find out, that they have green parts, better throw them away. If you peel them before cooking you can take out the green parts and "the eyes", which contain solanine. Lots of solanine will dissolve into the water, which you shouldn´t use. If I find potatoes which contain more than a third of green parts I throw them away anyway. It´s because I once suffered from a solanine intoxication after eating green potatoes (I only looked at them properly after already having eaten most of them).

[1vegan]

I usually peel potatoes, unless baking them whole. If it's green underneath the skin, I peel until it's gone. Is this okay?

That's ok.

[blinkered]

I have a further question, I really hadn't heard of Solanine until reading this thread, I was wondering how big a problem this is...

A quick search found this page:
http://tigmor.com/food/library/articles/sol.htm

Which is fine, but it doesn't say how worried about Solanine I should be?

[1vegan]

I would not worry at all.

Only the green parts can be poisonous. Do not eat the stems or the leaves of a potato plant. (don't think people do it)

"New" potato's can be eaten with peel, but remove green spots or sprouts when these exist.

If you don't eat the sprouts or the green patches, than you don't have to worry.