Why do potatoes turn green like part of this potato?The potato tuber which contains nutrients like starches, proteins and minerals is meant to produce and grow next generation potatoes. As these tubers were uprooted for human consumption, they are exposed to light causing them to turn green; production of chlorophyll, a process called photosynthesis ~~ similar to leaves ~~ to make extra energy for the new plant.
Interestingly, the potato plant produces its own chemicals to protect from harmful insects, fungi and animals. These protective chemicals ~~ glycoalkaloids (usually solanine) ~~ are found in the leaves, sprouts and stems of the potato plant and usually at a very low levels in potato tubers. But with exposure to light, the level of glycoakaloids are elevated with the highest being in the emerging sprouts and the greenish part of the potato, usually under the skin where there is a cumulation of chlorophyll.Solanine (one of the glycoalkaloids) will be at a high level on bruising, cutting, rotting, bacteria and fungi attack and exposure to light.
What are Glycoalkaloids?
As explained in Wikipedia, Glycoalkaloids are a family of poisons. Glycoalkaloids are alkaloids + sugars which are toxic in nature. A prototypical glycoalkaloid is sugar (solanose) + alkaloid (solanidin) = solanine which is found in potatoes. It has a bitter tasting sensation usually cause burning irritation in the back of mouth, tongue and intestinal tract.
The toxins, alkaloids called solanine and chaconine apparently interfere with the structure of all our cell membranes and with the processing of a nerve transmitter. May cause hallucinations and convulsions. Because colour change in potato parallels to accumulation of alkaloids, greeness in potato is a good indicator of toxicity.
Conclusions
It is not necessary that potato with traces of green will contain the level of glycoalkaloid to pose as a health threat. But it is sensible to cook your potatoes before greening, sprouting or with any physical damage.
Remove plastic wrappings from potatoes and store them in a cool dry place away from light. Better still to buy potatoes as and when you need to use them.
Alkaloids remain in the bloodstream for longer than 24 hours and for those who eat potatoes everyday, there may be a chance of gradually accumulating of toxins in the blood.
