Does aged onion/garlic turn green when frying?
I was frying onions and garlic the other day and the paste turned green. I had bought the onions/garlics many days ago (20-30 days) I guess. Could that be the reason? There was no fungi or something suspicious when I cut them by the way.
Best Answer
I've also had this happen when cooking an onion-garlic paste. I've found several web pages where the phenomenon is discussed, listed below. In summary, it's normal and happens due to certain chemical reactions between the garlic, cooking utensils and water. In your case, it's probably not due to the age of your garlic or onions though, as one source suggests it is less likely to occur with aged garlic. I've only seen the paste turn green myself, though interestingly you could also get blue garlic:
Garlic contains sulfur compounds which can react with copper to form copper sulfate, a blue or blue-green compound. The amount of copper needed for this reaction is very small and is frequently found in normal water supplies.
Garlic Can Turn Blue
Raw garlic contains an enzyme that if not inactivated by heating reacts with trace amounts of sulfur (in the garlic) and copper (from water or utensils) to form blue copper sulfate. The garlic is still safe to eat.
Garlic can turn Green
If the garlic was not fully mature or dry, pigments in the garlic may turn green when in the presence of acid. Garlic will also turn green (develop chlorophyll) if exposed to an temperature change or is exposed to sunlight. Some people say it can be stored for 32 days at or above 70 - 80° F to prevent greening, but I'm not yet sure that is true. Green garlic is safe to eat.
Some other pages where this is discussed: http://chowhound.chow.com/topics/471608, http://www.cheftalk.com/forum/thread/45254/onions-turned-green-while-frying, http://whatscookingamerica.net/Q-A/bluegarlic.htm.
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Why have my fried onions gone green?
What happened? Red onions\u2014as well as other red produce, including cabbage and cherries\u2014are rich in pigments called anthocyanins. When they're cooked with acid, their color intensifies, but when combined with an alkaline component, they can turn a startling bluish-green color.Why did my garlic turn green while cooking?
The colour is probably the result of a reaction between sulphur compounds and amino acids (building blocks of protein) that are naturally present in garlic. In certain cooking conditions, these compounds (assisted by enzymes) interact to produce new molecules that give a green tint to the garlic.Is it safe to eat garlic when it turns green?
It's sharp in flavor, without any of the natural sweetness that garlic should have. But even though the flavor is a little less than ideal, sprouted garlic is fine to eat. TBH, if you're just incorporating one or two cooked cloves into a larger dish, you probably won't notice a difference at all.Is it safe to eat onions that have turned green?
Genetics might make a given onion more prone to green flesh. This onion is still fine to eat, though the chlorophyll could contribute some bitterness. You may be a little worried about this green color if you're aware that potatoes with green skins are known to contain toxins.Ginger and Garlic paste turning green?Here is how to prepare paste and prevent it from turning green
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