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Old 08-27-2006, 06:25 AM   #11
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perfectly normal and indeed equaly harmless :)
it`s a simple reaction acting upon anthocyanins present in garlic, the same anthocyanin found in blue berries egg plant and some chili types.

and don`t worry about the Cyanin group, although it is a Carbon Nitrogen bond the same as Cyanides, we have absolutely no way of breaking this down to anything toxic either, eat them! :)

Katherine Snow. xx
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Old 08-28-2006, 05:51 PM   #12
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I just made my first refrigerator dill pickles from the cucumbers my neighbor grew threw in a couple of garlic cloves and they are starting to turn blue on the ends.Well I remembered this topic did a search so here I am.

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Old 10-11-2006, 06:11 AM   #13
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Discolouration of garlic on canning

Discolouration of bottled garlic in vinegar

Users of bottled garlic in vinegar are occasionally alarmed to find that the product has turned green or blue-green. These colour changes do not make the product unsafe but are obviously undesirable.
The problem of garlic changing colour is associated with the addition of acid which changes the normal pH of the product. This is precisely what is required to ensure that the garlic remains safe but the change in acidity brings about chemical changes in pigments in the garlic.
All plant materials contain various pigments some of which change colour as the pH of the plant tissue is changed by the addition of vinegar or other acids. The most common of these pigments are the anthocyanins which may be blue, colourless or red depending on the pH.
These pigments may be involved in some colour changes observed in preserved garlic but American scientists have identified another more general explanation.
Certain amino acids, natural components of foods, are responsible for many of the pigment characteristics of the onion family which includes garlic. The American scientists have shown that the outstanding difference in composition between garlic which turns green and garlic which does not is the presence of much higher levels of one particular amino acid in the green garlic.
It is not possible to tell by looking at untreated garlic whether it is likely to become green on crushing and acidification. However the work reported indicates that if garlic bulbs are stored for four weeks at a temperature above 23C prior to processing, the production of the green pigment is prevented.
This may not be practical at the domestic level, but could be a valuable precaution for commercial producers.

This excerpt taken from
Food Science Australia Fact Sheet

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Old 12-22-2006, 09:12 PM   #14
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Location: Canberra, Australia - The Nations Capitol and Home of the Pollies
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This information comes from this site: Frequently asked questions (FAQ) about garlic

Q: What happens when garlic turns green or blue during pickling or cooking?
A:According to Food Network at Food Network : Cooking, Recipe Collections, Party Ideas, Quick & Easy Recipes, Cooking Videos (published in the Rocky Mountain news 2/20/2002), looked into the reason pickled garlic sometimes turns blue. Garlic contains anthocyanins, water-soluble pigments that turn blue or purple in an acid solution. While this color transformation tends to occur more often with immature garlic, it can differ among cloves within the same head of garlic. The garlic flavor remains unchanged, and it totally edible without bodily harm.

On the same subject, our friend, Bob Anderson, explains that 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. Raw garlic contains an enzyme that if not inactivated by heating reacts with sulfur (in the garlic) and copper (from water or utensils) to form blue copper sulfate. The garlic is still safe to eat.

Garlic exposed to direct sunlight can also turn green and acquire a bitter taste.


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