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Reply	Freeganisto says:   This also happened to me.   In my Freegan foragings I found a large quantity of reasonably fresh garlic. Having no refrigerator or freezer at the time I decided to pickle the blanched and peeled cloves to preserve them for later use. They turned a number of shades of blue, from turquoise to purple. I attributed this to a chemical reaction between the acetic acid (vinegar) and organic compounds in the garlic behaving in a manner similar to an indicator (of acidity - like litmus).   I didn't bother to identify the compounds. The garlic's new colour made it unappetising so I had to re-disposed of it.    (no votes) Tags: Food, blue, garlic, saladdressing, pHindicator, pickle, vinegar.
	posted on 2010-03-18 12:42:08 | Report abuse Reply Freeganisto says:   Subsequent to my previous response I discovered at http://everything2.com/title/Garlic+oil that the reaction that produces the blue colouration may produce toxins making me wonder if the blue colour is prussian blue or a derivative.  (no votes) Tags: Food, blue, garlic, saladdressing, pHindicator, pickle, vinegar, prussianblue, hydrocyanicacid. posted on 2010-04-04 13:18:34 | Report abuse

Reply	its4kay@aol.com says:     It is a well recognised phenomenon that pickling raw garlic cloves in an acidic solution will produce a blue colour. When garlic is damaged, the main odourless compound, alliin is converted by the enzyme alliinase to form allicin , a thiosulphinate which gives garlic its smell and taste. The  blue colour is caused by a further reaction between the thiosulphinate compounds and naturally occurring amino acids in the garlic itself, forming a range of blue pigments. Kay Bagon Radlett HERTS  (1 vote) average rating:5 Tags: blue, garlic, saladdressing, bluegarlic.
	posted on 2010-03-18 18:25:05 | Report abuse