Sunday, November 04, 2007

Colours of Vegetables

The green color of leafy vegetables is due to the existence of the green pigment chlorophyll. Chlorophyll is pretentious by pH and changes to olive green in acid conditions, and bright green in alkaline conditions. Some of the acids are released in steam during cooking, mainly if cooked without a wrap.

The yellow/orange colors of fruits and vegetables are payable to the presence of carotenoids, which are also affected by normal cooking processes or changes in pH.

The red/blue coloring of some fruits and vegetables (e.g. blackberries and red cabbage) are due to anthocyanins, which are sensitive to changes in pH. When pH is neutral, the pigments are purple, when acidic, red, and when alkaline, blue. These pigments are very water soluble.

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