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Practices -- Cooking

Why do some cooked foods undergo a color change?

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In some baked products, you may notice a color change to blue or green tints around the areas where nuts, berries, or carrots are found in the product. This is a color change in natural pigments in the nuts, fruits, and vegetables. When they come into contact with either acid or alkaline conditions, the color of their surfaces may change. It is similar to the color change that takes place when you put acid (vinegar) on red cabbage and it turns a brighter red. If you put an alkaline substance (baking soda) on the cabbage it would turn blue. These products are safe to eat.

PREPARED BY: Angela M. Fraser, Ph.D., Associate Professor/Food Safety Specialist, and Carolyn J. Lackey, Ph.D., R.D., L.D.N., Professor/Food and Nutrition Specialist, North Carolina State University (August 2004)

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