Will substituting sunflower butter for peanut butter in recipes for cookies turn them green?
This was a new problem to us, so we made a batch of our Soft and Chewy Peanut Butter Cookies, substituting sunflower seed butter to see if we got green cookies. The cookies looked fine, but after two days they started to develop green spots on their interiors, and by six days their insides were forest green.
We reached out to our science editor for insight as to why this was happening. He explained that, while they may be unappetizing to look at, the green cookies are perfectly safe to eat.
Sunflower butter contains chlorophyll, the green pigment present in all green plants. The color is not visible in the jar of sunflower butter because it is being bound by other substances. It’s released when it’s heated in the presence of alkaline ingredients (ones with low acid and a high pH). Many peanut butter cookie recipes (including ours) call for baking soda, which is alkaline. This combination caused the color to slowly appear, although the green cookies didn’t taste any different.
THE BOTTOM LINE: Sunflower butter may sometimes create a green color in baked goods. The baked goods taste fine and are perfectly safe to eat—the color comes from the chlorophyll present in sunflower butter.