Young Brunette Girl Undresses Her Yellow Top And Short Jeans On The Floor With Many Fruit And Vegetables

Color pigments
The green color of leaf vegetables is due to the presence of the green pigment chlorophyll. Chlorophyll is affected by the pH, and it changes to olive green in acid conditions, and to bright green in alkaline conditions. Some of the acids are released in steam during cooking, particularly if cooked without a cover.
The yellow/orange colors of fruits and vegetables are due to the presence of carotenoids, which are also affected by normal cooking processes or changes in pH.