Answer to Question 1
When heat is applied to products that contain green chlorophyll, the product will change to a bright green color; however, prolonged heating will result in the formation of pheophytins, causing the vegetable to turn an olive-green/brown. The release of natural organic acids when cooking or the addition of acids will also result in pheophytin formation and a brownish color.
Answer to Question 2
Vegetables that contain anthocyanin pigments include red cabbage, eggplant, radish, and red potatoes. Fruits that contain anthocyanin pigments include cherries, blueberries, strawberries, plums, and purple grapes.