What substance can result from overcooked chlorophyll?

When chlorophyll is overcooked, it breaks down and leads to the formation of pheophytin. Pheophytin is a derivative of chlorophyll that occurs when the magnesium ion at the center of the chlorophyll molecule is lost due to heat and acidity. This process typically causes the bright green color of vegetables to change to an olive green or brownish hue. The cooking process alters the structure of chlorophyll, transforming it into pheophytin, which is less vibrant and can affect the nutritional quality and appeal of the food.

Chlorophyll a remains intact only if the cooking process is gentle and quick, while carotene and ferulic acid are not direct derivatives of chlorophyll and do not directly result from its overcooking. Carotene is a different pigment found in various fruits and vegetables, and ferulic acid is a phenolic compound found in the cell walls of plants. Therefore, understanding the degradation of chlorophyll leads clearly to identifying pheophytin as the correct answer.