What color does magnesium turn into when it becomes pheophytin?

When magnesium is removed from chlorophyll, the resulting pigment is pheophytin, which appears as a brown or olive green color. This transformation occurs during the process of cooking or during the senescence (aging) of plant tissues, where chlorophyll degrades.

The presence of magnesium is crucial for the bright green color of chlorophyll, which plays a significant role in photosynthesis by absorbing light. Once the magnesium ion is removed, the structure of the pigment is altered, leading to the subdued brown or olive green color that characterizes pheophytin. This change in color can be observed in overcooked vegetables, where chlorophyll breaks down, thus demonstrating the effects of heat and time on plant pigments.

Other color options, such as bright green, yellow, or red, do not accurately represent the transformation of chlorophyll to pheophytin. Bright green would indicate the presence of chlorophyll, yellow may refer to other pigmentations like carotenoids, and red is not associated with pheophytin at all. Therefore, brown or olive green is indeed the correct representation of the color of pheophytin after the degradation of chlorophyll.