Why do yams turn yellow when cut?

Yams turn yellow when cut due to the oxidation process that occurs when they are exposed to air. The exposure triggers the breakdown of certain compounds in the yam, leading to the formation of pigments that give it a yellow hue. Additionally, the presence of carotenoids, which are natural pigments found in many vegetables, can also contribute to the yellow coloration. This color change is generally harmless and doesn't affect the yam's taste or safety.