Why does a yam turn yellow when cut?

A yam turns yellow when cut due to the oxidation process that occurs when its cells are exposed to air. This exposure causes the breakdown of certain compounds, leading to the formation of pigments that can give the flesh a yellowish tint. Additionally, the presence of natural enzymes and phenolic compounds can contribute to this discoloration. To minimize yellowing, it's best to store cut yams in water or airtight containers.