What should I do if there are many black spots after peeling the yam?

After peeling, soak it in water. If you soak it in hot water, it will not only prevent it from being oxidized and blackened, but also neutralize the alkaloids in the yam that make people's hands itch, reducing the need to use hands. Allergic reaction to scratching.

The phenolic substances in yam are oxidized when exposed to oxygen in the air to form colored quinone substances. They only need to be not in direct contact with the air, such as soaking in water. You can use salt water. You can also put some white vinegar in a bowl of water. The cut yam will not turn black when placed in the vinegar water.

Yam that has changed color due to oxidation is edible. Fresh yams are easily oxidized by oxygen in the air, and they are also prone to browning when in contact with metals such as iron knives. It looks like white yams turn black. So there is no problem if the yam turns black, just eat it without worry.

The blackening of cut yams is due to enzymatic browning that causes the color to become darker. There are three main conditions for the occurrence of browning: polyphenols, polyphenol oxidase and oxygen. When yam is peeled and exposed to the air, the polyphenols react with oxygen to produce o-quinones, which are further oxidized and polymerized to form brown pigments and melanins