Why does fried yam turn black

There are many ways to prepare yam, and you can choose the best method to satisfy people's preferences based on their desired taste. For example, stir-frying yam is a common preparation method, but the taste of stir-fried yam is rather strange. Because everyone's taste requirements are different, sometimes the problem of blackening means a qualitative change. So why does fried yam turn black?

1. This is because the peeled yam undergoes enzyme browning, causing the color to darken. There are three main conditions for the occurrence of browning: polyphenols, polyphenol oxidase and oxygen. After the yam is peeled and exposed to the air, the polyphenols in it react with oxygen to produce o-quinone, which is further oxidized and polymerized to form brown pigment and melanin.

2. The blackening of yam mainly occurs in two stages, one is after the yam is cut, and the other is when the yam is fried. After cutting the yam, if you want to prevent it from turning black, you can soak it in water, which can effectively isolate the air and prevent it from being oxidized, so the yam will not turn black. However, it should be noted that the soaking time should not be too long to avoid nutrient loss. Before frying the yam, you can mix a small amount of salt on the surface of the yam, so that the yam will not change color during the frying process.

How to peel yam without turning it black?

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

If you don't want the yam to be oxidized, it is recommended to peel it and soak it in water. If you soak it in hot water, it can not only prevent it from being oxidized and blackened, but also neutralize the biological alkali in the yam that makes people's hands itchy, and reduce allergic reactions when scratching with your hands.

When cooking yam, you should also pay attention to some tips, because the new yam is easily oxidized by oxygen in the air, and will also change color after coming into contact with iron and other metals. Therefore, it is best to process the cut yam after some treatment. You can use a bamboo knife or plastic blade to draw lines on the skin, and then peel it into sections with your hands. You can also soak the cut yam in rice wine first, and then blow it with a hair dryer to promote the healing of the incision, then wrap it with a napkin, wrap it with several layers of newspaper, and place it in a cool corner for later use.