How to store cut yam (Chinese yam) short-term without it turning black?

Yam is a food loved by many people. Besides adding savoriness to soups, yam can also be pan-fried and stir-fried. Yam has also achieved a great deal in the food and processing industries. So how do you store cut yam? Why does yam turn black? How do you prevent yam from turning black? What short-term storage methods for yam are there?

1. How to store cut yam

After buying yam, peel it and cut it into pieces, then divide it into portions according to the amount eaten each time and put them into plastic bags. Once portioned, put them immediately into the upper part of the refrigerator for quick freezing. Keep in mind that after slicing, yam should be soaked in salt water immediately to prevent oxidation and blackening. Fresh yam releases a slimy substance when cut, which makes the knife slip easily and can cut your hand; you can first wash it with water plus a little vinegar, which reduces the slime. When eating, just put it straight into the pot once the water has come to a boil; there is no need to thaw it, which is both convenient and ensures the yam's quality.

Fresh yam generally has a fairly smooth skin and a color that is its natural skin color. If it needs to be stored for a long time, the yam should be buried in wood sawdust; for short-term storage, it is enough to wrap it in paper and put it in a cool, dark place. If what you bought is cut yam, then avoid contact with air, and it is best to wrap it well in a plastic bag and put it in the refrigerator to keep it chilled. Chopped yam can also be put in the freezer. Peeled yam is very slippery in the hand; rubbing something like vinegar or salt on your hands will make it easier to handle.

2. Why does yam turn black?

Cut yam turns black because enzymatic browning occurs, causing the color to darken. There are three main conditions for browning to occur: polyphenol substances, polyphenol oxidase and oxygen. After yam is peeled and exposed to air, the polyphenol substances in it react with oxygen to produce ortho-quinones, which then undergo further oxidative polymerization to form brown pigments and black pigments.

This situation is not uncommon in everyday life; apples, eggplants, lotus root and so on all undergo enzymatic browning after peeling, causing the color to darken. Soaking the peeled yam in cold water to isolate it from the oxygen in the air will keep it from changing color. If you eat it there is no problem, but after the dish is cooked the color does not look very good.

3. How to prevent yam from turning black?

1. When cutting yam, do not use metal tools (stainless steel is fine); use wooden or plastic knives.

2. Soak the cut yam in salt water or in cold water with oil and vinegar added; it can also be soaked in lemon water, then drained out when it is time to stir-fry the yam.

3. You can also stir-fry the yam in water first.

4. Short-term storage methods for yam

After buying yam, if you are not going to eat it right away, you must handle it properly immediately to ensure that its quality and texture do not change. The specific handling methods are as follows:

① After peeling and cutting the yam into pieces, divide it into portions according to the amount eaten each time and put them into plastic bags. Once portioned, put them immediately into the upper part of the refrigerator for quick freezing.

② When eating the yam there is no need to thaw it; once the water comes to a boil it can go straight into the pot, which is both convenient and ensures the yam's quality.