Can you eat yam when it turns purple?

Whether the yam can still be eaten after it turns purple depends on the reason why the yam turns purple. First of all, there is a kind of yam, the iron stick yam, which has a layer of light purple inside after peeling off the skin. This is its normal color and will not affect its consumption or medicinal use at all. Another situation is that the yam itself becomes moldy, causing the yam to turn purple or brown. In this case, it cannot be eaten. The details are as follows.

1. Purple is the sign of iron stick yam. Generally, there is no purple on yam. It is rust. There is no problem. You can see it without peeling it. It is normal to have a light purple layer after peeling it.

2. The purple color is usually on the inside and can be seen after peeling off the skin. This purple color is usually only seen in winter and is rarely seen when the weather gets hot.

3. The purple and browning after peeling are mainly caused by three conditions: 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.

4. This is because the peeled yam undergoes enzymatic browning, causing the color to darken. 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.

5. This situation is not uncommon in real life. After peeling, apples, eggplants, lotus roots, etc. will undergo enzymatic browning, causing the color to darken. Soaking the peeled yam in cold water to isolate it from the oxygen in the air will prevent it from changing color. There is no problem if you eat it, but the color will not look good after the dish is cooked.

6. It is normal for yam to change color after peeling. Yam needs to be soaked in salt water immediately after peeling or slicing to prevent oxidation and blackening. Fresh yam is mostly used for consumptive cough and diabetes, and can be fried and eaten to treat spleen, stomach and kidney deficiency. Don't eat yam raw, because it contains certain toxins. Yam should not be taken together with alkaline drugs. Yam, also known as Dioscorea batatas, is also known as Huai yam, Huai yam, native yam, mountain yam, yam, and Yuyan. A perennial herb with creeping stems, often purple, cylindrical tubers, opposite leaves, ovate or elliptical, milky white flowers, and dioecious plants.

7. It is normal for yam to change color after peeling. After the yam is peeled and comes into contact with the air, the mucus on the surface undergoes an oxidation-reduction reaction with the air, resulting in a light yellow color. You can still eat yam like this and it will not cause poisoning.

8. Yams contain phenols and classified oxidases, while the air contains oxygen. After the yams are peeled, a reaction will occur. The generated quinones will appear brown or black, and when slightly oxidized, they may appear lavender, which is also edible. Therefore, after peeling the yam, it is necessary to soak it in salt water or vinegar water as soon as possible, or sprinkle lemon water on the surface of the yam to prevent it from oxidation and discoloration.