Why does sweet potato boiled rice turn black? Why is the water in which sweet potatoes are boiled bl

Reasons why sweet potatoes cook rice black:

Sweet potatoes are rich in many trace elements.

Several of them are polyphenols, which are generally found in the pulp or leaves of plants, and are elements that can react with air. Sweet potatoes are isolated from the air by the peel when they are not peeled, so they do not turn black, but after peeling, the protective film of the peel is removed, and the polyphenols in the pulp come into contact with the air, and the oxidation reaction will soon occur.

The reason why an apple will turn yellow after peeling it for a while.

Treatment: Because it is the same reason as apples to turn black, so the preservation method of not blackening is the same, you need to soak the knife in salt water before peeling, so that the sweet potato will not turn black so quickly when peeling and cutting, and after the sweet potato is cut, it is also soaked in salt water, which can ensure that the sweet potato will not turn black and will not damage the taste of the sweet potato, which can be described as killing two birds with one stone.

Sweet potatoes are rich in many trace elements, several of which are polyphenols, which are generally found in the pulp or leaves of plants, and are an element that can react with air.

After cutting, the cut surface quickly reacts with the oxygen in the air to form oxides such as oxide, which are generally dark brown in color, so raw sweet potatoes will change color quickly after cutting.

1.Prepare a small sweet potato and peel it well.

2.Cut the sweet potatoes into slices and then small pieces, and wash the blackcurrant raisins.

3.Wash the rice, put the sweet potato wedges in it and cook the rice.

4.When the rice is cooked, put the washed blackcurrant raisins on top, cover and let it sit for a while!

In most cases, it is relatively common for steamed sweet potatoes to turn black, it may be caused by oxidation, it may be caused by freezing, it may also be caused by spoilage, etc. Let's take a closer look!

Polyphenols. Oxidation blackening Sweet potatoes contain more phenolic substances, and there is generally no oxidation when the sweet potato is complete, but in the process of peeling and cooking sweet potatoes, the phenolic substances inside the sweet potato will come into contact with the oxygen in the air to form quinone compounds, and the temperature can promote oxidative browning, and the quinone compounds will form melanin after accumulation.

dough, causing the sweet potatoes to turn black.

Sweet potatoes turn black after freezing The best storage temperature for sweet potatoes is between 10 and 14 degrees Celsius.

When it is lower than 10 degrees Celsius, sweet potatoes are prone to chilling injury, so the sweet potatoes that are not properly stored will appear black under the condition of chilling damage, and the inside of the sweet potatoes has deteriorated at this time.

Sweet potatoes spoil and turn black Sweet potatoes contain more water and carbohydrates.

It is a good medium for bacterial growth.

Therefore, it is very easy for bacteria to grow, and the growth of bacteria on the sweet potato will cause the sweet potato to deteriorate and the sweet potato tissue will be damaged, and the invasion of oxygen will also become easy, so the sweet potato will turn black after boiling.

In fact, start with high heat, and then turn to medium heat and slowly simmer.

1. When steaming sweet potatoes, use high heat first, wait until the water in the pot boils, turn the heat to medium-low heat, and steam for 10 to 15 minutes (depending on the block of sweet potatoes, the big ones will be steamed for a longer time, and the small ones will be steamed faster). However, it should be noted that in the process of steaming sweet potatoes, it is necessary to ensure the airtightness of the utensils and do not open the lid frequently, so as not to affect the taste of the steamed sweet potatoes.

2. Be sure to steam the skin of the sweet potato into half-ripe in a short period of time with high heat and hot water, so that the steamed sweet potato tastes sweet.

3. If you cut the sweet potatoes into relatively large pieces, then you can consider keeping the skin and steaming together. The remaining sweet potato skin prevents the potato from coming into contact with too much moisture during the steaming process, which can affect the taste.

It depends on how big the piece is, if it is too big, you can also cut it and steam it, and it is generally okay to boil the pot for 15-20 minutes. In fact, when steaming to a certain time, prick it with chopsticks, and you can feel that there is no hard heart that is cooked.

The method of steaming sweet potatoes is also very simple, that is, wash and peel the sweet potatoes you bought. Cut sweet potatoes into chunks for easy steaming and save energy. Steam the sliced sweet potatoes in a steamer for about half an hour. Finally, serve the steamed sweet potatoes on a plate.

If your cooked sweet potatoes turn black in color, the main reason is that you have not mastered the skills of cooking sweet potatoes, which leads to the oxidation reaction of the phenols in the sweet potatoes when they come into contact with the air.

Sweet potatoes contain more phenolic substances, which are particularly easy to oxidize after contact with air to form puff quinone compounds, and are more likely to undergo oxygenation reaction when the temperature is high. When a large number of quinones are formed on the surface of sweet potatoes, they accumulate together to form melanin blouses, which can cause cooked sweet potatoes to turn black in color.

The way to prevent sweet potatoes from turning black after cooking is super simple, as long as you master the eight words, you can easily do it: "boil the pot under water, cut and cook".

When we were children, we all grew up eating sweet potatoes, and a big pot of sweet potatoes would be cooked at home every day, and people would take the rest to feed the pigs, and there was never a phenomenon of blackening when cooked. Because our old family boiled whole sweet potatoes with the skin on, and they were all boiled in a pot, the chunbihuol substances in the sweet potatoes had no chance to be oxidized at all.

Modern people like to peel off the skin of sweet potatoes when boiling sweet potatoes, so when cooking sweet potatoes, they must master the eight-character mantra of "boiling the pot, cutting and cooking". The correct way to cook it is like this-

First, sit in a pot and boil water, and use the boiling time to wash the sweet potatoes with the skin on. When the water is boiling, quickly peel off the skin of the sweet potatoes and adjust the heat to keep the pot boiling.