Experts say baked sweet potatoes can be eaten as snacks
At present, there are many small vendors selling roasted sweet potatoes on the streets of Beijing. Many people will buy a few pieces, and eating a steaming sweet potato on a day when the chill is gradually coming, can be considered a pleasant thing.
But many people also pointed out that roasted sweet potatoes bought at outside stalls are harmful to health and cannot be eaten.
Is that so?
Today, Fan Zhihong, associate professor of the Department of Nutrition and Food Safety of China Agricultural University, commented in detail on the reasons why everyone opposed to selling sweet potatoes by small vendors, and talked about the way in it.
The charcoal fire in the barbecue method can be heated and indirectly roasted. The reason may be opposed: the sweet potatoes sold by small merchants outside are burned with coal, which is harmful to health.
Expert opinion: Generally speaking, direct open-roast baking is prone to produce harmful substances, mainly acrylamides produced by starches heated at temperatures above 140 ° C, substituted amines produced by protein coke, and produced at slightly high temperatures.Benzo pyrenes.
However, because sweet potatoes are hardly unfortunate and have little protein, they are not dangerous at normal baking temperatures.
In theory, setting the temperature and time to bake sweet potatoes in an electric or infrared oven is the safest.
But these costs are relatively high and are not suitable for roasting on the road.
And the civilians often use charcoal to indirectly dormant, so small vendors outside are acceptable as long as the sweet potatoes do not directly contact the open flame.
Most of the sweet potato roasting tools on the street are large round iron buckets, and some even transform chemical buckets into sweet potato barbecue stoves. If the sweet potatoes roasted in this way are eaten, they are definitely not good for the body.
Expert opinion: Whether roasted sweet potatoes in round iron buckets is harmful depends on what substances they previously contained, which cannot be generalized.
For example, this barrel used to contain alcohol or cooking oil.
If it was used to hold gasoline, although gasoline itself is not edible, it will completely evaporate after being heated a few times.
After the volatilization is clean, it will no longer bring harmful substances.
Unless it is filled with non-volatile toxic substances, and it is not long after being used up, there is obvious harm.
Of course, everyone hopes that sweet potato processors can use an infrared or electric oven to bake in a clean room.
In fact, there are indeed such workshops now, making clean and safe baked sweet potatoes for people, this will be its development direction.
However, we don’t need to treat the sweet potatoes baked in round iron buckets as poison, and use this bucket to make a fuss.
The sweetness of the sweet potatoes that have not been moldy stored for a long time in the baking ingredients naturally rises. Reason: Some vendors will use the stored sweet potatoes for a long time. Although sweet, they may damage the nutritional value.
Expert opinion: Such roasted sweet potatoes are harmless.
Many potatoes, fruits, vegetables, etc. have this basic characteristic. After cold storage in winter, the sugar content in the raw materials will rise, which is an instinctual biochemical change in plants to improve freeze resistance.
Therefore, you can rest assured that you have eaten sweet potatoes for half a year. Drying the surface will not hinder the nutritional value, and it will not mold.
It is reminded to note that raw sweet potatoes will produce toxins after they become moldy and black, so do not eat them, or sweet potatoes that are softened and frosty after frostbite, do not eat.
Do n’t worry if the skin is roasted during the baking process. Just remove it and eat it. Reason: Sometimes, the skin of roasted sweet potatoes often has roasted or even blackened parts, which must contain harmful substances.
Expert opinion: If it is brown, sticky, basically don’t worry, because this is the result of “caramelization reaction”.
The sugar in the sweet potato is concentrated at high temperature, and the caramelization reaction occurs when it is heated to more than 140 seconds, and the color gradually becomes darker with the increase of the conversion temperature, and finally becomes black and carbonized, but it is non-toxic.
This process will produce a seductive and sweet smell, which is one of the reasons people love roasted sweet potatoes.
If the skin is not brown at all and the aroma is insufficient, I am afraid that not many people will be tempted.
Of course, at the same time as the caramelization reaction occurs, the small amount of protein contained in the sweet potatoes will also be burnt together, a Maillard reaction will occur, and acrylamide will be produced.
But don’t worry too much, because the content of sweet potato protein is very low, you can remove the scattered black parts when eating.
Experts remind children to eat sweet potatoes as a “snack”. It is a starchy food, it is rich in vitamin C, and there are many carotene in the heart.
Surprisingly, the starch contained in sweet potatoes will protect the vitamins in it, and the losses after steaming, boiling, baking, etc. are very small.
Roasted sweet potato is actually a reasonable processing method. It does not introduce oil or add sugar. It is a natural low-fat, high-fiber food, and it can retain its own properties that help prevent bowel cancer.
If children use baked sweet potatoes instead of cookies, cakes, cookies, etc., it can be said to be a healthy snack option.
Especially recommended, in fact, you can also make baked sweet potatoes at home, if you like to eat, you may try.
Wash the sweet potatoes and heat in a microwave oven for 5-6 minutes on high heat to allow the interior to heat through.Then transfer to the oven, bake at 140 kW for 20 minutes, and then bake for 20 minutes for 100 seconds. After the heat is turned off, cool naturally in the oven to room temperature.
Wash the sweet potatoes, cut them into thick pieces, put them in the oven lunch box, and heat for 2-5 minutes depending on the number of sweet potatoes pieces; then take a pan, put a small amount of oil on the bottom, spread the pre-heated sweet potato pieces and coverCover, bake on low heat for 10 minutes, turn over and bake for another 8 minutes.
Note that the fire is small, observe often, and avoid bottoming.