During New Year in Chinese, we often inevitably have leftovers in dining out or cooking at home. If we keep it to the next meal, and we worry that it will produce harmful substances such as nitrite and it even will cause cancer!
So, what kind of substance produced in the leftovers? What is the better treatment in the leftover for our health? Which can be preserved and which should not be preserved? Listen to authoritative nutrition experts!
Eating leftovers bad for you?
The fourth point of the five keys to food safety proposed by WHO is mentioned. The cooked food should not be stored for more than 2 hours at room temperature. It should be refrigerated in time (preferably below 5°C) and do not put it in the refrigerator for more than 3 days. The number of times of heating in the leftover should not exceed one.
If leftover in green vegetables directly places at room temperature overnight, it is preferably can not eat anymore. Bacteria in the leftovers will produce and multiply at room temperature. Excessive bacteria in food is a great unsafe factor. Nitrate in the leftover also will be converted into nitrite and the content of nitrite will rise rapidly under the effect of bacteria. Nitrate is another unsafe factor.
Ingesting micro nitrite affects dilating blood vessels, but it is dangerous to ingest a large amount of nitrite, which promotes the synthesis of nitrosamine carcinogens in the stomach. When the amount of ingestion is large, hemoglobin may not be able to carry oxygen and cause acute poisoning.
If the vegetables are cooked and not stirred by chopsticks, take a portion, put it into a clean crisper, gently cover the lid, and then put it in the refrigerator. This kind of overnight dish needs to be heated and sterilized before eating and the leftover can be eaten safely.
Can leftovers dilate blood vessels? Rumors!
In recently, an article entitled Nongda University Professor points out that there is the best vasodilator substance in the leftovers! No need additional supplements! Is widely spread in the post of WeChat. The article says that the leftovers contain nitrite and helps to expand blood vessels.
The article also stated that the opinion was published by Shen Qun, a professor at the College of Food Science and Nutritional Engineering of China Agricultural University, and Fan Zhihong, an associate professor at the College of Food Science and Nutritional Engineering of China Agricultural University. It also accompanied photos of two experts and noted that part of the article came from a certain media.
Do leftovers help to dilate blood vessels? After checking the relevant information online, the reporter found that a certain media published an article entitled Nitrite is nothing on April 13th, 2012. A public account in WeChat intercepted some of the contents from this article and grafted the contents of the blog named Fan Zhihong_Original Nutrition Information. Finally, it was integrated into an article with logical confusion, Grable and eye-catching title, and tells everyone that leftovers are good for health and cardiovascular.
What is the truth about this problem? Experts say that they have never received relevant interviews. And experts remark in the hot spot that nitrates in green vegetables are good for health. A portion of the nitrates ingested from food can slowly transform into small amounts of nitrite in the body and then nitrite can turn into nitric oxide, which helps to dilate blood vessels and improve blood circulation. This function has been used by the foreign sports medicine field. To improve their athletic ability, they allow athletes to use nitrate-rich vegetable juices.
This research evidence is still not related to the leftovers with benefits for health because foreign athletes not eat leftovers, but vegetable juice made from fresh vegetables. As long as you eat enough green vegetables, you can get the benefits of nitrates, which are not poisonous. You don't need to get nitrates from leftovers.
Fresh green vegetables are healthy, it is not only rich in potassium, calcium, magnesium, vitamin B2, folic acid, vitamin K, lutein, flavonoids, and other health care ingredients, but also without much nitrates concerned by people.
Nitrate and nitrite are different in toxicity
Nitrate and nitrite are inorganic nitrogen compounds widely found in nature. They are commonly used as color protectants in food processing. For example, adding a proper amount of (sodium) sodium nitrate (potassium) to cured meat products can not stabilize the product. The pink color also has a special inhibitory effect on microorganisms such as Clostridium botulinum and can improve the flavor of the cured meat.
Existing studies have shown that nitrate and its conversion product nitrite are easily absorbed in the upper digestive tract, but nitrate and nitrite are different in toxicity. The former is non-toxic and the latter is toxic when the amount of it is large. It is no problem to eat a hundred milligrams of nitrate at a time, but eating 200 milligrams of nitrite at a time has a great risk of poisoning.
In other words, eating green vegetables to expand blood vessels do not require eating leftovers. Furthermore, ingesting a large amount of nitrite at one time is harmful. It can play a beneficial role when nitrite is slowly converted into nitrite in the body by digestion.
These three kinds of leftovers must be dumped
If you can finish a meal cooked in fresh, it is better to avoid leftovers. If you can't, you should stick to the principle that meat can be remained in the leftover, while green vegetables and the cool dishes can not.
1. vegetables should not be left
The nitrates in vegetables absorbed from fertilizers and soils under the effect of bacteria are slowly reverted into nitrites that may cause cancer in humans. The content of nitrite is the highest in the leftovers of vegetables placed for a long time.
Besides, the vitamins in green vegetables almost disappear after repeated heating. Therefore, fried vegetarian dishes or salad dishes should not be preserved.
2. seafood is not worth staying
The delicious taste of seafood is favored by people. If we place them overnight, it will lose their umami taste, and it is better for us to finish them on time.
3. soy products are also difficult to keep fresh
The room temperature in summer is suitable for microbial production and growth. Tofu contains much water and is rich in protein and other nutrients, which is like a microbial culture medium. Therefore, soy products must be eaten at in time.
4. Meat products or stewed meat should be frozen firstly
It is better to choose glassware or enamel porcelain for this type of food. Because the harmful substances contained in some plastic containers are fat-soluble, they will penetrate the food as the oil penetrates, including oily dishes such as stir-fried dishes and stewed vegetables.
5. The staple food should be preserved separately
Steamed bun, steamed twisted roll, and cakes can be placed in the frozen layer of the refrigerator if they are not expected to be eaten. They can be stored for about a week at minus 15 degrees Celsius.
Rice and porridge are better kept closed due to their high content of moisture and need to be consumed within 24 hours. People often ignore the preservation of cooked staple foods. Many foods induce diarrhea caused by its deterioration. Therefore, freshness in dumplings and steamed buns are also better in preservation.
6.Three tips to keep leftovers in the refrigerator
Leftovers are not impossible to eat, but reservation conditions must pay attention. The leftover should be placed in the refrigerator immediately after cooling. At the same time, it needs to pay attention that the storage of leftovers should be separated, and storage time should not be too long.
(1) Put the food in the refrigerator after cooling
When food in hot suddenly enters into the environment at low temperature, and the hot air will cause the water vapor, which promotes growth and multiplication of the mold and bacteria in food in the refrigerator.
After cooling, the leftover should be put it in the refrigerator in time, even in the winter. And do not put it outside for a long time, because it will produce bacteria and the refrigerator has a certain antibacterial effect.
(2) Separate storage of different leftovers
To avoid bacterial cross-contamination, leftovers need to stored in a clean container, such as crisper, fresh-keeping bag, or put a layer of plastic wrap on the dish.
(3) storage time should not be too long
It is better to eat leftovers kept within 5-6 hours. Under normal circumstances, heating at a high temperature can kill most pathogenic bacteria for a few minutes. However, if the food is stored for too long, heating does not work in killing nitrite and aflatoxin produced in the leftover.
7. Three tips to cook leftovers
(1) To change the cutting skill
Large pieces of meat are suited for cutting into a small one. It can be sliced, diced, chopped, and mix with fresh vegetables, whole grains, etc. For example, you can mix the pork cut into pieces, the chicken is torn into pieces, the sliced meat cut into shredded pork with the cold vegetables, or make them into the raw materials of the pie and spring rolls.
(2) To change the seasoning
There are two purposes for changing the seasoning. One is to change the taste of the dishes, and the other is to adjust the saltiness. If you have to remain the braised prawns, then remove the foil and add some tomato sauce. It can be transformed into a delicious tomato prawn.
(3)To add ingredients
It can add vegetables, instead of increasing the meat dish and make it into a new meal, which helps to improve the nutritional balance. For example, you can add some onions, mushrooms, potatoes, carrots, corn, etc., in the original braised pork rib and made it into fried ribs with vegetables.
You can also make leftovers into soup. For example, you can mix stewed pork ribs in the leftover, with vegetables and noodles and make it into vegetable ribs noodle soup. And you can mix fried eggs with tomato in leftover, with fungus and noodles and make it into tomato miso soup.
If you have staple food left, you can still follow the above 3 methods. Finally, to avoid stomach upset after eating, it should be reminded that the leftovers should be cooked for a certain time at high temperature.