Tea is what we commonly call tea, and China can be regarded as one of the origins of tea. According to scientific research, tea has a history of more than 2,100 years. With the spread of tea culture, almost all of the world is planting tea. , Both have the technology of growing tea.
However, most of these technologies are directly or indirectly introduced from China. British scholar Alan McFarlane once said in a book that only tea has successfully conquered the world, so the culture of tea is really too It's a long time. The tea-growing areas in my country are mainly distributed in various parts of the south of the Yangtze River, and the climatic conditions in the south are slightly more suitable for tea-growing.
There are many chemical components in tea, such as: tea polyphenols, plant alkaloids, proteins, amino acids and so on. It also contains inorganic mineral elements, such as potassium, calcium, magnesium, cobalt, iron and so on. Of course, different tea leaves contain different elements, because their varieties are different, so not all tea leaves are the same. As we say, Tieguanyin, manganese, iron, fluorine, potassium, and sodium are all higher than other teas. So it is different. This is a basic way of saying tea.
Many people say that "overnight tea" is like poison and cannot be drunk at all. Is it true?
Indeed, every time we talk about "overnight tea", everyone will think of a substance, that is, nitrite, and nitrite is a carcinogen, so everyone will definitely think about this question.
What exactly is nitrite? Nitrite is indeed a toxic substance, and it has also been recognized by the World Health Organization in the list of 2A carcinogens. According to some scientific data, as long as 0.3 to 0.5 grams of nitrite ingested can cause poisoning, and 3 grams can cause death, so it sounds scary. This is why some people say that "overnight tea" is like poison. I can't drink it at all because nitrite is toxic, but what is the fact?
Is there any relationship between overnight tea and nitrite? In fact, this research experiment has also been carried out. CCTV has used Longjing, Pu'er, and chrysanthemum as experimental samples to brew these three kinds of tea for 24 hours. Through the detection of nitrite, it is found that Pu'er and chrysanthemum, regardless of whether they are freshly brewed It was overnight, and the nitrite content was less than 0.2mg/L. After 24 hours of brewing, the content of nitrite in Longjing tea increased to 0.26mg/L, which still meets the sanitary standard GB 5749-2006 (1mg/L) for drinking water (open experimental data).
Relatively speaking, the nitrite content of Longjing tea is higher than that of Pu'er tea and chrysanthemum tea. This also directly proves that this is what kind of tea does contain nitrite in it. However, regarding the toxicity of nitrite, according to the minimum standard of nitrite, 200mg/kg is needed to show signs of poisoning (data difference conversion), so this is far lower than the risk, so you don’t need to Worry. "Overnight tea" is like poison, you can't drink it at all? It is also incorrect, the experimental data has already told you the truth.
At least from the experimental evidence of nitrite content, there is no problem. But experts also advise against drinking "hot tea" or "mouldy tea". "Moldy tea" above 65°C may have an impact. At the same time, "mouldy tea" is polluting and contains a lot of toxins, so you can't drink it. This is the general situation.
Summarize
Overnight tea does contain nitrite, but through the analysis of experimental data on some teas, we can see that the content of nitrite is very low. Under normal circumstances, drinking tea properly is still beneficial. It is not as serious as everyone thinks. Nitrite is a substance that is not good for people. However, as long as there is no excess, it is unlikely to bring huge amounts. The impact of this, so don’t worry.
At the same time, when you buy tea, you must take the initiative to buy and sell tea through regular tea channels. Although tea is unlikely to have the possibility of fraud, the quality of tea still needs to be "guaranteed."