Salt introduction:
Edible salt includes well salt, sea salt, pond salt and rock salt. , and contains iron, calcium, zinc, potassium, sodium, iodine and other nutrients. The salt people use is a kind of salt, which refers to the salt rich in sodium, that is, sodium chloride. Salt is also an indispensable element for human body, which can regulate human activities.
The state stipulates that the content of sodium chloride in well salt and mineral salt shall not be less than 95%. Salt contains barium salt, chloride, magnesium, lead, arsenic, zinc, sulfate and other impurities. We stipulate that the content of barium should not exceed 20 mg/kg. Too much magnesium and calcium in salt will make the salt bitter, and too high fluorine content will also cause poisoning. In recent years, many experiments have confirmed that there is a certain relationship between salt intake and the incidence of hypertension. Excessive salt intake in the diet can cause high blood pressure.
Type:
There were many kinds of salt in ancient times, including crimson snow, peach blossom, blue, purple and white. From the source, it can be divided into: sea salt is fried by sea brine, well salt is fried by well brine, alkali salt is fried by scraping alkaline earth, pool salt is dried by pool brine, and cliff salt is born between soil cliffs. Sea salt, well salt and alkali salt come from people, while pool salt and cliff salt come from heaven.
The historical records of the Ming Dynasty are as follows: the salt in Xiezhou was formed by geomantic omen, the salt in Ningxia was scraped from the ground, the salt in Huaizhe was boiled, the salt in Sichuan and Yunnan was pumped into the well, the salt in Fujian and Guangdong was fried, the salt in Huainan was fried, the salt in Huaibei was baked, and the salt in Shandong was fried and baked, which was relatively large. The famous doctors in Tao Hongjing in the Southern Dynasties recorded the following: Donghai salt, Beihai salt, Nanhai salt, Hedong salt pond, Liang Yi salt well, Xiqiangshan salt and Huzhongshu salt. Different colors, Hedong salt wins.
Related methods:
In industry, salt is dried with seawater (also called salt field method) or boiled with well water or salt lake water to precipitate salt crystals. The salt made in this way has many impurities and is called raw salt. Crude salt can be dissolved, precipitated, filtered and evaporated to produce refined salt. In order to eliminate the harm of iodine deficiency and protect the health of citizens, the state adopts comprehensive prevention and control measures based on long-term supply of iodized salt (hereinafter referred to as iodized salt).