On the issue of iodine in salt, the iodine content in table salt

That liquid should be starch suspension (starch is insoluble in water, so it cannot be said to be a solution), iodine will turn blue immediately when it encounters starch, and the speed is very fast, so starch is the best reagent to test iodine or iodine ions

The iodine contained in salt is in the form of potassium iodate (kiO3), which can be tested using a starch solution.

Starch, didn't the middle school teacher tell you that you can use starch to test for iodine?

The iodine content in table salt is 20 mg kg to 30 mg kg.

At present, the iodine content of iodized salt regulated by countries around the world varies greatly. In the past, the World Health Organization recommended that some countries in Western Europe use 10 milligrams to 20 milligrams per kilogram, most countries in the Americas use 50-100 milligrams per kilogram, and the United Kingdom is 25 milligrams per kilogram.

The current iodized salt content in China is 35 15 milligrams per kilogram as stipulated in the "New Standard for Edible Salt" officially promulgated by the State Bureau of Technical Supervision in 2000. 20 to 30 mg kg. Iodine is an essential trace element for the human body, and an appropriate amount of iodine should be consumed every day.

In daily life, it is best to use iodized salt as a condiment, which has the trace elements that the human body must absorb. Lack of iodine causes some adverse effects, but the intake of iodine should be moderate. When seasoning with salt, it is necessary to eat too much salt, and it is not good to eat too much salt, so try not to eat too salty for the sake of your body.

Consumption of iodine

Edible iodine is an essential trace element of the human body, one of the halogen elements, iodine is the weakest chemical activity in the halogen group, but it can still be directly combined with most elements, and is widely present in nature in the form of compounds. Iodine is slightly soluble in water, and hydrolysis produces stable periodic acid, which can make the brownish-yellow aqueous solution acidic.

Iodine is soluble in organic solvents such as ethanol, ether, glycerol, etc. Iodine is blue when it meets starch, which can be used for qualitative and quantitative detection. Seaweed is the most abundant in iodine and is the main raw material for extracting pure iodine.

Industrial iodine is also used in seaweed, mainly used in medicine, fuel, photosensitive materials and chemical reagents.

Edible salt contains iodine.

Edible salt refers to processed edible salt with sodium chloride as the main ingredient obtained from seawater, underground rock salt sediments, and natural brine, excluding low-sodium salt. The main ingredient of Duan Xiao's edible salt is sodium chloride (NaCl), which also contains a small amount of water and impurities, as well as other elements such as iron, phosphorus and iodine.

Edible salt is iodized salt made by adding a certain amount of iodine to refined salt, crushed washing salt, and sun-dried salt. The iodine in salt can only be biologically active in the human body after it is converted into iodine ions. The properties of iodide are extremely unstable, easy to decompose, volatilize and fail.

The iodine content in table salt is 20 mg to 30 mg.

The amount of iodine in iodized salt varies from country to country. Some countries in Western Europe use salt iodine content of 10 mg-20 mg/kg, most countries in the Americas at 50 mg/kg to 100 mg/kg, and the UK at 25 mg/kg.

China's national food safety standard "Iodine Content of Edible Salt" published in 2011 stipulates that the average level of iodine content (in terms of iodine) per kilogram of edible salt products is 20 mg and 30 mg, and the allowable fluctuation range (uniformity) of iodine content of edible salt is 30% of the average iodine content of edible salt.

The iodine content in iodized salt is the iodine content in the product, not the iodized content at the production level specified in the past; Each province (autonomous region, municipality) can select the average level of iodine content of edible salt suitable for the local population according to the actual iodine nutrition level of the local population.

Precautions for storage and use of iodized salt:

Iodized salt should not be stored in packaging bags for a long time, and should be placed in glass or ceramic jars with caps for preservation. And take care to keep the salt shaker in a cool, away from direct sunlight, and do not heat the salt, because iodized salt is more likely to lose iodine when stored in a high temperature environment than in a low temperature environment. Because iodine is volatile when exposed to heat, salt should be added when the dish is almost cooked, and salt should not be used to fry the pan, and salt should not be fried in the oil pan.

Experiments have shown that if iodized salt is added to stir-fry vegetables, the iodine consumption rate will drop to 10. If it is put in the process of stir-frying, the iodine consumption rate is 60; If the food is put when it is almost cooked, the iodine consumption rate is 90; If it is placed in cold vegetables, the iodine consumption rate is close to 100.

When stewing, boiling, simmering, and stewing food, iodized salt should also be put when it is almost ripe, because putting salt too early will not only lose a lot of iodine, but also make the meat not easy to stew. In addition, it is best to cook and eat the dishes freshly, and it is not advisable to return to the pot to heat them repeatedly, otherwise it will also cause more iodine loss.