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Calcium citrate

physical science Maturity 11-13 Next article →

Calcium citrate is a special kind of salt. It comes from citric acid. People use it in many different ways. It is a common food additive known as E333. This means it can be added to food. It often works as a preservative to keep food fresh. Sometimes, it is used to change the flavor of food.

Making this salt is a very interesting thing that happens. First, a fungus is used to make citric acid. This happens in a large industrial process. Then, workers add limewater to the liquid broth. This causes the calcium citrate to fall out as a solid. Workers filter this solid and wash it to make it clean. They can sell it as it is. Or, they can turn it back into citric acid using sulfuric acid.

This substance can be found in nature too. It exists as a mineral called Earlandite. In a lab, scientists can make needle-shaped crystals. They use a method called hydrothermal synthesis to do this. These crystals have a complex three-dimensional network. They are held together by citrate anions and hydrogen bonds. This structure is very organized at a tiny level.

There are important numbers to know about this salt. In its anhydrous form, calcium makes up 24.1% of its mass. In the tetrahydrate form, it makes up 21.1% of the mass. Calcium citrate is also used in many health supplements. You might see it in brands like Citracal or Caltrate. These pills help people get more calcium in their diet.

Your body can use this calcium very well. Scientists call this bioavailability. This means how easily the body takes in the nutrient. Calcium citrate does not change the acid in your stomach. This is different from calcium carbonate. That other salt can cause something called acid rebound. This is when the stomach makes too much acid. Calcium citrate is a gentler choice for many people.

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