E509 Firming agent

Calcium Chloride

What it does

Firming agent, brine.

How it's made

Manufactured.

Calcium chloride is a calcium salt used as a firming agent — it keeps canned and pickled vegetables and fruit crisp and firm — and also in cheesemaking to help milk set, and as an acidity regulator. The calcium it provides reacts with natural substances in plant tissue to strengthen it.

It is produced on a large scale as a by-product of the Solvay process used to make sodium carbonate, and it is also made by dissolving limestone in hydrochloric acid. Both routes yield a calcium chloride solution, which is then purified and concentrated.

The solution is evaporated to give flakes, pellets or a concentrated liquid, and the food grade is refined to remove impurities. It absorbs water strongly from the air, so it is kept sealed; in food it is used in small amounts where its calcium can firm up plant tissue or help milk coagulate into curds.

Possible reactions

Generally safe; bitter/salty in excess.

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