Diphosphates
What it does
Raising agent, emulsifier, stabiliser.
How it's made
Manufactured phosphates.
Diphosphates (also called pyrophosphates) are a group of phosphate salts used mainly as raising agents in baking, where they provide the acid that reacts with bicarbonate of soda to release carbon dioxide and make cakes and breads rise. They are also used to retain moisture and improve texture in other foods.
They are made from phosphoric acid and phosphate salts. Sodium or potassium phosphates are heated so that two phosphate units join together, driving off water and forming the diphosphate (pyrophosphate) linkage. By choosing the sodium or potassium form and the exact conditions, manufacturers produce diphosphates that react at different speeds.
The salts are purified, dried and milled to white powders. In self-raising flour and baking powder, a diphosphate is paired with bicarbonate of soda so that the two react, either when mixed with liquid or when heated, to generate the gas bubbles that leaven the bake; the choice of diphosphate controls whether that happens early or in the oven.
Possible reactions
High phosphate concerns for kidneys and bones with heavy intake.