Food

Sodium phosphates are multi-functional ingredients commonly with the following functions in food:

General sequestrant

Chelating metal ions (e.g. Cu2+ and Fe2+) and therefore preventing the oxidation, discoloration, and decomposition of vitamin C caused by these metal ions, finally prolong food shelf life, reduce cooking time and etc.

Chelating calcium (Ca2+)

Pyrophosphates remove naturally occurring calcium ions from proteins and combine with proteins, and therefore increase the water retention ability of meat products.

PH buffering

Adjust PH in food.

Emulsifier

Prevent the separation of protein and fat, increase viscosity, improve the mouthfeel. Such as in processed cheeses.

Retaining moisture

Polyphosphates prevent protein denaturation, and maintain water retention for frozen seafood (e.g. fish, shrimp) and poultry products.

Leavening acid

Combined used with sodium carbonate in bakery to release CO2 to increase the loaf volume

http://www.chinafooding.com/Monosodium_Phosphate