What is Sodium Tripolyphosphate？

Description

Sodium tripolyphosphate is a preservative for seafood, meats, poultry, and animal feeds. It is common in food production as E number E451. In foods, STPP is used as an emulsifier and to retain moisture. Many governments regulate the quantities allowed in foods, as it can substantially increase the sale weight of seafood in particular.

Sodium tripolyphosphate is also added, along with other sodium polyphosphates, to processed cheeses as an emulsifier. The polyphosphates are negatively charged chains of phosphorus and oxygen that attract water molecules. When added to the cheese, they remove calcium from casein matrix and also bind themselves to the casein while bringing moisture with them. The effect is that the polyphosphates loosen the protein matrix helping keep the mixture emulsified and ensure even melting. This applies to other uses such as force-meats: STPP will help prevent the poultry, fish, or meat from becoming greasy and falling apart during heating.

Application

1 Food Additive

Sodium tripolyphosphate also gives a fresh appearance to meat and seafood while slowing down spoilage. The chemical helps to preserve the natural color of meat and fish and improves their texture. This is done by improving the water-holding capacity of animal products and consequently slowing down their drying.

2 Tanning Agent for Leather

Sodium tripolyphosphate is listed as a tanning agent for leather. Interestingly, the chemical is also used as an oil contamination resistance agent in paper production. So, it can both help manufacturers apply the right color to a medium as well as keep unwanted color away.

3 Other Uses

Other uses of sodium tripolyphosphate include petroleum refining, metallurgy, mine applications and water treatment. The last application is made possible by its pH buffering ability, meaning that it can "soften" acidic water by neutralizing its acidity. This quality is one of the reasons it is added to detergents.