Sodium tripolyphosphate (Na5P3O10) is a salt of phosphate ester and sodium, with the chemical formula Na5P3O10. The sodium salt of tripolyphosphate (STPP), one of the most important water-soluble polyphosphate compounds, is often used in detergents as builders to soften hard water, to prevent the formation of limescale on household appliances, and to improve both whiteness and brightness of fabrics. food chemical supplier

What is sodium tripolyphosphate?

Sodium tripolyphosphate (STPP) is a sodium salt of tripolyphosphoric acid. It is a water-soluble, crystalline powder that is used as a food additive, pharmaceutical ingredient, and flame retardant.

STPP is produced by combining phosphoric acid with sodium hydroxide and carbon dioxide. The resulting precipitate is filtered, washed, and dried to produce the white powder.

STPP’s chemical formula is Na5[(PO3)4] or 3Na(PO4)2·8H2O. It contains sodium ions, phosphorus ions, and oxygen atoms in various proportions according to its source material.

What is sodium tripolyphosphate used for?

Sodium tripolyphosphate is used in foods as a preservative to keep them looking fresh.

It’s also used in the pharmaceutical industry as a thickening agent and buffer.

Sodium tripolyphosphate is also added to cleaning agents, laundry detergents, dishwashing liquids and toothpastes. It may be used in personal care products such as toothpaste, hand soap and mouthwash as an anti-irritant or mild abrasive agent.

In cheese making, sodium tripolyphosphate helps control moisture loss and prevents unwanted odors such as ammonia from developing during ripening. custom chemical supplier

Sodium tripolyphosphate may be used to increase the viscosity (thickness) of drilling fluids used in the oil industry.

Why is sodium tripolyphosphate uses in food?

Sodium Tripolyphosphate (STPP) is used in the food industry as a leavening agent or dough conditioner. It can also be used as a buffering agent, emulsifier, and stabilizer. The Food and Drug Administration (FDA) has approved sodium tripolyphosphate for use in commercial food products.

Food manufacturers add sodium tripolyphosphate to foods such as baked goods, beverages, candy, and other snacks to enhance their texture, color, and flavor. The salt also helps to keep these items moist during storage.

Sodium tripolyphosphate is approved by the FDA as an indirect food additive that acts as an anti-caking agent, anti-foaming agent, firming agent, preservative agent, sequestrant and thickener in foods such as cheese spread; sausage casings; ice cream mix; frozen yogurt mix; powdered drink mixes; non-dairy creamers; peanut butter; salad dressing mixes; salad oils; mayonnaise dressings.

How is sodium tripolyphosphate made?

In sodium tripolyphosphate, three simple phosphate units are linked together to form a polyphosphate.

Here are the brief manufacturing processes:

  1. A mixture of monosodium phosphate and disodium phosphate is produced by neutralizing phosphoric acid with sodium hydroxide.
  2. After that, heat the mixture to 500-550°C. This is the reaction equation: NaH2PO4 + 2Na2HPO4 → Na5P3O10 + 2H2O


What is the application of sodium tripolyphosphate?

The primary use of food-grade sodium tripolyphosphate is to improve the eating quality of food products, particularly meat and fish. Additionally, it is used in pet food to keep the animal feed fresh and to bind water.

Additionally, it can be used to modify food starch.

The technical grade STPP is widely used in the production of laundry detergents and dishwashing detergents, industrial water softeners, industrial cleaners, grease remover, leather pre-tanning agents, dyeing auxiliary agents, and so on.

Here are its detailed uses in fish and meat.


The primary purpose of STPP is to reduce the amount of thaw water (or maintain water) and make seafood look more firm and smooth. It is often added to fish (e.g. salmon) before freezing. As well as scallops, shrimp, and lobster, which you may also find in frozen seafood.

Most seafood is easily damaged by ice crystals and protein denaturation during freezing storage, which damage taste, odor, texture, and juiciness.

Fish meat’s water retention performance is determined by its protein content. During freezing, polyphosphate prevents protein denaturation by retaining water.

A solution of sodium tripolyphosphate at a certain concentration is used in the production of frozen fish fillets.

A fish’s ability to retain water is closely related to its texture, tenderness, sliceability, elasticity, and taste. Without sodium tripolyphosphate, most seafood loses weight (water), turns darker, and becomes fragile when thawed.


Sodium polyphosphate, sodium pyrophosphate, and sodium hexametaphosphate are some of the phosphates commonly used and produced in the meat industry.

In the meat processing industry, polyphosphates are commonly used as additives. In addition to improving texture and color, STPP reduces cooking loss and increases product yield. Increasing pH, strengthening ionic power, and chelating metal ions are believed to be the mechanisms.

In meat, STPP interacts with amino acids or hydroxyl groups to improve water retention and gel strength.

Furthermore, combining it with sodium chloride can reduce meat’s sodium content compared with just using sodium chloride alone. Sodium tripolyphosphate (anhydrous) contains only 31.3% sodium, whereas NaCl contains 39.3% sodium.

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