Industrial grade Food Grade Sodium tripolyphosphate CAS 7758-29-4 STPP

What is Trisodium phosphate (CAS 7601-54-9)?

Trisodium phosphate, also known as sodium orthophosphate (TSP), is the sodium salt of orthophosphate obtained by the complete neutralization of phosphoric acid. Its chemical formula is usually written as:

Na3PO4 (CAS No.: 7601-54-9, molecular weight approximately 163.94, dodecahydrate CAS No.: 10101-89-0)

At room temperature, it is a colorless to white needle-like crystal or crystalline powder, odorless, and generally exists in both anhydrous and dodecahydrate forms. The dodecahydrate has a melting point of approximately 73.4℃ and a density of approximately 1.62 g/cm³. It readily effloresces in dry air and loses all its water of crystallization at 100℃. Trisodium phosphate is readily soluble in water, and its aqueous solution is strongly alkaline due to the vigorous hydrolysis of phosphate ions (PO₄³⁻) (pH approximately 11.5 for a 1% aqueous solution). It is insoluble in ethanol.

From a molecular structure perspective, trisodium phosphate consists of three sodium ions (Na+) and one orthophosphate ion (PO4³-), making it a completely neutralized salt of phosphoric acid. In food systems, phosphate can chelate metal ions, regulate pH, promote the binding of proteins and water, and help meat products retain moisture, tenderize, stabilize emulsions, and buffer systems—this "chelation + water retention + buffering" capability constitutes the core basis for its widespread application in the food industry.

Chemically, trisodium phosphate is strongly alkaline and can react with acids to form phosphates. It can also form insoluble precipitates with calcium and magnesium ions in water. It has a certain corrosive effect on the skin, and precautions should be taken for prolonged contact. Food-grade trisodium phosphate must meet the quality standards for food additives and should be stored in a dry, sealed container.

Food-grade trisodium phosphate refers to products specifically designed for food processing, used as food additives (moisture retainers, stabilizers, emulsifiers, pH adjusters). Compared to industrial-grade products, food-grade products place greater emphasis on the following indicators:

Main content

Purity directly affects water retention and chelation effects.

Heavy metal limits (lead, arsenic, fluorine, etc.)

Food additives have strict limits on harmful impurities such as lead, arsenic, and fluorine, and must meet the quality standards for food additives, which are important safety indicators.

Water-insoluble matter

Water-insoluble matter affects the sensory quality and processing performance of food and needs to be kept at a low level.

alkalinity and pH

The aqueous solution is strongly alkaline, and its pH stability affects the buffering and water retention properties of the food system, which must meet the specifications.

Moisture

The dodecahedral hydrate differs from the anhydrous hydrate in form, and the moisture content must meet specifications, affecting the accuracy of measurement and storage stability.

What are the uses of food-grade Trisodium phosphate?

1. Water retention and tenderization of meat products (core application)

Trisodium phosphate is an important meat processing tenderiser and moisture retainer. It can chelate metal ions when combined with pyrophosphate, tripolyphosphate, etc., promote water absorption and swelling of muscle protein, greatly improve the water retention and tenderness of meat products such as ham, sausage and meatballs, improve taste and reduce cooking loss.

2. Aquatic products increase water and weight

It is used in seafood processing to help shrimp, fish balls and crab sticks to retain moisture, reduce juice loss in thawing and cooking, improve the colour and elasticity of the product, and increase the yield.

3. Emulsifying and Stabilising Dairy Products

Trisodium phosphate is used as an emulsifying salt and stabiliser in dairy products, helping dairy products like cheese to emulsify evenly when heated, preventing fat separation and improving meltability and texture.

4. Beverage stability and buffering

Trisodium phosphate can be used as a stabilizer and pH buffer in beverages, chelating metal ions in beverages, preventing turbidity and precipitation, and helping to maintain the clarity and flavor stability of beverages.

5. Quality improvement of flour products

Trisodium phosphate is used in noodle and dumpling wrappers and other flour products. It can adjust pH, improve the gluten network structure, and help flour products maintain good extensibility and chewy texture.

6. Confectionery and Leavening Systems

Compound leavening agents may contain trisodium phosphate as the alkaline salt component. When mixed with acidic salts, it can be used in baked goods such as pastries and biscuits to control the rate of gas production and improve the leavening effect.

7. Other food applications

The use of food-grade trisodium phosphate is increasing and is being used to improve the quality of canned foods, stabilise condiments and purify syrups, among other applications.

8. Detergents

Trisodium phosphate is used as a detergent builder and water softener to help remove calcium and magnesium ions from hard water, saponify grease and enhance cleaning. The formulations of the laundry powders and liquids we use may contain trisodium phosphate.

9. Boiler and water treatment (indirect contact)

Trisodium phosphate is a classic boiler water softener and descaling agent used for water treatment in industrial boilers and hot water systems. The water treatment of our water heaters and heating systems may indirectly involve it.

10. Metal products and rust prevention (indirect contact)

Trisodium phosphate is used as a metal degreasing and cleaning agent and a rust inhibitor. It is used for surface treatment of metal products, and its production chain may indirectly involve hardware tools and mechanical parts.

11. Textiles and dyeing products (indirect contact)

Trisodium phosphate is used in the textile industry for scouring, degreasing, and softening water to help remove impurities from fibers. The fabrics we wear may be indirectly involved in its processing chain.

Summarize

Trisodium phosphate (TSP) is a white crystalline powder, a salt of a strong base and a weak acid, readily soluble in water and its aqueous solution is strongly alkaline. It has many functions including chelation, water retention, emulsification and buffering. In daily life it is indirectly met in detergents, boiler water treatment, metal products, textile printing and dyeing and the food industry. Food-grade trisodium phosphate (TSP) finds wide application in the food industry as a water-binding and tenderising agent in meat and seafood products, an emulsifying stabiliser in dairy products, a stabilising buffer in beverages, a quality improver in noodle products and an ingredient in pastry leavening systems. It is a significant food additive that guaranties the taste, texture and stability of food.