What is Tripotassium Phosphate E340(iii) in Food and Functions in Cereals?

Production | Property | Uses

Tripotassium Phosphate (abbreviation TKP), the soluble phosphoric acid salt of tripotassium with the chemical formula K3PO4, also known as potassium phosphate tribasic. 

This ingredient is vegan & gluten free and can be used as a buffering agent, emulsifying agent and nutrient fortification in food with the European food additive number E340(iii)

Compared with another two potassium phosphate salts, monopotassium phosphate and dipotassium phosphate, it is used less as a fertilizer.

Also, it is different with trisodium phosphate, but with similar applications with the latter and can be used as its substitute for free sodium in many uses, such as in cereals.

How is Tripotassium Phosphate made? 

TKP can be chemically synthesized by the reaction of phosphoric acid with potassium hydroxide or potassium carbonate. The following are the chemical equation:

  • H3PO4 + 3KOH = K3PO4 +3H2O
  • 2H3PO4 + 3K2CO3 = 2K3PO4 + 3CO2 + 3H2O


Other names Tripotassium orthophosphate, Tripotassium monophosphate
Chemical formula K3PO4 (Anhydrous), K3PO4 · H2O (Monohydrate), K3PO4 · 3H2O (Trihydrate)
Molecular weight 212.27 (Anhydrous)
CAS number 7778-53-2
Appearance Colourless or white, odourless hygroscopic powder or granular. 
Solubility Freely soluble in water, insoluble in ethanol
PH 11.5 to 12.3 (1% solution)

K3PO4 is an ionic salt which is freely soluble in water. It is a strong base, which dissociates PO43- and K+ after dissolved in water. 

And then, it reacts with water to form HPO3- and OH- as the following chemical equation indicates:

PO43- + H2O → HPO3- + OH-

What are the Uses of Tripotassium Phosphate?

TKP is mainly used as an alkaline phosphate to adjust pH or as an alkaline buffering in food and other uses. It is also used to replace trisodium phosphate where reduced sodium is desired. 


Food grade tripotassium phosphate is a multifunctional ingredient that can be used as an acidity regulator, emulsifying agent, sequestrant, potassium enhancement, stabilizer and low-sodium replacement in food. 

You may have found this ingredient in the following food lists:

  • Meat
  • Extruded & dry cereals
  • Sauces
  • Cheeses
  • Whipped cream

TKP may be employed as a salt to assist caramelization in manufacturing caramel color. (1). 

TKP may also be used together with fatty acids to reduce some bacteria and yeasts in poultry processing. (2)


We can find this ingredient in the label of Cheerios Cereals (3). TSP has the similar following purposes with trisodium phosphate in cereal products:

  • Adjust the acidity.
  • The high alkalinity of TKP accelerates the cooking process in cooked breakfast cereals and provides the cereals a more creamy or yellow color. 
  • Due to its hygroscopicity, it can also act as an antickaing agent to ensure the extruded cereal dry and free-flowing through extruder equipment. 
  • Enhance potassium and phosphorus supplement.
  • As an alternative of trisodium phosphate.

Other uses

Technical grade TKP can be used in fertilizers, washing & cleaning products, water softeners and water treatment chemicals. (4)

Is Tripotassium Phosphate Safe to Eat?

Consumers may have health concerns about why this cleaning agent can be used in food, but that is the technical grade, not the food grade.

When used as a food additive, it almost has no side effects and its safety has been approved by the FDA (the only potassium phosphate salt that is generally recognized as safe (GRAS) as a food additive is dipotassium phosphate), EFSA (5) and JECFA (6) (7). 


Now you may have a knowledge of the food additive – Tripotassium phosphate E340(iii), from its production, properties, uses, approved safety and so on.

What kinds of food packaging have you found this ingredient in? Let me know in the comments.


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