Sodium acid pyrophosphate (SAPP), or disodium dihydrogen pyrophosphate, its food grade is commonly used with sodium bicarbonate as a leavening agent in bakery products; also, it maintains the color in processed potatoes and also prevents struvite crystal in canned seafood. The European food additive number for it is E450(i). Generally, it is vegan and gluten free.
SAPP is an inorganic compound consisting of sodium cations and pyrophosphate anion. It is used in food mainly for its two properties:
- As a leavening acid which combines with baking soda to release carbon dioxide to improve the texture and volume of baked goods.
- As a chelating agent to chelate iron to prevent discoloration in processed potato.
SAPP is a condensed phosphate, commonly synthesized by the neutralization of phosphoric acid with sodium hydroxide or sodium carbonate at the ratio of 1:1 to produce monosodium phosphate (NaH2PO4), and then heated approximately 250°C to remove the water.
2 NaH2PO4 → Na2H2P2O7 + H2O
White free-flowing crystalline powder or granular. SAPP would hydrolyze to sodium orthophosphate if exposed to the environment.
10g/100ml, 20°C in water. The PH value of 1% solution 4-4.5. Insoluble in ethanol.
- Disodium Pyrophosphate
- Disodium Diphosphate
- Disodium Dihydrogen Diphosphate
- Disodium Dihydrogen Pyrophosphate
- Diphosphoric Acid, Disodium Salt
- Pyrophosphoric Acid, Disodium Salt
Generally, SAPP food grade is used as an acid component in baking powder; as a chelating agent or combines with other polyphosphates to sequester magnesium and iron ions, e.g. chelate iron during the processing of potatoes to prevent a dark discoloration.
In the bakery, it is a slow leavening acid and it may contain a suitable aluminum and/or calcium salt to control the rate of reaction.
SAPP is used together with baking powder as a leavening agent to release carbon dioxide. It is ideal for refrigerated doughs, cakes, muffins and pancake mixes where a slow reaction rate is desired.
Both SAPP and GDL have a slightly bitter aftertaste.
Struvite crystal is occasionally found in canned seafood, and SAPP is used to inhibit its formation, such as in canned tuna. (1)
SAPP can be used to replace sulfur dioxide, sulfites and bisulfites to maintain the appearance and texture of cooked potato products. The application of SAPP reduces the dark color from after-cooking darkening in cooked and processed potato products, such as in oil-blanched french fries and potato salad.
It is the naturally present or equipment iron that generates “after cooking darkening” in potatoes. SAPP stabilizes the color of potatoes and prevents the iron complex from forming a dark pigment due to its strong sequestering properties.
Yes, its safety when used as a food additive has been approved by the U.S. Food and Drug Administration (FDA), European Food Safety Authority (EFSA), Joint FAO/WHO Expert Committee on Food Additives (JECFA), as well as other authorities.
SAPP is generally recognized as safe when used in accordance with good manufacturing practice (2) AND can be used as a color or coloring adjunct, dough strengthener, emulsifier or emulsifier salt, flavoring agent or adjuvant, flour treating agent, formulation aid, leavening agent, oxidizing or reducing agent, and sequestrant in food. (3)
Disodium diphosphate (E450i) is listed in Commission Regulation (EU) No 231/2012 as an authorised food additive and categorized as “additives other than colours and sweeteners” (4)
Safety re-evaluation in 2019
In 2019, EFSA considered disodium pyrophosphate to be of low acute oral toxicity and there was no concern with respect to genotoxicity and carcinogenicity.
Also, no effects were reported in developmental toxicity studies. EFSA derived a group acceptable daily intake (ADI) for phosphates expressed as phosphorus of 40 mg/kg body weight (bw) per day and concluded that this ADI is protective for the human population.
Authorised Uses And Use Levels
Its application is listed in diphosphates E450 and the max uses level is 5000 (mg/l or mg/kg as appropriate).
The following foods may contain with it (5):
- Processed fish and fishery products
- Biscuits and rusks
UK Food Standards Agency
Categorized in “Others” (6)
Food Standards Australia New Zealand
It is an approved ingredient in Australia and New Zealand with the code number 450. (7)
Function Class: food additives, acidity regulator, raising agent, sequestrant. (8)
Tolerable Intake: MTDI 70 mg/kg bw (as P) set in 1982. (9)
It is common that sometimes consumers have questions whether sodium acid pyrophosphate is bad for our health and what are the possible health risks. We understand that consumers prefer natural food additives and have concerns about the synthesized ingredients in the foods we eat. It is generally considered safe but some people may be allergic or sensitive to it.
Is it Safe for Pregnant?
Yes, it is generally safe but better consult with your doctor in the condition of use.
Is it Natural?
No, it is made from chemical synthesis.
Is it Vegan?
Yes, it is vegan as the raw materials phosphoric acid (from phosphate rocks) and sodium hydroxide or sodium carbonate (from trona ore) are not animal-derived. So SAPP is vegan and suitable for the diet of vegetarians.
Is it Halal?
Yes, it is generally recognised as halal as it is permitted under the Islamic Law and fulfill the conditions of Halal. And we can find some manufacturers certificated with MUI halal.
Is it Kosher?
Yes, it is kosher pareve. E450(i) has met all the “kashruth” requirements and can be certified as kosher.
Is it Gluten Free?
Yes, it is typically gluten-free and people with celiacs can eat it. It is an ingredient commonly found in both gluten-free and gluten-containing food labels. The manufacturing process complies with the FDA’s definition of gluten free, that it does not contain wheat, rye, barley, or crossbreeds of these grains.
Is SAPP A Preservative?
No information sources reviewed that function/purpose of SAPP is as a preservative.
After reading, you may have a good understanding of sodium acid pyrophosphate (E450i), from its production; 3 main food uses: bakery, canned sea food and potatoes; approved safety; possible side effects and some FAQs such as is it vegan, gluten free, synthetic or natural and etc.
What kinds of food packaging have you found this ingredient in? Let me know in the comments.