E503 (Ammonium carbonate) is a chemical compound, a mixture of ammonium carbonate and ammonium carbamate.

It appears in the form of a white powder. 

Food

Ingredient included in the list of European food additives as E503 with the function of raising Agent.

It is used as an alkaline catalyst in the production of lactulose from whey (1), has a positive effect on enzymatic digestibility (2),

Industry

To counteract some fruit pests such as Rhagoletis, a fly that attacks various larvae from the deposition of its larvae, from the apple (Rhagoletis pomonella) to the walnut, traps with ammonium carbonate have captured more flies than other traps containing fruit mixtures that had provided good results in the past (3).
Still in the agrochemical field, a report was presented on the properties of ammonium carbonate, to intensify nitrogen fixation on the physiological and biochemical processes of microorganisms and agricultural plants (4)

Medicine

Together with p-aminosalicylic acid, ammonium carbonate interacts positively in solution, giving rise to a new type of drug in the field of pulmonary inhalation (5).

Cosmetics

Buffering agent. It is an iingredient that can bring an alkaline or acid solution to a certain pH level and prevent it from changing, in practice a pH stabiliser that can effectively resist instability and pH change.

• Molecular Formula: CH₈N₂O₃  CH₆N₂O₂, CH₈N₂O₃, CH₅NO₃, (NH₄)₂CO₃
• Molecular Weight: 96.086 g/mol
• CAS: 506-87-6  6721-33-1  8013-59-0 10361-29-2
• EC Number: 208-058-0  233-786-0
• UNII : PDP691CN28
• PubChem Substance ID 329755736
• MDL number MFCD00010890
• Beilstein Registry Number 4253487

• Hartshorn salt
• E503
• Carbonic acid, diammonium salt
• Diammonium carbonate
• Carbonic acid, ammonium salt
• Ammonia sesquicarbonate
• HSDB 6305
• EINECS 208-058-0
• EPA Pesticide Chemical Code 073501
• Carbonic acid, ammonium salt (1:2)
• ammoniumcarbonate

References_________________________________________________________________________

(1) Seo YH, Sung M, Han JI. Lactulose production from cheese whey using recyclable catalyst ammonium carbonate. --  Food Chem. 2016 Apr

(2) Kim I, Lee B, Song D, Han JI. Effects of ammonium carbonate pretreatment on the enzymatic digestibility and structural features of rice straw. --  Bioresour Technol. 2014 Aug

(3) Yee WL, Nash MJ, Goughnour RB, Cha DH, Linn CE, Feder JL. Ammonium carbonate is more attractive than apple and hawthorn fruit volatile lures to Rhagoletis pomonella (Diptera: Tephritidae) in Washington State.  Environ Entomol. 2014 Aug

(4) Mal'tseva NN, Vilesov GI, Davydova OE. The intensification of biological nitrogen fixation by using ammonium carbonate compounds and the routes of their action on microorganisms and plants.  Mikrobiol Z. 2000 May-Jun

(5) Gad S, Tajber L, Corrigan OI, Healy AM.  Preparation and characterisation of novel spray-dried nano-structured para-aminosalicylic acid particulates for pulmonary delivery: impact of ammonium carbonate on morphology, chemical composition and solid state.  J Pharm Pharmacol. 2012 Sep;64(9):1264-74. doi: 10.1111/j.2042-7158.2012.01465.x. Epub 2012 Feb 21