Scientific Evaluation and Purchasing Assessment of Food-Grade Ammonium Bicarbonate: Changhong Product Specification, Functional Performance, Regulatory Compliance, and Buyer-Oriented Quality Assessment
Abstract
Ammonium bicarbonate (NH₄HCO₃), also known as ammonium hydrogen carbonate, is an established food additive used primarily as a chemical raising agent in bakery products, particularly low-moisture products such as biscuits, crackers, and cookies. Its technological functionality is associated with thermal decomposition into ammonia, carbon dioxide, and water, allowing gas generation without leaving a persistent nonvolatile alkaline residue in the baked product [1–4].
The quality of commercial ammonium bicarbonate should not be evaluated solely on the basis of nominal assay. A scientifically appropriate assessment should consider chemical identity, assay, inorganic impurities, heavy metals, nonvolatile residue, pH, physical characteristics, microbiological quality, regulatory compliance, storage stability, traceability, and batch-specific analytical verification [1,2].
In the present evaluation, the supplied Technical Data Sheet (TDS) of a food-grade ammonium bicarbonate manufactured by Shandong Changhong Food Additives Co., Ltd. was assessed against internationally recognized food-additive specifications and relevant scientific literature. The TDS reports an ammonium bicarbonate content of 99.56%, with maximum levels of 0.003% chloride, 0.003% sulfate, 0.0002% lead, 0.008% residue, 2 mg/kg arsenic, and 1 mg/kg mercury, together with a pH range of 7.5–8.5 [5].
The declared 99.56% assay is higher than the 99.0% minimum specified by JECFA and the European specification for E503(ii) ammonium hydrogen carbonate [1,2]. The declared arsenic and nonvolatile-residue limits are also lower than the corresponding European maximum limits, whereas the chloride, sulfate, lead, and mercury specifications are consistent with those limits [2,5]. The product therefore represents a potentially suitable high-purity food-grade ammonium bicarbonate for appropriate food applications.
From a purchasing perspective, the principal advantages are the high declared assay, defined impurity limits, food-grade identity, suitability as a chemical leavening agent, and availability of technical specifications. However, the TDS alone does not constitute independent batch certification. Therefore, a current batch-specific Certificate of Analysis (CoA) should be obtained before commercial acceptance.
An additional consideration is acrylamide formation. Scientific studies have demonstrated that ammonium bicarbonate can promote acrylamide formation in certain bakery formulations, particularly in the presence of reducing sugars and under appropriate thermal conditions [6–9]. Consequently, the suitability of the ingredient must be evaluated together with formulation composition, product moisture, baking temperature, baking time, and the final acrylamide level.
Keywords: ammonium bicarbonate; ammonium hydrogen carbonate; NH₄HCO₃; INS 503(ii); E503(ii); food additive; raising agent; bakery products; food-grade ingredient; acrylamide; quality control; purchasing assessment.
- Introduction
Ammonium bicarbonate, chemically designated as ammonium hydrogen carbonate, has the molecular formula NH₄HCO₃, molecular weight 79.06 g/mol, and CAS number 1066-33-7. It is internationally identified as food additive INS 503(ii) and E503(ii) and is classified primarily as a raising agent [1,2].
The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has established specifications for ammonium hydrogen carbonate, including a minimum assay of 99.0% and limits for nonvolatile residue, chloride, sulfate, arsenic, lead, and mercury [1]. The JECFA specification identifies ammonium hydrogen carbonate as a raising agent and describes it as white crystals or a crystalline powder [1].
The European Union specification similarly establishes an assay of not less than 99.0%, together with maximum limits of 500 mg/kg for nonvolatile matter, 30 mg/kg for chloride, 30 mg/kg for sulfate, 3 mg/kg for arsenic, 2 mg/kg for lead, and 1 mg/kg for mercury [2].
From a food-technology perspective, ammonium bicarbonate is particularly valuable because it decomposes during heating:
NH₄HCO₃ → NH₃ + CO₂ + H₂O
The volatile products provide leavening and can escape from low-moisture baked products. Unlike sodium bicarbonate, ammonium bicarbonate does not leave a persistent alkaline mineral residue after appropriate thermal decomposition [3,4].
Therefore, its principal scientific description should be food-grade chemical raising agent/leavening agent, rather than preservative.
- Chemical Identity and Basic Characteristics
| Parameter | Specification |
| Chemical name | Ammonium hydrogen carbonate |
| Common name | Ammonium bicarbonate |
| Molecular formula | NH₄HCO₃ |
| Molecular weight | 79.06 g/mol |
| CAS number | 1066-33-7 |
| INS number | 503(ii) |
| E number | E503(ii) |
| Physical form | White crystals/crystalline powder |
| Main technological function | Raising agent |
These characteristics are consistent with the JECFA specification and European food-additive specification [1,2].
An important distinction should be made between ammonium bicarbonate (INS 503(ii)) and ammonium carbonate (INS 503(i)). They are not identical materials. Ammonium carbonate consists of ammonium carbamate, ammonium carbonate, and ammonium hydrogen carbonate in varying proportions [2].
- Concept of High-Purity Food-Grade Ammonium Bicarbonate
The term “high-purity” should not be interpreted solely from the assay value. A scientifically appropriate evaluation should consider:
Chemical identity + assay + impurity profile + heavy-metal control + physical quality + microbiological quality + regulatory compliance + batch verification.
JECFA specifications are specifically intended to establish identity and purity criteria for food additives and to support the application of toxicological evaluations to additives manufactured according to those specifications [1].
Therefore, a product with an assay above 99% and controlled levels of inorganic impurities and toxic elements may reasonably be described as a high-purity food-grade material, provided that the specifications are analytically verified.
- Changhong Food-Grade Ammonium Bicarbonate: Product Specification
According to the supplied TDS, the Changhong product is identified as Ammonium Bicarbonate Food Grade, associated with GB 1888-2014 [5].
The principal declared specifications are:
| Parameter | Changhong TDS |
| NH₄HCO₃ assay | 99.56% |
| Appearance | White crystalline |
| Chloride | ≤0.003% |
| Sulfate | ≤0.003% |
| Lead | ≤0.0002% |
| Nonvolatile residue | ≤0.008% |
| Arsenic | ≤2 mg/kg |
| Mercury | ≤1 mg/kg |
| pH | 7.5–8.5 |
| Salmonella | Negative |
| Colibacillus | Negative |
| Shigella | Negative |
These values are reported directly in the supplied TDS. [5]
- Comparison with International Food-Grade Specifications
5.1 Assay
The JECFA and European specifications require ammonium hydrogen carbonate to contain at least 99.0% NH₄HCO₃ [1,2].
Changhong reports:
NH₄HCO₃ = 99.56%
Therefore:
99.56 − 99.00 = 0.56 percentage points
The declared assay is therefore 0.56 percentage points above the international minimum specification.
This is a favorable specification for a food-grade ingredient.
5.2 Chloride
The European specification establishes a maximum chloride concentration of 30 mg/kg [2].
Changhong reports:
0.003% = 30 mg/kg
Therefore, the declared specification meets the European limit exactly.
It should not be described as “better than the standard”; the scientifically correct statement is:
The declared maximum chloride concentration complies with the European specification.
5.3 Sulfate
The European maximum sulfate concentration is 30 mg/kg [2].
Changhong:
0.003% = 30 mg/kg
Therefore, the declared specification meets the European limit exactly.
5.4 Lead
The European maximum lead concentration is 2 mg/kg [2].
Changhong:
0.0002% = 2 mg/kg
Therefore, the declared lead specification meets the European maximum limit.
Importantly, “≤2 mg/kg” means that 2 mg/kg is the maximum permitted specification; it does not mean that the tested batch actually contains 2 mg/kg.
5.5 Arsenic
The European specification establishes a maximum arsenic concentration of 3 mg/kg [2].
Changhong reports:
≤2 mg/kg
Therefore, the declared maximum is 1 mg/kg below the European limit.
This represents a favorable aspect of the supplier specification.
5.6 Mercury
The European maximum mercury concentration is 1 mg/kg [2].
Changhong reports:
≤1 mg/kg
Therefore, the specification meets the European maximum limit.
5.7 Nonvolatile Residue
The European specification allows a maximum of 500 mg/kg [2].
Changhong reports:
0.008% = 80 mg/kg
Therefore:
500 / 80 = 6.25
The declared Changhong limit is approximately 6.25-fold lower than the European maximum criterion.
This is one of the more favorable specifications of the product.
- Overall Specification Comparison
| Quality parameter | Changhong TDS | International benchmark | Assessment |
| NH₄HCO₃ assay | 99.56% | ≥99.0% | Favorable |
| Chloride | ≤30 mg/kg | ≤30 mg/kg | Meets |
| Sulfate | ≤30 mg/kg | ≤30 mg/kg | Meets |
| Lead | ≤2 mg/kg | ≤2 mg/kg | Meets |
| Arsenic | ≤2 mg/kg | ≤3 mg/kg | More stringent |
| Mercury | ≤1 mg/kg | ≤1 mg/kg | Meets |
| Nonvolatile residue | ≤80 mg/kg | ≤500 mg/kg | More stringent |
| pH | 7.5–8.5 | About 8.0 | Consistent |
| Appearance | White crystalline | White crystals/crystalline powder | Consistent |
The international benchmark values are based principally on JECFA and the European E503(ii) specification [1,2].
- Functional Properties and Food Applications
Ammonium bicarbonate is primarily used as a chemical raising agent.
During heating:
NH₄HCO₃ → NH₃ + CO₂ + H₂O
The released gases contribute to expansion and porous structure formation in bakery products [3,4].
A major technological advantage is that ammonium bicarbonate can decompose without leaving a persistent alkaline residue. This makes it particularly suitable for low-moisture products such as crackers, biscuits, and cookies [3,4].
However, ammonium bicarbonate is less suitable for high-moisture products because residual ammonia may remain in the product and produce undesirable ammoniacal odor or flavor [3,4]. The scientific literature therefore supports application primarily in products where ammonia can escape effectively during baking.
- Processing Stability and Storage
The useful technological property of ammonium bicarbonate is also its principal handling consideration: it is thermally decomposable and volatile.
The supplier’s TDS recommends dry, cool and airtight storage [5]. This is appropriate for maintaining physical quality and minimizing undesirable changes during storage.
For industrial purchasing, the supplier should provide:
- Batch number
- Manufacturing date
- Expiration/retest date
- Storage conditions
- Packaging information
- Current batch-specific CoA
The TDS should therefore be regarded as the general product specification, while the CoA provides evidence regarding the quality of the particular batch being purchased.
- Microbiological Quality
The Changhong TDS reports negative results for:
- Salmonella
- Colibacillus
- Shigella [5]
This is favorable for preliminary food-ingredient qualification.
However, the TDS does not provide all information normally required to independently interpret these results, such as analytical method, detection limit, sample size, test date, laboratory identification, and batch number.
Therefore, the scientifically appropriate wording is:
The supplier TDS declares negative microbiological results for the listed microorganisms; batch-specific microbiological verification should be obtained when required by the manufacturer’s quality system or applicable food regulations.
- Safety and Regulatory Considerations
JECFA has evaluated ammonium hydrogen carbonate and established an ADI of “not specified” [1,6]. This designation should not be interpreted as unrestricted use under all conditions. Rather, it means that, under the intended conditions of food-additive use, a numerical ADI was not considered necessary [6].
Accordingly, the scientifically appropriate statement is:
Ammonium hydrogen carbonate has been evaluated by JECFA and assigned an ADI of “not specified.”
It should not be described as “completely risk-free.”
The Codex GSFA also identifies ammonium hydrogen carbonate (INS 503(ii)) as a food additive with functions including raising agent and acidity regulator, with conditions of use specified according to food category and good manufacturing practice [10].
- Acrylamide: An Important Purchasing and Formulation Consideration
One of the most important limitations associated with ammonium bicarbonate is its potential contribution to acrylamide formation in certain bakery products.
Acrylamide is formed during thermal processing of foods through reactions involving reducing sugars and free asparagine. Scientific studies have demonstrated that ammonium bicarbonate can substantially increase acrylamide formation in some bakery formulations [6–9].
For example, Amrein et al. demonstrated that ammonium hydrogen carbonate strongly enhanced acrylamide formation in gingerbread, whereas replacing it with sodium hydrogen carbonate reduced acrylamide formation by more than 60% [6].
A broader scientific review similarly identifies ammonium bicarbonate as one of the factors that can promote acrylamide formation in bakery products [7].
Therefore:
High purity of ammonium bicarbonate ≠ guaranteed low acrylamide in the final food.
Acrylamide risk depends on the complete formulation and process, including:
- ammonium bicarbonate concentration;
- reducing sugar concentration;
- free asparagine;
- baking temperature;
- baking time;
- pH;
- final moisture;
- degree of browning.
Consequently, a buyer should evaluate the ingredient together with the intended food process rather than considering purity alone.
- Comparison with a Premium Commercial Reference
A useful purchasing comparison is a commercial high-purity ammonium hydrogen carbonate supplied for laboratory/analytical applications.
For example, a Merck/Sigma-Aldrich specification reports an assay of 99.0–101.0% and substantially tighter limits for several trace contaminants than the Changhong TDS [11].
This comparison highlights an important distinction:
Food-grade suitability is not identical to analytical/reagent-grade purity.
Therefore, Changhong should not be described as “the purest ammonium bicarbonate available.”
Instead, it is more scientifically defensible to state that the product has a high declared assay and food-grade specification compatible with the principal international criteria evaluated in this study.
- Recommended Quality-Control Program Before Purchase
Before industrial acceptance, the following should preferably be verified:
Stage 1 – Identity
Confirm:
- ammonium ion;
- carbonate/bicarbonate functionality;
- molecular identity;
- CAS number;
- conformity with NH₄HCO₃.
Possible analytical approaches include validated identification tests, FTIR, ion chromatography, or other appropriate methods.
Stage 2 – Assay
Determine the actual NH₄HCO₃ content.
The target is:
NH₄HCO₃ ≥99.0%
The actual batch result should be reported rather than relying only on the supplier specification.
Stage 3 – Inorganic impurities
Determine:
- chloride;
- sulfate;
- nonvolatile residue.
Stage 4 – Elemental impurities
At minimum:
- Pb;
- As;
- Hg;
- Cd where applicable;
- other relevant elements according to the intended application.
ICP-OES or ICP-MS may be appropriate depending on the required detection limits.
Stage 5 – Microbiology
Verify relevant microorganisms according to the applicable food-grade specification.
Stage 6 – Physical quality
Where relevant, evaluate:
- moisture;
- particle-size distribution;
- bulk density;
- flowability;
- solubility;
- caking;
- storage stability.
- What Documentation Should a Buyer Request?
Before purchasing a commercial lot, the buyer should preferably request:
- Current TDS
- Batch-specific CoA
- Actual assay result
- Identity confirmation
- Chloride result
- Sulfate result
- Nonvolatile residue
- Lead
- Arsenic
- Mercury
- Other relevant elemental impurities
- Microbiological results
- Batch number
- Manufacturing date
- Expiration/retest date
- Country of origin
- Manufacturing standard
- Packaging specification
- Storage conditions
- Regulatory documentation
References
- Joint FAO/WHO Expert Committee on Food Additives (JECFA). Ammonium Hydrogen Carbonate. Combined Compendium of Food Additive Specifications, Monograph 1. Rome: Food and Agriculture Organization of the United Nations; 2006. CAS No. 1066-33-7; INS No. 503(ii).
- Food and Agriculture Organization of the United Nations (FAO). Ammonium Hydrogen Carbonate: Food Safety and Quality—JECFA Specifications. Rome: FAO; 2006. Available from the FAO JECFA database.
- Gélinas P. Gas sources in chemical leavening and other baker’s yeast substitutes: lessons from patents and science. International Journal of Food Science & Technology. 2022;57(2):865–880. doi:10.1111/ijfs.15447.
- Amrein TM, Schönbächler B, Escher F, Amadò R. Acrylamide in gingerbread: critical factors for formation and possible ways for reduction. Journal of Agricultural and Food Chemistry. 2004;52(13):4282–4288. doi:10.1021/jf049648b.
- Sarion C, Codină GG, Dabija A. Acrylamide in Bakery Products: A Review on Health Risks, Legal Regulations and Strategies to Reduce Its Formation. International Journal of Environmental Research and Public Health. 2021;18(8):4332. doi:10.3390/ijerph18084332.
- Pasqualone A, Haider NN, Summo C, Coldea TE, George SS, Altemimi AB. Biscuit Contaminants, Their Sources and Mitigation Strategies: A Review. Foods. 2021;10(11):2751. doi:10.3390/foods10112751.
- European Commission. Commission Regulation (EU) No 231/2012 of 9 March 2012 laying down specifications for food additives listed in Annexes II and III to Regulation (EC) No 1333/2008. Official Journal of the European Union. 2012. E503(ii), Ammonium Hydrogen Carbonate.
- Codex Alimentarius Commission. General Standard for Food Additives (GSFA): Ammonium Hydrogen Carbonate (INS 503(ii)). Rome: Food and Agriculture Organization of the United Nations/World Health Organization.
- U.S. Department of Agriculture, Agricultural Marketing Service. Ammonium Bicarbonate and Carbonate: Technical Report. Washington, DC: USDA Agricultural Marketing Service; 2025.
- American Society of Baking. Ammonium Bicarbonate. Baking Industry Technical Resource. American Society of Baking.
