What Is Ammonium Alginate (E403)? Uses, Specifications and Cost Factors

Ammonium alginate is the ammonium salt of alginic acid, a polymer obtained from alginate raw material. FAO/JECFA identifies it as CAS 9005-34-9, INS 403 and uses the repeat expression (C₆H₁₁NO₆)_n. In EU food-additive nomenclature it is E403. Because it is a variable-chain polymer, procurement should define the required viscosity method, identity tests, purity criteria, intended market and application rather than relying on one small-molecule “molecular weight” or the E number alone.

Ammonium alginate identity at a glance

Sources: the FAO/JECFA Ammonium Alginate monograph and FAO Combined Compendium record. These establish public identity and specification context; they do not prove the current composition, grade, viscosity, conformity, stock or suitability of a Longchang lot.

Why ammonium alginate does not have one fixed molecular weight

Alginates are polysaccharide polymers containing mannuronate and guluronate residues in sequences that vary with raw material and processing. The subscript n in the repeat expression indicates a chain of variable length. For that reason, a buyer normally controls functional behavior through a defined viscosity method, concentration, temperature, spindle or shear condition, plus identity and purity tests—not by treating 193.16, 217 or another unit value as the molecular weight of every commercial polymer chain.

The older Longchang article displayed C₆H₇NO₆ and 193.14 g/mol as if they were a complete commercial identity. The older product page displayed C₁₃H₁₆N₃NaO₄S and 333.33861, which describe neither the JECFA nor EU ammonium-alginate identity. Those fields are not carried forward.

What does E403 or INS 403 mean?

E403 and INS 403 identify ammonium alginate in food-additive systems. They do not, by themselves, show that a supplier lot complies with a destination market, that a requested food category permits the use, or that the material meets the applicable purity, microbiological and documentation requirements.

What is ammonium alginate used for?

JECFA lists stabilizer, thickener, gelling-agent and emulsifier functions. The current U.S. eCFR lists specific food categories and maximum use levels, including confections and frostings, fats and oils, gelatins and puddings, gravies and sauces, jams and jellies, sweet sauces, and a separate condition for other categories. That is a defined U.S. regulatory context, not evidence that every proposed formulation or jurisdiction permits the same use.

Performance also depends on polymer distribution, viscosity grade, concentration, hydration, pH, ions, temperature, shear, other hydrocolloids and the food matrix. Generic claims such as “works across pH 4–10,” “prevents ice crystals,” “improves yield” or “forms a firm gel” cannot replace formulation trials and an agreed test method.

What should be compared in an ammonium alginate specification?

What affects ammonium alginate manufacturing plant or production cost?

“Manufacturing plant cost” and “product purchase price” are different questions. A plant study needs defined capacity, alginic-acid feedstock and yield, neutralization and pH control, washing or purification steps, drying, milling, viscosity grading, quality-control methods, utilities, labour, wastewater handling, packaging and the destination’s regulatory system. A product quotation instead depends on the required specification, viscosity method, batch size, documents, packaging, delivery destination and current availability.

Longchang does not publish a universal plant-capital or production-cost number on this page. A defensible estimate requires an engineering scope and dated regional inputs. A product RFQ should not be presented as a plant project report.

Safety and regulatory interpretation

JECFA recorded a group ADI “not specified” for alginic acid and its salts. EFSA’s 2017 re-evaluation concluded that a numerical ADI was not needed and found no safety concern at the refined exposure assessment for reported food-additive uses, while also recording limitations and special considerations for infant and young-child medical/special-formula categories. See the EFSA E400–E404 opinion.

Those conclusions have a defined assessment scope. They are not a blanket instruction that any product, level, formulation, consumer group or market is “safe to consume.” This page is not a product specification, food-safety plan, legal determination or medical guide. Review the current applicable rules and supplier documents for the exact lot, use and destination.

Ammonium alginate versus sodium alginate

Both are salts of alginic acid, but the counterion and controlled identity differ. Ammonium alginate is CAS 9005-34-9 / INS 403; sodium alginate has its own identity and INS number. Do not infer equivalent viscosity, gel behavior, sodium-reduction suitability, regulatory conditions or substitution ratio from the shared word “alginate.” Compare controlled specifications and run application trials.

Request current supplier documents

Open the Ammonium Alginate CAS 9005-34-9 product page to request the current supplier specification, complete viscosity method, applicable lot COA, SDS status, food-use or regulatory documents, sample, packaging, MOQ, availability, quotation and confirmed lead time.

Email info@longchangchemical.com with the destination market, intended function/category, target viscosity and method, quantity, packaging and required documents.

Frequently asked questions

Is E403 proof of food grade?

No. E403 is an identity in EU food-additive nomenclature. Lot conformity and legal use still depend on the current specification, analytical results, applicable category and conditions, documentation, labelling and destination rules.

Why is viscosity method detail essential?

Viscosity changes with concentration, temperature, instrument settings, hydration and sample preparation. Two suppliers’ numbers cannot be compared unless their method and basis match.

Does ammonium alginate have a fixed formula and molecular weight?

The official repeat expression is (C₆H₁₁NO₆)_n. The variable chain length means there is no single small-molecule molecular weight for every material.