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Propylene glycol alginate

Propylene glycol alginate suppliers and sourcing guide

Propylene glycol alginate is an ester of alginic acid made by reacting alginic acid from brown seaweed with propylene oxide. Partial esterification makes it more stable in acid than sodium alginate and gives it some surface activity. It is sold as a powder and used to stabilize beer foam, thicken acidic dressings and stabilize drinks.

See suppliersWhat to ask for on the COA
Also known as
PGA · E405 · hydroxypropyl alginate · alginic acid propylene glycol ester
Facts checked
November 2026

Forms and grades of propylene glycol alginate

Suppliers sell different products under the same name. Specify the one you need.

  • Degree of esterification grades

    Grades with different shares of esterified carboxyl groups, which set acid stability and calcium tolerance.

  • Viscosity grades

    Low to high viscosity grades for dressings, drinks or beer.

  • Beer foam grades

    Grades sold specifically for foam stabilization in brewing.

What to check on the COA

Compare each result with your own specification when the lot arrives.

Degree of esterification
Share of carboxyl groups esterified, checked against the FCC limit.
Viscosity
Brookfield viscosity of a 1% solution.
Free and total propylene glycol
By gas chromatography or titration per the FCC monograph.
Loss on drying and ash
Moisture and ash content.
Heavy metals and microbiology
Lead and arsenic by ICP-MS; total plate count, yeast and mold, E. coli and Salmonella.

Storage, lots and expiry

Storage and shelf life

Store PGA sealed in a cool, dry place away from heat and humidity. Viscosity can fall during storage, especially in warm conditions. Shelf life follows the supplier's specification.

Lots and expiry dates

Record degree of esterification and viscosity for each lot, since both change performance in acidic drinks and dressings. Re-check stability in your formula when switching lots or suppliers.

Regulatory status

Facts from regulators and standards bodies, each linked to its source.

  • 21 CFR 172.858 permits propylene glycol alginate as an emulsifier, flavoring adjuvant, formulation aid, stabilizer, surfactant or thickener in listed foods, with up to 85 percent of carboxylic acid groups esterified.

    Source: ecfr.gov (opens in a new tab)

  • Health Canada's List of Permitted Emulsifying, Gelling, Stabilizing or Thickening Agents includes propylene glycol alginate, with beer among the listed foods.

    Source: canada.ca (opens in a new tab)

This is general information, not regulatory advice. Status differs by country and by how the ingredient is used, so check the rules for your product and market.

Propylene glycol alginate suppliers

Manufacturers and distributors whose own websites say they sell it.

We are checking propylene glycol alginate suppliers now

Every listing is checked against the supplier’s own website before it goes live, so this list fills in over the coming weeks. The specs and COA checklist above are ready today.

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Frequently asked questions

What forms of propylene glycol alginate can brands buy?

Common forms include degree of esterification grades, viscosity grades and beer foam grades. Ask each supplier for the specification sheet of the exact grade they quote.

What should the COA for propylene glycol alginate include?

Expect degree of esterification, viscosity, free and total propylene glycol, loss on drying and ash and heavy metals and microbiology, each with its method, specification and result for that lot.

How should propylene glycol alginate be stored?

Store PGA sealed in a cool, dry place away from heat and humidity. Viscosity can fall during storage, especially in warm conditions. Shelf life follows the supplier's specification.

What is the regulatory status of propylene glycol alginate?

21 CFR 172.858 permits propylene glycol alginate as an emulsifier, flavoring adjuvant, formulation aid, stabilizer, surfactant or thickener in listed foods, with up to 85 percent of carboxylic acid groups esterified. Health Canada's List of Permitted Emulsifying, Gelling, Stabilizing or Thickening Agents includes propylene glycol alginate, with beer among the listed foods.

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