PGA (Propylene Glycol Alginate)

  PGA (Propylene Glycol Alginate)


English Name: Propylene glycol alginate

Alias: Hydroxypropyl alginate

Molecular Formula: (C9H14O7)n

A part of carboxyl can generate esterification with propylene glycol and the other part occur neutralization by alkali. Molecular Weight: 234.21 (theoretical value)

Physicochemical Properties: white to yellowish white; relatively thick or slightly fine powders; basically odorless or with a tint of fragrance; soluble in water to form viscous colloidal solution but insoluble in organic solvents like ethanol.


Toxicology Basis

①LD50:oral taking by rats 7200mg/kg(bw)。

②ADI:0~ 70mg/kg(bw)(FAO/WHO,1994)。

③GRAS:FDA-21CFR 171.858

Propylene Glycol Alginate

PGA (propylene glycol alginate) is made by deep processing of alginates extracted from natural algae. It presents white or yellowish powder in appearance and its water solution takes the shape of viscous colloid. Since there are two genes, both lipophilicity and hydrophilicity in the molecular structure, PGA has emulsifying, thickening, swelling, acid resistance and stabilizing properties. It is an excellent food additive and widely used in fruit juice, salad dressing, emulsified flavor, beer foam and lactic acid bacteria beverage. Above all, it is the most ideal efficient stabilizing agent in acid protein beverages.

The beer foam stabilizer is a typical application of high esterification degree PGA and its general dosage is 40-100mg/kg. PGA can unite with foam-producing natural protein and consolidate the wall, delay elimination of liquids from foam, and thus delay the duration of foam (2-3 minutes) and affect foam adherence to the wall. Furthermore, foam is pure white with lasting adherence to glass but the taste and storage period of beer won’t change.


In order to improve transparency of beer, during the beer brewing process, PGA helps to reduce opacity and improve clarity of beer, so it is a favorable clarifying agent.

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