Mechanism of Beer Foam Stabilization by Propylene Glycol Alginate

Propylene glycol alginates give greater increases in foam stability than are given by equal amounts of neutral polysaccharides. This is due to electrostatic interaction between carboxyl groups on the glycol alginate molecules and amino groups on the peptides in the bubble wall. This interaction within the bubble wall is responsible for the stabilizing action of propylene glycol alginate against the harmful effects of lipid-like materials in beer foam.