Propyleneglycol alginate

Propyleneglycol alginates do not precipitate from acidic media and their acid stability increases in proportion to the propyleneglycol content. Additionally, those esters with DS > 60% are not precipitated by Ca2 +, because the bulky propyleneglycol substituent hinders the prerequisite alignment for gelation and precipitation. These esters are more tolerant of alcohol than the unesterified alginate. 

The foam building properties of beer are due to proteins, polysaccharides and bitter constituents. The P-glucans stabilize the foam through their ability to increase viscosity. Addition of semisynthetic polysaccharides, e.g., propyleneglycol alginate (40 g/hectoliter), to beer provides a very stable foam although the addition is judged as unfavorable. 

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