Propylene oxide alginates

Propylene oxide alginates, made from propylene oxide and seaweed extracts, are used as food thickeners. 

Note Oxidation of Propylene Glycol Alginate yields formaldehyde and acetaldehyde. 

A reaction with propylene oxide produces the nontoxic propylene glycol alginate, which, unlike the alkali alginates, does not gel at high concentrations. Typical uses are as stabilizers for puddings, ice cream, orange juice, beer foam (in the United States), inks, cosmetics, etc. 

Manuf. by reaction of alginic acid with propylene oxide. White to yellowish fibrous or granular powder. Sol. H2O. 

Propylene glycol alginate (PGA, propane 1,2-diol alginate) E405 Alginic acid Propylene oxide Salad dressings, meringues, ice cream, noodles, fermented milk drinks, dairy desserts, beer... 

Propylene glycol alginate is a derivative of economic importance. This ester is obtained by the reaction of propylene oxide with partially neutralized alginic acid. It is soluble down to pH 2 and, in the presence of Ca + ions, forms soft, elastic, less brittle and syneresisfree gels. 

Similar to the chemical modifications applied to alginate, chitosan can be treated with chloro-acetic acid, ethylene oxide, and propylene oxide to obtain sodium car-boxymethyl chitosan, hydroxyethyl chitosan, and hydroxypropyl chitosan, respectively. These derivatives are highly absorbent and can be used for the production of superabsorbent fibers for medical applications. In addition to enhanced absorption properties, it is known that carboxymethyl chitosan possesses unique wound-healing properties whereby the application of foams, hydrogels, or nonwoven dressings can effectively promote the healing of chronic ulcerative wounds. 

Carboxylic acid-containing polysaccharides can be easily functionalized by reactions such as esterification, amination, or amidation. Industrial esterification of polyuronides, including alginic acid (O Chap. 6.4), in aqueous medium can be easily accomplished by reaction with ethylene, propylene, butylene, andpentylene oxides in 50-80% yield [123]. 

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