POTASSIUM ALGINATE

Chemical Properties

Potassium alginate occurs as a white to yellowish, fibrous or granular powder; it is almost odorless and tasteless.

Chemical Properties

Occurs in filamentous, grainy, granular, and powdered forms. It is colorless or slightly yel- low and may have a slight characteristic smell and taste. Slowly soluble in water, forming a viscous solution; insoluble in alcohol.

Uses

Potassium Alginate is a gum that is the potassium salt of alginic acid. It is soluble in cold water, forming a viscous colloidal solution. It functions as a stabilizer, thickener, and gelling agent. It is used in dietetic foods, low-sodium foods, dry mixes, and dental impression material. Typical usage levels range from 0.05 to 0.50%.

Uses

Thickening agent and stabilizer in dairy prod- ucts, canned fruits, and sausage casings; emulsifier. See alginic acid.

Production Methods

Alginate obtained from brown seaweed is subjected to demineralization, extraction, and precipitation of alginic acid. Following neutralization, the potassium alginate obtained is dried and milled.

Definition

Hydrophilic colloid having a molecular weight of 32,000–250,000.

Pharmaceutical Applications

Potassium alginate is widely used in foods as a stabilizer, thickener, and emulsifier; however, its use as a pharmaceutical excipient is currently limited to experimental hydrogel systems. The viscosity, adhesiveness, elasticity, stiffness, and cohesiveness of potassium alginate hydrogels have been determined and compared with values from a range of other hydrogel-forming materials.The effect of calcium ions on the rheological properties of procyanidin hydrogels containing potassium alginate and intended for oral administration has also been investigated.

Safety

Potassium alginate is widely used in food products. It is currently used as an excipient only in experimental pharmaceutical formulations.

storage

In the solid state, potassium alginate is a stable material that is not prone to microbial spoilage. Over time, a slow reduction in the degree of polymerization can occur, which may be reflected in a reduction in the viscosity of solutions. As both temperature and moisture can impair the performance of potassium alginate, storage below 25°C is recommended.
Potassium alginate solutions are stable at pH 4–10; long-term storage outside this range can result in depolymerization of the polymer through hydrolysis. Gelation or precipitation of the alginate can occur at pH values less than 4. Liquid or semisolid alginate formulations should be preserved: suitable preservatives are sodium benzoate, potassium sorbate, or parabens.
Potassium alginate should be stored under cool, dry conditions in a well-closed container.

Incompatibilities

Incompatible with strong oxidizers.

Regulatory Status

GRAS listed. Accepted for use in foods in the USA and Europe.