Alginate
Mixing & Dispersing Alginate and Processing Alginic Acid
Alginates are salts of the long-chain, carbohydrate biopolymer alginic acid. They are extracted from various species of brown algae (seaweed) and purified to a white powder. The alginates have different characteristics of viscosity and reactivity based on the specific algal source and the ions in solution. Alginic acid is insoluble, but the salts are hydrocolloids (materials that bind or absorb water). The common salts used in the food and pharmaceutical industries are sodium alginate, potassium alginate, and propylene glycol alginate.
Alginates are generally acid stable and heat resistant. Adjusting the concentration of calcium ions (which cause crosslinking), controls gel strength, and combining alginate with other gums, such as pectin, increases viscosity dramatically.
Dispersing low concentrations of alginate is usually easy in ambient temperature water, but hard or very cold water makes it more difficult. Alginate concentrations above 2% require high shear mixing to eliminate clumps and fisheyes.
