Sequestrant

A substance added to a hydrocolloid emulsifier or thickener to aid in hydration. While many emulsifiers and thickeners require calcium ions in order to work, if these ions are present (either in the hydrocolloid or the liquid) before hydration, the hydocolloid may be more difficult to dissolve, requiring very hot liquid or a long time to do so. To modify this effect, a sequestrant—usually sodium citrate or sodium hexametaphosphate—is added to “tie up” the stray calcium ions and allow the compound to hydrate more easily. Once the compound is hydrated, if it needs calcium to act, the calcium can be added.