A sequestrant is a food additive whose role is to improve the quality and stability of the food products. Sequestrants form chelate complexes with polyvalent metal ions. Especially copper, iron and nickel serve as catalysts in oxidation of the fats in the food.
An ingredient that releases itself or other ingredients slowly into a product over a period of time. Usually refers to preservatives, which have a "time-release" action in maintaining the color, consistency, and fragrance of a product.