A sequestrant is a food additive

Food additive

Food additives are substances added to food to preserve flavor or enhance its taste and appearance.Some additives have been used for centuries; for example, preserving food by pickling , salting, as with bacon, preserving sweets or using sulfur dioxide as in some wines...

 whose role is to improve the quality and stability of the food products. Sequestrants form chelate complexes with polyvalent

Polyvalent

In chemistry, polyvalence or multivalence refers to species that are not restricted to a distinct number of valence bonds....

 metal ions, especially copper

Copper

Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

, iron

Iron

Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

 and nickel

Nickel

Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...

, which serve as catalysts in the oxidation of the fats in the food. Sequestrants are a kind of preservative

Preservative

A preservative is a naturally occurring or synthetically produced substance that is added to products such as foods, pharmaceuticals, paints, biological samples, wood, etc. to prevent decomposition by microbial growth or by undesirable chemical changes....

.

The name comes from Latin and means "to withdraw from use" .

Common sequestrants are:

• Calcium disodium ethylene diamine tetra-acetate (E385)
• Glucono delta-lactone
  Glucono delta-lactone
  Glucono delta-lactone is a naturally-occurring food additive with the E number E575 used as a sequestrant, an acidifier, or a curing, pickling, or leavening agent. It is a lactone of D-gluconic acid. Pure GDL is a white odorless crystalline powder.GDL is commonly found in honey, fruit juices,...
  
   (E575)
• Sodium gluconate
  Sodium gluconate
  Sodium gluconate is a compound with formula NaC6H11O7. It is the sodium salt of gluconic acid.It has E number E576....
  
   (E576)
• Potassium gluconate
  Potassium gluconate
  Potassium gluconate is a mineral supplement and sequestrant.Potassium gluconate is a loosely bound salt of potassium and gluconic acid. Potassium is essential to life. It is involved with sodium in maintaining the body's acid-base balance and promoting physiological and metabolic processes. It...
  
   (E577)
• Sodium tripolyphosphate
  Sodium tripolyphosphate
  Sodium triphosphate is an inorganic compound with formula Na5P3O10. It is the sodium salt of the polyphosphate penta-anion, which is the conjugate base of triphosphoric acid. It is produced on a large scale as a component of many domestic and industrial products, especially detergents...
  
  
• Sodium hexametaphosphate
  Sodium hexametaphosphate
  Sodium hexametaphosphate is a hexamer of composition 6. Sodium hexametaphosphate of commerce is typically a mixture of polymeric metaphosphates, of which the hexamer is one, and is usually the compound referred to by this name. It is more correctly termed sodium polymetaphosphate. It is prepared...
  
   (E452i)

Sodium and calcium salts of EDTA

EDTA

Ethylenediaminetetraacetic acid, widely abbreviated as EDTA , is a polyamino carboxylic acid and a colourless, water-soluble solid. Its conjugate base is named ethylenediaminetetraacetate. It is widely used to dissolve limescale. Its usefulness arises because of its role as a hexadentate ligand...

are also commonly used in many foods and beverages.