Food Chemistry and Fish in Nutrition ( 2+1)

12.1.4.Sequestrant

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

Common sequestrants

1. Calcium disodium ethylene diamine tetra-acetate (E385)
Sodium and calcium salts of EDTA are commonly used in many foods and beverage

2. Glucono delta- lactone (E575)

Glucono delta-lactone (GDL) E575a is a naturally-occurring food additive used as a sequestrant, an acidifier, or a curing, pickling, or leavening agent. 3. Sodium gluconate (E576)

4. Potassium gluconate (E577)

5. Sodium tripolyphosphate

6. Sodium hexamataphosphate (E452i)

Sodium hexametaphosphate (SHMP) is a hexamer of composition (NaPO3)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. SHMP is used as a sequestrant and has applications with in a wide variety of industries, including as a food additive in which it is used under the E number E452i .

7. Sodium tripolyphosphate

It is prepared by heating a stoichiometric mixture of disodium phosphate, Na₂HPO₄ and monosodium phosphate, NaH₂PO₄ under carefully controlled conditions.

2Na₂HPO₄ + NaH₂PO₄ → Na₅P₃O₁₀ + 2H₂O

It is used in various applications such as a preservative for seafood, meats, poultry and pet foods. In foods, STPP is used to retain moisture. Many governments regulate the quantities allowed in foods, as it can substantially increase the sale weight of seafood in particular.