Also known as sequestrant, chelants, or metal scavengers
What are Chelating Agents?
Chelating agents are food additives that prevent oxidation and increase shelf life of baked goods. They sequester metals, preventing them from taking part in color or flavor deterioration. Chemically, chelating agents are organic compounds with a ring-like center which forms at least two bonds with the mineral ion to produce complex structures, referred to as chelates.1
Examples of include:
- Ethylenediaminetetraacetic acid (EDTA)
- Organic acids such as citric or tartaric
The word ‘chelate’ is derived from the Greek ‘chele’ which means crab’s claw. Two key characteristics are essential for chelating agents’ functionality:1
- The presence of two different binding sites for the metal it chelates.
- Ability to coordinate with the metal ion to achieve a ring formation.
Metals such as calcium, zinc, iron, copper and many others can interact with components of food systems or can act as cofactors for enzymatic activity. By binding metals, chelating agents can delay/retard these activities, thus preserving the functional and sensory properties of food products. Some chelating agents can also act as effective antioxidants.
For example, EDTA is the most universally known chelating agent. Several salts of EDTA are produced mainly calcium disodium EDTA, disodium EDTA, tetrasodium EDTA, etc.
Chemical structure of EDTA
Characteristics of EDTA species:
- Bind tightly to pro-oxidants such as iron (Fe2+) and copper (Cu+).
- Work in aqueous media but not in fats and oils
- Prevent the development of metallic taste.
- Maintain their chelating capacity in highly acidic beverages (pH 3–5), this is in contrast to most organic acids which would lose their chelating capabilities.
- Can be used in combination with the antioxidants BHT and propyl gallate
EDTA is manufactured using a variation of the original method developed by Munz in 1935 in Germany. The process involves treating ethylenediamine with formaldehyde and a source of cyanide such as HCN or NaCN.The reaction yields the tetrasodium EDTA species, which is converted in a subsequent step into the acid form.3
Natural chelating agents
The synthetic origin of EDTA and its non-biodegradable nature have prompted the search for alternative clean label ingredients such as:
- Food-Grade Activated Charcoal
However, none of...