The chelates listed below are what could be considered authentic chelates. Although varying in levels of efficacy, these are all chelates that could conceivably occur in nature. They are all metal ions attached to naturally occurring amino acids or carbohydrates.
Formulation Category Solubility Availability
“Amino acid chelates”
good absorption in both plants and animals, a correctly manufactured amino acid chelate should be translocated to every cell in the body and plant.
Glycine chelates (glycinate) a true amino acid chelate - soluble – excellent absorption, glycine makes up part of glutathione the key antioxidant in the cytoplasm of every cell. Mineral tied to glycine is translocated to every cell.
- soluble – medium absorption – proteinates are made up of a number of amino acids attached to a single metal ion. As such this is a large molecule offering poorer absorption, when compared to either an amino acid chelate or a glycine chelate The less controlled manufacturing process means proteinates are less costly to manufacture.
- soluble – medium availability - unstable – no rumen protection
The AAFCO (Association of American Feed Control Officials) was among the first organisations to exactly define what constituted a true Amino Acid Chelate. This has since become the standard definition used throughout the feed and fertiliser industries.
AAFCO basic definitions for chelates as follows:
METAL AMINO ACID CHELATE
– The product resulting from the reaction of a metal ion from a soluble metal salt with amino acids. It has a mole ratio with 1 mole of metal to 1-3 (preferably 2) moles of amino acid to form coordinate covalent bonds. The average weight of the amino acids must be approximately 150 daltons and the resulting molecular weight of the chelate must not exceed 800 daltons. When used as a commercial feed ingredient it must be declared as a specific metal amino acid chelate. (Adopted 1988)
– The product resulting from the chelation of a soluble salt with amino acids and/or partially hydrolyzed protein. It must be declared as an ingredient as the specific metal proteinate: i.e., copper proteinate; zinc proteinate; magnesium proteinate; iron proteinate; cobalt proteinate; manganese proteinate; or calcium proteinate. (Amended 1987).
METAL POLYSACCHARIDE COMPLEX
– The product resulting from the complexing of a soluble salt with a polysaccharide solution declared as an ingredient as the specific metal complex: i.e., copper polysaccharide complex; zinc polysaccharide complex; iron polysaccharide complex; cobalt polysaccharide complex; and manganese polysaccharide complex. (Adopted 1973).
Additional to this more recent research has shown that to achieve a truly functional chelate, the following further requirements should be met:
1) The chelate must be electrically neutral. The chelate must not be complexed with an easily ionisable anion, such as a halogen or a sulphate group. The ligand must satisfy both the oxidative state and a coordination number of the metal ion.
3) The chelate must have a high enough stability constant to avoid competitive chemical interactions prior to absorption, yet the stability constant must not be so high as to interfere with release or cause the binding of other elements during digestion and absorption.
4) The ligand (Amino Acid) must be small enough to be easily absorbed through the intestinal wall from whence it will be translocated to the widest range of body cells possible. (some amino acids are more specific to certain body cells than others).