Phytic acid
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Phytic acid |
|
|---|---|
| Chemical name | myo-Inositol- 1,2,3,4,5,6- hexakisphosphate |
| Chemical formula | C6H18O24P6 |
| Molecular mass | 660.08 g/mol |
| Melting point | ? °C |
| Boiling point | ? °C |
| Density | ? g/cm3 |
| CAS number | 83-86-3 |
| SMILES | C1(OP(=O)(O)(O))C(OP(=O)(O)(O))C(OP(=O)(O)(O)) C(OP(=O)(O)(O))C(OP(=O)(O)(O))C1(OP(=O)(O)(O)) |
Phytic acid (known as inositol hexaphosphate (IP6), or phytate when its salt form) is the principal storage form of phosphorus in many plant tissues, especially bran and seeds. Phosphorus in this form is generally not bioavailable to non-ruminant animals because they lack the digestive enzyme, phytase, required to separate phosphorus from the phytate molecule. On the other hand, ruminants readily utilize phytate because of the phytase produced by rumen microorganisms.
In modern agriculture, non-ruminant livestock such as swine and poultry are fed mainly grains such as soybeans and maize. Because phytate from these grains is unavailable for absorption, the unabsorbed phytate passes through the gastrointestinal tract, elevating the amount of phosphorus in the manure. Excess phosphorus excretion can lead to environmental problems such as eutrophication.
The bioavailability of phytate phosphorus can be increased by supplementation of the diet with phytase enzyme. Also, viable low phytic acid mutant lines have been developed in several crop species in which the seeds have drastically reduced levels of phytic acid and concomitant increases in inorganic phosphorus. However, reported germination problems have hindered the use of these cultivars thus far.
[edit] Food science
Phytic acid is found within the hulls of nuts, seeds, and grains. Soaking seeds and nuts in water for several hours prior to consumption, and sprouting grains, is advocated in order to reduce the phytic acid content in these foods. Some argue that cooking and processing (such as what happens with bread) can adequately break down the phytic acid.
Phytic acid is a strong chelator of important minerals such as calcium, magnesium, iron and zinc and can therefore contribute to mineral deficiencies in developing countries [1]. In this way, it is an antinutrient. For people with a particularly low intake of essential minerals, especially young children and those in developing countries, this effect can be undesirable.
Dietary mineral chelators helps, through reducing the available minerals, to prevent over-mineralization of joints, blood vessels, and other parts of the body, which is most common in older persons. They do not correct the disorder that causes this negative distribution of substances though, and can reduce the availability of these minerals for other essential processes.
The Journal of Environmental Nutrition (April 2004 volume 27 issue 4) has stated phytic acid may be considered a phytonutrient, providing an antioxidant effect. Phytic acid's same mineral binding properties may also prevent colon cancer by reducing oxidative stress in the lumen of the intestinal tract. Scientific research [2] also indicates that it may reduce the risk of colon cancer. Researchers now believe that IP6, found in the fiber of legumes and grains, is the major ingredient responsible for preventing colon cancer and other cancers.
Its chelating effect may serve to prevent, inhibit or even cure some cancers by depriving those cells of the minerals (especially iron) they need to reproduce. The deprivation of essential minerals like iron would, much like other broad treatments for cancers, also have negative effects on non-cancerous cells. It is unknown if this would affect other cells in the body that require iron (such as red blood cells) or if the deprivation of minerals is more localized to the internal colon region.
Phytic acid has no known toxicity and is not known to cause mutagenic activity. It may have more therapuetic value when added to water rather than when naturally absorbed in foods as it is difficult to free from fiber.
As a food additive, phytic acid is used as a preservative with E number E391.
Food must be well cooked in order to free IP6 from the fiber and enable it to be absorbed in the system. IP6 rarely appears in soluble fiber. It's usually attached to the bran, the hard (insoluble) fiber, which is difficult to digest. IP6 is found in legumes, peas, wheat, barley, and oats. Of any studied legumes, whole soybeans have the highest levels of phytic acid.
Those who argue for the beneficial effects of phytic acid, and freeing it up for interaction with the system through cooking, do not argue that cooking destroys the phytic acid. This is a major deviation between those arguing for the merits of processed grain products.
