Phytic acid

Phytic acid
Names
IUPAC name
(1R,2R,3S,4S,5R,6S)-cyclohexane-1,2,3,4,5,6-hexayl hexakis[dihydrogen (phosphate)]
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.001.369
E number E391 (antioxidants, ...)
UNII
Properties
C6H18O24P6
Molar mass 660.03 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Phytic acid (known as inositol hexakisphosphate (IP6), inositol polyphosphate, or phytate when in salt form), discovered in 1903,[1] a saturated cyclic acid, is the principal storage form of phosphorus in many plant tissues, especially bran and seeds.[2] It can be found in cereals and grains.

Catabolites of phytic acid are called lower inositol polyphosphates. Examples are inositol penta- (IP5), tetra- (IP4), and triphosphate (IP3).

Significance in agriculture

Phosphorus and inositol in phytate form are not, in general, bioavailable to nonruminant animals because these animals lack the digestive enzyme phytase required to remove phosphate from the inositol in the phytate molecule. Ruminants are readily able to digest phytate because of the phytase produced by rumen microorganisms.[3]

In most commercial agriculture, nonruminant livestock, such as swine, fowl, and fish,[4] are fed mainly grains, such as maize, legumes, and soybeans. Because phytate from these grains and beans is unavailable for absorption, the unabsorbed phytate passes through the gastrointestinal tract, elevating the amount of phosphorus in the manure.[3] Excess phosphorus excretion can lead to environmental problems, such as eutrophication.[5]

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.[6] However, germination problems have reportedly hindered the use of these cultivars thus far. This may be due to phytic acid's critical role in both phosphorus and metal ion storage.

The use of sprouted grains will reduce the quantity of phytic acids in feed, with no significant reduction of nutritional value.[7]

Phytate variants also have the potential to be used in soil remediation, to immobilize uranium, nickel and other inorganic contaminants.[8]

Biological and physiological roles

Although indigestible for many animals, phytic acid and its metabolites as they occur in seeds and grains have several important roles for the seedling plant.

Most notably, phytic acid functions as a phosphorus store, as an energy store, as a source of cations and as a source of myoinositol (a cell wall precursor). Phytic acid is the principal storage form of phosphorus in plant seeds.[9]

In animal cells, myoinositol polyphosphates are ubiquitous, and phytic acid (myoinositol hexakisphosphate) is the most abundant, with its concentration ranging from 10 to 100 µM in mammalian cells, depending on cell type and developmental stage.[10][11]

This compound is not obtained from the animal diet, but must be synthesized inside the cell from phosphate and inositol (which in turn is produced from glucose, usually in the kidneys). The interaction of intracellular phytic acid with specific intracellular proteins has been investigated in vitro, and these interactions have been found to result in the inhibition or potentiation of the physiological activities of those proteins.[12][13] The best evidence from these studies suggests an intracellular role for phytic acid as a cofactor in DNA repair by nonhomologous end-joining.[12] Other studies using yeast mutants have also suggested intracellular phytic acid may be involved in mRNA export from the nucleus to the cytosol.[14] There are still major gaps in the understanding of this molecule, and the exact pathways of phytic acid and lower inositol phosphate metabolism are still unknown. As such, the exact physiological roles of intracellular phytic acid are still a matter of debate.[15]

Food science

Phytic acid, mostly as phytate, is found within the hulls of nuts, seeds, and grains.[2] No detectable phytate (less than 0.02 % of wet weight) was observed in vegetables such as scallion and cabbage leaves or in fruits such as apples, oranges, bananas, or pears.[16] In-home food preparation techniques can break down the phytic acid in all of these foods. Simply cooking the food will reduce the phytic acid to some degree. More effective methods are soaking in an acid medium, sprouting and lactic acid fermentation such as in sourdough and pickling.[17]

Phytic acid has a strong binding affinity to important minerals, such as calcium, iron, and zinc, although the binding of calcium with phytic acid is pH-dependent.[18] The binding of phytic acid with iron is more complex, although there certainly is a strong binding affinity, molecules like phenols and tannins also influence the binding.[19] When iron and zinc bind to phytic acid they form insoluble precipitates and are far less absorbable in the intestines. This process can therefore contribute to iron and zinc deficiencies in people whose diets rely on these foods for their mineral intake, such as those in developing countries[20][21] and vegetarians.[22]

As a food additive, phytic acid is used as the preservative E391.

Food sources of phytic acid (g/100g)

[23] [16]

[24][25][26][27][28][29]
Food [% minimum dry] [% maximum dry]
Pumpkin seed 4.3 4.3
Linseed 2.15 2.78
Sesame seeds flour 5.36 5.36
Chia seeds 0.96 1.16
Almonds 1.35 3.22
Brazil nuts 1.97 6.34
Coconut 0.36 0.36
Hazelnut 0.65 0.65
Peanut 0.95 1.76
Walnut 0.98 0.98
Maize (Corn) 0.75 2.22
Oat 0.42 1.16
Oat Meal 0.89 2.40
Brown rice 0.84 0.99
Polished rice 0.14 0.60
Wheat 0.39 1.35
Wheat flour 0.25 1.37
Wheat germ 0.08 1.14
Whole wheat bread 0.43 1.05
Beans, pinto 2.38 2.38
Buckwheat 1.00 1.00
Chickpeas 0.56 0.56
Lentils 0.44 0.50
Soybeans 1.00 2.22
Tofu 1.46 2.90
Soy beverage 1.24 1.24
Soy protein concentrate 1.24 2.17
New potato 0.18 0.34
Spinach 0.22 NR
Avocado fruit 0.51 0.51
Food sources of phytic acid (fresh weight)[25]
Food [% minimum fresh weight] [% maximum fresh weight]
Taro 0.143 0.195
Cassava 0.114 0.152

Chestnuts contain 47 mg of phytic acid for 100g.[30]

Oak acorn of Quercus ilex contains 127 mg of phytic acid for 100g.[31]

Medical uses

Studies examining the effects of phytic acid demonstrate that they are important in regulating vital cellular functions. Both in vivo and in vitro experiments have demonstrated striking anticancer (preventive as well as therapeutic) effects of phytic acid. Research shows anti-carcinogenic effects, albeit to a lesser extent and it acts in inhibiting cancer. In addition to reduction in cell proliferation, phytic acid increases differentiation of malignant cells often resulting in reversion to the normal phenotype.[32]

The study concludes that: "Given the numerous health benefits, phytates participation in important intracellular biochemical pathways, normal physiological presence in our cells, tissues, plasma, urine, etc., the levels of which fluctuate with intake, epidemiological correlates of phytate deficiency with disease and reversal of those conditions by adequate intake, and safety – all strongly suggest for phytates inclusion as an essential nutrient, perhaps a vitamin."

See also

References

  1. Mullaney, Edward J.; Ullah, Abul H.J. "Phytases: attributes, catalytic mechanisms, and applications" (PDF). United States Department of Agriculture–Agricultural Research Service. Retrieved May 18, 2012.
  2. 1 2 Phytic acid. phytochemicals.info
  3. 1 2 Klopfenstein, Terry J.; Angel, Rosalina; Cromwell, Gary; Erickson, Galen E.; Fox, Danny G.; Parsons, Carl; Satter, Larry D.; Sutton, Alan L.; Baker, David H. (July 2002). "Animal Diet Modification to Decrease the Potential for Nitrogen and Phosphorus Pollution". Council for Agricultural Science and Technology. 21.
  4. Romarheim, O.H.; Zang, C.; Penn, M.; Liu, Y.-J.; Tian, L.-H.; Skrede, A.; Krogdahl, Å.; Storebakken, T. (2008). "Growth and intestinal morphology in cobia (Rachycentron canadum) fed extruded diets with two types of soybean meal partly replacing fish meal". Aquaculture Nutrition. 14 (2): 174–180. doi:10.1111/j.1365-2095.2007.00517.x.
  5. Mallin, M. A. (2003). "Industrialized Animal Production—A Major Source of Nutrient and Microbial Pollution to Aquatic Ecosystems". Population and Environment. 24 (5): 369–385. JSTOR 27503850. doi:10.1023/A:1023690824045.
  6. Guttieri, M. J.; Peterson, K. M.; Souza, E. J. (2006). "Milling and Baking Quality of Low Phytic Acid Wheat". Crop Science. 46 (6): 2403–8. doi:10.2135/cropsci2006.03.0137.
  7. Malleshi, N. G.; Desikachar, H. S. R. (1986). "Nutritive value of malted millet flours". Plant Foods for Human Nutrition. 36 (3): 191–6. doi:10.1007/BF01092036.
  8. Seaman JC, Hutchison JM, Jackson BP, Vulava VM (2003). "In situ treatment of metals in contaminated soils with phytate". Journal of Environmental Quality. 32 (1): 153–61. PMID 12549554. doi:10.2134/jeq2003.0153.
  9. Reddy NR, Sathe SK, Salunkhe DK (1982). "Phytates in legumes and cereals". Adv Food Res. 28: 1–92. PMID 6299067. doi:10.1016/s0065-2628(08)60110-x.
  10. Szwergold BS, Graham RA, Brown TR (1987). "Observation of inositol pentakis- and hexakis-phosphates in mammalian tissues by 31P NMR". Biochem Biophys Res Commun. 149 (3): 874–881. PMID 3426614. doi:10.1016/0006-291X(87)90489-X.
  11. Sasakawa N, Sharif M, Hanley MR (1995). "Metabolism and biological-activities of inositol pentakisphosphate and inositol hexakisphosphate". Biochem Pharmacol. 50 (2): 137–146. PMID 7543266. doi:10.1016/0006-2952(95)00059-9.
  12. 1 2 Hanakahi LA, Bartlet-Jones M, Chappell C, Pappin D, West SC (2000). "Binding of inositol phosphate to DNA-PK and stimulation of double-strand break repair". Cell. 102 (6): 721–729. PMID 11030616. doi:10.1016/S0092-8674(00)00061-1.
  13. Norris FA, Ungewickell E, Majerus PW (1995). "Inositol hexakisphosphate binds to clathrin assembly protein 3 (AP-3/AP180) and inhibits clathrin cage assembly in vitro". J Biol Chem. 270 (1): 214–217. PMID 7814377. doi:10.1074/jbc.270.1.214.
  14. York JD, Odom AR, Murphy R, Ives EB, Wente SR (1999). "A phospholipase C-dependent inositol polyphosphate kinase pathway{meaning?} required for efficient messenger RNA export". Science. 285 (5424): 96–100. PMID 10390371. doi:10.1126/science.285.5424.96.
  15. Shears SB (2001). "Assessing the omnipotence of inositol hexakisphosphate". Cell Signalling. 13 (3): 151–158. PMID 11282453. doi:10.1016/S0898-6568(01)00129-2.
  16. 1 2 Degradation of Phytate in Foods by Phytases in Fruit and Vegetable Extracts B.Q. PHILLIPPY AND C.J. WYATT
  17. "Phytates in cereals and legumes". fao.org.
  18. Dendougui, Ferial; Schwedt, Georg (2004). "In vitro analysis of binding capacities of calcium to phytic acid in different food samples". European Food Research and Technology. 219 (4). doi:10.1007/s00217-004-0912-7.
  19. Prom-U-Thai, Chanakan; Huang, Longbin; Glahn, Raymond P; Welch, Ross M; Fukai, Shu; Rerkasem, Benjavan (2006). "Iron (Fe) bioavailability and the distribution of anti-Fe nutrition biochemicals in the unpolished, polished grain and bran fraction of five rice genotypes". Journal of the Science of Food and Agriculture. 86 (8): 1209–15. doi:10.1002/jsfa.2471.
  20. Hurrell RF (September 2003). "Influence of vegetable protein sources on trace element and mineral bioavailability". The Journal of Nutrition. 133 (9): 2973S–7S. PMID 12949395.
  21. Committee on Food Protection; Food and Nutrition Board; National Research Council (1973). "Phytates". Toxicants Occurring Naturally in Foods. National Academy of Sciences. pp. 363–371. ISBN 978-0-309-02117-3.
  22. American Dietetic, A.; Dietitians Of, C. (2003). "Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets". Journal of the American Dietetic Association. 103 (6): 748–765. PMID 12778049. doi:10.1053/jada.2003.50142.
  23. Dephytinisation with Intrinsic Wheat Phytase and Iron Fortification Significantly Increase Iron Absorption from Fonio (Digitaria exilis) Meals in West African Women (2013)
  24. Reddy, N. R.; Sathe, Shridhar K. (2001). Food Phytates. Boca Raton: CRC. ISBN 1-56676-867-5.
  25. 1 2 Phillippy, B. Q.; Bland, J. M.; Evens, T. J. (2003). "Ion Chromatography of Phytate in Roots and Tubers". Journal of Agricultural and Food Chemistry. 51 (2): 350–3. PMID 12517094. doi:10.1021/jf025827m.
  26. MacFarlane, B. J.; Bezwoda, W. R.; Bothwell, T. H.; Baynes, R. D.; Bothwell, J. E.; MacPhail, A. P.; Lamparelli, R. D.; Mayet, F (1988). "Inhibitory effect of nuts on iron absorption". The American Journal of Clinical Nutrition. 47 (2): 270–4. PMID 3341259.
  27. Gordon, D. T.; Chao, L. S. (1984). "Relationship of components in wheat bran and spinach to iron bioavailability in the anemic rat". The Journal of Nutrition. 114 (3): 526–35. PMID 6321704.
  28. Cereal Grains for the Food and Beverage Industries -autor: Elke K Arendt, Emanuele Zannini - see page 388 - https://books.google.com/books?id=j_9DAgAAQBAJ&pg=PA388&dq=phytic+buckwheat+mg&hl=fr&sa=X&ved=0ahUKEwiMv_ugueLOAhXC6xoKHQ04DfQQ6AEIIzAB#v=onepage&q=phytic%20buckwheat%20mg&f=false
  29. CONCENTRATION OF NUTRIENTS AND BIOACTIVE COMPOUNDS IN CHIA (SALVIA HISPANICA L.), PROTEIN QUALITY AND IRON BIOAVAILABILITY IN WISTAR RATS
  30. Scuhlz, Markus. "Paleo Diet Guide: With Recipes in 30 Minutes or Less: Diabetes Heart Disease: Paleo Diet Friendly: Dairy Gluten Nut Soy Free Cookbook". PWPH Publications via Google Books.
  31. "First Phytochemiical Analysis of the Anti-Nutritional Aspect of Holm OOak Acorn (Quercus Ilex L)) of Tessala (Algeria NW) befoore and after Cooking (PDF Download Available)". ResearchGate.
  32. "Anti-cancer function of phytic acid". International Journal of Food Science and Technology.: Listed as IP-6 Inositol Hexaphosphate
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