Phytate

Calcium Absorption. Phytates in cereal grains have also been reported to interfere with the absorption of calcium. However, a long-term study indicated a retention of calcium in subjects that consume large amounts of bread made with high extraction of flour (19). 

Soybean concentrate production involves the removal of soluble carbohydrates, peptides, phytates, ash, and substances contributing undesirable flavors from defatted flakes after solvent extraction of the oil. Typical concentrate production processes include moist heat treatment to insolubilize proteins, followed by aqueous extraction of soluble constituents aqueous alcohol extraction and dilute aqueous acid extraction at pH 4.5. 

Of nutrient chelates in the human diet, oxalates and phytates are the most common. OxaUc acid (8), found principally in spinach, rhubarb leaves, beet leaves, some fmits, and mushrooms, is a primary chelator of calcium. Oxalate present in pineapple, kiwifmit, and possibly in other foods, occurs as calcium... 

Vitamin D withdrawal is an obvious treatment for D toxicity (219). However, because of the 5—7 d half-life of plasma vitamin D and 20—30 d half-life of 25-hydroxy vitamin D, it may not be immediately successful. A prompt reduction in dietary calcium is also indicated to reduce hypercalcemia. Sodium phytate can aid in reducing intestinal calcium transport. Calcitonin glucagon and glucocorticoid therapy have also been reported to reduce semm calcium resulting from D intoxication (210). 

Sodium phytate (H2O) [myo-inositolhexakis(H2P04) Na salt] [14306-25-3] M 857.9. Crystd from water. 

Heretofore, no economical method for preparing pure phytic acid was known. The classical method was to dissolve calcium phytate in an acid such as hydrochloric acid, and then add a solution of a copper salt, such as copper sulfate to precipitate copper phytate. The latter was suspended in water and treated with hydrogen sulfide, which formed insoluble copper sulfide and released phytic acid to the solution. After removing the copper sulfide by filtration, the filtrate was concentrated to yield phytic acid as a syrup. 

The phytic acid in the form of a calcium phytate press cake may however be contacted with a cation exchange resin to replace the calcium with sodium to yield phytate sodium. 

DOUGLAS M W, PETER C M, BOLING S D, PARSONS C M, BAKER D H (2000) Nuttitional evaluation of low phytate and high protein corns. Poult Sci. 79 1586-91. 

SPENCER J D, ALLEE G L, SAUBER T E (2000) Phosphotus bioavailability and digestibility of normal and genetically modified low-phytate com for pigs. JAnim Sci. 78 675-81. 

IP6 and phytates Kidney and gall bladder stone (calcium stones) management, hypercalcuria prevention (Ohkawa et al. 1984). Gastro-intestinal and colon health (Folino et al., 1995). 

Myo-inositol is one of the most biologically active forms of inositol. It exists in several isomeric forms, the most common being the constituent of phospholipids in biological cell membranes. It also occurs as free inositol and as inositol hexaphosphate (IP6) also known as phytate which is a major source from food. Rice bran is one of the richest sources of IP6 as well as free inositol. Inositol is considered to belong to the B-complex vitamins. It is released in the gastrointestinal tract of humans and animals by the dephosphorylation of IP6 (phytate) by the intestinal enzyme phytase. Phytase also releases intermediate products as inositol triphosphate and inositol pentaphosphate. Inositol triphosphate in cellular membrane functions as an important intra- and intercellular messenger, that merits its value as a nutritional therapy for cancer. 

Defatted soy flour was suspended in water to 8% (v/w) protein, pH was adjusted to 6 by HCl before 640 mg/L Novozyme 415 (a-galactosidase), 10 mg/L Phytase L (Novo Nordisk) and 53 mg enzyme protein/L rhamnogalacturonase B were added. After 4 hours at 50 C the pH was adjusted to 8 by NaOH, and the slurry was centrifuged. The supernatant was pasteurized (85°C, 5 minutes) and freezedried. Protein was measured as 6.25 x Kjeldahl N. Phytate was measured as described in [16], and dietary fibres were analysed as described in [17]. 

The ability of RGase B to solubilise soy fibres is useful for the production of a fibre enriched dietetic soy product. Soy milk has the disadvantages that it has a low fibre content and a high content of phytate and of stachyose and raffinose. To overcome these disadvantages a-galactosidase was used to reduce the amount of stachyose and raffinose, phytase to degrade the phytate, and RGase B to release fibre material. 

The composition of the resulting soy product is shown on Table V, where it is seen that the protein content was unchanged, whereas raffinose, stachyose and phytate were almost removed, and the amount of dietary fibres was improved. This demonstrates that the availability of relatively pure pectinolytic enzymes, like the used RGase B, opens up for the new types of soy processes and products. 

Graf, E. and Eaton, J.W. (1985). Dietary suppression of colonic cancer. Fiber or phytate. Cancer 56, 717-718. 

Jariwalla, R.J., Sabin, R., Lawson, S., Bloch, D.A., Prender, M., Andrews, V. and Herman, Z.S. (1988). Effects of phytic acid (phytate) on the incidence and growth rate of tumours... 

L. BeiBner and W. Romer, Improving the availability of phytate-phosphorus to sugar beet (Beta vulgaris L.) by phytase application to soil, 9th International Kollo-c/uiuin for the Optimization of Plant Nutrition, Prague, Czech Republic, 1996. p. 327. 

G. R. Findenegg and J. A. Nelenians, The effect of phytase on the availability of P from myo-inositol hexaphosphate (phytate) for maize root. Plant Soil 754 189 (1993). 

Degradation of phytate in animal feed Male sterility, tolerance to glufosinate... 

The phytate content of coffee beans is 1.2 to 5.4 mg/g, and only a portion of this is water extractable.28-29 Inositol with six phosphate groups (IP6) is decomposed to inositol with fewer phosphate groups, on roasting.30 A list of alicyclic compounds found in coffee is given in Table 4. 

Inhibitors of non-haem iron absorption include polyphenols and phytates. The former, secondary plant metabolites rich in phenolic hydroxyl groups, are found... 

Iron-deficiency anaemia results from a discrepancy between iron availability and the amount required for production of red blood cells. The causes of acquired iron deficiency in so-called underdeveloped and developed countries must be differentiated. In underdeveloped countries, the main causes of iron deficiency are (a) the poor availability of iron in the diet due to low haem and high fibre and phytate content (D Souza et ah, 1987), and (b) chronic blood loss due to hookworm, schistosomiasis and malaria (Stoltzfus et ah, 1997 Olsen et ah, 1998 Dreyfuss et ah, 2000). Inflammation and vitamin A deficiency often interfere with the above causes of iron deficiency, causing a mixed type of anaemia. In underdeveloped countries diet improvement, iron fortification of natural foods and eradication of parasites will have a much higher impact than will refinement of diagnostic procedures and therapy of iron-deficiency anaemia. 

Rat Traditional versus Improved (with fertilisers and pesticides) grown sorghum Improved sorghum contained higher phytate and feeding resulted in lower incorporation of zinc and iron in bones compared with traditional sorghum (Ali and Harland, 1991)... 

Ali HI and Harland BF (1991) Effects of fiber and phytate in sorghum flour on iron and zinc in weanling rats - a pilot-study . Cereal Chemistry, 68, 234-238. 

Phytate (myo-inositol hexaphosphate Fig. 15.3, structure 33) is found in many food species and can be considered as a phytochemical. Its role in the plant is primarily as a phosphate store in seeds, but it is found in other tissues as well, for example, tubers (Harland et al., 2004). Phytate and its hydrolysis products are anti-nutrients that chelate metal ions and thus reduce their bioavailability (Persson et al., 1998 House, 1999). This is particularly a problem with cereal grains, but pre-processing can improve mineral absorption from these foods (Agte and Joshi, 1997). There is some concern that high phytate foods could also contain higher levels of toxic heavy metals caused by natural accumulation. Plants also contain phytate-degrading enzymes that can also influence metal ion bioavailability (Viveros et al., 2000). 

Agte V V and Joshi S R (1997), Effect of traditional food processing on phytate degradation in wheat and millets , J Agric Food Chem, 45,1659-1661. 

Harland B F, Smikle-Williams S and Oberleas D (2004), High-performance liquid chromatography of phytate (IP6) in selected foods , J Food Comp Anal, 17, 227-233. 

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