Soybeans phytate

Mason, A. C., Weaver, C. M., Kimmel, S., and Brown, R. K. (1993). Effect of soybean phytate content on calcium bioavailability in mature and immature rats. /. Agric. Food Chem. 41, 246-249. 

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. 

CCM is considered to ameliorate the interfering effect of phytates consumed by animals, and as a result enhance Ca absorption and bioavailability. A study in chicks by Lihono et ah (1997a) directly investigated this possibility in food derived from soy beans. The effects of microbially derived phytase enzyme treatments on the bioavailability of Ca from soy-based foods fed to young male broiler chickens were examined in two separate experiments. In experiment one, the effect of phytase was tested when day-old chicks were fed com/soybean-meal-based diets, with or without 0.12% added phytase, that also included Ca from CCM (at levels 0%, 0.1%, 0.2%, and 0.3% to provide total Ca of 0.45%, 0.55%, 0.65%, and 0.75%, respectively) or Ca from CaCOs (at the 1% level, which... 

Z. Yi, E. T. Kornegay, V. Ravindran, and D. M. Denbow, Improving phytate phosphorus availability in corn and soybean meal for broilers using microbial phytase and calculation of phosphorus equivalency values for phytase, Poultry Sci. 1996c, 75, 240-249. 

Soybean meal is generally low in minerals and vitamins (except choline and folic acid). About two-thirds of the P in soybeans is bound as phytate and is mostly unavailable to animals. This compound also chelates mineral elements including Ca, magnesium, potassium, iron and zinc, rendering them unavailable to poultry. Therefore, it is important that diets based on soybean meal contain adequate amounts of these trace minerals. Another approach to the phytate problem is to add phytase, a phytic acid degrading enzyme, to the feed to release phytin-bound P. A benefit of this approach is that less P needs to be added to the diet, reducing excess P loading into the environment. 

Feed peas, like cereal grains, are low in Ca but contain a slightly higher level of P (about 4g/kg). They contain about 12g/kg phytate, similar to that in soybeans (Reddy et al., 1982). The levels of trace minerals and vitamins in peas are similar to those found in cereal grains. 

Kumagai, H., Shizawa, Y., Sakurai, H., Kumagai, H. 1998. Influence of phytate removal and structural modification on the calcium-binding properties of soybean globulins. Biosci... 

The ash content of soybeans is relatively high, close to 5 percent. The ash and major mineral levels in soybeans are listed in Table 5-7. Potassium and phosphorus are the elements present in greatest abundance. About 70 to 80 percent of the phosphorus in soybeans is present in the form of phytic acid, the phosphoric acid ester of inositol (Figure 5-5). Phytin is the calcium-magnesium-potassium salt of inositol hexaphosphoric acid or phytic acid. The phytates are important because of their effect on protein solubility and because they may interfere with absorption of calcium from the diet. Phytic acid is present in many foods of plant origin. 

Manganese is a nutritionally important trace element for chicks. Dietary energy and protein sources contain very little bioavailable Mn, and these feed ingredients reduce the biopotency of inorganic Mn supplements. This adverse effect is exerted primarily in the intestine as a result of reduced Mn absorption and is mediated by the fiber and/or ash components of the feedstuffs. Gut absorption efficiencies are higher when a phytate-and fiber-free casein-dextrose diet is fed than when a corn-soybean meal diet is fed. Dietary interrelationships exist between Mn and Co and between Mn and Fe. Cobalt increases Mn absorption and may precipitate Mn toxicosis. Excess dietary Mn reduces Fe utilization, but excess Fe does not affect Mn utilization. Eimeria acervulina infection increases Mn absorption. 

Phytate has been studied extensively with regard to mineral (mostly Zn and Ca) status of animals, and it has been shown to reduce whole-body Mn retention in rats (12). Phytate, however, is not present in the neutral detergent fiber or in the ash component of feedstuffs. Therefore, phytate does not appear to be responsible for the reduction of Mn uptake in chicks fed corn, soybean meal, wheat bran or fish meal (9). That phytate negatively impacts Mn nutriture also disagrees with the research of Reinhold et aK (13), who reported that fiber, and not phytate, was the pTTmary factor determining bioavailability of divalent mineral elements in breads. 

Phytate. Phytic acid is an organic polyphosphate found widely in plants, particularly cereals, nuts and legumes. It has been shown to complex with various divalent cations in the gastrointestinal tract and thus reduce mineral bioavailability (33,44,52). Davis et al. (53) reported that feeding a diet based on isolated soybean... 

Our laboratories have been concerned with the role that unit food processing operations play in the bioavailability of zinc from complete diets. Soybean foods have served as models for the evaluation of processing effects upon both endogenous and added zinc. Below are described results from both rat bioassays and in vitro tests for zinc bioavailability. Prediction of zinc bioavailability from soy-containing diets is far more complex than an analysis of phytate and zinc molar ratios. 

As pointed out earlier in this review, increasing the level of dietary calcium decreases the zinc bioavailability from phytate-containing foods. Presumably the mechanism is through the formation of chemical complexes containing zinc, phytate and calcium which are insoluble at intestinal pH and nonabsorbable (24). Recently, our laboratories used slope ratio techniques to compare the bioavailability of zinc contained in calcium sulfate-and in magnesium chloride-precipitated soybean curd (Tofu) to that of zinc added as the carbonate to egg white diets by slope ratio techniques (25). Total dietary calcium level in all diets was adjusted to 0.7% with calcium carbonate. The results (not shown) indicated that the relative availability of zinc from both tofu preparations was 51% as measured by weight gain and 36-39% for bone zinc. These results are similar to those reported for full fat soy flour (16) in Table I. 

Meis, S.J., Fehr, W.R., and Schnebly, S.R., 2003, Seed source effect on field emergence of soybean lines with reduced phytate and raffinose saccharides. Crop Sci. 43 1336-1339. 

It has been estimated that two thirds of the phosphorus of soybean oil meal is bound as phytate and, as such, is unavailable to the chick and furthermore interferes with the availability of calcium (56). The treatment of soybean meal with the culture filtrate of Aspergillus ficcum, however, caused a 90% release of the phytate-bound phosphorus and reduced the chick s requirement for calcium by at least one third (57). 

In soybean concentrates and isolates much of the phytate remains associated with the protein in fact, phytate may constitute as much as 2-3% of the weight of a commercial protein isolate (57). A low-phytate soybean protein isolate can be prepared from soybean flour, however, by allowing endogenous phytase to act on the phytate in a 6% suspension of the flour at pH 5 at a temperature of 65°C (58). Hydrolysis of the phytate facilitates its separation from the bulk of the soybean protein which is then concentrated by ultrafiltration using a membrane which is permeable to phytate and its hydrolysis products but impermeable to protein. The product obtained by this method contains over 90% protein and only about 0.3% phosphorus. 

Oltmans, S.E. W.R. Fehr G.A. Welke V. Raboy K.L. Peterson. Agronomic and seed traits of soybean lines with low-phytate phosphorus. Crop Sci. 2005, 45, 593-598. 

Wilcox, J.R. G.S. Premachandra KA.. Young V. Raboy. Isolation of high seed inotganic P low-phytate soybean mutant. Crop Sci. 2000, 40, 601—1605. 

Yamka, R.M. D.L. Harmon WD. Schoenherr C. Khoo K.L. Gross S.J. Davidson D.K. Joshi. In vivo measurement of flatulence and nutrient digestibility in dogs fed poultry by-product meal, conventional soybean meal, and low-oligosaccharide low-phytate soybean meal. Am. J. Vet. Res. 2006, 67, 88-94. 

Yamka, R.M. B.M. Hetzler D.L. Harmon. Evaluation of low-oligosaccharide, low-phytate whole soybeans and soybean meal in canine foods./. Anim. Sci. 2005, 83, 393—399. 

Phytate is the calcium, magnesium or potassium salt of phytic acid, which is inositol hexaphosphoric acid (Fig. 10.9). More than half of the total phosphorus in soybeans is in the form of phytic acid (Liu, 2004a). Because of its chelating power, phytic acid makes many essential minerals in soybeans or in diets unavailable for absorption and utilization for both human and domestic animals thus phytic acid is known as an anti-nutritional factor. 

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