Phytic acid wheat

The diet treatments were level of phytate intake, either 0.2 or 2.0 g/day. Each level was consumed for 15 days, three consecutive repeats of the 5-day menu cycle. To provide 2.0 g/day of phytic acid, 36 g of wheat bran was baked into 6 muffins and two muffins were eaten each meal. Dephytinized bran was prepared by incubating the bran in water and allowing the endogenous phytase to hydrolyze the phytate, then the entire incubation mixture was freeze-dried (4) and 36 g baked into 6 muffins. Thus, the intake of all nutrients and neutral detergent fiber was the same for both phytate intakes. Five subjects consumed the whole bran muffins for 15 days followed by the dephytinized bran muffins for 15 days and the other 5 subjects in the reverse order. Brilliant blue dye was given at breakfast on the first day of each collection period to aid in demarcation of stools. Stool composites were made for days 1-5, 6-15, 16-20 and 21-30 and urine composites for days 6-15, and 21-30. Daily food composites were made, homogenized, freeze-dried and then analyzed to determine mineral nutrient intakes. 

Some Andean potatoes have iron content comparable to levels found in some cereals (rice, maize, and wheat Scurrah et al., 2007). Potato iron should be quite bioavailable because it has very low levels of phytic acid, unlike the cereals. 

Other workers (115-124 for example) have also centered their efforts on the role of phytic acid on zinc and iron bioavailabiliy from both soy and wheat products. It has been suggested (120) that the phytate-to-zinc molar ratio could be used to predict zinc bioavailability in high-phytate foods. Several groups (115, 117), including ours (113), 1 least partially supporT this hypothesis. However, recent work from our laboratory (112) involving soy protein of similar phytate-to-zinc molar ratios clearly demonstrates that zinc bioavailability is also altered by food processing. In this study, zinc from neutralized soy concentrates and isolates was shown to be less available to the rat than was the corresponding acid-precipitated products. This is unfortunate as alkaline conditions are commonly utilized for soy and other plant proteins to obtain beneficial functional properties. 

Enzymes should be added to the feed together with the pre-mix. Granulated enzyme products may readily be mixed with feed components, as they are based on normal feed components such as wheat or soy grits. A wide range of enzyme products are available. Enzyme products should contain specific enzyme activities necessary to degrade specific substances such as glucans, starch, protein, pectin-like polysaccharides, phytic acid, raffinose, stachyose, hemicellulose, and cellulose. 

Zinc deficiency has been found among peasant populations in rural areas of the Middle East. Unleavened whole wheat bread can account for 75% of the energy intake in these areas, that is, Iran, Egypt, and Turkey. This diet, which does not contain meat, does contain zinc, but it also contains phytic acid at a level of about 3 g/day. The phytic acid inhibits zinc absorption. The yeast used to leaven bread produces phosphatases that hydrolyze the phosphate groups from phytic acid. 

Monoferric phytate is the major fraction of iron in wheat bran, and is a highly bioavailable form of dietary iron in contrast to insoluble di- or tetra-ferric phytate. Monoferric phytate equilibrates with the miscible nonheme iron pool of a meal in extrinsic label iron absorption tests. Whole wheat bran depressed absorption by humans of nonheme iron in a meal. Dephytinized wheat bran also inhibited nonheme iron absorption by humans and the inhibition could not be clearly attributed to either the insoluble or soluble fractions of the dephytinized bran. Adult men who consumed 36 g of wheat bran per day had positive iron balances. Iron balance was not increased when dephytinized bran was consumed. The form of ferric phytate must be known to properly explain the effect of phytic acid on iron absorption. The overall meal composition must be considered to evaluate the effect of wheat bran on iron nutrition of humans. 

Phytic acid is inositol hexaphosphate. Analysis of the iron containing product isolated from the wheat bran extracts for inositol, phosphorus and iron gave molar ratios of 0.97 6.26 1, respectively, corresponding to a theoretical ratio of 1 6 1 for monoferric phytate. The isolated product exhibited a characteristic absorption spectrum in the 200- to 320-nm range (Figure 1) that corresponded to the spectrum for synthetic monoferric phytate. The Mbssbauer spectra (Figure 2) of the iron in wheat bran and of synthetic monoferric phytate also correspond (8). 

Each meal included two-bran muffins that contained 6 g each of either whole bran or dephytinized bran (36 g of bran consumed each day). The bran was milled from a single lot of hard red spring wheat and one-half was dephytinized by action of the endogenous phytase. The mean iron intake was 18.2 mg per day, approximately one-third in the muffins. Phytic acid intakes were 2.0 and 0.2 g per day, respectively, when whole bran muffins or dephytinized bran muffins were consumed, but there was no difference in neutral detergent fiber intakes, 17 g per day. 

Lolas, G.M. N. Palamidas P. Markakis. The phytic acid—Total phosphorus relationship in barley, oats, soybeans and wheats. Cereal Chem. 1976, 53, 867-871. 

Phytic acid (Figure 4.3) is the hexaphosphoric ester of me o-inositol. The affinity of ferric iron for phosphoric anions, already described in connection with the ferric casse mechanism, is responsible for calcium phytate s effectiveness in eliminating iron from red wines. Under these conditions, phytic acid produces a mixed calcium-iron salt, known as Calciphos, with the following composition Ca, 20%, P, 14% and Fe +, 2%. This mixed salt is not very soluble in water and easily precipitates, thus eliminating the excess ferric iron. Phytic acid is very widespread in plants. It acts as a phosphorus reserve, located in the seed coat, i.e. in wheat, rice and corn bran. Wheat bran may be used directly to eliminate iron from wine. 

Phytic acid removal Lentinula edodes Wheat bran [45]... 

The high concentration of iron and calcium in tobacco fiber would be desirable from a nutritional viewpoint. The bloavall-abillty of mineral elements in dietary fibers has been discussed in the literature ( ). Aside from fiber per se, phytic acid was found to be the major determinant of bivalent metal deficiencies (21). Phytate content is high in wheat bran and other... 

In his Natural History (1826), Pliny the Elder stated that those persons who are dieted npon fermented bread are stronger in body , which is an early statement on the health benefits of sourdough breads. Whole meals of cereals are a good source of minerals. Their bioavailability is limited, as they are often bound to phytic acid (myo-inositol-hexophospate). Wheat and rye contain about 1.2% of dry matter (Fretzdorff Briimmer, 1992). With the drop in pH during sourdough fermentation, endogenous phytases of the cereals are activated and the bound minerals are released (Fretzdorff Briimmer, 1992). Lactic acid bacteria and yeasts also possess phytase... 

In wheat, the element P is present as Ca and Mg salts of phytic acid, KH2PO4, B vitamins and relatively minor quantities of phospholipids and nucleic acids. Some typical phytic acid contents are indicated in Table 12.23. In bran and nnts most of the P is present as phytic acid salts. Although phytates (inositol phosphates) are believed to have some nutrient value, they form complexes with essential trace metals such as Zn and Fe making them less available for nutritional purposes [57]. 

Diets based on unleavened wheat bread contain a relatively large amount of phytic acid (inositol hexaphosphate), which can bind calcium, iron and zinc to form insoluble complexes that are not absorbed. Phytases in yeast catalyse dephosphorylation of phytate to products that do not chelate the minerals. 

There is no consistent information on the influence of fibre on the resorption of iron and other minerals. Many studies have focused on the effect of fibre added to food or food with a high proportion of fibre. Cereal fibre contains fairly high amounts of phytic acid, so in these cases it is not possible to distinguish between the effect of fibre and the phytate effect. When the effect of wheat fibre itself on iron resorption was observed in rats (experimental and control diet contained the same concentrations ofphytates and various amounts of fibre), there were no differences in iron resorption. Fibre itself does not affect iron resorption, but the combined effect of fibre and... 

Table 6.9 Utilisable energy, calcium, zinc and phytic acid contents and values for phytate Zn and Ca x phytate/Zn in wheat products.

---