Calcium phytate

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. 

Two metabolic balance studies were conducted using healthy adult men to study the effect of phytate on bioavailability of dietary calcium. Dietary treatments were each 15 days in duration. In the first study, a mean daily calcium balance of 208+58 (SD) mg was observed when 2.0 g of phytate from 36 g of whole wheat bran was consumed daily with 1100 mg of calcium, phytate/calcium molar ratio 0.11. Calcium balance was 184+87 mg when 36 g of dephytinized bran was consumed with the same intake of calcium, phytate/calcium molar ratio 0.01. In the second study, calcium intake was 740 mg/day. 

Dietary intake data for calcium, phytate and phytate/calcium ratio are summarized in Table II. Mean calcium intake for HS-I was about 300 mg greater than the recommended dietary allowance (RDA) of 800 mg established for adults by the National Research Council (8) and for HS-II just slightly less than the RDA. The range of calcium intakes, because of different caloric needs was from 927 to 1490... 

Figure 4 illustrates the quantity of precipitate formed when equimolar concentrations of phytate, zinc and/or calcium (1 1 or 2 1) are mixed in an open vessel and pH s adjusted first to less than 3, than carefully to the appropriate pH. The pH range between 3 and 9 was selected to encompass the physiologically important range. The results indicate that 1) calcium and phytate, in equimolar concentration, are quite soluble at all pH s under these conditions 2) zinc phytate is less soluble than calcium phytate and at pH 6 is less soluble than calcium at twice the molar concentration 3) zinc, calcium and phytate in all combinations tested was less soluble than either zinc or calcium phytate or the sum of these alone at pH 6. The pH 6 is very important physiologically because this is the approximate pH of the duodenum and upper jejunum, an area of the gastrointestinal tract in which zinc must be absorbed. At pH 6 and a 2 1 1 calcium zinc phytate molar ratio, 98% of the zinc was in the precipitate (, 39). 

One compound around which there is notable ambiguity is myo-inositol hexa-kisphosphate. This commonly occurring organic phosphate is also known as phytic acid, although the term phytate is used for salt forms, and phytin is sometimes used to refer specifically to the calcium-magnesium salt. To avoid ambiguity, the term myoinositol hexakisphosphate is used throughout the book, unless reference is made to a specific salt form (e.g. calcium phytate). 

Potassium ferrocyanide treatment is restricted to white and rose wines, at least in France. Excess iron is eliminated from red wines using calcium phytate. 

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. 

Standard doses of calcium phytate, for example 20 g/hl, are sometimes recommended. At this concentration, the phytate never precipitates completely and, in spite of its low solubility, some of it remains in the wine. This is an unsatisfactory situation, although calcium phytate is quite harmless to health. 

As only Fe reacts with calcium phytate, the first stage in treatment is to aerate the wine by racking or injecting oxygen. It is then left to rest for four days, so that the ferric iron concentration reaches a maximum level. The wine must be protected by sulfuring at 3-5 g/hl to avoid extensive spoilage due to oxidation. At this concentration, SO2 does not prevent iron from oxidizing. 

White calcium phytate powder is dissolved in hot, concentrated, citric acid solution. The resulting solution is thoroughly mixed into the wine. The ferric phytate starts to flocculate a few hours later. Three to four days are necessary to complete the treatment. The wine should then be fined (with gelatin, casein or blood albumin) to ensure that all the colloidal ferric phytate flocculates and, finally, filtered. 

Calcium phytate is an efficient treatment for ferric casse in white, but above all red wines. Its effectiveness may be enhanced by adding citric acid or gum arabic (Section 4.6.3). If the above procedure is properly implemented, no residue is left in the wine, and so there can be no objections on health grounds. 

Calcium phytate treatment has been criticized for increasing the calcium content (20-30 mg/1). Its main disadvantage, however, lies in the fact... 

Citric acid (Section 4.6.3), gum arable (Sections 4.6.3, 9.4.3), ascorbic acid (Section 4.6.4 and Volume 1, Section 9.5.3), potassium ferrocyanide (Section 4.6.5), calcium phytate (Section 4.6.6)... 

Synonyms photophor diphosphide tricalcium Calcium Phytate... 

Calcium phosphorofluoridate. See Calcium monofluorophosphate Calcium phosphosilicate. See Calcium silicophosphate Calcium phytate CAS 7776-28-5... 

Hexabromodiphenyl. See Hexabromobiphenyl Hexabutyidistannoxane. See Tributyltin oxide Hexa C.B.. See Hexachlorobenzene Hexacalcium phytate. See Calcium phytate Hexacarbonyl chromium. See Chromium carbonyl... 

Phytic acid, sodium salt. See Sodium phytate Phyt iod. See Ethiodized oil Phytocalcium. See Calcium phytate Phytoderm Compiex U. See Usnic acid... 

Lithium oxidized polyethylene Polyethylene Polyethylene, high-density ink additive, lithographic Sodium 2-ethyl hexanoate ink corrosion treatment, iron-gall Calcium phytate ink mfg. 

Inositol-hexaphosphoric acid phytic acid salt source Calcium phytate phytic acid source Calcium phytate phytol source Chlorophyll pickling agent... 

Ammonium lignosulfonate sequestrant, wine Calcium phytate set time regulator, concrete Citric acid... 

C6H6Cae024P6 Calcium phytate CeHeCIN m-Chloroaniline o-Chloroaniline p-Chloroaniline C6H6CINNa02S Chloramine-B C6H6CI2N2... 

---