[Phytic phosphorus and phytase activity in cereal-based infant formulas]. / Fósforo fítico y actividad de fitasa en fórmulas infantiles basadas en cereales.

Phytic acid is an organic acid present in cereal grains. The phosphorus inside its molecule (PPhy) is not available because of its low solubility, though the bioavailability could be increased by the activity of phytase enzymes (PhyA). With the purpose of quantifying the PPhy and PhyA in supplements manufactured from cereals and intended for lactating infants, five formulas of wide distribution in local markets were selected and identified depending on the main vegetable ingredients as A (rice), T (wheat), ATS (rice, wheat and soy isolate), ATM (rice, wheat and maize) and ATMS (rice, wheat, maize and soy isolate). Five samples were taken from each formula, each one corresponded to a commercial brand (400 to 500 g), coming from different batches and before their expiration date. The crude protein ranged from 7.2 to 16.8%, with de highest value for ATS and the lowest for T and ATM (P < 0.01). Ether extract varied from 0.31 to 0.75%, while the calcium: phosphorus ratio from 1.6 for ATM, to 1.1 for the rest. The PPhy was 61.5% of the total phosphorus in T, with differences (P < 0.01) compared to the other formulas (39.9 +/- 6.8%). PhyA was only detected in ATS, T and ATM (152, 300 and 570 U/kg, respectively). The chemical composition complied with the manufacturer report, with a high content of PPhy and PhyA associated to the wheat presence in the formula.