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Commercial preparations of 6-phytase A alone and in combination with phytase B were used in rye breadmaking. Determination of bioavailability of myo-inositol phosphates from bread was performed by an in vitro digestion method followed by the measurement of an uptake by Caco-2 cells in culture. In bread supplemented with a combination of 6-phytase A and phytase B, a significant reduction in phytate content was observed from 3.62 μmol/g in the control to 0.7 μmol/g. Bioavailability of phytate estimated by an in vitro method simulating digestion in the human alimentary tract was 9% in the bread supplemented with phytase B, 7% (6-phytase A) and 50% in the control bread. In cell culture, the bioaccessibilities of inositol triphosphates from bread baked with the addition of 6-phytase A was higher by 36% as compared to the samples baked with phytase B and by 32% in breads baked with combination of both phytases.

Phytases of different origin were covalently bound onto Fe3O4 magnetic nanoparticles (12 nm). Binding efficiencies of all three phytases were well above 70% relative to the number of aldehyde groups available on the surface of the magnetic nanoparticles. Temperature stability for all three phytases was enhanced as a consequence of immobilisation, whereas pH dependence of enzyme activity was not affected. Maximum catalytic activity of the immobilised phytases was found at 60°C (rye), 65°C (Aspergillus niger) and 70°C (Escherichia albertii). The immobilised enzymes exhibited the same excellent substrate specificities and unique myo-inositol phosphate phosphatase activities as their soluble counterparts. However, the catalytic turnover number dropped drastically for the immobilised phytases. The amount of the desired partially phosphorylated myo-inositol phosphate isomer could be easily controlled by the contact time of substrate solution and immobilised enzymes. The immobilised phytases showed a high operational stability by retaining almost full activity even after fifty uses., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Abstract: Potentiometric, conductometric and 31P NMR titrations have been applied to study interactions between myo-inositol hexakisphosphate (phytic acid), (±)-myo-inositol 1,2,3,5-tetrakisphosphate and (±)-myo-inositol 1,2,3-trisphosphate with iron(III) ions. Potentiometric and conductometric titrations of myo-inositol phosphates show that addition of iron increases acidity and consumption of hydroxide titrant. By increasing the Fe(III)/InsP6 ratio (from 0.5 to 4) 3mol of protons are released per 2mol of iron(III). At first, phytates coordinate iron octahedrally between P2 and P1,3. The second coordination site represents P5 and neighbouring P4,6 phosphate groups. Complexation is accompanied with the deprotonation of P1,3 and P4,6 phosphate oxygens. At higher concentration of iron(III) intermolecular P–O–Fe–O–P bonds trigger formation of a polymeric network and precipitation of the amorphous Fe(III)–InsP6 aggregates. 31P NMR titration data complement the above results and display the largest chemical shift changes at pD values between 5 and 10 in agreement with strong interactions between iron and myo-inositol phosphates. The differences in T 1 relaxation times of phosphorous atoms have shown that phosphate groups at positions 1, 2 and 3 are complexated with iron(III). The interactions between iron(III) ions and inositol phosphates depend significantly on the metal to ligand ratio and an attempt to coordinate more than two irons per InsP6 molecule results in an unstable heterogeneous system. [Copyright &y& Elsevier]

Abstract: An integrated process was developed to hydrolyze the phytates in light steep water (LSW) and to simultaneously isolate inorganic phosphate (Pi) and myo-inositol products. The proposed integrated process will be helpful in resolving the environmental and nutritional concerns in the use of corn gluten feed (CGF) in the animal diets. This process comprised of partial and total hydrolysis of LSW and intermediate anion exchange separation technique. The phytates in LSW were initially degraded to negatively charged myo-inositol phosphates (InsP2–InsP5). The optimized experimental parameters for the partial hydrolysis of LSW were determined to be 2h hydrolysis with 1FTU Aspergillus niger/g substrate at 35°C. The negatively charged species of the partially hydrolyzed substrate were separated on a strong base anion exchange resin. The negatively charged species, retained by the resin, were eluded with 1M NaCl solution and were subjected to complete hydrolysis with the Escherichia coli, A. niger derived phytases and their respective combinations. The maximum amount of myo-inositol released from the anion exchange column was 3.73±0.03mg/NaCl elution which was detected after 48h reactions catalyzed by 100FTU E. coli, 150FTU E. coli, and 150FTU the combination of A. niger and E. coli. The time course of Pi released showed a similar trend to that of myo-inositol and the released Pi reached a maximum amount of 3.30±0.05mg/g NaCl elution after 48h incubation at the enzyme loadings for which the maximum concentration of myo-inositol were reached. [ABSTRACT FROM AUTHOR]

Abstract: Two myo-inositol phosphates, myo-inositol 1,2,3-tris(dihydrogen phosphate) and myo-inositol 1,2,3,5-tetrakis(dihydrogen phosphate), have been synthesised in several steps from myo-inositol (in Chem. Abstr.: d-myo-inositol) in the form of their sodium salts. They were shown to prevent iron-gall-ink decay in cellulose items at the same level as phytic acid dodecasodium salt. [Copyright &y& Elsevier]