Comportamento do ácido fítico na presença de Fe(II) e Fe(III)

Quirrenbach, Hanna Raquel; Kanumfre, Francieli; Rosso, Neiva Deliberali; Filho, Marco Aurélio Carvalho

doi:10.1590/s0101-20612009000100005

Cited by 19 publications

(9 citation statements)

References 17 publications

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“…The results suggest the storage of ferrous iron, possibly as Fe(II) phytate. Recently, phytic acid has been reported to sequester both Fe(II) and Fe(III) (Quirrenbach et al , 2009; Bretti et al , 2012a,b). The present results showed that most of the Fe(III) was in association with O and P. About 19% of trivalent iron was found in coordination of O and S. The results agree with the fact that P and S are major constituents of iron-binding compounds in grains.…”

Section: Discussionmentioning

confidence: 99%

Pattern of iron distribution in maternal and filial tissues in wheat grains with contrasting levels of iron

Singh

Vogel‐Mikuš

Arčon

et al. 2013

Journal of Experimental Botany

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Iron insufficiency is a worldwide problem in human diets. In cereals like wheat, the bran layer of the grains is an important source of iron. However, the dietary availability of iron in wheat flour is limited due to the loss of the iron-rich bran during milling and processing and the presence of anti-nutrients like phytic acid that keep iron strongly chelated in the grain. The present study investigated the localization of iron and phosphorus in grain tissues of wheat genotypes with contrasting grain iron content using synchrotron-based micro-X-ray fluorescence (micro-XRF) and micro-proton-induced X-ray emission (micro-PIXE). X-ray absorption near-edge spectroscopy (XANES) was employed to determine the proportion of divalent and trivalent forms of Fe in the grains. It revealed the abundance of oxygen, phosphorus, and sulphur in the local chemical environment of Fe in grains, as Fe-O-P-R and Fe-O-S-R coordination. Contrasting differences were noticed in tissue-specific relative localization of Fe, P, and S among the different genotypes, suggesting a possible effect of localization pattern on iron bioavailability. The current study reports the shift in iron distribution from maternal to filial tissues of grains during the evolution of wheat from its wild relatives to the present-day cultivated varieties, and thus suggests the value of detailed physical localization studies in varietal improvement programmes for food crops.

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Section: Discussionmentioning

confidence: 99%

Pattern of iron distribution in maternal and filial tissues in wheat grains with contrasting levels of iron

Singh

Vogel‐Mikuš

Arčon

et al. 2013

Journal of Experimental Botany

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“…39 Phytates interact strongly also with iron(III) ions and play an important role in biologically-relevant processes as described in numerous papers. 8,35,[40][41][42][43][44] Complexation of iron(III) ions with phytate show different behavior than alkaline or alkaline earth cations. Three distinct EPs are detected on titration curves of phytic acid in the presence of various amounts of Fe 3+ ions (Fig.…”

Section: +mentioning

confidence: 99%

Potentiometric Determination of Phytic Acid and Investigations of Phytate Interactions with Some Metal Ions

Marolt

Pihlar

2015

ACSi

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Dedicated to the memory of Prof. Dr. Jurij Bren~iÃ bstract Determination of correct amount (concentration) of phytic acid is of vital importance when dealing with protonation and/or metal complexation equilibria. A novel approach for precise and reliable assay of phytic acid, based on the difference between end points by potentiometric titration, has been presented. Twelve phytic acid protons are classified into three groups of acidity, which enables detection of 2 to 3 distinct equivalent points (EPs) depending on experimental conditions, e.g. counter-ion concentration. Using the differences between individual EPs enables correct phytate determination as well as identification of potential contamination and/or determination of initial protonation degree. Impact of uncertainty of phytate amount on the calculation of protonation constants has been evaluated using computer simulation program (Hyperquad2013). With the analysis of titration curves different binding sites on phytate ligand have been proposed for complexation of Ca 2+ and Fe 3+ ions.

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“…The resultant solution was colorless and became brown. Quirrenbach et al (2009) report the degree of interaction of phytic acid with metal ions Fe (II) and Fe (III). In the cited study it was found that phytic acid, both in solution and in the solid state, interacts strongly with the metal ions Fe (II) and Fe (III).…”

Section: Introductionmentioning

confidence: 99%

Study of thermal behavior of phytic acid

Daneluti

Matos

2013

Braz. J. Pharm. Sci.

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Phytic acid is a natural compound widely used as depigmenting agent in galenic cosmetic emulsions. However, we have observed experimentally that phytic acid, when heated to 150 o C for around one hour, shows evidence of thermal decomposition. Few studies investigating this substance alone with regard to its stability are available in the literature. This fact prompted the present study to characterize this species and its thermal behavior using thermal analysis (TG/DTG and DSC) and to associate the results of these techniques with those obtained by elemental analysis (EA) and absorption spectroscopy in the infrared region. The TG/DTG and DSC curves allowed evaluation of the thermal behavior of the sample of phytic acid and enabled use of the non-isothermal thermogravimetric method to study the kinetics of the three main mass-loss events: dehydration I, dehydration II and thermal decomposition. The combination of infrared absorption spectroscopy and elemental analysis techniques allowed evaluation of the intermediate products of the thermal decomposition of phytic acid. The infrared spectra of samples taken during the heating process revealed a reduction in the intensity of the absorption band related to O-H stretching as a result of the dehydration process. Furthermore, elemental analysis results showed an increase in the carbon content and a decrease in the hydrogen content at temperatures of 95, 150, 263 and 380 °C. Visually, darkening of the material was observed at 150 °C, indicating that the thermal decomposition of the material started at this temperature. At a temperature of 380 °C, thermal decomposition progressed, leading to a decrease in carbon and hydrogen. The results of thermogravimetry coupled with those of elemental analysis allow us to conclude that there was agreement between the percentages of phytic acid found in aqueous solution. The kinetic study by the non-isothermal thermogravimetric method showed that the dehydration process occurred in two stages. Dehydration step I promoted a process of vaporization of water (reaction order of zero), whereas dehydration step II showed an order of reaction equal to five. This change in reaction order was attributed to loss of chemically bonded water molecules of phytic acid or to the presence of volatile substances. Finally, the thermal decomposition step revealed an order of reaction equal to one. It was not possible to perform the kinetic study for other stages of mass loss.Uniterms: Thermal analysis. Phytic acid/thermal behavior. Emulsion/stability. IR/dehydration. EA/thermal decomposition.O ácido fítico é um composto natural muito utilizado como despigmentante em emulsões cosméticas magistrais. No entanto, observou-se experimentalmente que o ácido fítico, quando aquecido a 150 °C durante cerca de uma hora, mostra evidências de decomposição térmica e que poucos estudos envolvendo essa espécie, isoladamente quanto a sua estabilidade, estão disponíveis na literatura. Esse fato motivou o estudo de caracterização e de comportamento térmico dessa espécie, ...

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Comportamento do ácido fítico na presença de Fe(II) e Fe(III)

Cited by 19 publications

References 17 publications

Pattern of iron distribution in maternal and filial tissues in wheat grains with contrasting levels of iron

Pattern of iron distribution in maternal and filial tissues in wheat grains with contrasting levels of iron

Potentiometric Determination of Phytic Acid and Investigations of Phytate Interactions with Some Metal Ions

Study of thermal behavior of phytic acid

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