Dialyzability of minerals in corn masa gruel (atole) fortified with different iron compounds: effects of ascorbic acid, disodium EDTA, and phytic acid.

Background: Lime-treated corn gruel (atole) is a common weaning food in iron-deficient populations, especially in Mexico and Central America, and is a potential vehicle for fortification with iron.
Objective: The objective of this study was to screen promising iron compounds for use in the fortification of atole, using in vitro enzymatic digestion-dialysis techniques, while also considering their response to known iron absorption enhancers and inhibitors.
Methods: Atole, unaltered or preincubated with phytase, was fortified with iron (10 mg/L) from ferrous sulfate, ferrous bisglycinate, or ferrous fumarate, or with ferric chloride, ferric ammonium citrate, or ferric sodium ethylenediaminetetraacetic acid (NaFeEDTA), and submitted to in vitro digestion. Dialysis of calcium, copper, iron, phosphorus, and zinc (analyzed by inductively coupled plasma atomic emission spectrometry) was measured when atole was fortified with iron compounds alone or together with ascorbic acid or disodium ethylenediaminetetraacetic acid (Na2EDTA).
Results: Iron dialyzability was higher with NaFeEDTA (p < .05) than with all other iron compounds, which did not differ among themselves in iron dialyzability. Addition of ascorbic acid had no significant effect on iron dialysis, whereas Na2EDTA enhanced iron dialyzability by 7 to 10 times in unaltered atole and 15 to 20 times in phytase-preincubated atole (p < .05). Addition of Na2EDTA always increased intrinsic zinc dialyzability, and most of the time this increase was significant. Phytase pretreatment generally increased mineral dialysis.
Conclusions: Adding EDTA (either as NaFeEDTA or as Na2EDTA) to atole can increase the dialyzability of ferrous and ferric iron compounds and enhance the dialyzability of intrinsic zinc without any negative effects on calcium, phosphorus, or copper dialysis.