Relative contribution of phytates, fibers and tannins to low iron in vitro solubility in faba bean (Vicia faba L.) flour and legume fractions

Abstract

Purpose

The bioavailability of iron from faba bean is low because it is present as an insoluble complex with food components such as phytate, fiber and tannin. The purpose of this paper is to try to identify the nature of the complexes between anti‐nutritional factors and iron in faba bean and legume fractions by using simulations of gastro‐intestinal digestion.

Design/methodology/approach

To this aim, the authors evaluated the effect of the action of fiber‐ and/or phytate‐degrading enzymes on solubilization of iron from insoluble residues obtained after gastro‐intestinal digestion of faba bean flour and fractions.

Findings

In insoluble residues of raw faba bean flour, simultaneous action of cellulase and phytases made it possible to release about 28 percent units more iron than that released with the treatment without enzymes. About 49.8 percent of iron in raw faba bean flour was solubilized after in vitro digestion and simultaneous action of cellulase and phytase. In the residues of the hull fraction, a significant increase in iron solubility has not been seen (p>0.05) after action of cellulase or phytases. Simultaneous action of cellulase and phytase led to the release of more than 60 and 18 percent units of additional iron for residues of dehulled faba bean and hull fractions, respectively.

Originality/value

In dehulled faba bean, iron was chelated by phytates and fibers. In the hull of faba bean, a high proportion of iron was chelated by iron‐tannins, while the rest of iron was chelated in complexes between phytates and fibers.

Citation

Luo, Y. and Xie, W. (2013), "Relative contribution of phytates, fibers and tannins to low iron in vitro solubility in faba bean (Vicia faba L.) flour and legume fractions", British Food Journal, Vol. 115 No. 7, pp. 975-986. https://doi.org/10.1108/BFJ-11-2010-0204