title: Enzymatic degradation of phytate, polyphenols and dietary fibers in Ethiopian injera flours: effect on iron bioaccessibility.
abstract: The effect of removing phytate (IP6), iron-binding polyphenols, and dietary fibers on iron bioaccessibility in wheat-red sorghum (WrS) and teff-white sorghum (TwS) flour blends used in Ethiopia to make injera, a fermented pancake, was evaluated through the application of exogenous enzymes. Phytase treatment led to >90% reduction in IP6 and to an IP6:Fe molar ratio <1, but iron bioaccessibility was not improved (P > 0.05). Phytase + xylanase + cellulase (P + X + C) treatment increased iron bioaccessibility in TwS (non-detectableto1.6%) and WrS (1.9-3.2%), whereas phytase + polyphenol oxidase (P + PPO) treatment only showed improvement in the TwS blend. P + X + C + PPO treatment of the WrS blend increased the soluble non-dialysable iron fraction (6.7%) more than P + PPO treatment (3.9%). Although responses to enzyme treatments and iron bioaccessibility were matrix dependent, a positive effect of dietary fiber hydrolysis with X + C was obtained, irrespective of the blend. Dietary fibers had a negative effect on iron bioaccessibility independent of phytates.
authors.affiliation: Center for Food Science and Nutrition, Addis Ababa University, P.O. Box 150201, Addis Ababa, Ethiopia.
authors.forename: Kaleab
authors.initials: K
authors.lastname: Baye
authors.affiliation: IRD UMR 204 Nutripass, IRD/UM1/UM2, BP 64501, 34394 Montpellier Cedex 5, France.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Guyot
authors.affiliation: IRD UMR 204 Nutripass, IRD/UM1/UM2, BP 64501, 34394 Montpellier Cedex 5, France.
authors.forename: Christèle
authors.initials: C
authors.lastname: Icard-Vernière
authors.affiliation: IRD UMR 204 Nutripass, IRD/UM1/UM2, BP 64501, 34394 Montpellier Cedex 5, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Rochette
authors.affiliation: IRD UMR 204 Nutripass, IRD/UM1/UM2, BP 64501, 34394 Montpellier Cedex 5, France. Electronic address: claire.mouquet@ird.fr.
authors.forename: Claire
authors.initials: C
authors.lastname: Mouquet-Rivier
mesh_terms: D010832:6-Phytase / Q000737:chemistry; D055162:Biocatalysis; D002480:Cellulase / Q000737:chemistry; D004043:Dietary Fiber / Q000032:analysis* / Q000378:metabolism; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry; D005002:Ethiopia; D005285:Fermentation; D005433:Flour / Q000032:analysis*; D006801:Humans; D007501:Iron / Q000032:analysis / Q000378:metabolism*; D008954:Models, Biological; D010833:Phytic Acid / Q000737:chemistry* / Q000378:metabolism; D059808:Polyphenols / Q000737:chemistry* / Q000378:metabolism; D045868:Sorghum / Q000737:chemistry* / Q000378:metabolism
chemical_list: D004043:Dietary Fiber; D059808:Polyphenols; D010833:Phytic Acid; D007501:Iron; D010832:6-Phytase; D002480:Cellulase; D043364:Endo-1,4-beta Xylanases
keywords: Cellulase; Iron bioaccessibility; Phytase; Polyphenol oxidase; Sorghum; Teff; Wheat; Xylanase