title: Phytase-mediated mineral solubilization from cereals under in vitro gastric conditions.
abstract: BACKGROUND
  Enzymatic dephosphorylation of phytic acid (inositol hexakisphosphate) in cereals may improve mineral bioavailability in humans. This study quantified enzymatic dephosphorylation of phytic acid by measuring inositol tri- to hexakisphosphate (InsP3-6) degradation and iron and zinc release during microbial phytase action on wheat bran, rice bran and sorghum under simulated gastric conditions.
  
  
  RESULTS
  InsP3-6 was depleted within 15-30 min of incubation using an Aspergillus niger phytase or Escherichia coli phytase under simulated gastric conditions, with the two enzymes dephosphorylating cereal phytic acid at similar rates and to similar extents. Microbial phytase-catalyzed phytate dephosphorylation was accompanied by increased iron and zinc release from the cereal substrates. However, for wheat bran at pH 5, the endogenous wheat phytase activity produced mineral release equal to or better than that of the microbial phytases. No increases in soluble cadmium, lead or arsenic were observed with microbial phytase-catalyzed phytate dephosphorylation.
  
  
  CONCLUSIONS
  Microbial phytase treatment abated phytate chelation hence enhanced the release of iron and zinc from phytate-rich cereals under simulated gastric conditions. The data infer that acid-stable microbial phytases can help improve iron bioavailability from phytate-rich cereal substrates via post-ingestion activity. © 2015 Society of Chemical Industry.
authors.affiliation: Center for BioProcess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Soeltofts Plads 229, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Anne Vf
authors.initials: AV
authors.lastname: Nielsen
authors.affiliation: Center for BioProcess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Soeltofts Plads 229, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Anne S
authors.initials: AS
authors.lastname: Meyer
mesh_terms: D010832:6-Phytase / Q000378:metabolism*; D001234:Aspergillus niger / Q000201:enzymology*; D001682:Biological Availability; D050260:Carbohydrate Metabolism; D002614:Chelating Agents / Q000378:metabolism; D002523:Edible Grain / Q000737:chemistry*; D004926:Escherichia coli / Q000201:enzymology*; D041981:Gastrointestinal Tract; D006801:Humans; D066298:In Vitro Techniques; D007501:Iron / Q000378:metabolism; D008903:Minerals; D010758:Phosphorus / Q000378:metabolism; D010833:Phytic Acid / Q000378:metabolism*; D012995:Solubility; D014131:Trace Elements / Q000378:metabolism*; D014908:Triticum / Q000737:chemistry*; D015032:Zinc / Q000378:metabolism
chemical_list: D002614:Chelating Agents; D008903:Minerals; D014131:Trace Elements; D010758:Phosphorus; D010833:Phytic Acid; D007501:Iron; D010832:6-Phytase; D015032:Zinc
keywords: iron; phytate; rice; sorghum; wheat; zinc