Determination of bioavailable-zinc from biofortified wheat using a coupled in vitro digestion/Caco-2 reporter-gene based assay

作者：Salunke Rajani; Rawat Nidhi; Tiwari Vijay Kumar; Neelam Kumari; Randhawa Gursharn Singh; Dhaliwal Harcharan Singh; Roy Partha^*

来源：Journal of Food Composition and Analysis, 2012, 25(2): 149-159.

DOI：10.1016/j.jfca.2011.09.006

• Micronutrients
• Biofortification
• Bioavailability
• Aegilops derivatives
• In vitro digestion/Caco-2 model
• MTF1/MRE transactivation
• Food analysis
• Food composition

The zinc bioavailability from wheat-Aegilops derivatives and Triticum monococcum low phytic acid (lpa) mutants with varying zinc concentrations was assessed using a novel metal response element (MRE)-binding transcription factor-1 (MTF-1)/MRE luciferase reporter gene based transactivation assay in the coupled in vitro digestion/Caco-2 model. The zinc content in the genotypes studied ranged from 19 to 65 mu g/g. The bioavailability enhancement of zinc as determined from the luciferase response of MTF1/MRE transfected cells to cooked digests of biofortified derivatives and the lpa mutants was recorded as a 1.2-2.0 fold-increase, corresponding to 1.8-3.3 fold increases in the zinc content over the respective WL711-cultivar and T. monococcum wild-type controls. The strong positive and negative correlations observed for zinc bioavailability with respect to zinc content and phytate:zinc molar ratios in the derivatives (r = 0.74 and -0.76) as well as lpa mutants (r = 0.89 and -0.94) illustrate the significance of using these parameters in zinc biofortification programmes. Genotypes with phytate: zinc molar ratios of less than 15, with remarkably enhanced zinc bioavailability, were identified. This method could thus serve as a sensitive transactivation assay for a screening approach that could accurately rank bioavailability of zinc from biofortified staples for subsequent animal studies and advance select lines for human studies.

• 出版日期2012-3