The Effect of Simulated Digestion on Element Speciation in Rye Flakes

To investigate element speciation in digested rye flakes, a simulated digestion using pig’s pepsin and pancreatin was performed at 37 °C. The digest was analyzed by SEC/ICP-MS (Superdex 75, 0.02 mol l-1 Tris-HCl buffer). Most elements in flakes are solubilized by enzymatic hydrolysis. P and Mo recoveries in SEC analysis of the digest approach to 100 %, those of Fe and Cu range from 60 to 80 % and that of Zn varies from 10 to 40 %. Ionic species or labile complexes were not recovered. The proportions of elements change as a result of enzyme digestion. No Fe is recovered in SEC analysis of flake extracts. Most Fe in the digest is bonded to a medium-molecular-weight fraction. Low-molecular-weight (<2 kDa) fractions with bonded Cu and Zn partly persist in the digest.