In vitro hydrolysis of phytate at 95°C and the influence of metal ion on the rate

The in vitro hydrolysis of phytate at 95·C across the pH range 1–12 is reported. The reaction is slow. The first order rate constant varied from 3·98 × 10−4 min−1 at pH 1 to 0·28 × 10−4 min−1 at pH 12 with a maximal value of 8·74 × 10−4 min−1 at pH 4. The reaction is very similar in rate and profile to that of a phosphoric acid ester anion, [(RO)PO3H]−1. The 12 metal ions tested had little influence on the hydrolysis reaction although the phytate: metal ion ratio was necessarily high because of the insolubility of phytate metal salts at lower ratios.