The synergistic effects of condensed phosphates along with a mixed tocopherols concentrate (m-Toc) on the oxidative deterioration of margarine with iron (III) were investigated. Margarine was prepared from the aqueous phase with iron (III) chloride and condensed phosphates, and lard with vitamin A, β-carotene and m-Toc. Its stability toward oxidative deterioration was evaluated on the basis of change in POV and content of vitamin A and β-carotene during storage at 25°C.
1) The addition of sodium pyrophosphate by 0.05% inhibited the oxidation of margarine with iron (III) to some extent, and synergistically enhanced the antioxidant effect of m-Toc. However, further addition of it did not affect the antioxidant effect. Similar results were also obtained by adding sodium metaphosphate or sodium polyphosphate.
2) The condensed phosphates inhibited almost entirely the accelerating effect of iron (III) on the oxidative decomposition of vitamin A and β-carotene in margarine.
3) The remnant percentages of tocopherols in margarine indicated condensed phosphates to prevent the decomposition of tocopherols through their action as masking reagents for metallic ion.
