A COMPARATIVE EVALUATION OF THE STABILITY OF APPLE ACID COMPLEXES AND SOYA OIL PHOSPHOLIPIDS WITH IRON AND COPPER IONS

The effectiveness of hydration, which is the first stage of refining vegetable oils, depends primarily on the ability of the hydrating agent to convert nonhydratable phospholipids into their hydratable forms. The latter are complex compounds with polyvalent metal ions. Iron and copper ions have a negative effect on the quality of hydrated oils and the resulting lecithins, as their resistance to oxidation reduces. Malic acid solutions can be used as a hydrating agent.
The complexation process of malic acid with iron and copper ions was studied by potentiometric titration. It was established that the introduction of iron and copper ions into the malic acid solution led to a decrease in pH values, which indicated the presence of complexation in these systems. It was established that malic acid with iron ions formed more stable complexes compared to copper ions. It was shown that the stability of complexes of malic acid with iron ions of [MeL2] type and copper ions of [MeL] type, formed in the system in the maximum amount, was significantly higher than the stability of the complex compounds of phosphatidylserines, phosphatidylinositols and phosphatidic acids with these ions. Comparison of the stability constants of complexes of iron and copper ions with succinic and malic acids showed that «Me – malic acid complexes» were more stable. Thus, the obtained results allow us to recommend aqueous solutions of malic acid as a hydrating agent for hydration of phospholipids from vegetable oils.

vegetable oils, lecithins, hydration, phospholipids, metal ions, malic acid, complexation, stability constants

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