MINERAL CATIONS AFFECT MICROSTRUCTURE OF EGG-YOLK GRANULES

Granule dialysis caused partial release of calcium and breakage of the granular structure. In the presence of sodium chloride, sodium replaced calcium bound to the proteins and destabilized the structure of granules. By contrast, iron binding was not modified by the presence of sodium. EDTA bound all the cations, broke the phosphocalcic bridges and destabilized the structure. On the other hand, the addition of bivalent or trivalent cations at low concentration strengthened the structure which resisted changes in pH or ionic strength. All data showed the importance of ionic bridges (especially phosphocalcic bridges) in the association of LDL, lipovitellin and phosvitin in the form of spherical structures.