Revealing the oxidation mechanism of Antarctic krill oil induced by metal ion: Focusing on the influence of reverse micelles

Water-soluble copper (CuSO 4 ), oil-soluble copper and different amount of water were added to demetallized and dehydrated Antarctic krill oil (AKO) for accelerated storage. The results showed that water-soluble copper (100 μmol/kg oil) could not significantly promote the oxidation of dehydrated AKO. While water-soluble copper (100 μmol/kg oil) exhibited stronger prooxidative property than oil-soluble copper (100 μmol/kg oil) in AKOs adding water. Meantime, with prolonged storage time of AKO adding water, the size of reverse micelle increased, the electronegativity and surface tension of the oil-water interface decreased, and adding water-soluble copper ions aggravated the above changes. Therefore, it was speculated that Cu 2+ is adsorbed to the oil-water interface by the action of electric charge to promote the oxidation of phospholipids containing unsaturated fatty acids (UFAs) and free UFAs present at the interface by initiating the free radical chain reaction, thereby accelerating the oxidation of AKO.