Dioleylphosphatidylcholine increases the antioxidant properties of ascorbyl palmitate in bulk oils compared to other hydrophilic and lipophilic antioxidants.

Effects of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and moisture on the solubility of hydrophilic and lipophilic antioxidants were evaluated in medium-chain triacylglycerol (MCT) by 2,2-diphenyl-1-picrylhydrazyl (DPPH) reactivity. Next, we assessed the oxidative stability of antioxidant-containing corn oil depending on the presence of DOPC. The critical micelle concentration (CMC) of DOPC decreased when the moisture content was increased from 300 to 495 mg/kg oil and gradually increased when the moisture was further increased to 2122 mg/kg oil. As the DOPC concentration increased, the DPPH reactivity of ascorbyl palmitate in the control MCT increased by 10.23-fold, whereas that of the ascorbic acid and α-tocopherol was slightly affected both by the DOPC and moisture content. Presence of DOPC significantly increased the oxidative stability of ascorbyl palmitate-containing corn oil (p < 0.05), whereas these synergistic antioxidant effects were not observed in ascorbic acid-or α-tocopherol-containing corn oil. In conclusion, DOPC displays a synergistic antioxidant effect with ascorbyl palmitate in bulk oil.