Under others 95) for the degradation oxidation, a rate constant not significantly of total soybean PLs was 0.056/d, which was different from that under iron-catalyzed autoxida- tion. PI showed a significantly (P< 0.05) higher degradation rate (0.078/d) than PC (0.053/d) or PE (0.046/d). This result is con- flicting with the result in iron-catalyzed oxidation, and could be attributed to a mechanistic difference between iron-catalyzed ox idation and chlorophyll-photosensitized oxidation. Radicals such ch as alkyl radical and peroxy radical are important factors in iron- catalyzed oxidation, and radical scavenging by hydrogen donation in action mechanism of PLs as antioxidants. Hydrogen d is a Cho nation to alkyl radicals of lipids by PLs results in their own Ch and thus PE with a higher hydrogen-donating capability than PI could be degraded faster. On the contrary, singlet oxygen production is important in chlorophyll-photosensitized oxidation hich may be affected by charged molecules. Charged groups in PLs contribute to fast adsorption of PLs to the oil/water in- Garti terface, formation of swollen lamellar structures, and electrostatic D repulsion (Rydhag and Wilton 1981), resulting in a less resistive Hida interfacial film in emulsions. This, in turn, can cause high oxy- H gen diffusion into the oil. Under neutral pH conditions, PC and PE act as ampholytes, which contain both a negatively charged phosphate group and positively charged choline or ethanolamine, Judde B whereas PI contains only a negatively charged phosphate group nd uncharged inositol (Bosanac and others 2004; Wang and Wang 80 2008). Therefore, oxygen diffusion into the oil in emulsion is in creased by PI compared to PC or PE, causing higher production Koo l of singlet oxygen. This could have resulted in higher contact of PI than PC or PE with singlet oxygen, causing its faster degradation The antioxidant activity of PC during oxidation of water-in-oil Kristi microemulsion in the presence of chemically produced singlet o en was attributed to the reaction between PC and singlet oxygen chemical quenching (Lee and Choe 2008). The singlet oxygen L roniec and quenching rate by PC was reported to be 10 /M/s (B others 2011). There was no significant difference in degradation rate between PO and PE during chlorophyll-photosensitized oxi Mo dation, which was a similar result to that of wheat bran oil during photooxidation (Choi and Choe 2009)