Degradation of PLs in the canola oil emulsion with added s bean lecithin during iron-catalyzed or chlorophyll photosensitized oxidation followed a 1st-order kinetics (r 0.82). Rate constants (k value) for the 1st-order degradation of PLs were estimated by regression of the natural log (n) of the PL content ratio (LA]t/LAlo where [A]o and [A] are PL contents at oxidation times 0 and t respectively) against time, as shown in Table 3. A rate constant for the degradation of total soybean PLs during iron-catalyzed oxidation of the emulsion was 0.068/d, and the rate constants for PC, PE, and PI degradation were 0.065, 0.094, and 0.044/d respectively. Among soybean PLs, degradation of PE was signifi- cantly faster (P 0.05) than that of PC or Pl during iron-catalyzed oxidation. Lower stability of PE compared to PC was reported during autoxidation of wheat bran oil (Choi and Choe 2009)