show that both lipid and protein oxidation proceed in highly heterogeneous fashion in WPI-stabilized emulsions, which cannot be derived from bulk measurements of lipid oxidation products. We expect that our work will contribute to improving the understanding of local co-oxidation of lipids and proteins at droplet interfaces. (3) Then, masks and raw data were multiplied using MATLAB. (4) The average intensity of each droplet was used for further analyses, and the radius of the droplet was calculated from the number of pixels with the assumption of circle shape; r (radius, µm) = 0.12•√(Sum of pixel numbers / π), 1 pixel = 0.12 µm. ( ) Finally, we obtained a list of droplet numbers and radii with the average intensity per droplet. (6) To compare data obtained under different conditions over different days, the initial intensity was set to 1, and all other data points were divided by the average intensity of all droplets at day 0.