To sum up, in WPI-stabilized emulsions, both lipid and protein oxidation at the interface occurred faster in the polydisperse emulsion than in the monodisperse one (Figures & and &). This finding can be explained by both the differences in the emulsification process and the presence of smaller droplets, as we described in the previous section. Thus, our results can help to explain ambiguous outcomes of previous studies on the droplet size dependency of lipid oxidation, as different emulsification methods can lead to different droplet surface coverage and/or droplet size distributions. Unfortunately, our current data do not provide clear evidence of protein oxidation induced by lipid oxidation. Both oxidation mechanisms may occur independently, or the oxidation initiator (AAPH) does not only promote lipid oxidation but also protein oxidation at the interface.