In this study, the effect of external treatment conditions [i.e., heat treatment conditions, storage conditions, pH, and high-intensity ultrasound (HIU)] on the stability of low-density lipoprotein (LDL) in egg yolk plasma modified by phospholipase A(2) (PLA(2)) was studied. Asymmetrical flow field-flow fractionation (AF4) coupled with ultraviolet-visible (UV/Vis), multiangle light scattering (MALS) and differential refractive index (dRI) detectors was employed for the analysis of LDL modified with PLA(2). The AF4 results show that PLA(2) modification enhanced the stability of LDL in terms of heat treatment and -18 degrees C storage. However, the extent of aggregation of PLA(2)-modified egg yolk plasma with HIU treatment (400 W for 10 min) was larger than that of raw egg yolk plasma, and the stability decreased. Alkaline condition (i.e., pH 10) promoted the aggregation of egg yolk plasma regardless of modification with PLA(2). The increased knowledge of how external factors studied in this work affect the stability of PLA(2)-modified LDL could increase the understanding and controlling of properties of the food made of the egg yolk.