Modification of liquid egg yolk with phospholipase A2 ‐hydrolyzed yolk granules: thermal stability and interfacial characteristics

Abstract BACKGROUND Thermal treatment of liquid egg yolk promotes lipoprotein denaturation and aggregation, resulting in increased viscosity and impaired emulsifying properties. This study investigated whether phospholipase A2‐hydrolyzed egg yolk granules (PLA2‐HEYG) could improve the thermal stability and interfacial functionality of recombined egg yolk liquid. RESULTS Native egg yolk was recombined with 0–200 g kg −1 PLA2‐HEYG and heated at 75 °C for 7 min. Increasing the PLA2‐HEYG level reduced the apparent viscosity of both unheated and heated samples and progressively suppressed heat‐induced aggregation. After heating, the volume‐weighted mean particle diameter D [4,3] decreased from 904.163 μm in the control (TH0) to 5.764 μm and 2.207 μm at 150 and 200 g kg −1 PLA2‐HEYG, respectively, corresponding to decreases of 99.36% and 99.76%. Confocal microscopy further showed fewer large aggregates at higher PLA2‐HEYG levels. The addition of PLA2‐HEYG also reduced the contact angle and interfacial tension, indicating improved interfacial properties. After heating, emulsifying capacity increased with PLA2‐HEYG addition; the sample containing 200 g kg −1 PLA2‐HEYG reached 111.25 mL, comparable to unheated native egg yolk (110 mL) and 51.36% higher than the heated control. Emulsifying stability also increased with PLA2‐HEYG addition, whereas emulsifying activity increased at lower addition levels and then decreased slightly. CONCLUSION Incorporating PLA2‐HEYG, particularly at 150–200 g kg −1 , effectively suppressed heat‐induced aggregation and preserved the interfacial and emulsifying functionality of liquid egg yolk during thermal treatment, demonstrating its potential for improving the thermal processability of egg yolk products. © 2026 Society of Chemical Industry.