Mechanistic insights into heat-induced emulsion destabilization of key fractions in egg yolk: Betaine-mediated suppression of thermal aggregation

This study aims to investigate the effects and mechanisms of EY fractions and betaine on thermal stability and emulsifying property. Rheological results illustrated that granules exhibited a 41.22 °C higher thermal aggregation temperature than plasma, betaine raised the thermal aggregation temperatures of plasma and granules by 10.18 °C and 11.88 °C, respectively. ζ-potential measurements demonstrated inherent electrostatic interactions between plasma and granules, and the charge in granules was stronger. Plasma displayed excellent solubility and emulsifying activity, whereas granules predominantly maintained emulsifying stability. Betaine enhanced hydrogen bond interactions, stabilizing protein structures. SDS-PAGE analysis suggested that thermal-induced destabilization of EY fractions might involve γ-livetin or apo-LDL in plasma. In conclusion, betaine effectively retarded heat-induced aggregation of key EY fractions (plasma) and sustain interfacial stability. This study advances understanding of thermal aggregation behavior at the EY fraction level, and provides new insights into modulating thermal aggregation and extending emulsifying properties in food applications