The influence of lyophilisation on the stability and structural properties of egg yolk granules and prepared emulsion

Non-lyophilised and lyophilised egg yolk granules (EYG) were analysed using small-angle X-ray scattering. The results showed that the peak at 0.19 Å -1 in the scattering curves disappeared after lyophilisation, indicating the loss of low-density lipoprotein from the granules. At the same time, the Porod slope became steeper, suggesting sharper protein-water interfaces. Enhanced hydration was further confirmed by the higher hydrodynamic radii obtained from dynamic light scattering measurements, which reflect increased water association or swelling of the particles. Additionally, the zeta potential decreased, indicating reduced colloidal stability and increased interfacial activity. The stability of emulsions at 1.5, 3, and 10 % concentrations of both non-lyophilised and lyophilised EYG was investigated using backscattering analysis over 24 hours, following testing of a broader range of concentrations. Backscattering stability indices showed that lower concentrations experienced a faster rate of stabilisation change, while higher concentrations demonstrated better stability. Lyophilisation improved stability at higher concentrations, as evidenced by confocal microscopy and SDS-PAGE results. These findings offer insights into the structure-function processing relationships of EYG and their potential applications in emulsions. • Lyophilisation dissociated the egg yolk granules low-density lipoprotein structure • Lyophilisation impacted the HDL structure expansion and reduction of surface charge • Lyophilised EYG acted as a good stabiliser, especially at higher concentrations • Lyophilised EYG yielded hydrocolloids with excellent emulsifying capabilities