Cryogenic ultrasound-assisted ethyl acetate extraction enables selective defatting of egg yolk powder with enhanced...

Current defatting techniques for egg yolk powder (EYP) remain constrained by protein denaturation, non-selective phospholipid loss, and low process efficiency. To overcome these challenges, a cryogenic ultrasound-assisted ethyl acetate extraction method was developed to preferentially remove neutral lipids and enrich phospholipids within 15 min. Under the optimized conditions (0 °C, 320 W, 15 min, solid-to-solvent ratio of 1:5, w/v), the treatment reduced total lipids by 36.58% and increased the phospholipid content in the defatted powder to 19.2%, corresponding to a markedly higher phospholipid-to-total lipid ratio than that achieved by conventional ethanol defatting (E-EYP). The observed compositional and functional changes suggest that ultrasound cavitation may facilitate the loosening of protein-lipid aggregates and solvent penetration, while ethyl acetate is likely to preferentially extract neutral lipids because of polarity compatibility. In addition, operation at 0 °C may have limited phospholipid co-extraction and reduced thermal perturbation of proteins, which is consistent with the improved functional properties of the resulting powder. Compared with E-EYP, the ultrasound-treated powder showed higher solubility and improved emulsifying properties. Overall, this rapid and low-temperature strategy provides a practical route to produce phospholipid-enriched defatted egg yolk powder for emulsion-based food applications.