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

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.