Hesperidin (HES) is a citrus flavanone glycoside with promising bioactivities but limited aqueous solubility, which restricts its utilization in food systems. Here, a solvent-free pH-driven strategy was developed to encapsulate HES using ovalbumin (OVA) as a protein carrier, and the structural responses and antioxidant performance of the resulting OVA-HES systems were systematically evaluated at the alkaline driving stage (pH 12) and after neutralization (pH 7). Encapsulation efficiency (EE) increased monotonically at pH 12 and reached 74.75% at 0.8 mg/mL HES, whereas EE exhibited a bell-shaped dependence after neutralization and peaked at 51.64% at 0.6 mg/mL. Fluorescence quenching, Stern-Volmer analysis and docking collectively supported complex formation dominated by static quenching and multiple hydrogen-bond interactions, with stronger binding at pH 12 (K = 49.3 × 10¹⁰ L/mol) than at pH 7 (K = 3.45 × 10¹⁰ L/mol). Moderate HES loading enhanced free sulfhydryl exposure (maximum at 0.6 mg/mL) and improved 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) cation radical scavenging ability, with a peak value of 64.51% at pH 7. Fourier transform infrared spectroscopy, water-holding capacity, low-field nuclear magnetic resonance, and scanning electron microscope analyse further indicated that intermediate HES levels (0.4–0.6 mg/mL) promoted a denser and more continuous gel network, whereas excessive HES induced heterogeneous aggregation and reduced water retention. Overall, this work demonstrates a pH- and dosage-dependent route for incorporating HES into OVA matrices and provides mechanistic insights for designing antioxidant protein gels via solvent-free encapsulation.

As a high nutritional value egg processing product, egg yolk powder has a wide range of applications, However, its emulsification is affected by the processing conditions and is not satisfactory, which limits its wide application in the food industry. Based on this, this paper presents a systematic review of emulsification modification techniques for egg yolk powder, including physical, chemical, and enzyme modification techniques, to improve its emulsification properties and processing adaptability, and to provide a reference for solving such problems. The characteristics of various modification methods were analysed and compared. Future research should focus on optimising the modification process, gaining a deeper understanding of the modification mechanism and developing more mechanisms for the joint application of modification techniques, to maximise the application potential of egg yolk powder and to meet the growing and diversified needs of the food industry.