Regulation of water and oil absorption of whey protein aerogels by gel parameter control: Exploring structure-function relationship

Whey protein aerogels were prepared via supercritical CO₂ drying to investigate the effects of gelation conditions on their water/oil absorption behavior, and the structure–function relationship. Gelation temperature, pH and protein concentration all significantly affected the absorption capacities ( p < 0.05), with pH being the most influential factor. Accordingly, hydrophilic (HPAG) and oleophilic (OPAG) aerogels with tailored adsorption selectivity were constructed. Their overall preparation conditions were similar, whereas OPAG required lower gelation pH and temperature. Their adsorption kinetics fitted well to exponential models: biexponential for water absorption and monoexponential for oil absorption. Compared with OPAG, HPAG exhibited a more open porous structure with larger specific surface area (160.17 vs. 78.50 m 2 /g), pore volume (0.78 vs. 0.32 cm 3 /g), and average pore diameter (18.96 vs. 15.61 nm), as well as higher protein denaturation extent. These results demonstrate that gelation conditions regulate adsorption performance by synergistically modulating protein conformation and pore structure. • Whey protein aerogels were prepared using the supercritical CO₂ drying. • Effects of gelation conditions on the properties of aerogels were investigated. • Water/oil absorption behavior of aerogels can be described by the exponential model. • Aerogels' adsorption depends on synergy of molecular conformation and porous structure. • Oleophilic aerogels exhibit superior thermal stability and mechanical strength.