Structural and textural enhancement of oleogels via l-lysine-mediated whey protein cryogel modification

To improve the suboptimal textural properties of oleogels prepared by the freeze-drying template method, this study introduced l-lysine (Lys) to optimize the structure of whey protein isolate cryogels (WPIC). Results demonstrated that Lys effectively induced conformational rearrangement of whey protein through electrostatic and hydrogen bonding interactions. This rearrangement was evidenced by significant secondary structure changes: β-sheet content increased from 31% to 33% and β-turn content from 22% to 33%. Lys incorporation also exposed hydrophobic residues, reducing hydrophilicity (24.8° to 38.85°) and promoting the formation of a denser network through cross-linking with WPIC molecules. This dense network effectively confines the oil phase, endowing the oleogel with superior viscoelasticity, enhanced mechanical strength, and improved thermal stability (the maximum mass loss temperature increased by 11 °Cwith 2% Lys compared to the control.). The application of this oleogel in bread making showed that a 50% replacement of butter achieved the most ideal texture.