Noncovalent interaction-driven self-assembly endows interfacial β-lactoglobulin amyloid fibrils with inhibitory activities against lipid-hydrolyzing enzymes.

Pancreatic lipase (PL) and cholesterol esterase (CE) are dominant lipid-hydrolyzing enzymes involved in the digestion and absorption of lipids, making them attractive targets for obesity prevention. β-lactoglobulin (β-LG) can transform into amyloid fibrils with potential inhibitory activity against PL and CE because of its amphiphilic and self-assembling properties. In this study, Dielectric Barrier Discharge atmospheric cold plasma treatment was employed to regulate the fibrillation process of β-LG (P-β-LGF) at three stages of fibril growth, namely, the initial stage (t0), the end of the lag phase (t0.1), and the exponential phase (t0.9). P-β-LGF exhibited enhanced β-sheet content, increased surface hydrophobicity, enhanced colloidal stability, and superior emulsifying and foaming properties. Furthermore, the elongated fibrillar morphology of P-β-LGF with a high aspect ratio and large specific surface area facilitated multivalent binding to the surface of enzymes, which resembled a "grape-on-a-vine" arrangement with enhanced inhibition at the oil/water interface. P-β-LGF exhibited competitive inhibition towards PL and mixed-type inhibition towards CE, indicating structure-specific enzyme inhibition mechanisms that collectively reduced lipid hydrolysis by interfacial behavior. Results demonstrated that P-β-LGF delayed in vitro lipid digestion by modulating enzyme activity effectively, indicating its potential as a functional ingredient for obesity management and lipid-lowering food applications.