Abstract: To further enhance the functional properties of octenyl succinic anhydride (OSA) starch, a sequential modification process involving lysozyme (Ly) glycosylation (OSA-Ly) followed by fibrillation (OSA-Lyx) was employed. The structural characteristics and interaction mechanisms of the OSA-Lyx complex were systematically elucidated. Fourier transform infrared (FT-IR) spectroscopy revealed enhanced stretching vibrations of C–N and C=O bonds, confirming successful OSA-Ly binding. Circular dichroism (CD) spectroscopy indicated a substantial decrease in the proportion of α-helix and a marked increase in the proportion of β-sheet structures following OSA-Ly glycosylation and fibrillation reactions. Intrinsic fluorescence spectroscopy and surface hydrophobicity results indicated that the fibrillar structure of OSA-Lyx was primarily driven by hydrophobic interactions. Compared with OSA starch and OSA-Ly, OSA-Lyx exhibited the highest emulsifying activity (80.57 m2/g) and emulsion stability (85.59 min). High-internal-phase emulsions (HIPEs) prepared with OSA-Lyx as an emulsifier possessed smaller particle sizes and maintained high structural stability after centrifugation and heat treatment. This enhanced stability is attributed to the fibrillar network of OSA-Lyx, which forms a more robust interfacial layer at the oil-water interface, effectively preventing droplet coalescence and resisting aggregation.

Key words: octenyl succinic anhydride starch; lysozyme; glycosylation; fibrillation; emulsifying properties