Ultrasound-assisted preparation of lactoferrin-EGCG conjugates and their application in forming and stabilizing algae oil emulsions

DThe aim of this study was to prepare lactoferrin-epigallocatechin-3-gallate (LF-EGCG) conjugates and to determine their ability to protect emulsified algal oil against aggregation and oxidation. LF-EGCG conjugates were formed using an ultrasound-assisted alkaline treatment. The ultrasonic treatment significantly improved the grafting efficiency of LF and EGCG and shortened the reaction time from 24 h to 40 min. Fourier transform infrared spectroscopy and circular dichroism spectroscopy analyses showed that the covalent/non-covalent complexes could be formed between LF and EGCG, with the C--O and C-N groups playing an important role. The formation of the conjugates reduced the alpha-helix content and increased the random coil content of the LF. Moreover, the antioxidant activity of LF was significantly enhanced after conjugation with EGCG. LF-EGCG conjugates as emulsifiers were better at inhibiting oil droplet aggregation and oxidation than LF alone. This study demonstrates that ultrasound-assisted formation of protein-polyphenol conjugates can enhance the functional properties of the proteins, thereby extending their application as functional ingredients in nutritionally fortified foods.

Automated summary

This study aimed to prepare lactoferrin-epigallocatechin-3-gallate (LF-EGCG) conjugates and evaluate their ability to protect emulsified algal oil against aggregation and oxidation. The ultrasound-assisted alkaline treatment significantly improved the efficiency of conjugation and reduced the reaction time. The formation of LF-EGCG conjugates enhanced the antioxidant activity and emulsifying properties of LF, making it a promising ingredient in fortified foods.