Influence of ultrasound on the mechanism of conjugation between epigallocatechin gallate and β-lactoglobulin for function improvement

Epigallocatechin-3-gallate (EGCG) can improve functional properties of beta-Lactoglobulin (beta Lg) by conjugation. The effects of ultrasound, a useful tool in improving the conjugation efficiency, on the various functional properties of beta Lg-EGCG conjugates were investigated in this study. Results revealed beta Lg-EGCG conjugates transformed from cross-linked state to fragments of various forms with ultrasound treatment with increased of binding affinity. Meanwhile, ultrasound increased secondary structural changes in beta Lg in the conjugated state. Functionally, ultrasound decreased the immunoglobulin E (IgE) combing capacity of beta Lg and enhanced its antioxidant properties by promoting the interaction between EGCG and beta Lg. Moreover, ultrasound induced an increase in hydrodynamic diameter and lowered the absolute zeta potential of beta Lg-EGCG conjugates, resulting in an increase in digestibility, as well as foaming and emulsification abilities, while, a decrease in thermal stability. The results provide valuable information for obtaining beta Lg with better functional properties for industrial production by ultrasound-assisted covalent binding of EGCG with beta Lg.

Automated summary

This study investigated the effects of ultrasound on the functional properties of beta-Lactoglobulin (beta Lg)-Epigallocatechin-3-gallate (EGCG) conjugates. The results showed that ultrasound treatment improved the properties and functions of the conjugates, as well as promoted the interaction between EGCG and beta Lg.