Interactions between the protein-epigallocatechin gallate complex and nanocrystalline cellulose: A systematic study

Abstract

In this work, the noncovalent interactions between the protein-epigallocatechin gallate (protein-EGCG) complex and nanocrystalline cellulose (NCC) were systematically investigated. Rheological properties, including large amplitude oscillation shear (LAOS), transient rheology, and conventional rheology of the mixture were also evaluated. As obtained, flexible myofibrillar protein-epigallocatechin gallate (MP-EGCG) and rigid ovalbumin-epigallocatechin gallate (Ova-EGCG) follow different rules in the stability of the regulatory system because of the difference in noncovalent interactions, triggering different rheological responses of the complexes. Additionally, MP-EGCG/NCC showed an obvious strain overshoot during LAOS flow, which could not be obtained in Ova-EGCG/NCC. Notably, the fibrous MP-EGCG network was the factor that dominated the formation of a more stable suspension system with strong hydrogen bonding, dipole-dipole interactions and/or van der Waals forces. This study can provide some ideas for the future study of the interaction between protein-polyphenol complexes and polysaccharides.

Keywords: Atomic force microscopy (AFM); Large amplitude oscillatory shear (LAOS); Microstructure; Myofibrillar protein (MP); Nanocrystalline cellulose (NCC); Ovalbumin (Ova).