Effect of β-cyclodextrin on whey protein-epigallocatechin gallate interaction

This study aimed to explore the influence of whey protein-epigallocatechin gallate interaction. Nonreducing cyclic polysaccharide (beta-cyclodextrin, i.e., beta-CD) was added to epigallocatechin gallate (EGCG) and whey protein (WP) to regulate the interaction between polyphenols and proteins. Based on the transmittance, oxidation resistance, and spectral analysis, we used differential scanning calorimetry, Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) to characterize the effects of beta-CD on the interaction between polyphenols and proteins. The light transmittance of WP was 74.61%, and the EGCG addition reduced the light transmittance of WP by 2.8%. The maximum absorption peak of WP was around 280 nm. EGCG enhanced the fluorescence intensity of WP, caused the blue shift, and also reduced the fluores-cence intensity of WP. In addition, the interaction between WP and EGCG also weakened the antioxidant activity of EGCG. beta-CD could improve the light transmission and oxidation resistance of the EGCG-WP hybrid system to a certain extent. The beta-CD addition had little effect on the thermal stability of the mixed system. In WP-EGCG and beta-CD-WP-EGCG systems, the peak intensity of absorption peaks in each group was different. The EGCG addition reduced the crystallinity of the mixed system by 6.25%, and beta-CD alleviated this phenomenon to a certain extent. The formed complex became relatively chaotic by adding WP and EGCG, and the system became tightly connected and ordered with the interaction of 0.03% beta-CD with WP-EGCG. This study provided the basis for the interaction between beta-CD, WP, and EGCG.

Automated summary

This study explores the interaction between whey protein and epigallocatechin gallate (EGCG), and finds that the addition of β-cyclodextrin can regulate this interaction. The addition of EGCG reduces the light transmittance and fluorescence intensity of whey protein, while also weakening the antioxidant activity of EGCG. β-cyclodextrin improves certain properties of the EGCG-whey protein hybrid system.