Structure Characterization and Functional Properties of Flaxseed Protein–Chlorogenic Acid Complex

Abstract

This study aimed to investigate the effects of the covalent binding of flaxseed protein (FP) and chlorogenic acid (CA) on the structure and functional properties of FP–CA complexes fabricated using the alkali method. The results suggested that the encapsulation efficiency of CA encapsulated by FP ranged from 66.11% to 72.20% and the loading capacity of CA increased with an increasing addition ratio of CA with a dose-dependent relationship, which increased from 2.34% to 10.19%. The particle size, turbidity, zeta potential and PDI of FP and the FP–CA complexes had no significant discrepancy. UV–Vis and fluorescence spectra showed the existence of the interaction between FP and CA. SEM images showed that the surface of the FP–0.35%CA complex had more wrinkles compared to FP. Differential scanning calorimetry analysis indicated the decomposition temperature of FP at 198 °C was higher than that (197 °C) of the FP–0.35%CA complex, implying that the stability of the FP–CA complexes was lower than FP. The functional properties suggested that the FP–CA complex with 1.40% CA had a higher water holding capacity (500.81%), lower oil holding capacity (273.495%) and lower surface hydrophobicity. Moreover, the FP–CA complexes had better antioxidant activities than that of FP. Therefore, this study provides more insights for the potential application of FP–CA covalent complexes in functional food processing.