The Effect of (−)-Epigallocatechin-3-Gallate Non-Covalent Interaction with the Glycosylated Protein on the Emulsion Property

Abstract

The effect of (−)-epigallocatechin-3-gallate (EGCG) on protein structure and emulsion properties of glycosylated black bean protein isolate (BBPI-G) were studied and compared to native black bean protein isolate (BBPI). The binding affinity of BBPI and BBPI-G with EGCG belonged to non-covalent interaction, which was determined by fluorescence quenching. EGCG attachment caused more disordered protein conformation, leading to a higher emulsification property. Among the different EGCG concentrations (0.10, 0.25, 0.50 mg/mL), the result revealed that the highest level of the emulsification property was obtained with 0.25 mg/mL EGCG. Therefore, the BBPI-EGCG and BBPI-G-EGCG prepared by 0.25 mg/mL EGCG were selected to fabricate oil-in-water (O/W) emulsions. After the addition of EGCG, the mean particle size of emulsions decreased with the increasing absolute value of zeta-potential, and more compact interfacial film was formed due to the higher percentage of interfacial protein adsorption (AP%). Meanwhile, EGCG also significantly reduced the lipid oxidation of emulsions.

Improvement of protein emulsion stability through glycosylated black bean protein covalent interaction with (−)-epigallocatechin-3-gallate

“…Destruction of secondary structure was due to the changes of van der Waals forces and hydrogen bonding among protein molecules inuenced by glycosylation. 28 Covalent binding of EGCG made a further structure disorder of both BBPI and BBPI-G as observed in Table 1. The a-helix and b-sheet content in BBPI and BBPI-G both reduced with increasing content of EGCG, while the b-turn and random coil content enlarged, owing to the reaction of oxydic phenol product and glycinin protein via amino, thiol groups and tryptophan.…”

“…2a, showing that BBPI-G-EGCG red-shied more obviously compared with BBPI-EGCG, which meant that BBPI-G-EGCG might have more incompact structure than BBPI-EGCG. 28 3.1.3. Fourier transform infrared (FTIR) spectroscopy.…”

Inhibition of the in vitro Activities of α-Amylase and Pancreatic Lipase by Aqueous Extracts of Amaranthus viridis, Solanum macrocarpon and Telfairia occidentalis Leaves

“…However, at 25 and 50 μg/mL, there was increased red shift to 350 nm for all the extracts. This suggests that the tryptophan residues inside the protein molecules were more exposed to the protein surfaces thus making the tryptophan environment more polar ( 54 ). Results showing changes in FI and λmax indicate that the α-amylase inhibitory activity of the AV, SM, and TO leaf extracts as shown in Figure 1 is due to ability of the extracts to change the enzyme protein structure from a conformation that facilitated substrate catalysis into those not favorable for optimum enzyme activity.…”

Comparison of Different Protein Emulsifiers on Physicochemical Properties of β-Carotene-Loaded Nanoemulsion: Effect on Formation, Stability, and In Vitro Digestion

“…The PPI-, SPI-, RBPI-, and WPI-stabilized nanoemulsions were stored at 4 °C for 14 days to evaluate their primary oxidation (POV) and secondary oxidation (TBARS) stabilities, while the same oil content was used as a blank control group. As shown in Figure 7 (specific data shown in Tables S3 and S4 of Supplementary Materials ), the two oxidation rates of the four nanoemulsions were lower than those of the control group, thus proving that the nanoemulsions could effectively reduce oxidation [ 52 ]. In the initial stage of storage, all groups showed an increase in both POV and TBARS values.…”