Abstract:
The objective of this study was to determine structural changes, including carbonyls, sulfhydryls, free amino, particle size distribution, secondary structure in egg white protein exposed to FeCl
3/Asc/H
2O
2 hydroxyl radical-generating systems.Protein carbonyl content in EWP increased ( p < 0.05) with increasing concentrations of H
2O
2, free SH, total SH groups and free amino decreased ( p < 0.05) in a similar fashion.EWP average particle size increased.When the H
2O
2 concentration was increased to 20 mmol/L, there was 2.01-fold increase in carbonyl group, 29.1% decrease in free amino acid, compared with control group.The average particle size reached 666 nm.The results showed that there were increases in α-helix and β-fold of relative content, decrease in β-turn of relative content with the increase of oxidizing agent ( H
2O
2< 5 mmol/L) .Higher level oxidation ( H
2O
2> 5 mmol/L) would induce fragmentation through direct breakage of peptide bonds, resulted in changes in the secondary structures.These oxidation-induced changed demonstrate high susceptibility of EWP to oxidative stress.