Analysis of α‐helix unfolding in the pine nut peptide Lys‐Cys‐His‐Lys‐Pro induced by pulsed electric field

BACKGROUND A variety of analytical techniques were applied to explore the effects of pulsed electric field ( PEF ) on α‐helix structural changes in the novel antioxidant peptide Lys‐Cys‐His‐Lys‐Pro ( KCHKP , 611.76 Da). RESULTS The relative α‐helix content of the KCHKP peptide was significantly altered from 100% to 89.91 ± 0.97% when the electric pulse frequency was 1800 Hz and the field intensity was 10 kV cm −1 . Moreover, the 1,1‐diphenyl‐2‐pycryl‐hydrazyl ( DPPH ) and 2,2‐azinobis diammonium salt ( ABTS ) radical‐scavenging activities of PEF ‐treated KCHKP were increased from 56.31% ± 0.74% to 84.33% ± 1.23% and from 40.56% ± 0.78% to 51.33% ± 0.27%, respectively. CONCLUSION PEF treatment increased peptide linkage stretch vibration and altered hydrogen bonding of KCHKP . The stability of the α‐helix structure was influenced by hydrogen bonds within the peptide linkage of KCHKP induced by PEF and was related to changes in antioxidant activity. © 2017 Society of Chemical Industry