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

Xing, Jie, Zhang, Sitian, Zhang, Mingdi, Lin, Songyi
Journal of the science of food and agriculture 2017 v.97 no.12 pp. 4058-4065
2,2-diphenyl-1-picrylhydrazyl, analytical methods, antioxidant activity, antioxidants, hydrogen bonding, pulsed electric fields, vibration
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