Comparison of ovotransferrin and lactoferrin in oxidative stability

Oxidative stability was compared between ovotransferrin( OVT) and lactoferrin( LF). 2,2'- azobis( 2-amidinopropane) hydrochloride( AAPH) was used to induce OVT and LF oxidation,and their chemical and structural changes were assessed by sodium dodecyl sulfate- polyacrylamide gel electrophoresis( SDS- PAGE),solubility,contents of total sulfhydryl and carbonyl,and free radical scavenging activity on ABTS( 2,2'- azino- bis( 3-ethylbenzthiazoline-6-sulfonic acid) and DPPH( diphenyl picryl hydrazinyl radical) free radicals. Results showed that AAPH( 5 mmol / L) induced new protein bands of LF at the high molecular weight area,while AAPH( 20 mmol / L) induced the new protein bands of OVT at the low molecular weight area on SDS- PAGE.The density of the new protein bands of OVT and LF increased significantly with the increasing of AAPH concentrations,while the density of their original bands decreased significantly.At 20 mmol / L AAPH,the new protein bands of LF appeared at 1 h,while the new protein bands of OVT appeared at 4 h.At 20 mmol / L AAPH,the new protein bands of OVT and LF appeared at 2 mg / m L,and the density of their original bands decreased significantly.The new protein bands of LF decreased gradually from 2 mg / m L to 10 mg / m L,while the new protein bands of OVT disappeared from4 mg / m L to 10 mg / m L. When OVT and LF were incubated with AAPH( 20 mmol / L) for up to 8 h,their solubility and total sulfhydryl content were gradually decreased,and carbonyl content were gradually increased. Scavenging activity of OVT and LF on ABTS and DPPH free radicals was increased with increasing OVT and LF concentrations.In conclusion,LF was oxidized by AAPH easier than OVT that led to their structural changes.