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Alkyl Tail Segments Mobility as a Marker for Omega-3 PUFA-rich Linseed Oil Oxidative Aging
  • Maysa Resende,
  • Charles Linder,
  • Zeev Wiesman
Maysa Resende
BGU
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Charles Linder
BGU
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Zeev Wiesman
BGU
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Abstract

The goal of the present study is to demonstrate 1H LF-NMR time relaxation measurements for efficient and rapid evaluation of Omega-3 polyunsaturated fatty acids (PUFA)-rich linseed oil (LSO) oxidative aging mechanisms, by monitoring primary chemical and structural changes occurring during thermal oxidative stress. The LF NMR monitors the different proton spin-spin coupling energy relaxation times, T2 within LSO molecular segments, from the initiation of free radical generation and hydroperoxide formation to the propagation of alkoxy radicals, and alpha, beta-unsaturated aldehydes formation, and a termination phase of crosslinked polymerization end products. The 1H LF NMR T2 values monitors both the covalent and secondary bonding interactions (e.g., electrostatic and hydrogen bonding) during the different oxidation phases. The present paper shows that LSO tail segments mobility in terms of T2 multi-exponential relaxation decays, generated by data reconstructing of 1H transversal relaxation components are providing a clear, sharp and informative understanding of LSO sample’s autoxidation aging processes. This is supported by high field band selective 1H NMR pulse excitation for hydroperoxide and aldehydes quantification of the same LSO samples at 25, 40, 60, 80, 100, and 120oC with pumped air for 168 h. Peroxide value, viscosity and self-diffusion, as well as fatty acids profile and by- products determined by GC-MS were also carried out, and correlated with the LSO tail T2 relaxation results. In conclusion the selective determination of LSO alkyl tail T2 energy relaxation time domain values was demonstrated as a rapid evaluation marker for following omega-3 PUFA-rich oils oxidative aging.

Peer review status:ACCEPTED

17 Feb 2020Submitted to Journal of the American Oil Chemists' Society
20 Feb 2020Submission Checks Completed
20 Feb 2020Assigned to Editor
05 Mar 2020Reviewer(s) Assigned
04 Apr 2020Review(s) Completed, Editorial Evaluation Pending
13 Apr 2020Editorial Decision: Revise Major
10 May 20201st Revision Received
12 May 2020Assigned to Editor
12 May 2020Submission Checks Completed
19 May 2020Reviewer(s) Assigned
17 Jun 2020Review(s) Completed, Editorial Evaluation Pending
29 Jun 2020Editorial Decision: Revise Minor
21 Jul 20202nd Revision Received
21 Jul 2020Submission Checks Completed
21 Jul 2020Assigned to Editor
22 Jul 2020Reviewer(s) Assigned
23 Jul 2020Review(s) Completed, Editorial Evaluation Pending
11 Aug 2020Editorial Decision: Accept