Low field NMR Time Domain (TD) Characterization of PUFA-rich Linseed and
Fish Oil Emulsions During Thermal Air Oxidation
Abstract
Linseeds contains high levels of PUFA α-linolenic acid, naturally
protected against thermal oxidation by their encapsulation within LS oil
bodies by multiple components including antioxidant proteins and
mucilage emulsifying agents. By LS grinding, adding of water, adjusting
pH, and sonication LS oil bodies emulsions (LSE) can be formed which can
also encapsulate externally added PUFAs, to minimize their thermal
oxidation, as it does for the intrinsic ALA PUFAs. Fish oil
encapsulation into this LSE platform (LSFE) offers the possibility of a
nutritive delivery system of the biologically essential PUFA fish oil’s,
protected from oxidation, which to date is difficult to achieve. In this
study structural and chemical properties LF 1H NMR T1-T2
characterization of LSE and LSFE was used to analyze their stability and
changes, under thermal oxidizing conditions. Peak changes in these LF
1H-NMR spectra were correlated with the stability of chemical and
physical variables during thermal (55oC for 96 hrs) oxidation. The
present study demonstrates the capability of 1H LF-NMR relaxation sensor
to monitor the time domain fingerprints of chemical and structural
changes of LSE and with co-encapsulated fish oil (LSFE) under thermal
autoxidation conditions. The results of the LF-1H NMR analysis are
further supported and correlated with conventional peroxide value tests,
self-diffusion, droplets size distribution, zeta potential estimation of
surface stability under thermal oxidation conditions. The results of
this study demonstrate the efficacy of LSE to minimize linseed and
encapsulated fish oil PUFA oxidation.