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A novel approach to the rapid assignment of 13 C NMR spectra of major components of vegetable oils such as avocado, mango kernel and macadamia nut oils
Author(s) -
Retief Liezel,
McKenzie Jean M.,
Koch Klaus R.
Publication year - 2009
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.2463
Subject(s) - chemistry , macadamia nut , nmr spectra database , pear , fatty acid , nut , carbon 13 nmr , brazil nut , nuclear magnetic resonance spectroscopy , chemical shift , food science , organic chemistry , botany , spectral line , physics , structural engineering , astronomy , engineering , biology
Assignment of 13 C nuclear magnetic resonance (NMR) spectra of major fatty acid components of South African produced vegetable oils was attempted using a method in which the vegetable oil was spiked with a standard triacylglycerol. This proved to be inadequate and therefore a new rapid and potentially generic graphical linear correlation method is proposed for assignment of the 13 C NMR spectra of major fatty acid components of apricot kernel, avocado pear, grapeseed, macadamia nut, mango kernel and marula vegetable oils. In this graphical correlation method, chemical shifts of fatty acids present in a known standard triacylglycerol is plotted against the corresponding chemical shifts of fatty acids present in the vegetable oils. This new approach (under carefully defined conditions and concentrations) was found especially useful for spectrally crowded regions where significant peak overlap occurs and was validated with the well‐known 13 C NMR spectrum of olive oil which has been extensively reported in the literature. In this way, a full assignment of the 13 C{1H} NMR spectra of the vegetable oils, as well as tripalmitolein was readily achieved and the resonances belonging to the palmitoleic acid component of the triacylglycerols in the case of macadamia nut and avocado pear oil resonances were also assigned for the first time in the 13 C NMR spectra of these oils. Copyright © 2009 John Wiley & Sons, Ltd.