Practical nuclear magnetic resonance analysis of liquid oil in oilseeds: I factors affecting peak width

Abstract

If proton nuclear magnetic resonance (NMR) spectra of single seeds can be improved, a rapid, low-cost method of screening seeds for oil composition could be developed for use as a selection tool in plant breeding. NMR spectroscopy was performed on single seeds of borage, flax, and canola to evaluate methods for improving spectra quality (narrowing peak widths and increasing signal-to-noise ratio) to a degree necessary to measure differences among seeds in a breeding program. Immersion of seeds in a variety of solvents, including deuterated chloroform, deuterated acetone, deuterated dimethyl sulfoxide (DMSO) and completely fluorinated hydrocarbons (FC-77), narrowed peaks obtained from seeds when compared with spectra from seeds analyzed in the absence of a solvent. Deuterated chloroform and FC-77 were free of interfering solvent proton peaks while deuterated acetone and deuterated DMSO contributed interfering peaks. The spectra of dehulled seeds had narrower peak widths than did seeds with hulls. Treatments that decreased seed oil viscosity failed to substantially narrow spectral peak widths of seeds. High magnetic field strength did not improve the spectral quality of seeds, as peak widths increased with field strength. Conversely, low field strength limited resolution of oil spectra. Although the 300 MHz spectrum of vegetable oil had greater resolution (narrower peaks) than the 60 MHz spectrum, spectra of seeds produced at 60 MHz had superior resolution to 300 MHz spectra.Paper no. J8831 in JAOCS 76, 859-862 (July 1999).

Use of NMR for predicting protein concentration in soybean seeds based on oil measurements

“…The negative slope of the regression (with a correlation of -0.69) supports previous findings of an inverse relationship between protein and oil concentration (6,13,14). For each increase in oil concentration there was a general decrease in protein concentration on the magnitude of 1.26 times the observed increase in oil concentration.…”

“…Previous indirect selection for protein using NMR oil measurements was successful in obtaining BC 1 -and BC 2 -derived high-protein (44.0%) lines (13) and individual high-protein F 2 plants (45.7%) (15). These studies were conducted on populations generated with G. max plants.…”

“…Large sample sizes are not required, as accurate readings can be obtained from individual seeds (9). NMR has been used to measure the oil concentrations of many crops, such as maize (9), soybeans (12), flax, and canola (13). Oil readings generated by NMR were reported to be highly correlated with values obtained by extraction with petroleum ether (r = 0.993) (2) and with gravimetric oil analysis (r = 0.995 to 0.999) (9).…”