Measuring the oil content of seeds is important for two reasons: firstly, for non-destructive measurement of single seeds, to select high oil content specimens for propagation, secondly, for bulk measurement of oil content for trading or processing.
What is NMR is used for?
Nuclear Magnetic Resonance Spectrometry (NMR), is used for determining oil, protein and moisture content in seeds of various oil crops. The instrument is calibrated for several oil crops including soybean, camelina, canola, meadowfoam, and euphorbia, and can be calibrated for other species as needed. Tests can be performed in whole seeds or meals.
The need for NMR
With the diversification of crops in Oregon and the search for crops to be used for biodiesel production, the need to determine the oil content of such crops has emerged. In addition, the meal in some oil seeds such as soybean is used for feed after extracting the oil and it is useful to determine the protein content in the meal as well as in the seeds. Both the USDA and Canadian Grain Commission use NMR analyzer in determining oil seed content in oil crops.
In the past, researchers have had to send their oil seeds out of the state for oil and protein analysis. The Niumag’s recent acquisition of a Nuclear Magnetic Resonance Spectrometer means this service is now available in-state. This provides an advantage to Northwest researchers and commercial producers both in testing turnaround and in the availability of the equipment and service for conducting customized research.
The principle of the test
The oil content test estimates the amount of oil that can be extracted from seeds using an industrial extraction method. Direct pressing extracts 90-92%, whereas solvent extraction remove 97-99% of oils contained in seeds.
The benchtop NMR technique measures the resonance energy absorbed by hydrogen atoms in the sample. Usually oil contents are expressed based on a specific moisture basis (e.g., 8.5%, 10%, etc.).
Sample size and test period
Sample size is 5-10 grams for all analyses (not for each test), i.e., for oil, protein and moisture. We can calibrate the NMR for a smaller amount of seeds (i.e., 1-2 grams), if needed. It takes 24 hours to complete the test from the time of receiving the sample. The NMR is a non-destructive method, so seeds can be returned if needed. Please enclose the sample in a moisture-proof bag.