The determination of oil in rapeseed by solvent extraction methods is being replaced by rapid, nondestructive methods based on nuclear magnetic resonance (NMR). Calibration of these methods can be conveniently made with rapeseed whose oil content is determined by a solvent method. Results given by 3 solvent methods have been compared in order to assign a common reference value for oil content required for NMR calibration. The provisional certified values for the oil content (expressed on dry matter) are as follows:
CRM 446 (low oil content): 42.5 (+/- 0.1)%;
CRM 447 (medium oil content): 45.3 (+/- 0.2)%;
CRM 448 (high oil content): 49.2 (+/- 0.2)%.
The price paid by seed-crushers directly depends on the oil content of rapeseed and it is therefore essential to have rapid and accurate methods that can be used in the factory situation. Oil content is also important for reasons connected with the Common Agricultural Policy (CAP).
Traditionally, oil in rapeseed has been determined by solvent extraction methods, slow and potentially hazardous procedures which are being replaced by rapid, non-destructive methods based on Nuclear Magnetic Resonance (NMR). Calibration of these methods can be conveniently made with rapeseed having an oil content determined by a solvent method. There are three similar solvent methods in use for different purposes, ISO and EEC methods and that of the trade association FOSFA. These methods differ in details which could give rise to small but significant systematic differences in the results.
The object of the work is to compare the results given by the three methods and, if possible, to assign a common reference value for oil content to three rapeseed reference materials required for NMR calibration.
Funding SchemeCSC - Cost-sharing contracts
3002 AA Rotterdam
DA8 IDL Erith
KT22 7RY Leatherhead
3200 Ae Spijkenisse