ISO 659:2009 specifies a reference method for the determination of the hexane extract (or light petroleum extract), called the “oil content”, of oilseeds used as industrial raw materials. The procedure for sunflower seed is different from those for other seeds as it includes an additional moisture content determination after the seed has been ground to prepare the test sample.
The method has been tested on rapeseed, soya beans and sunflower seed. This does not, however, preclude its applicability to other commercial seeds.
If required, the pure seeds and the impurities can be analysed separately. In the case of groundnuts, the pure seeds, the total fines, the non-oleaginous impurities and the oleaginous impurities can be analysed separately.