EFFECT OF DEHULLING ON THE COMPOSITION OF ANTINUTRITIVE COMPOUNDS IN VARIOUS CULTIVARS OF RAPESEED

Eight different rapeseed cultivars (Brassica napus L.) have been dehul led by hand. The contents of glucosinolates, sinapine, condensed tanni ns and inositol phosphates have been investigated in the resulting fra ctions of dehulled seeds and hulls as well as in the whole seeds by HP LC methods and a spectroscopical method for condensed tannins. After d ehulling the content of glucosinolates as well as the content of sinap ine and inositol phosphates increased significantly (P = 0.01) in the seeds of the different cultivars by 2.0 to 35.0%, 14.1 to 57.1% and 11 .9 to 38.2%, respectively. The content of condensed tannins decreased by 26.0 to 81.2% after the dehulling process. In most of the cultivars the enrichment of antinutritive compounds corresponded to the share o f hulls separated from the seeds. Only in the case of condensed tannin s unproportional losses in the dehulled seeds were observed.