DETERMINATION OF INOSITOL PHOSPHATES IP3-IP6 IN RAPESEED AND RAPESEEDMEAL BY AN HPLC METHOD .2. INVESTIGATIONS OF RAPESEED AND RAPESEED MEAL AND COMPARISON WITH OTHER METHODS

Because of their structure, phytic acid and its degradation products a re able to bind other feedstuff ingredients, such as proteins, starch, cations or enzymes. This ability depends on the grade of phosphorylat ion. In order to investigate the influence of industrial processing on the inositol phosphate composition of rapeseed, 17 rapeseed samples a nd 8 rapeseed meal samples were analysed by an HPLC method. Only a sma ll grade of degradation of IP6 was noticed both in rapeseed meal, wher e also IP4 could be determined, and in rapeseed. The results were comp ared with two other phytic acid determination methods. The precipitati on method with FeCl3 of Wheeler and Ferrel and a photometric method we re used for this comparison, both methods for determination of the sum of inositol phosphates. The results of the HPLC method and the method of Wheeler and Ferrel correspond in most cases, but the values or the photometric method are far higher.