Degradation of Phytosterols During Near-Ambient Drying of Rapeseeds in a Thick Immobile Layer

The effect of the drying method applied and subsequent rapeseed storage on changes in phytosterols was determined. After harvest, rapeseeds were dried by the near-ambient method in a thick immobile layer of 2 m and using air heated to a temperature of 60, 80 and 100 °C. Analyses of phytosterol contents were performed immediately after drying and after 6 and 12 months of storage at a temperature of 10 ± 2 °C. Results showed a significant effect of drying conditions, cultivar-specific differences and storage time on the contents of phytosterols. Near-ambient drying of seeds resulted in a reduction in total sterol contents by 6-20 %, while for drying with hot air it was by 14-40 %. The level of sterols decreased by 13-18 % after a 1 year storage of seeds dried by the near-ambient methods. A reduction in 12-22 % in sterols for seeds dried by high temperature occurred after 1 year of storage.