Increased interest manifested by consumers in products rich in biologically active components makes it necessary to minimize their loss during drying and storage of raw materials for food production. In this study, the effect of drying conditions and further storage of rapeseed on changes in contents of tocopherols (T) and was examined. Seeds of rape cv. Californium, Elektra and Livius, dried after harvest using the near-ambient drying method in a bed of 2-m thickness and air heated to a temperature of 60, 80 and 100C, were used. Contents of T and PC-8 were determined immediately after drying and after 6 and 12 months of storage at 10 Ϯ 2C. Quality and quantity of antioxidants in seeds were determined using high-performance liquid chromatography. The near-ambient seed drying method resulted in a decrease in T content by 6-11%, while that for hot air drying was 4-8%. Seed storage reduced the level of T by a further 23-30%. Similar dependences were found for PC-8. The analyzed results demonstrated the effect of varietal differences, drying conditions and storage time on the contents of T and PC-8 in rapeseed. PRACTICAL APLICATIONSDrying of rapeseed is one of the most energy-intensive stages of its production. At the same time, one needs to consider that these seeds, as 3 Corresponding biological material, are highly sensitive to thermal treatment. Thus, search for best drying conditions with special emphasis on the preservation of bioactive components that affect human health is necessary. The analyses carried out compared the range of loss of natural antioxidants, tocochromanols, during drying and further storage of rapeseed dried using an energy-saving nearambient drying and dried using hot air. Near-Ambient DryingSeeds of cv. Californium were dried using the near-ambient method from initial moisture content of 16.2% on a farm belonging to the Agricultural University of Poznań (at present, renamed to the Poznań University of Life Sciences). The Experimental Station presented by Gawrysiak-Witulska et al. (2008) was built on the basis of a 28-ton metal silo with a diameter of 3.2 m, equipped with a computer controller (type BIT-04) of the near-ambient drying process with a set of measurement probes, a fan and an electronic air heater. During the experiment, the BIT-04 controlled the operation of the air heater so that the air blown into the silo had an adequate drying potential. The experiment 526 M. GAWRYSIAK-WITULSKA, A. SIGER and M. NOGALA-KALUCKA

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Tocopherols and plastochromanol-8 were evaluated in seeds of Brassica napus L. during adverse conditions of storage at different temperatures (25 and 30°C) and moisture levels (10, 12.5 and 15.5%). Both temperature and moisture content of seeds had a significant effect on the hydrolysis of triacylglycerols in rapeseed oil and on the contents of tocopherols and PC-8. The biggest losses of tocopherols (a drop by 14.4% after 18 days) were recorded for seeds with a moisture content of 15.5% and stored at a temperature of 30°C. Losses of the a-T homologue were bigger than those of c-T. The loss of PC-8 ranged from 4 to 24% depending on storage conditions and it was almost two times bigger than the loss of tocopherols.

A b s t r a c t. Investigations were performed to examine the possibility of using an electronic nose to monitor development of fungal microflora during the first eighteen days of rapeseed storage. The Cyranose 320 device manufactured by Sensigent was used to analyse volatile organic compounds. Each sample of infected material was divided into three parts and the degree of spoilage was measured in three ways: analysis of colony forming units, determination of ergosterol content, and measurement of volatile organic compounds with the e-nose. Principal component analysis was performed on the generated patterns of signals and six groups of different spoilage levels were isolated. An analysis of sensorgrams for a few sensors with a strong signal for each group of rapeseed spoilage was performed. The ratio of the association time to the steady state was calculated. This ratio was different for the low level and the highest level of ergosterol and colony forming units. The results have shown that the e-nose can be a useful tool for quick estimation of the degree of rapeseed spoilage.

The aim of the conducted investigations was to determine the effect of drying temperature on the changes in free fatty acid, phytosterol and tocopherol (T) contents in yellow‐seeded Brassica napus oils. Seeds were dried in a thin layer at 40, 60, 80, 100 and 120°C. Changes in phytosterols were assessed using GC‐MS, while tocopherols were assessed by HPLC. Degradation of phytosterols and tocopherols and an increased content of free fatty acids followed the applied drying temperature. During drying at 40 and 60°C, changes were statistically non‐significant, while at 120°C, losses of phytosterols reached 29% and tocopherols 23%. Practical applications: Drying of rapeseeds is an important stage of its production. However, we need to remember that these seeds are biological material highly sensitive to thermal treatment. Thus we need to search for the most advantageous conditions for their drying, with special emphasis on the preservation of bioactive components affecting human health. The analyses conducted compared the range of losses of bioactive components—phytosterols, tocopherols and plastochromanol‐8 during drying. Yellow‐seeded Brassica napus were dried in a thin layer at 40, 60, 80, 100 and 120°C. The effect of drying temperature on the free fatty acid, phytosterol and tocopherol content changes in oils was determined. Degradation of phytosterols, tocopherols and the increase in free fatty acid content were related to the applied drying temperature.