CONCLUSIONS
1. The method of obtaining oil did not affect the composition
of fatty acids and was typical of the low-erucic rapeseed
oil. The analysed oils did not contain trans isomers of fatty
acids with the exception of fully deodorised oils (1.1%).
2. The quality of oils significantly depends on the method
of their processing (cold or hot pressing, extraction) and further
refinining processing. The quality of cold pressed and
virgin oils was good and fulfilled the Codex Alimentarius requirements
for edible oils. Cold pressed oils differed negatively,
in a statistically significant manner, compared to virgin
oils and deodorised oils obtained from the same seeds in all
examined parameters: colour, acid value, peroxide value, Totox,
induction time and only in the case of the anisidine value
they showed a beneficially lower value.
3. The highest oxidative stability was observed for hot
pressed oils (induction time 50% longer as compared to cold
pressed oils). Cold pressed oils were less stable in comparison
to oils after full refining.
4. The highest content of tocopherols was observed in
crude oils. The refining process caused over 40% decrease
of their content in deodorised oils, as compared to their level
noted in cold pressed oils. The difference in the nutritive
value between cold pressed oils and fully refined oils cannot
be stated. However, the 25% higher tocopherol content and
the lack of trans isomers of fatty acids speak for cold pressed
oils.