The Influence of Pressing Temperature and Storage Conditions on the Quality of the Linseed Oil Obtained from Linum Usitatissimum L.

Flax is one of the most significant natural fiber providing plants. However, linseed oil originated from flax is also considered as health-promoting edible oil providing omega-3 fatty acids, mostly linolenic acid and tocopherols (including vitamin E). It is still unknown, how the moderate increase in temperature of machine press may influence the technological parameters of press and quality of the obtained oil. In this study, numerous variants of linseed oils pressed at different temperatures (from 50 to 90 degrees C) from seeds of two varieties of Linum usitatissimum cultivars (i.e. brown-seeded and gold-seeded variety) were for the first time comprehensively investigated with respect to technological parameters of the pressing (press efficiency, throughput, power consumption), and quality of the obtained oils (acid value, peroxide value, oil color). The quality of the oils was assessed either for freshly pressed oils or oils stored at 5 degrees C or 25 degrees C for 30 days. The results suggest that higher press temperatures (80-90 degrees C) might not be suitable for linseed oil quality (change of the oil color) and power consumption of the press. For other temperature ranges, no negative effects were observed for the quality of the oils, while technical parameters for these variants were maintained at similar level for both flax varieties.