As part of our master's thesis, we tested whether the nutritional value of flaxseed oil can be increased by using pulsed electric field. For this purpose we used a prototype press, which also served as an electroporation chamber with movable electrodes. In so pressed flaxseed oil we determined the water and fat content, the fatty acid composition, the peroxide number, the antioxidant potential expressed as trolox equivalent concentration, and determined the color of the oil in comparison with the control sample. When oil was extracted by means of a pulsed electric field, we observed an increase in yield of 16% compared to the control sample. The percentage of the individual fatty acids did not differ significantly between sample and control. The oil contained the highest amount of alpha-linolenic acid with about 46 %. This was followed by oleic acid and linoleic acid. Both samples were within the legal limits of the peroxide number, but the value of the peroxide sample obtained by electroporation was statically significantly lower compared to the control. Lower peroxide value means lower level of primary oxidation. The sample obtained by electroporation was also slightly more yellowish in color, which can be attributed to the higher concentration of lutein. The use of electroporation increased the antioxidant potential of the oil, expressed as concentration of the trolox equivalent, by 11% compared to the control sample. The use of electroporation parameters with lower energy input resulted in a decrease of the antioxidative potential. Oil obtained by electroporation has a higher nutritional value, but for further confirmation of the thesis, we would need to use bigger press chamber that would whitstood a greater load. Thus we would obtain a larger sample volume and perform additional oxidtative stability analyzes. We would also determine the content fo various secondary compounds by HPLC analysis.
|
