EFFECT OF SEED QUALITY ON OXIDATIVE STABILITY OF COLD-PRESSED SUNFLOWER OIL

The objective of this study was to investigate the impact of the storage time, content Of the husk and impurities in the seed mass on the oxidative stability of the cold pressed sunflower oil. The oxidative stability of oil was analyzed by the Response Surface Methodology (RSM), where the response value (output) of the model was the content of oxidation products measured via specific absorbance at 232 nm for conjugated dienes and 270 nm for conjugated trienes. Analyses were performed on the fresh oil samples and oil samples tempered under the Schaal-Oven's test.conditions (96 h. at 63 +/- 2 degrees C). It was concluded that the seed storage time had significant impact on the primary (A(232nm)(1%)) and secondary (A(270nm)(1%)) oil oxidation products, both before (b1 p < 0.001; 131 p = 0.021) and after (b1 p = = 0.048; b(1)-p = 0.033) the heating of oil. The content of impurities and husks in the seeds used for pressing also had an influence of the conjugated dienes and trienes contents in both, fresh and heated oil samples. However, their impact was not statistically significant.. Interaction of seed storage time, the content of impurities and husks also exert some effect on the values of these quality parameters in the fresh oil, as well as in the oil after the heat treatment, even though their influence is not significant. The obtained results have shown that the cold pressed sunflower oil had a good oxidative stability at temperatures up to 63 +/- 2 degrees C.