Measurement of the total hydroperoxides in ozonated sunflower oil using the ferrous oxidation in xylenol orange assay

Total hydroperoxides (HPT) concentration using the ferrous oxidation in xylenol orange (OFX) assay and peroxide value (IP) using iodometric assay, were determined in sunflower oil samples ozonated at different ozone dosages. The effect of an increasing amount of ozonazed sunflower oil was evaluated by assembly assay, where a lineal relationship was obtained between oil amounts from 2 to 17 µg in the assay and absorbance units measured at 560 nm. The OFX reagent calibration and the extinction coefficient calculation were carried out for HPT measurement in ozonazed samples. The correlation established between IP and the concentration obtained by OFX assay showed a lineal relationship (r = 99.29; r2 = 98.59 %). These results confirm that this assay is appropriate for HPT measurement in ozonazed sunflower oil.