Comparative Study of Vegetable Oils Oxidative Stability using DSC and Rancimat Methods

Abstract: COMPARATIVE study was carried out to evaluate and compare the oxidative
stabilitystability of vegetable oils (olive, corn and sunflower) in Egypt, through evaluation of
accelerated oxidation at four different isothermal temperatures (110, 120, 130, 140 °C) using
two different instruments: a differential scanning calorimeter (DSC) and a Rancimat instrument,
taking into account the physicochemical quality characteristics and relationships between
oxidative stability and fatty acid composition of oils. The Rancimat instrument was set at the
four different isothermal temperatures with an air flow 20 L/h and measures the induction
period (IP) of the selected oils. The differential scanning calorimetry (DSC) technique involved
accelerated oxidation of oil samples in an air flow of 60 ml/min in DSC cell set at four different
isothermal temperatures. A rapid increase in evolved heat was observed with the appearance of
a sharp exothermic curve during initiation of the oxidation reaction. From the resulting
exothermic curve, the onset of oxidation time (To) was determined graphically by the DSC
instrument. There was an excellent correlation (p<0.0001) found between DSC (To) values and
Rancimat (IP) measurements where the Pearson correlation coefficient (>0.98) between the two
methods with coefficient of determination (R2 >0.89) for DSC independent of the vegetable oil
source, imply that DSC can be recommended as an alternative appropriate objective method for
assessing the oxidative stability of vegetable oils because of its simplicity, absence of toxic
chemicals, small amount of sample and time-saving nature and could be easily used for routine
analysis in oils and fats industry.
Keywords: Vegetable oils, Oxidative stability, DSC, Rancimat, Comparative study
Publication year 2021
Pages 299 - 312
Organization Name
serial title Egyptian Journal of Chemistry
Author(s) from ARC
Publication Type Journal