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Determination of the oxidative stability of vegetable oils by Differential Scanning Calorimetry and Rancimat measurements
Author(s) -
Kowalski Bolesław,
Ratusz Katarzyna,
Kowalska Dorota,
Bekas Witold
Publication year - 2004
Publication title -
european journal of lipid science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.614
H-Index - 94
eISSN - 1438-9312
pISSN - 1438-7697
DOI - 10.1002/ejlt.200300915
Subject(s) - chemistry , differential scanning calorimetry , arrhenius equation , isothermal process , activation energy , thermodynamics , physics
Samples of vegetable oils were oxidized at isothermal conditions in the cell of a Pressure Differential Scanning Calorimeter (PDSC) and in the Methrom Rancimat apparatus. The PDSC and Rancimat experiments were carried out at a temperature in the range of 90–160 °C. From resulting PDSC exotherms their times to reach the peak maximum (τ PDSC ) were determined and used for the assessment of the oxidative stability of the samples. Similarly the measured Rancimat induction times (τ Rancimat ) were used. As PDSC and Rancimat results were obtained at different temperatures the equations for temperature extrapolations of the τ PDSC and τ Rancimat values have been proposed. Using the Arrhenius type correlation between induction times and temperature and activated complex theory the reaction rate constants, activation energies, activation enthalpies and activation entropies for oils oxidation have been calculated.