Study of the oxidation kinetic parameters affected by different concentrations of galic acid

In this study, oxidation kinetic parameters of soybean oil affected by three different concentrations of gallic acid antioxidants (100, 200 and 300 ppm) in comparison with a blank sample were studied by rancimat in three different temperatures 383, 403 and 423 k. Factors calculated in this study were temperature coefficient (Tcoeff), special constant reaction (A), activation nergy (Ea), enthalpy (ΔH++) and entropy (ΔS++). They were estimated based on the Arrhenius, Vant Hoff and the Eyrings equations. Generally, reaction constant of oxidation increased with the rise of temperature, and there was a logarithmic relationship between them. Stability of the oil was also increased by the increase of the antioxidant concentration. The results indicated that there was a significant difference among the temperature coefficient, enthalpy, activation energy and special constant reaction values in the blank sample and samples with antioxidant. No difference was observed between samples with 200 and 300 ppm antioxidant. Concerning the entropy, there was a difference between the blank sample and samples with antioxidant, and a high correlation was observed among the regression relations (0.9479