Oxidative stability of sesame oil extracted from the seeds with different origins: Kinetic and thermodynamic studies under accelerated conditions

Abstract

A comparative study was carried out to identify the oxidative stability of sesame oils originated from three countries: Sudan, Turkey, and Yemen. Sesame oils were oxidized under Rancimat test conditions. Reaction rate constant (k), activation energy (Ea), activation enthalpy (H++), activation entropy (S++), and Gibbs free energy of activation (G(++)) were calculated according to both Arrhenius model and Eyring equation of activated complex approach. Quality parameters of the sesame oils were evaluated with respect to phenolic (TP) and flavonoid (TF) contents, free radical-scavenging activity (FRSA), and peroxide value (PV). Fourier transformed infrared-attenuated total reflectance (FTIR-ATR) was also used to assess the functional groups of the oils. Depending on the fundamental thermodynamic parameters (H++>0, G(++)>0, and S++<0), the nature of the oxidation reaction in the oils proves that it is an endothermic, nonspontaneous, and endergonic process. The predicted shelf-life of the oils ranged from 38 to 132days at ambient conditions.