Oxidative stability of pomegranate seed oil from blanched and microwave pretreated seeds: Kinetic and thermodynamic studies under accelerated conditions

摘要

This work aimed to evaluate the effects of blanching and microwave heating ofpomegranate seed on the oxidative stability and shelf-lifeof ultrasound-assistedand ethanol extracted oil. Pomegranate seeds (cv. Herskawitz) were independentlyblanched at 95°C for 3 min and microwave heated at 261 W for 102 s. The oil sampleswere subjected to accelerated oxidation (30, 40, and 50°C) to evaluate lipid oxidationkinetics, thermodynamics parameters, and estimate the shelf-life.The Arrheniusmodel and activated complex theory were used to estimate the energy for activation(E_a), enthalpy (ΔH‡), entropy (ΔS‡), and Gibbs-freeenergy (ΔG‡), which varied from6.2 to 8.59 kJ/mol, 3.69 to 6.38 kJ/mol, −146.62 to −155.06 J/K mol~(−1), and 48.13 to64.74 kJ/mol, respectively. According to the thermodynamics parameters, the lipidoxidation reactions in all oil samples were non-spontaneous,endothermic, and endergonic.Based on the developed Arrhenius models, blanching of pomegranate seedincreased the oil shelf-lifeat 25°C from 21 to 24 days, whilst microwave pretreatmentdid not change the oil shelf-life.