Kinetics of non-isothermal oxidation of raspberry and blackberry seed oils by DSC

Abstract

Studies were conducted to evaluate and compare the kinetic parameters related to the oxidation process of blackberry and raspberry seed oils in non-isothermal conditions by DSC. For that purpose, the oil samples were heated at six different heating rates, β (2, 5, 7.5, 10, 15, 20°C/min), starting from 40°C to the beginning of the oxidation process, under an oxygen flow of 50 ml/min. Experiments were performed using TA Instruments DSC Q1000, Differential Scanning Calorimeter (Delaware, USA). Kinetic parameters (activation energy, Ea (J/mol) andpre-exponential factor, A (min-1)) were calculated using isoconversional Ozawa-Flynn- Wall (OFW) method. Using the values of Ea and A the oxidation rate constant was calculated at 25°C and 120°C by Arrhenius equation. The oxidation rate constants of raspberry seed oil was about 2 times higher than that of blackberry seed oil, which indicates that blackberry seed oil is more stable in terms of oxidation.

Keywords

• blackberry seed oil
• raspberry seed oil
• oxidation kinetic
• dsc