Oxidative stability of camelina (Camelina sativa L.) oil using pressure differential scanning calorimetry and Rancimat method

Abstract

The camelina oil, registered in EU as Traditional Speciality Guaranteed, is an excellent edible oil rich in ω3 fatty acids, as well as a great raw material for biodiesel production. However, both variable seed quality and technological difficulties (cold pressing, no chemical refining procedure) exert an unfavorable impact on a final oil quality and its oxidative stability. Therefore, oxidative stability parameter seems to be a significant distinguishing feature of camelina oil. The aim of this work was to compare the oxidative stability of selected camelina oils and assessment of kinetic parameters of their oxidation determined by PDSC and the Rancimat methods. Cold-pressed camelina oils were initially characterized by basic quality parameters: fatty acids composition, free fatty acids, peroxide value and anisidine value. The isothermal PDSC and Rancimat procedures were conducted within the temperature range of 90–130 and 80–120 °C, respectively. From the obtained results, the times to reach the oxidation peak maximum (τmax) obtained from PDSC analysis were compared with induction times (τon) determined by Rancimat test. Based on the Arrhenius equation and transition state theory, activation energies (Ea), pre-exponential factors (Z) and specific rate constants (k) of oils oxidation at selected temperatures were calculated. Strong correlation between PDSC and Rancimat methods (R2 > 0.98) using a polynomial equation was obtained; thus, PDSC method can be preliminary recommended as an appropriate objective method for assessing the oxidative stability of camelina oils. To the best of our knowledge, this is the first study on the possible use of PDSC technique to analyze the kinetics of oxidation of camelina oil.