Multi-analytical Approach to Oxidative Stability of Unrefined Argan, Chia, Rosa Mosqueta and Olive OilsLeiva GE1#, Šegatin N2#, Mazzobre MF3, Abramovic H2, Abram V2, Vidrih R2, Buera MP1,3 and Poklar Ulrih N2*
- *Corresponding Author:
- Nataša Poklar Ulrih
Department of Food Science, Biotechnical Faculty
University of Ljubljana, Ljubljana, Slovenia
E-mail: [email protected]
Received date: November 16, 2015; Accepted date: December 22, 2015; Published date: December 30, 2015
Citation: Leiva GE, Šegatin N, Mazzobre MF, Abramovic H, Abram V, et al. (2015) Multi-analytical Approach to Oxidative Stability of Unrefined Argan, Chia, Rosa Mosqueta and Olive Oils. J Nutr Food Sci 6:450. doi: 10.4172/2155-9600.1000450
Copyright: © 2015 Leiva GE, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Fresh, unrefined argan (AR), chia (CH), rosa mosqueta (RM) and olive (OL) oils were evaluated for thermal stability with dielectric spectroscopy, differential scanning calorimetry, peroxide values (PV) and free fatty acids (FFAs). The dielectric constant ( '), dielectric loss ( ''), and melting temperature (Tm) of the oils correlated with degree of unsaturation, with the highest static dielectric constant (εs') for CH oil (3.311), the most unsaturated. AR and CH oils showed the highest electrical conductivities at 500 Hz (505, 230 pS/m, respectively), and CH and RM oils the lowest Tm (-41.0, -36.6°C, respectively). All oils stored at 65°C for 432 hr showed minor changes in εs'. After 180°C for 28 hr, εs' and ε'' increased from 5% to 7%. Initial PVs of these oils were <3.7 mmol O2/kg, and for highly unsaturated CH oil this increased to 221 mmol O2/kg after 65°C for 432 hr. At 180°C, the FFAs increased in all oils, except AR oil. Oxidation onset temperature of the oils correlated with PVs after 65°C for 432 hr (r=-0.91) and with FFAs and εs' after 180°C for 28 h (r=-0.81, -0.83, respectively).