DSC isothermal and non-isothermal assessment of thermo-oxidative stability of different cultivars of Camelina sativa L. seed oils

There is growing interest worldwide in the use of camelina oil for food as well as for biofuel purposes. For both of these applications, oxidative stability is an important feature of the oil. Therefore, the aim of this study was to test the thermal resistance to oxidation of three different cultivars of camelina oil i.e., Omega, Luna and Smilowska by means of isothermal and non-isothermal differential scanning calorimetry (DSC) oxidation measurement. For isothermal DSC analysis, different temperatures were tested (120, 140, 160 degrees C) and in the non-isothermal mode different scanning rates (1, 2, 5, 10, 15 degrees C min(-1)) were used. To support the DSC data, chemical analyzes were also performed i.e., fatty acid composition, peroxide value, p-anisidine value, acid value and radical scavenging activity by 2,2-diphenyl-1-picrylhydrazyl (RSA DPPH). The isothermal test indicated that for all camelina oils the oxidation induction time (OIT) decreased with an increase in temperature on average from 69.83 min for 120 degrees C to 5.13 min for 160 degrees C. The OIT values corresponded very well with non-isothermal DSC results, for which the onset temperatures (T-on) increased with the increase of heating rate on average from 142.15 degrees C for 1 degrees C min(-1) to 185.75 degrees C for 15 degrees C min(-1). The parameters of DSC oxidative stability i.e., OIT as well as T-on values were negatively correlated with some unsaturated fatty acids content e.g., alpha-linolenic acid (C18:3, n-3) and positively with yellowness b* and RSA DPPH. Oil from camelina seeds of Smilowska cultivar, which was characterized by the lowest content of alpha-linolenic acid and the highest b* value of color and RSA DPPH, was the most thermally stable oil.

Automated summary

There is growing interest worldwide in the use of camelina oil for food as well as for biofuel purposes. This study aimed to investigate the thermal resistance to oxidation of three different cultivars of camelina oil. Isothermal and non-isothermal differential scanning calorimetry (DSC) were used to measure the oxidation of the oils. The results showed that the thermal stability of the oil was negatively correlated with the content of unsaturated fatty acids and positively correlated with color and radical scavenging activity.