In this study, 27 market and edible cold-pressed oils from 10 different oilseeds were analysed. Oxidative stability and the chemical composition of oils were evaluated. The oils were investigated for their primary quality, fatty acid composition, total phenolic content and antioxidant activity. Rancimat and pressure differential scanning calorimetry (PDSC) were used to assess oils oxidative stability. Principal component analysis (PCA) was conducted to determinate impact of selected chemical characteristics on tested oils' oxidative stability in accelerated modes. PCA indicated that none of the chemical compounds correlated strongly with the oils' oxidative stability determined by the Rancimat method. Correlation coefficients describing the impact of different chemical compounds on induction time determined using the Rancimat method were between r = −0.54 (C18:3) to r = 0.62 (chlorophyll pigments). Oxidative stability of oils determined using the Rancimat and pressure differential scanning calorimetry (PDSC) were characterised by low correlation (r = 0.66). According to the statistical analyses, oils were divided into four groups, which depend on the method of oxidative stability evaluation did not differ.

In this study, 29 cold-pressed camelina (Camelina sativa L.) oils, pressed from seeds grown in Poland and purchased directly from local producers, were analyzed. The degree of change in the tested oils’ characteristic hydrolytic and oxidative lipid values was determined. Oxidative stability was determined using the Rancimat and PDSC methods. Fatty acid and phytosterol contents were determined by GC-FID, and tocopherols by HPLC. The analyzed oils were characterized by good, but variable, quality, and met the requirements specified for cold-pressed edible oils. Highly desirable fatty acid composition, low SFA content (about 6%), high α-linolenic acid content (34.7–37.1%), and optimal PUFA n-3 to PUFA n-6 ratio (1.79–2.17) were shown. The high nutritional value of camelina oils was confirmed on the basis of high contents of tocopherols (55.8–76.1 mg/100 g), phytosterols (331–442 mg/100 g), and carotenoids (103–198 mg of β-carotene/kg). The optimal nutritional quality indices were as follows: 0.05–0.07 for the atherogenicity index (AI), and 0.1–0.2 for the thrombogenicity index (TI). The significant impact of primary (PV) and total oxidation (TOTOX) of camelina oil on oxidative stability was evaluated using Rancimat and PDSC methods. Both methods were also confirmed to be appropriate for the assessment of the oxidative stability of camelina oils.

Oxidative stability and minor components of market linseed oils were evaluated. The oils were investigated for their primary and secondary oxidation products, fatty acid composition and pigment content, and samples were also examined for their scavenging of 1, 1‐ diphenyl‐2‐picrylhydrazyl (DPPH) and total phenolic content. Rancimat and pressure differential scanning calorimetry were used to assess oxidative stability. The analysed oils were of good quality, meeting the requirements of the Codex Alimentarius standard. Linseed oils were characterised by 45–65% content of α‐linolenic acid. The TEAC equivalent of linseed oils ranged from 1.25 to 1.42 mM of Trolox kg−1 oil, and FAE ranged from 60.25 to 115.12 mg of ferulic acid 100 g−1 oil. The correlation between linseed oil oxidative stability as measured by the Rancimat and PDSC methods was low (r = 0.55). Based on the obtained results of oxidative stability and the content of chemical compounds, principal components analysis was conducted. PCA indicated that none of the chemical compounds correlated strongly with the oxidative stability of linseed oils as determined by the Rancimat method. However, in the case of the PDSC method, the content of primary and secondary products of oxidation had the strongest impact on the oxidative stability of linseed oils. The correlation coefficients describing the impact of different chemical compounds on induction time using the Rancimat and PDSC tests were between −0.43 to 0.45 and −0.82 to 0.72, respectively. Practical applications: The results show that linseed oils available on the market were of differing but good quality. Results of oxidative stability tests demonstrate that Rancimat and pressure differential scanning calorimetry (PDSC) methods should not be used interchangeably for assessing linseed oil oxidative stability (r = 0.55). The initial degree of oxidation had the greatest impact on the oxidative stability of linseed oil, but none of the measured quality parameters showed a high correlation with the Rancimat induction time. Principal component analysis verified the designated correlations between induction times in the Rancimat and PDSC tests and quality features. PCA also confirmed differences between the examined linseed oils. Market linseed oils are examined to their oxidative stability using Rancimat and pressure differential scanning calorimetry, and their chemical composition. The influence of selected discriminants on the oxidative stability of linseed oil is determined.

The aim of this study was to compare the oxidative stability of linseed oil using the pressure differential scanning calorimetry (PDSC) and Rancimat methods, and to determine the kinetic parameters of linseed oil oxidation. Five cold pressed linseed oils were oxidized at different temperatures under PDSC (90-140 °C) and Rancimat (70-140 °C) test conditions. The oxidative stability of the linseed oils was calculated based on induction times (PDSCτ, Rancimat τ), the Arrhenius equation and activated complex theory, frequency factors (), the reaction rate coefficient () for all temperatures, activation energies (), numbers, activation enthalpies (∆), and activation entropies (∆). The PDSC method was more convenient for the determination of the induction time of linseed oils than the Rancimat method. During oxidation measurement by Rancimat method, the linseed oil polymerized, which affected the measurements. The reaction rate coefficient increased with rising temperature during measurement by both methods. The activation energy values of linseed oil oxidation using the PDSC and Rancimat methods ranged from 93.14 to 94.53 and 74.03 to 77.76 kJ mol, respectively. The , ∆, and ∆ values for the analyzed linseed oils were between 2.11-2.13, 90.54-91.30 kJ mol, -33.20 to -30.90 J mol K calculated by PDSC measurements, and 2.23-2.32, 71.03-74.76, -59.42 to -49.08 J mol K by Rancimat measurements, respectively.

Oxidative stability of cold‐pressed rapeseed oil was determined using two accelerated methods—Pressure Differential Scanning Calorimetry (PDSC) and Rancimat. Tests were carried out at six different temperatures (90–140°C), and the induction time (PDSC τmax, Rancimat τon) was a result. Based on the induction times, the Arrhenius equation and the activated complex theory, frequency factors (Z), constant reaction rate (k) for all temperatures, activation energies (Ea), Q10 numbers, activation enthalpies (ΔH‡), and activation entropies (ΔS‡) for cold‐pressed rapeseed oils oxidative stability were calculated. The activation energy values of rapeseed oil oxidation in PDSC and Rancimat method ranged from 86.71 to 90.54 kJ mol−1 and from 75.73 to 77.64 kJ mol−1, respectively. The Q10, ΔH‡, and ΔS‡ values for analyzed rapeseed oil were between 2.00 and 2.07, 83.48 and 87.31 kJ mol−1, −61.30 and −51.40 J molK−1 calculated for PDSC measurements, and from 1.84 to 1.86, 72.50 to 74.41 kJ mol−1, −66.30 to −60.84 J molK−1 for Rancimat measurements, respectively. Practical applications: This research present the differences in the oxidative stability of cold‐pressed rapeseed oil using PDSC and Rancimat method. The results of the PDSC test may be recommended as an appropriate objective method for assessing the oxidative stability of cold‐pressed rapeseed oil. Also, results of kinetic oxidation parameters may be helpful to predicting the oil oxidative stability at different temperatures of oxidation process. The study evaluate the oxidative stability of cold‐pressed rapeseed oils using Pressure Differential Scanning Calorimetry (PDSC) and Randimat method. The research shows a correlation (r = 0.9975) between two accelerated methods (PDSC and Rancimat) of assessing lipid oxidative stability.