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The effect of the thermal treatment on chemical parameters of margarines enriched with phytosteryl fatty acid esters is evaluated. Sterols, fatty acids, polar and volatile compounds, dimers, trimers, tocopherols, 3‐MCPD and glycidyl esters are analyzed applying GPC‐RI, GC‐FID, GC‐MS, and HPLC. Additionally, a Rancimat test is performed to compare the oxidative stability of margarines. This study shows that margarines with and without added phytosteryl esters are both stable at a mild temperature of 60 °C over a period of at least 7 days. On the other side after 15 min of pan‐frying at 180 °C a degradation of unsaturated fatty acids (14–47%), phytosterols (31–49%), and vitamin‐E‐active compounds (71–100%) is found. The supplementation of margarines with phytosteryl fatty acid esters have no effect on their oxidative stability during pan‐frying characterized by Rancimat test and total polar compounds. Volatile, degradation products of fatty acids as well as phytosterols, are found after pan‐frying. The composition of volatiles after pan‐frying significantly differed depends on the presence of additional PSE in margarines. For the first time, it is shown that pan‐frying with margarines over a period of 15 min results in a remarkable formation of 3‐MCPD esters while the increase of glycidyl esters is only very moderate. Practical Application: Based on this study results additional phytosteryl esters do not have antioxidative properties on margarines upon pan‐frying. What is more, they are not stable during pan‐frying at 180 °C. A significant amount of nutritionals as phytosterols, vitamin E active compounds, unsaturated fatty acids are degraded within 15 min and other undesired compounds as dimers, trimers, 3‐MCPD esters are formed. According to the research, heating at a high temperature over longer time should not be applied to this kind of product to avoid oxidation of valuable constituents and formation of degradation products. Volatile compounds which were found are characteristic for fatty acids and phytosterols degradation and can be used as indicators of margarines oxidation. The research presents chemical changes in margarines with and without additional phytosteryl/phytostanyl fatty acid esters. In the graphical abstract compounds which naturally occur in those margarines are presented and compounds which are formed after thermo‐oxidative degradation during pan‐frying. [ABSTRACT FROM AUTHOR]

Cold-pressed rapeseed oil is among the most popular virgin oils. Different processing methods yield oils varying in chemical composition and oxidative stability. The experiment aimed at identifying the differences (mostly in volatiles) between rapeseed oil obtained from peeled seeds (RO) and oils obtained by three pre-treatment methods: pressing whole seeds (WSO), flakes (FO) and roasted flakes (RFO). Volatiles were analysed using GCxGC-ToFMS and data were processed using statistical multivariate analysis. Fatty acid composition was determined using GC-FID. The oils' oxidative stability was measured using peroxide value. Free fatty acids' value, absorbance at 236 and 238 nm and chlorophyll content were also determined. Also, a sensory panel evaluation was performed. PCA was found to be effective tool for differentiating the oils on the basis of their volatile compounds. RO was most similar to WSO from the second pressing. Fatty acid composition analysis yielded differences between the experimental oils and RO. RO had the highest PV, p-AV and Totox values. WSO from the first pressing (WSO1) had the highest oxidative stability. Sensory analysis found that WSO1 was most similar to RO. Both oils had an intense cabbage-like and fruity odour. The study showed that the results of volatile compounds' analysis differs from those of sensory analysis in oils comparison. Practical applications: The results demonstrate that the rapeseed oil obtained from whole seeds may have a volatile compounds composition that is similar to that of rapeseed oil obtained from peeled seeds. PCA makes it possible to differentiate between samples varying in pre-treatment method as well as between samples subjected to the same pre-treatment method, but obtained from a second pressing. Sensory panel performed by trained panellists may demonstrate which oils are most desirable when rated for selected attributes. The results of sensory panel may differ from those of volatile compound analysis performed with GCxGC-ToFMS. In the current study, the volatile compounds in cold-pressed rapeseeds oil obtained from peeled seeds with those in rapeseed oils obtained from seeds prepared with various pre-treatment methods are compared. The obtained results are compared with those of sensory evaluation. The study shows that the results obtained by means of statistical analysis based on volatile compounds do not always correlate with those of sensory panel evaluation in oils comparison. [ABSTRACT FROM AUTHOR]

Cold-pressed linseed and camelina oils have been available on the global market for many years. They are known for their high contents of polyunsaturated fatty acids (PUFAs), mainly α-linolenic (ALA). This study aimed to evaluate the quality and oxidative stability of linseed and camelina cold-pressed oils purchased in retail outlets in Poland. The fatty acid composition, peroxide value, acid value, anisidine value, chlorophyll pigments, carotenoid pigments, and oxidative stability of these oils were analyzed. It was found that all analyzed oils meet the standards of requirements of the Codex Alimentarius (2009) for cold-pressed oils. The content of chlorophyll and carotenoid pigments of linseed and camelina oils was significantly different. The percentage composition of PUFAs was high in both types of oils, but it was significantly higher in linseed than in camelina oils. The results of Rancimat and PDSC tests show low oxidative stability of all tested oils, although camelina oils were more stable than linseed oils. Practical applications: Based on the study, it can be concluded that linseed and camelina oils should be included in the human diet to provide an optimal ratio of omega-6 to omega-3 fatty acids. The differences between tested oils of the same seed species were significant. This study shows that quick methods of testing an oils oxidative stability (Rancimat and PDSC) may be successfully applied in oil studies. The study evaluates the quality of cold-pressed linseed and camelina oils purchased in retail outlets in Poland. The research shows a correlation ( r = −0.673) between content of polyunsaturated fatty acids and oxidative stability of tested oils. Oxidative stability was determined by Rancimat test and fatty acid composition by GC-FID. [ABSTRACT FROM AUTHOR]