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This study evaluated the influence of the extraction method on the composition, quality and oxidation stability of chia seed oil. Commercial chia seeds were purchased from a local market and oils were obtained using various methods: Classical Soxhlet extraction using hexane and acetone, supercritical fluid extraction with CO2 at 70 and 90°C, and screw‐pressing from native seeds (cold process), and from seeds conditioned at 110°C (hot process). The oils were characterized by their contents of sterols, tocochromanols, phenolic compounds, carotenoids and squalene, acid and peroxide values and induction times. It was found that the method of obtaining oil had an influence on the extraction of components and oxidative stability. The most favorable method was classical extraction with acetone. This solvent was the most effective in the extraction of total lipids and bioactive components, especially phenolic compounds and carotenoids. The content of these components was highly correlated with induction time. The recovery of oil was generally lower by pressing than by extraction methods and the content of sterols and phenolic compounds was also reduced. In turn, fluid extraction at 70°C was effective in the extraction of squalene and the quality of oil extracted by this method was comparable to cold pressed oil. Practical applications: Chia seeds contain a large amount of oil (from 25 to 35%), which is rich in polyunsaturated fatty acids, mainly α‐linolenic and linoleic acids, with share of ca. 60–67% and 20%, respectively. The high content of PUFA makes this oil very susceptible to oxidation. The seeds are also abundant in many phytochemicals (sterols, tocopherols, squalene, waxes, carotenoids, and phenolics), but their extractivity to the oil depends on the processing conditions. In the study, we evaluated the composition and stability of chia seed oils obtained by classical solvent extraction, supercritical fluid extraction with CO2 and screw‐pressing. It was shown that the most favorable method was the extraction with acetone. This solvent was the most effective in extraction of total lipids and bioactive components, especially phenolic compounds and carotenoids. Oil obtained by extraction with acetone was additionally characterized by the highest oxidative stability. This information may be of support to producers for obtaining chia oil more stable and with better nutritional and nutraceutical properties. Oil obtained by extraction with acetone is very different from other oils considering the quality, stability, and contents of bioactive compounds.

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This study was conducted to evaluate the variation in chemical composition and oxidative stability of 21 different commercial rapeseed oils. Their composition was estimated immediately after opening the packaging and for the same oils at the end of their induction period. The oxidation of oils was conducted at 110°C in an oven test, while the induction time was determined in a Rancimat test at the same temperature. It was found that the initial ratio of n-6 to n-3 fatty acids was close to 2.2 to 1. These oils differed mainly in minor acids, such as C16:0 and C20:1. At the end of their shelf life, a reduction of C18:2 and C18:3 acids shares was found, which was accompanied by a slight increase of n-6 to n-3 ratio. The most variable oil-soluble compounds of oils were carotenoids, chlorophylls, and phenolics, while the tocopherols were the most stable. Induction time was the most positively correlated with the oil-soluble phenolics (r ¼ 0.76 for all samples) and chlorophylls (r ¼ 0.77 for refined oils), while carotenoids generally acted as pro-oxidants (r ¼ À0.66 for all oils). The degradation degree of tested compounds during oxidation (on average) was as follows: phytosterols > tocopherols > carotenoids > phenolic compounds > chlorophylls.Practical applications: Rapeseed oil is a popular edible oil and may be a good source of oil-soluble vitamins, polyunsaturated fatty acids and antioxidants in human diet. However, its composition depends mainly on the rape genotypes, cultivation conditions, industrial practices, and storage conditions. In this study, we evaluated the variability in chemical composition of typical commercial rapeseed oils immediately after opening the package and at the end of their induction time. We have shown that fatty acids composition of tested oils was relatively stable, while their minor compounds content were significantly different. Oils oxidative stability was mainly related to phenolic compounds. These informations are important both for the consumers (nutrition facts), and industry (phenolics as antioxidants).

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The study was carried out to optimize pumpkin oil recovery in the process of aqueous extraction preceded by enzymatic maceration of seeds, as well as to compare the quality of the obtained oil to the quality of cold-pressed pumpkin seed oil. Hydrated pulp of hulless pumpkin seeds was macerated using a 2% (by mass) cocktail of commercial pectinolytic, cellulolytic and proteolytic preparations (Rohapect UF, Rohament CL and Colorase 7089). The optimization procedure utilized response surface methodology based on Box- -Behnken plan of experiment. The optimized variables of enzymatic pretreatment were pH, temperature and maceration time. The results showed that the pH value, temperature and maceration time of 4.7, 54 °C and 15.4 h, respectively, were conducive to maximize the oil yield up to 72.64%. Among these variables, the impact of pH was crucial (above 73% of determined variation) for oil recovery results. The oil obtained by aqueous enzymatic extraction was richer in sterols, squalene and tocopherols, and only slightly less abundant in carotenoids than the cold-pressed one. However, it had a lower oxidative stability, with induction period shortened by approx. 30% in relation to the cold-pressed oil.