Search Results (13)

This study compares the nutritional and metabolic properties of unconventional cold-pressed vegetable oils available on the Polish market. Twelve oils—milk thistle, evening primrose, flaxseed, camelina sativa, black cumin, pumpkin seed, sesame, mustard seed, sea buckthorn, blue poppy seed, borage, and safflower—were examined. The chosen oils were investigated based on their fatty acids profiles, total phenolic compounds (TPC), tocopherols, and pigment contents. Despite the high polyunsaturated fatty acids (PUFAs) content raising concerns about oxidative stability, the significant tocopherol levels and polyphenols content contribute to antioxidative protection. These oils’ favorable hypocholesterolemic, antiatherogenic, and antithrombogenic properties were highlighted by key nutritional indices, showing potential benefits for cardiovascular health. These results suggest that these oils are a promising dietary supplement for promoting both cardiovascular health and sustainability, owing to their rich content of essential fatty acids and bioactive compounds. Moreover, high correlations were found between theoretical and experimental established oxidative stability of the tested oils at the ending stage of the thermostat test. Full article

There is an unmet need for an affordable, high-quality, and non-thermally processed source of omega-3 fatty acids. Cold-pressed flaxseed oil comes closest to meeting these criteria. Flaxseed oil is also subject to rapid oxidative degradation. Sesame, black cumin, and apricot kernel oils are already used as functional foods and are more resistant to oxidative degradation. GC, HPLC, DPPH, the Folin−Ciocalteu method, and OXITEST were applied to the four cold-pressed oils and their binary blends with flaxseed oil. The fatty acid profile showed that the dominant fatty acid in flaxseed oil was linolenic acid with a content of 52.27 ± 0.17%, while oleic acid dominated in apricot kernel oil (69.45 ± 0.18%) and linoleic acid (58.80 ± 0.07%) in black cumin oil, while sesame oil was characterized by approximately equal proportions of oleic (42.21 ± 0.20%) and linoleic acids (43.37 ± 0.07%). The content of oleic acid showed a moderate, statistically significant correlation with the oxidative stability of oils and blends. The antioxidant capacity of flaxseed oil (25 ± 1.4 μmol TE/g) was most strongly influenced by the addition of black cumin oil (75 ± 3.5 μmol TE/g), so that the highest antioxidant capacity was achieved by the blend with an addition of 50% of this oil (57.5 ± 2.4 μmol TE/g). Oxidative stability tests show that apricot kernel oil stabilizes flaxseed oil the most and increases the oxidative stability of the blend by up to 60%. Full article

This study aimed to evaluate the oxidative stability and surface properties of cold-pressed vegetable oils using the Langmuir monolayer technique. Six oils—milk thistle, evening primrose, flaxseed, camelina sativa, black cumin, and pumpkin seed—were analyzed to investigate their molecular organization and behavior at the air/water interface, particularly after undergoing oxidation. The results showed that oils rich in polyunsaturated fatty acids (PUFAs), such as flaxseed and evening primrose oils, formed monolayers with larger molecular areas and lower stability, which led to faster oxidative degradation, especially under thermal conditions. In contrast, pumpkin seed oil, with a higher content of saturated fatty acids (SFAs), formed more condensed and stable monolayers, enhancing its resistance to oxidation. Black cumin oil, with a balanced profile of SFAs and monounsaturated fatty acids (MUFAs), demonstrated similar stability. The Langmuir technique facilitated a detailed analysis of monolayer phase transitions: PUFA-rich oils transitioned more readily to less stable phases, while SFA-rich oils maintained durable, condensed structures. These findings underscore the utility of this method for assessing the oxidative stability of vegetable oils and highlight key parameters—such as surface pressure, molecular area, and elasticity modulus—that can support the optimization of oil storage and quality in the food industry and related sectors. Full article

Nigella sativa L. seeds and their industrial process products, oils, cake, and meal, are valuable sources of bioactive compounds with antioxidant properties. In this work, the effect of technological processes on the antioxidant capacity (AC) and total phenolic content (TPC) in the black cumin oils obtained by cold pressing and solvent extraction, as well as the by-products, were evaluated. The AC values of black cumin seeds (BCS), cold-pressed black cumin oil (BCCPO), black cumin oil extracted from seeds (BCEO-S), black cumin oil extracted from cake (BCEO-C), black cumin cake (BCC), and black cumin meal (BCM) were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and cupric reducing antioxidant capacity (CUPRAC) assays, whereas TPC in these samples was analyzed by the Folin–Ciocalteu (FC) method. Two applied conventional oil extraction methods, screw pressing and solvent extraction, significantly affected the AC and TPC in the obtained black cumin oils and by-products. The solvent-extracted black cumin oils revealed higher antioxidant properties (DPPH = 4041–16,500 μmol TE/100 g, CUPRAC = 1275–4827 μmol TE/100 g) than the cold-pressed black cumin oil (DPPH = 3451 μmol TE/100 g and CUPRAC = 3475 μmol TE/100 g). In addition, the oil yield (20.92–48.86%) and antioxidant properties of BCCPO (DPPH = 2933–5894 μmol TE/100 g and TPC = 135–199 mg GAE/100 g) and BCC (DPPH = 1890–2265 μmol TE/100 g and TPC = 284–341 mg GAE/100 g) closely depended on the nozzle diameters (5, 8, and 10 mm) mounted in a screw press. Although both by-products were a rich source of antioxidants, BCM had significantly lower CUPRAC (1514 μmol TE/100 g) and TPC (92 mg GAE/100 g) values than BCC (CUPRAC = 3397 μmol TE/100 g and TPC = 426 mg GAE/100 g). Nevertheless, acid hydrolysis and alkaline hydrolysis of BCM extracts significantly increased their antioxidant potential. However, the DPPH (35,629 μmol TE/100 g), CUPRAC (12,601 μmol TE/100 g), and TPC (691 mg GAE/100 g) results were higher for the BCM extract after acid hydrolysis than those for alkaline hydrolysate (DPPH = 2539 μmol TE/100 g, CUPRAC = 5959 μmol TE/100 g, and TPC = 613 mg GAE/100 g). Finally, the generated AGREEprep metrics highlighted the sustainability and the greenness of the cold pressing of oil from BCS. Full article

A variety of specific plant oils produced from plants other than sunflowers and olives has been offered on the food market, most of them obtained using cold pressing in order to preserve sensitive oil components. The objective of this study was to evaluate their fatty acid (FA) compositions by means of nutritional quality indices. FA profiles (37 FAs) of 20 commercially available specific edible plant oils were obtained using GC-FID and further evaluated by calculating lipid quality indices. FA profiles and their corresponding quality indices showed the expected variability, depending on the plant source. For the purpose of comparison, the same indices were determined for sunflower and olive oil: the polyunsaturated-to-saturated FA ratio (PUFA/SFA) was 5.1 and 0.5, the hypocholesterolemic/hypercholesterolemic ratio (HH) was 13.0 and 6.8, the index of atherogenicity (IA) was 0.08 and 0.14, the index of thrombogenicity (IT) was 0.23 and 0.24, and the unsaturation index (UI) was 146.6 and 93.5, respectively. A higher PUFA/SFA ratio is beneficial for cardiovascular health, as are a lower IA and IT. The UI indicates stability of unsaturated FAs during storage and processing. Flaxseed oil was the only one showing a PUFA/SFA ratio higher than sunflower oil (5.8). Regarding IA, flaxseed, almond, apricot, plum, hazelnut, macadamia, and sea buckthorn oils were similar to sunflower oil; sesame, black cumin, poppy, pumpkin, avocado, raspberry seed, argan, moringa, and rose seed oils resembled olive oil; and palm oil was isolated at 0.80, while coconut oil reached 23.4. Flaxseed, almond, apricot, plum, raspberry seed, macadamia, rose seed, and sea buckthorn oils showed a lower IT than sunflower and olive oils (range 0.06–0.18). Coconut and palm oils showed lower HH ratios than olive oil, whereas, in the case of flaxseed, almond, apricot, plum, hazelnut, and sea buckthorn oils, this ratio was higher than the one in sunflower oil (range 14.0–16.1). Flaxseed oil was characterized by the highest UI (208.4), while others were distributed along the 90–170 interval (except coconut and palm oils). According to their nutritional quality indices, a variety of plant oils are valuable sources of FAs in human nutrition. Full article

Oils derived from non-traditional seeds, such as safflower, milk thistle, and black cumin seeds, have recently grown in popularity. Seed oil is in high demand due to consumer interest in illness prevention and health promotion through healthier diets that include a high concentration of monounsaturated and polyunsaturated fatty acids and antioxidant phenolic components. This study assessed the quality characteristics of cold-pressed seed oil at three unique storage times: at the beginning of the trial (i.e., before storage), after 2 months, and after 4 months. The results of the performed analyses indicate that the acidity of extracted black cumin, safflower, and milk thistle seed oil fluctuates considerably over time. The highest acidity level change was detected for black cumin seed oil, from 10.26% after the extraction to 16.96% after 4 months of storage at 4 °C. Consequently, changes between pre- and post-storage peroxide concentrations were discernible after four months. Peroxide value in milk thistle and safflower seed oils increased by 0.92 meq/kg and 2.00 meq/kg, respectively, during the assessed storage time, while that of black cumin was very high and fluctuated. The storage period substantially affects oxidative changes and the oxidation stability of the oil. Major changes were observed in the polyunsaturated fatty acids in seed oil during storage. The essential changes were detected in the black cumin seed oil odor profile after 4 storage months. Their quality and stability, as well as the nature of the changes that occur during the storage of oil, require extensive investigation. Full article

In an attempt to discover a safe growth promoter and partial alternative for antibiotics, this existing study explores the efficacy of using assorted levels of cold-pressed oil mixtures consisting of 1:1 clove and black cumin (Nigella sativa) oils (CLNS) against the indices of growth and carcass traits, as well as blood components of growing Japanese quails. In a complete randomized design, three hundred growing unsexed Japanese quails (one week of age) were included in this experiment. The treated groups were as follows: (1) control basal diet (CLNS0), (2) basal diet + 1.50 mL CLNS/kg diet (CLNS1.5), and (3) basal diet + 3.00 mL CLNS/kg diet (CLNS3). The results showed that supplementing the diet with a 3.00 mL CLNS/kg diet insignificantly improved body weight (BW) compared with the CLNS0 and CLNS1.5 groups. A significantly (p < 0.05) higher feed intake and feed conversion ratio—FCR— (deterioration of feed conversion) were reported after the addition of CLNS. Feeding the quails on a 3.00 mL CLNS/kg enriched-diet yielded superior values of dressing percentage, carcass yield, and breast and thigh relative weights compared to other groups. A significant decline was noticed in creatinine and BUN levels in birds fed a 1.50 and 3.00 mL CLNS/kg diet compared with the CLNS0 group The liver enzymes and total bilirubin activities showed insignificant effects in quails fed CLNS-enriched diets. The total protein and globulins concentrations presented a significant augment in quails that received CLNS. The antiradical activity of CLNS supplementation showed increases in hepatic reduced glutathione (GSH) activity and the levels of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase, glutathione S transferase (GST), and glutathione reductase (GR) in birds. The concentration of MDA in hepatic homogenates that received CLNS-diets was significantly decreased compared with the control quails. These findings clarified that the dietary inclusion of CLNS can enhance the growth performance and antioxidative status of growing Japanese quails. Full article

The antioxidant capacity (AC); amounts of tocopherols, sterols, and polycyclic aromatic hydrocarbons; oxidative parameters; fatty acid composition (FAC); and sensory quality of cold-pressed black cumin oils (CPBCOs) available on the Polish market were analyzed and compared. The AC levels of the CPBCO samples were determined using four assays, namely 2,2-diphenyl-1-picrylhydrazyl (DPPH = 226.8–790.1 μmol TE/100 g), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS = 385.9–1465.0 μmol TE/100 g), cupric-reducing antioxidant capacity (CUPRAC = 975.3–19,823.3 μmol TE/100 g), and Folin–Ciocalteu assays (FC = 168.1–643.7 μmol TE/100 g). The FAC scores were typical for black cumin oil, except for the sample CPBCO4, which had a higher content of α-linolenic acid (C18:3 = 23.33%), pointing to possible oil adulteration. Additionally, the concentrations of total sterols (TSC = 372 mg/100 g) and tocopherols (TTC = 42.3 mg/100 g) in this sample were higher than those for other investigated oils (TSC = 159–222 mg/100 g, TTC = 1.9–10.4 mg/100 g respectively). The oxidative stability levels (IP = 8.21–37.34 h), peroxide values (PV = 21.36–123.77 meq O₂/kg), acid values (AV = 6.40–22.02 mg KOH/kg), and the sums of four specific polycyclic aromatic hydrocarbons (∑4PAHs = 4.48–46.68 μg/kg) in the studied samples differed significantly (p < 0.05). A sensory lexicon including 12 attributes was developed and applied for the sensory evaluation of oils using a quantitative descriptive analysis (QDA). Full article

The aim of the study was to analyse the chemical composition and oxidation stability of selected cold-pressed oils and oil mixtures. The oils were tested for their initial quality, fatty acid composition, total phenolic compounds, DPPH, and ABTS free radical scavenging activity. The Rancimat method was used to assess oxidative stability. The obtained results were subjected to principal component analysis (PCA) to determine the influence of selected chemical properties on the oxidative stability of the oil. It has been found that different factors of oil quality influence the stability of cold-pressed oils. The highest correlation coefficient was noted between the induction time, peroxide value, and TOTOX indicator (r = 0.89). Fatty acid composition, including the percentage of SFA, MUFA, PUFA, and the ability to scavenge ABTS captions radicals, did not significantly affect the oxidative stability of the oils. Black cumin seed oil was the most resistant to the oxidation processes in the Rancimat apparatus, mainly due to the high content of phenolic compounds (384.66 mg GAE/100 g). On the other hand, linseed oil and its mixtures were the least stable. Their fatty acid composition was dominated by a polyunsaturated α-linolenic fatty acid, significantly reducing the antioxidant resistance. Full article

Polar compounds and polymers are regarded as the most reliable indicators of oil degradation during heating, and it is desirable to find methods to reduce these undesirable changes. The aim of this study was (1) to determine the effect of enrichment with black cumin cold-pressed oil (CP) or essential oil obtained from black cumin cold-pressed oil in an equivalent amount (ES) on limiting the polar compounds and polymers content in blends based on refined rapeseed oil during high-temperature heating in a thin layer; (2) to determine tocochromanol losses and their effect on the change content of the polar compounds and polymers. Four fortified oils were made from refined rapeseed oil and one of the four additives (10% CP, 20% CP, 0.1% ES, and 0.2% ES). All fortified oils and refined rapeseed oil as a control sample were heated at 170 and 200 °C on the pan in a thin layer and evaluated regarding loss of individual tocochromanol homologs by HPLC-FL, polar compounds content, oxidized triacylglycerols (TAG), and polymers content by HPSEC-ELSD. Additionally, the fatty acid profile in nonheated oil was investigated. Tocochromanol analysis showed loss in all the samples. At 170 °C polymers were not detected; no difference was noted for polar compounds and oxidized TAG content; only the 20% CP sample showed a higher level. At 200 °C the 10% CP sample exhibited a significant protective effect with the lowest content of polar compounds, oxidized TAG, and dimers. Full article

Cold-pressed oils are becoming increasingly popular. The stability of these oils is the main concern, as changes occur in their organoleptic characteristics during storage, which could affect their suitability for consumption. Various natural plant components with antioxidant properties are added to cold-pressed oils to preserve their freshness for as long as possible. The present study assessed the effect of addition of garlic and chili pepper on the chemical properties of cold-pressed oil extracted from seeds of flax, hemp, and black cumin. First, the moisture level and the fat and protein content in the seeds were determined, and the oil was then extracted. The oil extraction yield was calculated, and the oil was analyzed to determine its fatty acid composition, acid value, peroxide value, and oxidative stability. Three samples were prepared for further analyses: a control sample with pure oil and two samples supplemented with 1 g/100 g of garlic or chili pepper. Changes in the oil samples stored for 2, 4, and 6 weeks were assessed based on the values of some parameters. The additives were found to exert antioxidant properties, as they caused effective inhibition of oxidative changes occurring during storage of the oils. The additives also extended the induction time. Full article

The aim of the study was to examine combinations of base oils and herbal additives with a view to obtaining macerates with improved health benefits. Base oils were cold-pressed from the seeds of black cumin, borage, evening primrose, safflower, walnut, common hazel, and oilseed rape, as well as the flesh of sea-buckthorn fruits. They were then supplemented with herbs, including basil, thyme, and sage, in order to create macerates. Total antioxidant activity and tocopherol level were analyzed in oils, macerates, and oil cakes. Additionally, chemical properties of oil cakes—such as the level of fibre, vitamin C, β-carotene, and lutein—were also examined. Supplementation with herbs caused diversified effects on antioxidant activity and tocopherol level in macerates depending on the base oil, herb, and supplementation method. The obtained results indicate that tocopherol level does not play a decisive role in determining the antioxidant properties of oils, macerates, and oil cakes, suggesting significant involvement of other antioxidants. Among the tested macerates, the most promising one seems to be oilseed rape oil enriched with sage or basil to maximize its health benefits. The study can serve as a starting point for the development and implementation of functional macerates and oil cakes in healthy nutrition. Full article

Cold-pressed oils are highly valuable sources of unsaturated fatty acids which are prone to oxidation processes, resulting in the formation of lipid oxidation products, which may deteriorate the sensory quality of the produced oil. The aim of the study was to determine the main volatile compounds which differentiate examined oils and could be used as the markers of lipid oxidation in various oils. In the experiment, cold-pressed oils—brown flaxseed, golden flaxseed, hempseed, milk thistle, black cumin, pumpkin, white poppy seed, blue poppy seed, white sesame, black sesame and argan oils from raw and roasted kernels—were analyzed. To induce oxidative changes, an accelerate storage test was performed, and oils were kept at 60 °C for 0, 2, 4, 7 and 10 days. Volatile compound profiling was performed using SPME-GC-HRToFMS. Additionally, basic measurements such as fatty acid composition, peroxide value, scavenging activity and phenolic compound contents were carried out. Multivariate statistical analyses with volatile compound profiling allow us to differentiate oils in terms of plant variety, oxidation level and seed treatment before pressing. Comparing black cumin cold-pressed oil with other oils, significant differences in volatile compound profiles and scavenging activity were observed. Compounds that may serve as indicators of undergoing oxidation processes in flaxseed, poppy seed, milk thistle and hemp oils were determined. Full article