Refined Rapeseed Oil Research Articles

The influence of nitrogen and carbon dioxide on the oxidative stability of fully refined rapeseed oil

The aim of this research was to assess the effect of nitrogen and carbon dioxide as well as of two methods of their application, i.e. the gas blanket method and the flushing method on the oxidation rate of the fully refined rapeseed oil. Both gases effectively reduced the oxidative changes in the tested rapeseed oil, however, carbon dioxide proved to be more effective in protecting the oil against oxidation compared to nitrogen. The peroxide values obtained in the Schaal oven test and the long‐term storage test were, in both methods, significantly lower when using carbon dioxide than when using nitrogen. In the long storing test, carbon dioxide significantly reduced the p‐anisidine value compared to nitrogen, regardless of the method used. The continuous flushing of oil with nitrogen or carbon dioxide protected the oil against oxidation almost completely, even at high temperatures (120°C). The oxygen dissolved in oil does not have any impact on oil oxidation.

Age-related macular degeneration: Effects of a short-term intervention with an oleaginous kale extract—a pilot study

ObjectiveAge-related macular degeneration (AMD) is a multifactorial degenerative disease of the retina, which accounts for slowly progressive visual impairment in the elderly. An increased dietary intake of xanthophylls is suggested to be inversely related to the risk of macular disease. MethodsThe present study was designed as a randomized, double-blind, placebo-controlled, parallel trial examining the influence of a short-term intervention with an oleaginous extract of Brassica oleracea var. sabellica L. (kale) on plasma xanthophyll concentrations and the optical density of the macular pigment xanthophylls (MPOD). Twenty patients with non-exudative AMD were recruited for a 10-wk study period (2-wk run-in, 4-wk intervention, 4-wk washout). All participants received 50 mL of a beverage containing either an oleaginous extract of kale (kale) or refined rapeseed oil (placebo). The verum product provides 10 mg lutein and 3 mg zeaxanthin per day. ResultsThe concentrations of the xanthophylls in plasma and the MPOD increased significantly in the kale group after 4 wk of intervention. The successive washout period resulted in a significant decline of the values in plasma and macula. The values at the end of the study were still significantly higher than the initial values. Nevertheless, the improvements did not persist over 4 wk of washout. ConclusionThe distribution of the xanthophylls in the macula seems to be more dynamic than originally assumed.

A study of rheological behavior for refined rapeseed oil

AbstractThe refined rapeseed oil were carefully studied in recent years because they may constitute a raw material for biodegradable lubricants getting organic. These oils are an alternative to synthetic mineral oils. This article presents rheological behavior of refined rapeseed oil. The dynamic viscosity of refined rapeseed oil was determined at temperatures range between 313 - 363 K and shear rates range from 3.3 - 120 s-1. For temperature ranging between 313 - 363 K refined rapeseed oil has a Bingham fluid behavior.

Micronutrients-fortified rapeseed oil improves hepatic lipid accumulation and oxidative stress in rats fed a high-fat diet

Intake of high-fat diet is associated with increased fatty livers. Hepatic lipid accumulation and oxidative stress are key pathophysiological mechanisms in this disease. Micronutrients polyphenols, tocopherols and phytosterols in rapeseed exert potential benefit to hepatoprotection, but most of these micronutrients are removed by the traditional refining process. The purpose of the present study was to determine whether rapeseed oil fortified with these micronutrients can decrease hepatic lipid accumulation and oxidative stress induced by high-fat diet. Sprague–Dawley rats received rodent diet contained 20% fat whose source was refined rapeseed oil (RRO) or fortified RRO with low, middle and high quantities of these micronutrients for 10 weeks. Intake of RRO caused a remarkable hepatic steatosis. Micronutrients supplementation was effective in reducing steatosis as well as total triglyceride and total cholesterol contents in liver. These micronutrients also significantly increased hepatic antioxidant defense capacities, as evaluated by the significant elevation in the activities of SOD and GPx as well as the level of GSH, and the significant decline in lipid peroxidation. These findings suggest that rapeseed oil fortified with micronutrients polyphenols, tocopherols and phytosterols may contribute to prevent fatty livers such as nonalcoholic fatty liver disease by ameliorating hepatic lipid accumulation and oxidative stress.

The use of oxygen content determination method based on fluorescence quenching for rapeseed oil shelf-life assessment

The knowledge of the storage characteristics over the intended shelf-life period is in the interest of the manufacturing companies and it follows from the requirements of consumers, retailers and law regulations. The aim of the study was an attempt to use non-invasive oxygen determination method based on fluorescence quenching to evaluate the shelf-life of rapeseed oil.The subjects of investigation were refined rapeseed oil samples stored at different temperature conditions (20, 40, 50 and 60 °C) under ambient air and modified atmosphere (50 °C). The samples were analyzed periodically for hydroperoxides using the iodometric method and for the oxygen content in the headspace (with the use of OxySense® 325i system).The results show that lipid degradation during storage was accompanied by oxygen loss in the headspace. The relationship between peroxide value and oxygen concentration fitted the polynomial models. The fluorescence quenching method of oxygen determination may be a suitable and rapid tool for non-destructive shelf-life evaluation of edible oils. In packaging with pure nitrogen, oxygen indicators provide valuable information on the correctness of the packaging process.

Differentiation of Refined and Virgin Edible Oils by Means of the trans- and cis-Phytol Isomer Distribution

The differentiation of nonrefined (e.g., cold-pressed) and refined edible oils is an important task in food control because of the higher commercial value of the former. Here, we explored the suitability of the relative abundance of cis-phytol as a marker for authentication of nonrefined edible oils. Phytol, the tetramethyl-branched, monoenoic alcohol, is found widespread in nature as a part of chlorophyll. In chlorophyll, only trans-phytol is found. In this study, we present a method for the analysis of the phytol isomers, considering that traces of cis-phytol (contributing 0.1% to the phytol content) can be determined next to trans-phytol. For this purpose, phytol was gathered with the unsaponifiable matter from the oil, trimethylsilylated, and analyzed by gas chromatography coupled to mass spectrometry. With this method, 27 samples of edible oils (16 refined and 11 nonrefined edible oils) were analyzed for the abundance of cis-phytol relative to trans-phytol. In the nonrefined oils (e.g., olive oil, rapeseed oil, maize oil, and sunflower oil), cis-phytol contributed 0.1% (n = 3) or less (n = 8) to the phytol content. In contrast, the refined olive oils (n = 4) contained a share of 1.3-3% cis-phytol; the refined rapeseed oil (n = 3) contained a share of 0.7-1.0% cis-phytol; and the refined sunflower oil (n = 4) contained a share of 0.3-0.9% cis-phytol. Only one refined pomegranate kernel did not contain cis-phytol. The phytol concentration was not suited to distinguish nonrefined from refined oils. In contrast, our data suggest that the virtual absence of cis-phytol can be used as a marker for nonrefined (e.g., cold-pressed) edible oils.

Effect of oat by-product antioxidants and vitamin E on the oxidative stability of pork from pigs fed diets supplemented with linseed oil

The aim of the experiment was to compare the antioxidative potential of an oat by-product with the effect of vitamin E on the oxidative stability of pork from pigs fed a diet enriched with linseed oil. Thirty-four crossbreed barrows were fed individually from 39 to 109 kg body weight (BW) on one of four diets: a control diet based on barley–triticale–soybean (Diet C), a diet containing an oat by-product (Diet O), and the same diets supplemented with vitamin E (100 mg/kg diet) (Diets CE and OE, respectively). The oat by-product, comprising oat hulls and bran, was included at 10 and 20% in the grower and finisher diets, respectively. To Diets O and OE, refined rapeseed oil was added to equalise their energy content to Diets C and CE. Compared to Diets C and CE, the inclusion of the oat by-product in Diets O and OE increased the antioxidative capacity of water-soluble and lipid soluble compounds in these diets. Dietary treatment did not influence growth performance, slaughter value, longissimus dorsi (LD) muscle quality measured by nutrient contents, pH, drip loss or colour. Vitamin E supplementation increased the α-tocopherol concentration in serum and meat (p < 0.01), and decreased the formation of thiobarbituric acid reactive substances (TBARS) in the fresh and stored LD (p < 0.01). In addition, diets with the oat by-product increased serum α-tocopherol concentration (p < 0.01) and decreased the TBARS levels in the fresh and stored LD (p < 0.05), without increasing muscle α-tocopherol concentration. The obtained results indicate that the phenolic compounds present in oat by-products have a considerable antioxidant potential and a beneficial effect on the pig organism and oxidative stability of meat. However, dietary inclusion with the oat by-product was not as efficient as supplementation with vitamin E.

Rapeseed oil fortified with micronutrients reduces atherosclerosis risk factors in rats fed a high-fat diet

BackgroundMicronutrients polyphenols, tocopherols and phytosterols in rapeseed exert potential benefit to cardiovascular system, but most of these micronutrients are removed by the refining process. The aim of this study was to determine the effect of rapeseed oil fortified with these micronutrients on the atherosclerosis risk factors in rats fed a high-fat diet.MethodsThe rodent diet contained 20% fat whose source was refined rapeseed oil (RRO) or fortified refined rapeseed oil with low, middle and high quantities of these micronutrients (L-, M- and H-FRRO). Forty male SD rats were divided into four groups. One group received RRO diet and other groups received L-, M- and H-FRRO diet for 10 weeks.ResultsMicronutrients supplementation significantly increased plasma antioxidant defense capacities, as evaluated by the significant elevation in the activities of GPx, CAT and SOD as well as the level of GSH, and the significant decline in lipid peroxidation. These micronutrients also reduced the plasma contents of TG, TC and LDL-C and increased the ratio of HDL-C/LDL-C. In addition, in parallel with the enhancement of these micronutrients, plasma levels of IL-6 and CRP declined remarkably.ConclusionRapeseed oil fortified with micronutrients polyphenols, tocopherols and phytosterols may contribute to prevent atherogenesis by ameliorating plasma oxidative stress, lipid profile and inflammation.

Micronutrient-Enriched Rapeseed Oils Improve the Brain Oxidant/Antioxidant System in Rats Fed a High-Fat Diet

The main proposal of this study was to evaluate in vivo whether micronutrient-enriched rapeseed oils obtained using different crushing and refining procedures and characterized by different quantities and qualities of micronutrients (optimized oils) could have any beneficial effect on the antioxidant status of the brain. Sprague-Dawley rats were fed a high-fat diet for 4 weeks. The lipid source consisted of 20% optimized rapeseed oils with different quantities and qualities of micronutrients. The control group received traditional refined rapeseed oil. The experimental optimized oils decreased lipid peroxidation and increased endogenous antioxidant status in parallel with the enhancement of micronutrients. No alteration in acetylcholinesterase activity was induced by the high-fat diet in any experimental group. These results indicate that a regular intake of optimized rapeseed oils can prevent oxidative stress, providing evidence that optimized rapeseed oils could be a functional food with potentially important neuroprotective properties.

Deactivation of HDS catalysts in deoxygenation of vegetable oils

Several rapeseed oils with different degree of upgrading were used as feedstocks for deoxygenation over sulfided CoMo/γ-Al 2O 3 catalyst. The rapeseed oil samples differed in the concentration of inorganic impurities, water, free fatty acids and phospholipids. The catalytic experiments were carried out in a fixed bed reactor at constant reaction conditions (310 °C, WHSV = 2 h −1, hydrogen pressure 3.5 MPa). Refined rapeseed oils were converted to hydrocarbons more efficiently than neat rapeseed oil, trap grease and waste oil. The high concentration of phospholipids in trap grease was the most likely cause of catalyst deactivation by coking. Decomposition of phospholipids as well as oligomerization of rapeseed oil by phosphoric acid at 310 °C was confirmed by separate laboratory experiments. The high concentration of alkalis in waste rapeseed oil was the main reason for increased deactivation in comparison with neat rapeseed oil. Sulfur removal from catalyst active sites affected adversely the deoxygenation of triglycerides. The catalyst deoxygenation activity was partially restored by pulse addition of dimethyldisulfide (DMDS) to the feedstock, however the degradation of active sites by loss of sulfur was not fully reversible. In contrast, continually added sulfur agent (DMDS) ensured significantly slower catalyst deactivation. Moreover, presence of H 2S lowered considerably hydrodeoxygenation/decarboxylation ratio.

Micronutrient-enriched rapeseed oils reduce cardiovascular disease risk factors in rats fed a high-fat diet

Many epidemiological studies have demonstrated that vegetable food consumption is associated with a reduced risk of cardiovascular diseases. The beneficial effects have been attributed to the content of bioactive molecules present in large quantities in plant food. The main proposal of this study was to evaluate in vivo whether micronutrient-enriched rapeseed oils (optimised oils) obtained using different crushing and refining procedures and characterised by different quantities and qualities of micronutrients, could have any beneficial effect on lipid profile and antioxidant status of plasma and liver. Sprague–Dawley rats were fed a high-fat diet for 4 weeks. The lipid source consisted of 20% optimised rapeseed oils with different quantities and qualities of micronutrients. The control group received traditional refined rapeseed oil. The experimental optimised oils all had a hypolipidaemic effect. In the group fed the highest levels of micronutrients, the reduction in plasma and hepatic triglycerides reached 25% and 17%, respectively, that of cholesterol 20% and 14%, respectively. In plasma, the ferric antioxidant capacity, superoxide dismutase, glutathione peroxidase and reduced glutathione significantly increased and lipid peroxidation decreased in parallel with the enhancement of micronutrients. The same trend was observed in the liver, except for glutathione peroxidase which was not affected by optimised oils. These results indicate that a regular intake of optimised rapeseed oils can help to improve lipid status and prevent oxidative stress, providing evidence that optimised oils could be a functional food with potentially important cardioprotective properties.

Antioxidant capacity of rapeseed meal and rapeseed oils enriched with meal extract

AbstractResponse surface methodology (RSM) was used to evaluate the quantitative effects of two independent variables: solvent polarity and temperature of the extraction process on the antioxidant capacity (AC) and total phenolics content (TPC) in meal rapeseed extracts. The mean AC and TPC results for meal ranged between 1181–9974 µmol TE/100 g and 73.8–814 mg sinapic acid/100 g of meal. The experimental results of AC and TPC were close to the predicted values calculated from the polynomial response surface models equations (R2 = 0.9758 and 0.9603, respectively). The effect of solvent polarity on AC and TPC in the examined extracts was about 3.6 and 2.6 times greater, respectively, than the effect of processing temperature. The predicted optimum solvent polarity of ε = 78.3 and 63.8, and temperature of 89.4 and 74.2°C resulted in an AC of 10 014 µmol TE/100 g and TPC of 863 mg SAE/100 g meal, respectively. The phenolic profile of rapeseed meal was determined by an HPLC method. The main phenolics in rapeseed meal were sinapine and sinapic acid. Refined rapeseed oils were fortified with an extract – rich in polyphenols – obtained from rapeseed meal. The supplemented rapeseed oil had higher AC and TPC than the refined oil without addition of meal extracts. However, AC and TPC in the enriched oils decreased during storage. The TPC in the studied meal extracts and rapeseed oils correlated significantly (p&lt;0.0000001) positively with their AC (R2 = 0.9387).Practical applications: Many bioactive compounds extracted from rapeseed meal provide health benefits and have antioxidative properties. Therefore, it seems worth to consider the application of antioxidants extracted from the rapeseed meal for the production of rapeseed oils with potent AC. Moreover, antioxidants extracted from the rapeseed meal were added to refined rapeseed oil in order to enhance its AC. AC was then tested by FRAP assay. FRAP method is based on the reduction of the ferric tripyridyltriazine (Fe3+‐TPTZ) complex to the ferrous tripyridyltriazine (Fe2+‐TPTZ), and it is simple, fast, low cost, and robust method. FRAP method does not require specialized equipment and can be performed using automated, semi‐automatic, or manual methods. Therefore the proposed FRAP method can be employed by the fat industry laboratories to asses the AC of rapeseed oils and meal.

Chemical Composition and Oxidative Stability of Selected Plant Oils

AbstractScientific data on the oxidative stability of borage oil, Camelina sativa oil, linseed oil, evening primrose oil and pumpkin seed oil are scarce. Chemiluminescence (CL) methods most commonly used to determine the oxidative stability of oils include measurement of hydroperoxide, intensity of light emitted during the accelerated oxidation process performed at high (&gt;100 °C) temperatures or assisted by forced flow of air/oxygen through the sample. The aim of this study was to investigate the chemical composition and oxidative stability of selected vegetable oils available on the Polish market. Oxidative stability was determined using a fast, novel chemiluminescence‐based method, in which light emitted during oxidation process conducted at 70 °C in the presence of some catalyzing Fe2+ ions is measured. A reaction of the applied type has not been reported so far. High contents of tocopherols and phytosterols were found in the analyzed oil samples. Oxidative stability of the samples was in most cases higher than the stability of refined rapeseed oil, a relatively stable substance from the oxidation point of view.

Conversion of Vegetable Oils into Hydrocarbons over CoMo/MCM-41 Catalysts

Deoxygenation of triglycerides over Co and Mo sulfides supported on a series of mesoporous molecular sieves (MCM-41) with varying Si/Al ratio has been investigated in this contribution. The catalysts were tested in a flow reactor at reaction temperatures 300 and 320 °C, hydrogen pressures 2–11 MPa and space velocities 1–4 h−1 using refined rapeseed oil as a feedstock. Incorporation of Al into the framework of MCM-41 led to an increase of both conversion of triglycerides and selectivity to hydrocarbons, namely n-heptadecane and n-octadecane. However, the conversion of triglycerides was lower than that achieved over alumina supported CoMo. Moreover, the rather high selectivity to oxygenated products, as compared with alumina supports, has made possible a detailed description of the reaction intermediates and their dependence on the reaction conditions.

Liquid rheology study on refined rapeseed oil

The rapeseed oil extracted from the mature seeds was purified by refining processing, and the rheological characteristic analysis of the viscosity and dynamic shear rate at gradient temperatures was made. The result shows that at 20, 40, 60 and 80 °C respectively, when the shear rate gradually rises, the torque increases accordingly but its viscosity does not vary distinctly. The result suggests that when rapeseed oil is used as the raw of edible oils and industries, the working procedures at high temperature will not influence its rheological characteristic distinctly.

Tocopherol retention in physically refined rapeseed oil as a function of deodorization temperature

AbstractThe effect of deodorization temperature (between 220 and 270 °C) on tocopherol retention in physically refined rapeseed oil during deodorization in a plant‐scale semi‐continuous tray‐type deodorizer was investigated. Among the three tocopherol homologues detected in the samples of rapeseed oils under study, the α‐ and γ‐tocopherol homologues, with the latter predominating, constituted the most abundant part of total tocopherols, accompanied by a small amount of δ‐tocopherol. The retention values calculated for both total and individual tocopherols decreased linearly with increasing deodorization temperature. The retention of total tocopherols decreased considerably from 91.5% at 220 °C to 54.7% at 270 °C, approaching a value of about 80% in the main area of concern between 230 and 240 °C. The retention values of individual tocopherols as well as the slopes resulting from the equations relating these retentions to deodorization temperature were observed to decrease in the same order as their molecular weights. Since the retention of α‐tocopherol is slightly higher than that of γ‐tocopherol, the average proportion of α‐tocopherol during deodorization slightly increases at the expense of γ‐tocopherol.

The use of electronic and human nose for monitoring rapeseed oil autoxidation

AbstractThis work was aimed at assessing the effectiveness of the electronic nose to monitor off‐flavor associated with lipid oxidation as a supplementary tool to human sensory panel assessment. Therefore, correlations between electronic nose and sensory analysis were determined. Also GC analyses and chemical analyses of oil samples were run to characterize the analyzed samples with well‐described parameters. Refined rapeseed oil was subjected to an accelerated storage test for 12 days at 60 °C and to an ambient temperature storage test in which it was stored in retail plastic bottles for up to 6 months. PCA of electronic nose data samples stored at an elevated temperature was related to PCA of sensory analysis, and similarities in sample clustering were observed. For samples stored at room temperature, the human panel showed greater sensitivity than the electronic nose. Prediction models based on PLS of electronic nose data were able to predict the sensory quality changes during storage at elevated and room temperature, ranging from 0.721 to 0.989 and from 0.849 to 0.881 (p &lt;0.05), respectively. PV and p‐AV were well predicted on the basis of both electronic nose (0.989, 0.998 for elevated temperature; 0.907, 0.881 for room temperature) and sensory analysis data (0.973, 0.993 for elevated temperature; 0.939, 0.886 for room temperature). Applicability of the electronic nose technology to verify sensory and rancidity changes during storage showed to be promising in quality control of oils.

Tocopherol, tocotrienol and plant sterol contents of vegetable oils and industrial fats

The tocopherol and tocotrienol (i.e. tocol) and plant sterol contents of 14 vegetable and 9 industrial fats and oils available on the Finnish market in 2005 were determined using NP-HPLC with fluorescence detection (tocols) and GC-FID (plant sterols). Best sources of α-tocopherol were wheat germ (192 mg/100 g) and sunflower oil (59 mg/100 g). Oils richest in γ-tocopherol were camelina (72 mg/100 g), linseed (52 mg/100 g) and organic rapeseed oil (51 mg/100 g). Total tocol contents were between 4.2 mg/100 g (coconut fat) and 268 mg/100 g (wheat germ oil). Plant sterol contents ranged from 69 mg/100 g in a frying fat to 4240 mg/100 g in wheat germ oil. Organic rapeseed oil, the second best source of plant sterols, contained 887 mg/100 g. The variations of the total tocol and sterol contents in 10 rapeseed oil sub-samples analysed separately were 9.7% for tocols and 9.9% for sterols in refined rapeseed oil, and 6.3% for tocols and 4.2% for sterols, respectively, in cold-pressed rapeseed oil. In addition to the target compounds, plastochromanol-8 could be determined in all plant-based samples with contents ranging from 0.13 (walnut oil) to 18 mg/100 g (linseed oil). The lignans sesamin and sesamolin could be identified in sesame oil.

Strain-dependent acute lung injury after intra-tracheal administration of a ‘refined’ aniline-denatured rapeseed oil: A murine model of the toxic oil syndrome?

Most attempts to reproduce the toxic oil syndrome in animals, either with case-related oils or with refined rapeseed oils, have been unsuccessful. An aniline-denatured rapeseed oil that was subsequently refined according to a protocol yielding relevant markers of “toxic oil” (oil RSO160401) had led to possibly relevant lesions following oral administration in mice. Therefore, in the present study, RSO160401 was subjected to a more extended in vivo testing. To try and maximize the response, BALB/c, DBA/2, A/J, and C57BL/6 mice were administered RSO160401 oil by a single intra-tracheal instillation (1 ml/kg), with sacrifice 2 or 7 days post-exposure. Intra-tracheal administration led to a strain-dependent acute response: acute pulmonary damage in DBA/2 and A/J mice, and increases in blood eosinophilia in DBA/2 mice (6.5% vs 3.1% in controls). The pulmonary lesions regressed with time after exposure, being more complete in A/J than in DBA/2 mice. The observation of strain-dependent effects suggests that genetic susceptibility is an important factor in disease induction by the RSO160401 oil.

Geometrical isomerization of polyunsaturated fatty acids in physically refined rapeseed oil during plant‐scale deodorization

AbstractThe effect of the operating temperature (between 220 and 270 °C) on the formation of trans isomers of linoleic and linolenic acids in physically refined rapeseed oil during deodorization in a plant‐scale semicontinuous tray‐type deodorizer (capacity 10 t/h) was investigated. The industrial procedures of physical refining consisted of a two‐step bleaching and deodorization process. The degree of isomerization of linoleic acid ranged from 0.33 to 4.77% and that of linolenic acid from 4.43 to 45.22% between 220 and 270 °C, respectively. A relation between the logarithm of the degree of isomerization and the deodorization temperature can be approximated by statistically highly significant linear functions for both linoleic and linolenic acids. Oleic acid was resistant to the heat‐induced geometrical isomerization. The values found for the ratio between the degrees of isomerization of linolenic and linoleic acids, slightly decreasing with increasing temperature, were equal to 13.6 and 12.9 at 230 and 240 °C, respectively. Two trans isomers of linoleic acid, exclusively with one double bond isomerized into trans configuration, and four trans isomers of linolenic acid, mostly with one double bond isomerized into trans configuration, were determined in deodorized rapeseed oils. Linolenic acid was observed to be the main source responsible for the formation of nearly all trans fatty acids in physically refined rapeseed oil. At 235 °C, a deodorization temperature considered as a reasonable technological compromise, the content of trans fatty acids in plant‐scale physically refined rapeseed oil was less than 1% of total fatty acids, which would be acceptable for further application.