Microwave‐assisted hydrodistillation of essential oil from Zataria multiflora Boiss

Microwave‐assisted hydrodistillation (MAHD) has recently gained attention for the extraction of essential oils. A concern with the use of MAHD is the possibility of sample deterioration during the extended exposure to microwave irradiation. In this study, MAHD was applied as a new and green technology for the extraction of essential oil from Zataria multiflora Boiss. (Shirazi thyme) aerial parts. Superior results were obtained with the proposed method in terms of extraction time [1 h vs. 4 h in hydrodistillation (HD)] for an essential oil recovery of 3.66 and 3.44%, respectively. Images obtained from thyme leaves using scanning electron microscopy indicated a sudden eruption of essential oil glands undergoing MAHD. GC‐MS analysis of the essential oils did not indicate any new or missing compounds in the essential oil obtained by MAHD in comparison with that by HD. Therefore, a microwave oven can be safely used for the extraction of essential oil from Shirazi thyme.     

Chemical composition, angiotensin I-converting enzyme inhibitory, antioxidant and antimicrobial activities of essential oil of Tunisian Thymus algeriensis Boiss. et Reut. (Lamiaceae)

The present study describes chemical composition, angiotensin I-converting enzyme (ACE) inhibitory, antioxidant and antimicrobial activities of the essential oil of wild growing Thymus algeriensis Boiss. et Reut. (Lamiaceae), a traditional medicinal plant which is mainly endemic in Tunisia and Algeria. The essential oil from the fresh leaves and flowers of T. algeriensis were extracted by hydrodistillation and analysed by GC and GC/MS. Fifty-seven compounds were identified accounting for 97.71% of the total oil, where oxygenated monoterpenes constituted the main chemical class (44.85%). The oil was dominated by camphor (7.82%), 4-terpineol (7.36%), α-pinene (6.75%), 1,8-cineole (5.54%) and cis-sabinene hydrate (5.29%). The T. algeriensis essential oil was found to possess an interesting inhibitory activity towards ACE with an IC50 value of 150 μg/ml. The obtained results also showed that this oil can act as radical scavengers (IC₅₀ = 0.8 mg/ml) and displayed a lipid peroxidation inhibitory activity (IC₅₀ = 0.5 mg/ml) as evaluated by 2,2-diphenyl-1-picrylhydrazyl and β-carotene bleaching methods, respectively. Furthermore, the oil was tested for antimicrobial activity against six bacterial strains and two fungal strains. The inhibition zones and minimal inhibitory concentration values of microbial strains were in the range of 13.5-64 mm and 1-6 μl/ml, respectively. The oil exhibited remarkable inhibitory activity against fungal and Gram-positive bacteria strains.     

Antioxidant activity of Satureja bachtiarica Bunge essential oil in rapeseed oil irradiated with UV rays

In this study, application of two concentrations (0.03 and 0.06%) of Satureja bachtiarica Bunge essential oil (EO) were examined on oxidative stability of rapeseed oil (RO) during autoxidation and after irradiation with ultraviolet (UV) rays (exposition 30 min) at 60°C. The main compounds of EO extracted by the recently designed ohmic ultrasonic extractor (distillation unit) were identified as thymol (～30%), carvacrol (～15%) and caryophyllene oxide (～12%). Antioxidant activity of EO was compared to butylated hydroxytoluene (BHT) during autoxidation. The UV rays induced oxidation process in RO samples both with and without additives. This effect was more vigorous when irradiation was carried out prior to addition of the additives. It was further established that antioxidant activity of EO was better than BHT in samples treated by UV rays. Moreover, EO was able to reduce the stable free radical 2, 2′‐diphenyl‐1‐picrylhydrazyl (DPPH) with a 50% inhibition concentration (IC₅₀) of 32.5 ± 0.6 µg/mL. The findings show the good potential of EO when it is used as a natural antioxidant in food lipids.     

Oxidative stability of sunflower oil bodies

This study investigates the oxidative stability of sunflower oil body suspensions (10 wt‐% lipid). Two washed suspensions of oil bodies were evaluated over 8 days at three temperatures (5, 25 and 45 °C) against three comparable sunflower oil emulsions stabilized with dodecyltrimethylammonium bromide (DTAB), polyoxyethylene‐sorbitan monolaurate (Tween 20) and sodium dodecyl sulfate (SDS) (17 mM). The development of oxidation was monitored by measuring the presence of lipid hydroperoxides and the formation of hexanal. Lipid hydroperoxide concentrations in the DTAB, SDS and Tween 20 emulsions were consistently higher than in the oil body suspensions; furthermore, hexanal formation was not detected in the oil body emulsions, whereas hexanal was present in the headspace of the formulated emulsions. The reasons for the extended resistance to oxidation of the oil body suspensions are hypothesized to be due to the presence of residual seed proteins in the continuous phase and the presence of a strongly stabilized lipid‐water interface.     

Lipid oxidation inhibiting capacities of blackseed essential oil and rosemary extract

Lipid oxidation is the main deterioration process that occurs in vegetable oils containing lipid molecules with polyunsaturation. The aim of the present study was to investigate the possible effects of blackseed (Nigella sativa L.) essential oil (BEO) and rosemary (Rosmarinus officinalis L.) extract (RE) on stabilization of sunflower oil under accelerated storage conditions. RE was obtained by soxhlet extraction using methanol, whereas BEO was hydrodistilled from the blackseed extract obtained by extraction using petroleum ether (b.p. 40–60°C). The results indicate that both extracts stabilize sunflower oil to a certain extent, the extent being greater with RE than with BEO based on measurements of peroxide value, p‐anisidine value, amount of nonoxidized linoleic acid in saponified oil samples by HPLC‐DAD, concentration of conjugated diene hydroperoxide, and UV light absorption. The oil stabilizing effect of BEO against lipid oxidation, especially at concentrations of 0.06 and 0.1 g/100 g oil was found to increase as the temperature increased, according to principal component analysis results. Based on its strong lipid oxidation inhibiting capacity, RE can be used as a potential natural extract for stabilizing sunflower oil against oxidation. BEO, at carefully selected concentrations, can be suggested as an alternative supplement of plant origin for improving oil stabilization. Practical applications: Sunflower oil is a widely used vegetable oil for cooking and frying, and has a high linoleic acid content of about 40–70%. Here we show that sunflower oil can be stabilized by adding rosemary and blackseed extracts. The treatment can be useful especially in applications which require heating the oil to high temperatures.     

Proficiency test on the determination of mineral oil in sunflower oil

Following the discovery of mineral oil contamination of Ukrainian sunflower oil in April 2008, the Institute for Reference Materials and Measurements (IRMM) of the European Commission's Joint Research Centre (JRC) was requested by the Directorate General Health and Consumers (DG SANCO) to organise a proficiency test on the determination of mineral oil in sunflower oil. The aim of this test was to evaluate the comparability of analysis results gained by laboratories in the EU and the Ukraine. The organisation of the study and the evaluation of the results were done in accordance with “The International Harmonised Protocol for the Proficiency Testing of Analytical Chemistry Laboratories” and ISO Guide 43. Altogether 62 laboratories from 19 EU member states, Switzerland and the Ukraine subscribed for participation in the study. Four test samples at concentration levels between about 100 and 350 mg/kg, comprising contaminated crude sunflower oil, contaminated refined sunflower oil, and spiked sunflower oil, and a solution of mineral oil in n‐heptane were dispatched to the participants. The participants were asked to determine the mineral oil content of the test samples by application of their in‐house analysis methods. In total, 55 sets of results were reported to the organisers of the study. The performance of laboratories was expressed by z‐scores for the oil samples and by relative bias for the mineral oil solution in n‐heptane. The percentage of successful laboratories in the determination of the mineral oil content of sunflower oil was for all sunflower oil test materials about 80%.     

Antioxidant activity of the essential oil and methanolic extract of cumin seed (Cuminum cyminum)

The antioxidant activities of the essential oil and crude methanolic extract (CEx) of cumin seed (Cuminum cyminum) were evaluated. Total phenolics and tocopherols contents, reducing power, DPPH radical‐scavenging capacity (EC₅₀), and the oxidative/oil stability index were assessed. The contents of total phenolics and total tocopherols in the essential oil (18.47 and 0.11 mg/g, respectively) were significantly lower than those of the CEx (29.12 and 0.42 mg/g, respectively). The CEx had an EC₅₀ value (0.74 mg/mL) significantly lower than those of the essential oil and α‐tocopherol (1.20 and 32.50 mg/mL, respectively). The reducing power of the CEx (459.46 mmol Fe²⁺ per mass) was significantly higher than those of the essential oil (18.47 mmol/L) and α‐tocopherol (99.96 mmol/L). The addition of CEx to the purified sunflower oil significantly improved its oxidative stability at the levels of 800 ppm and higher whereas the essential oil indicated no antioxidant activity at the levels experimented (200–2000 ppm). The CEx was considered to be a useful antioxidative compound in bulk oil and emulsion systems but the essential oil showed no antioxidant activities. The CEx in the bulk oil system had higher antioxidant activities than in the emulsion system. The CEx concentration of 2000 ppm showed the highest antioxidant activity and reduced the formation of hydroperoxides and secondary products more than the other antioxidative compounds applied in this study.     

Kinetics of the base-catalyzed sunflower oil ethanolysis

The kinetics of the sunflower oil ethanolysis process using NaOH as a catalyst was studied at different reaction conditions. The reaction system was considered as a pseudo-homogeneous one with no mass transfer limitations. It was also assumed that the chemical reaction rate controlled the overall process kinetics. A simple kinetic model consisting of the irreversible second-order reaction followed by the reversible second-order reaction close to the completion of the ethanolysis reaction was used for the simulation of the triglyceride conversion and the fatty acid ethyl ester formation. The proposed kinetics model fitted the experimental data well.     

Hydroconversion of sunflower oil on Pd/SAPO-31 catalyst

This work presents results from the hydroconversion of sunflower oil on the bifunctional Pd/SAPO-31 catalyst as a perspective technological way for single-stage production of hydrocarbons in the diesel fuel range that have improved low-temperature properties. Transformation of sunflower oil was performed at temperatures of 310-360 °C and WHSV = 0.9-1.6 h⁻¹, under a pressure of 2.0 MPa in a laboratory flow reactor. Gaseous and liquid reaction products were analyzed by GC using an internal standard method as well as by ¹H and ¹³C NMR spectroscopy. At temperatures 320-350 °C, liquid reaction product contained only hydrocarbons, the main components were identified as C₁₇ and C₁₈n-alkanes and i-alkanes. Pd/SAPO-31 catalyst demonstrated high initial activity for the hydroconversion of the feed and good isomerizating properties, but its deactivation was followed after several hours of operation. Physico-chemical properties of both fresh and spent catalysts were compared. The influence of reaction conditions on the composition of the reaction products is also discussed.     

Premium quality renewable diesel fuel by hydroprocessing of sunflower oil

Hydroprocessing of neat sunflower oil was carried out at 360-420 °C and 18 MPa over a commercial hydrocracking catalyst in a bench scale fixed bed reactor. In the studied experimental range, products consisted exclusively of hydrocarbons that differed significantly in composition. While the concentration of n-alkanes exceeded 67 wt.% in the reaction products collected at 360 °C, it decreased to just 20 wt.% in the product obtained at 420 °C. Consequently, the fuel properties of the latter product were very similar to those of standard (petroleum-derived) diesel fuel. Particularly, it exhibited excellent low-temperature properties (cloud point −11 °C; CFPP −14 °C). Reaction products obtained at 400 and 420 °C were blended into petroleum-derived diesel fuel in three concentration levels ranging from 10 to 50 wt.% and the fuel properties of these mixtures were evaluated. Diesel fuel mixtures containing the product of sunflower oil hydrocracking at 420 °C showed very good low-temperature properties including cloud point (−8 °C) and CFPP (−15 °C) that was further lowered to −25 °C due to addition of flow improvers.     

Influence of interesterification on the oxidative stability of marine oil triacylglycerols

To understand the relationship between triacylglycerol structure of marine oils and their oxidative stability, peroxide values and absorbed oxygen levels of whale, sardine, cod liver and skipjack oils, interesterified by lipase and NaOCH₃, were compared with those of native oils during storage at 40°C. Triacylglycerol structures of marine oils were characterized by high-performance liquid chromatography and differential scanning calorimetry analyses. Enzymatically interesterified fish oils were more stable than native oils because the level of highly unsaturated triacylglycerols was decreased. However, the oxidative stability of interesterified whale oil was more susceptible to oxidation than the native oil.     

柠檬香茅精油的提取及抗氧化活性研究

文中采用水蒸汽蒸馏法对海南产柠檬香茅进行精油提取,研究了提取时间、料液比、香茅粗细、香茅部位、提取液成分等因素对精油收率及主要成分存在影响,精油提取率为0.09-1.06%,50g 长2cm的干柠檬香茅在1400mL含8 g NaCl的水溶液,提取时间180min时精油出油率最高,为1.06%;随提取条件不同,精油成分有所变化,但主要成分无明显差异,主要为芳樟醇、橙花醛、香叶醛、香叶醇和香叶酸,此五种主要成分的含量约占精油总量的86-96%。电子自旋共振法（ESR）测试结果表明1%香茅精油乙醇溶液对羟基自由基具有一定清除活性,清除率32%。     

Pan-frying stability of NuSun oil,a mid-oleic sunflower oil

Pan-frying is a popular frying method at home and in many restaurants. Pan-frying stabilities of two frying oils with similar iodine values (IV)—mid-oleic sunflower oil (NuSun oil; IV=103.9) and a commercial canola oil (IV=103.4)—were compared. Each oil sample was heated as a thin film on a Teflon-coated frying pan at ∼180°C to a target end point of ≥20% polymer. High-performance size-exclusion chromatography analysis of the mid-oleic sunflower and canola oil samples indicated that the heated samples contained 20% polymer after approximately 18 and 22 min of heating, respectively. The food oil sensor values increased from zero to 19.9 for the canola sample and from zero to 19.8 for the mid-oleic sunflower sample after 24 min of heating. The apparent first-order degradation rate for the mid-oleic sunflower sample was 0.102±0.008 min⁻¹, whereas the rate for the canola sample was 0.092±0.010 min⁻¹. The acid value increased from approximately zero prior to heating to 1.3 for the canola sample and from zero to 1.0 for the mid-oleic sunflower sample after 24 min of heating. In addition, sensory and volatile analyses of the fried hash browns obtained from both oils indicated there were no significant differences between the two fried potato samples.     

Life Cycle Assessment (LCA) of the biofuel production process from sunflower oil, rapeseed oil and soybean oil

Once ratified the Kyoto protocol, Spain arises the great challenge of reducing the emissions of greenhouse gases. Among the measures proposed is the introduction of biofuels in the market, both for the transport sector and for the production of heat. This paper compares the environmental impact from the production of biofuels whose origin is the oil obtained from sunflower, rapeseed and soybeans. The environmental impact of each production is performed by applying the methodology of life cycle analysis (LCA). The categories where you get a greater impact are land use, fossil fuels, carcinogens, inorganic respiratory and climate change. The cause is mainly due to the processes of seed production. We have also found a significant impact on the drying and preparation processes of the seed as well as the crude soybean oil extracting process. Moreover as the LCA shows production of rapeseed and sunflower has a positive contribution to climate change.     

Composition of organic and conventionally produced sunflower seed oil

The aim of the present study was to highlight the main differences between seed oils produced from conventionally cultivated crops and organically cultivated ones and processed using mild extraction procedures. The composition and the nutritional and health aspects of both types of sunflower seed oils were compared and were analytically tested to determine the macroscopic differences in proximate composition, the main differences in the minor components, the main quality parameters, the in vitro antioxidant activity, and the presence of trans-ethylene steroisomers in FA. No significant trends were found in the oil samples for TAG and FA composition, but remarkable differences were found in the composition of minor components and in the main chemical and analytical quality properties. The organically grown samples had a higher total antioxidant activity compared with the conventional samples. Trans FA were found only in the conventional oils.     

Transesterification of sunflower oil catalyzed by flyash-based solid catalysts

Flyash-based base catalyst was used in the transesterification of sunflower oil with methanol to methyl esters in a heterogeneous manner. Catalyst preparation variables such as, the KNO₃ loading amount and calcination temperature were optimized. The catalysts were characterized by powder XRD. The catalyst prepared by loading of 5 wt.% KNO₃ on flyash followed by its calcination at 773 K has exhibited maximum oil conversion (87.5 wt.%). The influence of various reaction parameters such as % catalyst loading, methanol to oil molar ratio, reaction time, temperature, reusability of the catalyst on the catalytic activity was investigated. K₂O derived from KNO₃ might be an essential component in the catalyst for its efficiency.     

Polyphenolic fractions improve the oxidative stability of microencapsulated linseed oil

The main objective of this study was to evaluate the effect of incorporating polyphenolic‐enriched fractions from murta leaves on the oxidative stability of linseed oil microencapsulated by spray drying. For this purpose, polyphenol‐enriched fractions from murta leaves were separated by gel permeation chromatography and chemically characterized. The oxidative stability of microencapsulated linseed oil (MLO) with antioxidants was evaluated in storage conditions at 25°C for 40 days. The antioxidant effects of the polyphenolic fractions and commercial antioxidants (BHT and trolox) on microencapsulated oil were evaluated by the value of conjugated dienes, peroxide, and p‐anisidine. In the initiation step of the oxidation, no significant oxidation delay (p>0.05) in MLO containing fractions F₆, F₈, or BHT and trolox was observed. However, in the termination step of the oxidation, the addition of fractions F₆, F₈, and BHT and trolox decreases significantly (p ≤ 0.05) the rancidity in MLO. Furthermore, the results of this study demonstrated the importance of the addition of natural antioxidants such as fractions of murta leaf extract in microencapsulated linseed oil to increase its resistance to oxidation. Practical applications: For incorporating linseed oil, a source of omega‐3 fatty acids, in the diet it is necessary to protect it against oxidative rancidity, the main cause of deterioration that affects food with a high unsaturated fat content. Microencapsulation is effective in retarding or suppressing the oxidation of unsaturated fatty acids and natural plants extracts are effective in inhibiting the lipid oxidation of microencapsulated oil. The use of process technology and a natural additive is expected to increase storage stability and enable its use in dry foods such as instant products. Linseed oil can be used in human nutrition as well as in animal feed as a replacement for fish oil.     

Modification of polycaprolactone-styrene-vinyl trimethoxysilane terpolymer with sunflower oil for coating purposes

Polycaprolactone-styrene-vinyl trimethoxysilane terpolymer was prepared and then modified with sunflower oil partial glyceride (SFOPG) via a sol–gel method for use as a binder in coating applications. Therefore, a vinyl-functionalized polyester-based macromonomer (HPCL) was prepared via ring-opening polymerization of ?-caprolactone (CL) using 2-hydroxyethyl methacrylate (HEMA) followed by copolymerization with styrene (St) and vinyl trimethoxysilane (VTMS) to yield a terpolymer (HPCL-St-VTMS). The terpolymer was characterized by FTIR, GPC and ¹H NMR. To overcome the fact that the cured film of HPCL-St-VTMS was slightly soft, SFOPG was used as a modifier and was inserted to the structure via a sol–gel reaction between the hydroxyl groups and methoxy silane moieties of the terpolymer. After this modification, the softness disappeared. Nanosize inorganic domains were observed in the SEM image. Thermal analyses of the resulting cross-linked film of SFOM-HPCL-St-VTMS were performed with DSC and TGA. SFOM-HPCL-St-VTMS, which does not melt, resulted in a higher char yield and decomposition temperature at 5% weight loss compared to the unmodified HPCL-St-VTMS film. An evaluation of the film properties indicated that SFOM-HPCL-St-VTMS can be used as a coating material.