Showing papers in "Journal of the American Oil Chemists' Society in 2012"
TL;DR: A comprehensive overview of the state of the art in oleogel research can be found in this article, where the authors summarize the research on each one of these components in order to provide a comprehensive overview.
Abstract: Structuring liquid oils has become an active area of research in the past decade, mainly due to pressures to reduce saturated fat intake and eliminate trans fats from our diets. However, replacing hard fats with liquid oil can lead to major changes in the quality of food products. Recent strategies to impart solid-fat functionality to liquid oils include the addition of unusual compounds to oil, leading to its gelation. These include small-molecule organogelators such as phytosterols and 12-hydroxystearic acid, which self-assemble into crystalline fibers which trap oil. Other crystalline additives include waxes, ceramides, monoacylglycerides, and other surfactants. Recently, the polymer ethyl cellulose was reported to form a polymer gel in triacylglyceride (TAG) oils. Other non-conventional strategies also include the formation of protein-stabilized cellular solids with oil trapped within the cells. In this review, we summarize the research on each one of these components in order to provide a comprehensive overview of the state of the area in oleogel research and provide future perspectives.
519 citations
TL;DR: Chloroform–methanol 1:1 was shown to be the best solvent mixture for extraction of total lipids from microalgae and determination of non-polar lipid content should be performed by separation of the total lipid extract on an SPE column.
Abstract: An optimized procedure for extraction of total and non-polar lipids from microalgae is proposed. The effects of solvent, pretreatment (lyophilization, inactivation of lipases, and addition of antioxidants) and cell-disruption (liquid nitrogen, sonication, and bead beating) on total lipid content, lipid class, and fatty acid composition were examined. Chloroform–methanol 1:1 was shown to be the best solvent mixture for extraction of total lipids from microalgae. When performing this extraction, lyophilized algae can be used, no pretreatment with isopropanol to inactivate the lipases is needed and addition of antioxidants is not necessary. Furthermore, cell-disruption is not essential, although in that case two extractions must be performed in series to ensure that, irrespective of the microalgal species, all lipids are extracted. Determination of non-polar lipid content should be performed by separation of the total lipid extract on an SPE column. Extraction using petroleum ether is only appropriate when a bead beater is used for pretreatment.
421 citations
TL;DR: Sunflower wax (SW) showed the most promising results and all SW samples from three different suppliers could make a gel with concentrations as low as 0.5 wt%. Candelilla wax and rice bran wax also showed good gelation properties, which varied with different suppliers as mentioned in this paper.
Abstract: Many waxes including plant waxes and animal waxes were evaluated for the gelation ability toward soybean oil (SBO) and compared with hydrogenated vegetable oils, petroleum waxes and commercial non-edible gelling agents to understand factors affecting the gelation ability of a gelator. Sunflower wax (SW) showed the most promising results and all SW samples from three different suppliers could make a gel with concentrations as low as 0.5 wt%. Candelilla wax and rice bran wax also showed good gelation properties, which, however, varied with different suppliers. Gelation ability of a wax is significantly dependant on its purity and detailed composition. A wax ester with longer alkyl chains has significantly better gelation ability toward SBO than that with shorter alkyl chains indicating that the chain length of a component in a wax such as wax ester is an important factor for gelation ability. The SW–SBO organogel showed increased melting point with increased SW content, showing the melting point range from about 47 to 65 °C with 0.5–10 wt% SW. The effects of cooling rate on crystal size and firmness of a gel were investigated. The dependence of firmness on cooling rate was so significant that the desired texture of an organogel could be achieved by controlling the cooling rate in addition to controlling the amount of gelling agent. This research reveals that a small amount of food grade plant waxes including SW may replace a large amount of the hardstock containing trans-fat or saturated fat.
170 citations
TL;DR: This study demonstrates extraction, quantification, and diversity of lipid components from two microalgae of different types, and the method of pre-drying, dry ice-assisted grinding, and sequential solvent extraction gave the highest total lipid recovery.
Abstract: A full characterization of lipid components is critical for selecting the most suitable microalgae and for downstream processing for biofuel production. This study demonstrates extraction, quantification, and diversity of lipid components from two microalgae of different types. For total lipid quantification, three extraction methods were compared and the method of pre-drying, dry ice-assisted grinding, and sequential solvent extraction gave the highest total lipid recovery. For lipid class composition determination, the photosynthetic Nannochloropsis contained 37.0% polar lipids, 41.1% triacylglycerols, and 12.5% unsaponifiable matter, whereas, the heterotrophic Schizochytrium had much less polar lipids and unsaponifiable matter. Further separation and quantification showed that Nannochloropsis contained more glycolipids (37.1% of total polar lipids) than that in Schizochytrium (14.3%), while Schizochytrium contained much more phospholipids (85.7%) than that in Nannochloropsis (44.7%). The major components in unsaponifiable matter of Nannochloropsis were hydrocarbon and cholesterol (55.8 and 37.7% of the total GC quantifiable matter), which only accounted for 29.3% of total unsaponifiable matter. For Schizochytrium, 15.4% squalene, 28.9% cholesterol, and 43.2% stigmasta-4,7,22-trien-3-ol were found in its GC quantifiable matter, and the total quantified hydrocarbon and sterols accounted for 50.5% of unsaponifiable matter. The lipid compositions of the two types of microalgae are very different, therefore, processing performance, such as lipid extraction and conversion to biodiesel may be different. Similar lipid characterization for other biofuel types of microalgae needs to be made to ensure optimal biofuel processing and fuel quality.
111 citations
TL;DR: In this article, three petroleum-based polyurethane (PU) foams were compared with two soy-based PU foams, in terms of their foam characterizations and properties.
Abstract: Polyol derived from soybean oil was made from crude soybean oil by epoxidization and hydroxylation. Soy-based polyurethane (PU) foams were prepared by the in-situ reaction of methylene diphenyl diisocyanate (MDI) polyurea prepolymer and soy-based polyol. A free-rise method was developed to prepare the sustainable PU foams for use in automotive and bedding cushions. In this study, three petroleum-based PU foams were compared with two soy-based PU foams in terms of their foam characterizations and properties. Soy-based PU foams were made with soy-based polyols with different hydroxyl values. Soy-based PU foams had higher T
g (glass transition temperature) and worse cryogenic properties than petroleum-based PU foams. Bio-foams had lower thermal degradation temperatures in the urethane degradation due to natural molecular chains with lower thermal stability than petroleum skeletons. However, these foams had good thermal degradation at a high temperature stage because of MDI polyurea prepolymer, which had superior thermal stability than toluene diisocyanate adducts in petroleum-based PU foams. In addition, soy-based polyol, with high hydroxyl value, contributed PU foam with superior tensile and higher elongation, but lower compressive strength and modulus. Nonetheless, bio-foam made with high hydroxyl valued soy-based polyol had smaller and better distributed cell size than that using low hydroxyl soy-based polyol. Soy-based polyol with high hydroxyl value also contributed the bio-foam with thinner cell walls compared to that with low hydroxyl value, whereas, petroleum-based PU foams had no variations in cell thickness and cell distributions.
105 citations
TL;DR: In this article, the detection and quantification of extra virgin olive oil adulteration by soybean (SB) and sunflower (SF) oils using FT-IR spectroscopy based on the use of PLS modeling and variable importance of projection (VIP) scores.
Abstract: Determination of adulteration and authenticity of extra virgin olive oil (EVOO) was investigated by means of infrared spectroscopy and chemometric methods. The study was focused on the detection and quantification of extra virgin olive oil adulteration by soybean (SB) and sunflower (SF) oils using FT-IR spectroscopy based on the use of PLS modeling and variable importance of projection (VIP) scores. A PLS model, using orthogonal signal correction and mean centering data pretreatments, and VIP scores variable preselection, was able to predict the concentration of sunflower and soybean oil adulterants in the 1–24 % weight ratio range with relative prediction errors lower than 3 % (w/w), for external validation samples. Moreover, the PLS-DA (discriminant analysis) model using the same preselected wavelengths was able to explain 99.9 % of variance and to predict with 100 % accuracy both classes of adulteration (EVOO–SB and EVOO–SF) in the external validation.
100 citations
TL;DR: The oils of some unconventional oilseeds were obtained by a cold-press method in which the total oil content, fatty acids, tocopherol isomers, some metal contents, antioxidant activity and oxidative stability were determined and could be evaluated as an alternative to traditionally consumed vegetable oils or as additives to them.
Abstract: The oils of some unconventional oilseeds (hemp, radish, terebinth, stinging nettle, laurel) were obtained by a cold-press method in which the total oil content, fatty acids, tocopherol isomers, some metal contents (Ca, Mg, Fe, Cu), antioxidant activity and oxidative stability were determined. The total oil content was determined ranging between 30.68 and 43.12%, and the oil samples had large amounts of unsaturated fatty acids, with oleic acid and linoleic acid. Of all the oils, terebinth seed oil had the highest α-tocopherol content (102.21 ± 1.01 mg/kg oil). Laurel oilseed had the highest antiradical activity in both the DPPH and ABTS assays. The peroxide value of the non-oxidized oils ranged between 0.51 and 3.73 mequiv O2/kg oil. The TBARS value of the non-oxidized oils ranged between 0.68 ± 0.02 and 6.43 ± 0.48 mmol MA equiv/g oil. At 110 °C, the Rancimat induction period of the oils ranged between 1.32 and 43.44 h. The infrared spectra of the samples were recorded by FTIR spectroscopy. The absorbance values of the spectrum bands were observed and it was determined that some of the chemical groups of oxidized oils caused changes in absorbance. As a result of the present research, the analyzed oils could be evaluated as an alternative to traditionally consumed vegetable oils or as additives to them.
92 citations
TL;DR: In this paper, the authors compared methods for the extraction of algal lipids and showed that 2-ethoxyethanol (2-EE) provides superior lipid recovery (>150-200 %) compared to other common extraction solvents such as chloroform:methanol or hexane.
Abstract: Algae are a promising source of biofuel but claims about their lipid content can be ambiguous because extraction methods vary and lipid quantitation often does not distinguish between particular lipid classes. Here we compared methods for the extraction of algal lipids and showed that 2-ethoxyethanol (2-EE) provides superior lipid recovery (>150–200 %) compared to other common extraction solvents such as chloroform:methanol or hexane. Extractions of wet and dry algal biomass showed that 2-EE was more effective at extracting lipids from wet rather than dried algal pellets. To analyze lipid content we used normal-phase HPLC with parallel quantitation by an evaporative light scattering detector and a mass spectrometer. Analysis of crude lipid extracts showed that all major lipid classes could be identified and quantified and revealed a surprisingly large amount of saturated hydrocarbons (HC). This HC fraction was isolated from extracts of bioreactor-grown algae and further analyzed by HPLC/MS, NMR, and GC/MS. The results showed that the sample consisted of a mixture of saturated, straight- and branched-chain HC of different chain lengths. These algal HC could represent an alternative biofuel to triacylglycerols (TAG) that could feed directly into the current petroleum infrastructure.
89 citations
TL;DR: In this article, four varieties (Boribo, Dodo, Kagege, and Kent) of ripe mango (Mangifera indica, L.) fruits were collected directly from the farmers in Meru County (Kenya), peeled, depulped and the stones deshelled.
Abstract: Four varieties (Boribo, Dodo, Kagege, and Kent) of ripe mango (Mangifera indica, L.) fruits were collected directly from the farmers in Meru County (Kenya), peeled, depulped and the stones deshelled. The mango kernels obtained were crushed, sun-dried, and extracted using petroleum ether (b.p. 40–60 °C). The fat content of the mango kernels varied from 8.5 to 10.4 % depending on the variety. The mango seed kernels constituted about (4.76–6.70 %) crude protein (Nx6.25), (1.74–2.26 %) crude ash, (71.90–76.28 %) crude carbohydrate, (1743–1782 kJ) gross energy, (1547–1576 kJ) available energy, and mean protein:energy ratios of (2.63–3.76 mg/kJ) all on a moisture free basis. The moisture content of fresh mango seed kernels varied from 42.1 to 67.6 % depending on the variety. The fat had a melting point of 25–33 °C, an iodine value of 51.08–56.79, an acid value of 4.49–7.48, free fatty acid (as oleic) of 2.26–3.76, a saponification number of 188.8–195.9, unsaponifiable matter of 2.26–2.74 %, a peroxide value of 0.40–0.75, a refractive index(40 °C) of 1.4562–1.4597 and a specific gravity of 0.9017–0.9087. Investigation of the fatty acid composition revealed(GLC) nine fatty acids: tetradecanoic acid (trace-0.05 %), pentadecanoic acid (trace–0.09 %), hexadecanoic acid (4.87–10.57 %), heptadecanoic acid (trace-O.10 %), octadecanoic acid (24.22–32.80 %), 9-(Z)-octadecenoic acid (46.37–58.59 %), 9-(Z), 12-(Z)-octadecadienoic acid (6.73–10.35 %), 9-(Z), 12-(Z), 15-(Z)-octadecatrienoic acid (0.601–1.8 %), and eicosanoic acid (0.62–1.64 %). The fat had the typical characteristics of a vegetable butter.
80 citations
TL;DR: In this article, a biologically-based epoxy resin with good mechanical properties and flexibility was obtained, and the best thermal properties were obtained for samples with an EEW:AEW ratio of 1:1.0.
Abstract: Epoxidized soybean oil (ESBO), obtained from a renewable resource was used in the production of thermoset resins. Samples of the ESBO were initially treated with maleic anhydride, equal mixture of catalyst (1,3-butanediol anhydrous and benzyldimethylamine) and the mixture was cured for 5 h at different temperatures. After the curing process, the ratio between the ESBO and the anhydride (ratio EEW:AEW) was evaluated in terms of the different mechanical properties produced using flexural, Shore D hardness and Charpy impact tests. The sample with the best mechanical properties was that with an EEW:AEW ratio of 1:1.0 which leads to best balanced behavior and this could be representative for the maximum crosslinking degree. Also, thermal characteristics were evaluated during the crosslinking process using differential scanning calorimetry, In addition, other thermal characteristics of the cured materials were obtained by determining the heat deflection temperature and the Vicat softening temperature. The coefficient of thermal expansion was determined using thermo-mechanical analysis. In accordance with the mechanical behavior, the best thermal properties were obtained for samples with an EEW:AEW ratio of 1:1.0. As a result of this work, a biologically based epoxy resin with good mechanical properties and flexibility was obtained.
79 citations
TL;DR: In this paper, the authors evaluated the effectiveness of the addition of rosemary (ROS) and green tea (GT) extracts, tocopherols (TOC), ascorbyl palmitate (AP) and their blends, and studying the influence of storage conditions.
Abstract: The oxidative stability of chia oil was evaluated by measuring the effectiveness of the addition of rosemary (ROS) and green tea (GT) extracts, tocopherols (TOC), ascorbyl palmitate (AP) and their blends, and studying the influence of storage conditions. The addition of antioxidants increased induction time, depending on their type and concentration. Considering antioxidants individually, AP at 5,000 ppm was the most effective, whereas ROS + GT at 2,500 and 5,000 ppm provided the best protection among the antioxidant blends. Chia oil peroxide values of 10 mequiv/kg was observed for oils stored at 4 °C while values greater than 10 mequiv/kg were observed between 60 and 120 days when stored at 20 °C. Only AP 2,500 ppm protected oil did not reach 10 mequiv/kg during 225 days at 4 and 20 °C. Similar trends were observed with p-anisidine and Totox values. Differential scanning calorimetry further supported the presence of primary and secondary oxidation. Activation energy of chia oil thermoxidation was 71.9 kJ/mol increasing up to 87.5 kJ/mol when AP was added.
TL;DR: In this article, the effects of three production processes (pressing of roasted pumpkin seed paste, pressing of unroasted ground pumpkin seeds and pressing of ground pumpkin seed seeds while cooling the press) on the properties of pumpkin seed oils produced from two seed varieties (husked and naked) were investigated.
Abstract: In the present study, the effects of three production processes (pressing of roasted pumpkin seed paste, pressing of unroasted ground pumpkin seeds and pressing of unroasted ground pumpkin seeds while cooling the press) on the properties of pumpkin seed oils produced from two seed varieties (husked and naked) were investigated. Oils produced with roasting had a higher initial peroxide value (PV), twofold higher total phenol content and better oxidative stability while cold pressed oils had higher tocopherol content. Fatty acid and triacylglycerol compositions were not significantly affected by the processing conditions. Oxidative stability of the oils positively correlated with oleic acid content and negatively correlated with linoleic and linolenic acid contents. The lack of correlation in oxidative stability with tocopherol and polyphenol contents suggests that improvement in oxidative stability of roasted oils could have been caused by antioxidative Maillard reaction products or inactivation of oil degrading enzymes. In addition, oils produced from husked seeds had significantly higher linoleic acid, triacylglycerols (TAG) containing mainly linoleic acid (LLL, OLL and PLL), tocopherol and phenol contents while oleic acid and TAG containing mainly oleic acid (LOO and OOO) contents and oxidative stability were lower. Principal component analysis (PCA) of the analytical data confirmed the observed differences between oils from two varieties and three production processes.
TL;DR: In this article, the preparation of biodiesel from S. foetida oil using sodium hydroxide as catalyst was reported and the resultant biodiesel was evaluated for physico-chemical properties.
Abstract: Sterculia foetida oil contains cyclopropene fatty acids namely 8,9-methylene-heptadec-8-enoic acid (malvalic) and 9,10-methylene-octadec-9-enoic acid (sterculic) to an extent of 50–55%. The present study reports the preparation of biodiesel from S. foetida oil using sodium hydroxide as catalyst. The resultant biodiesel was evaluated for physico-chemical properties namely iodine value (72.6), free fatty acids (0.17%), phosphorous content (0 ppm), flash point (179 °C), cloud point (3 °C), pour point (3 °C), viscosity at 40 °C (4.72 cSt), oxidative stability at 110 °C (3.42 h), density (0.850 g/cm3 at 15 °C), and trace metals (Group I metals 0.21 ppm). The properties were compared with that of sunflower, soybean and rapeseed oil-based biodiesels and found to be comparable except for the pour point.
TL;DR: In this article, the authors developed polymeric materials from epoxidized vegetable oils in order to obtain materials with excellent mechanical properties for use as green matrix composites for green composites.
Abstract: In this work we have developed polymeric materials from epoxidized vegetable oils in order to obtain materials with excellent mechanical properties for use as green matrix composites. Epoxidized soybean oil (ESO), epoxidized linseed oil (ELO) and different mixtures of the two oils were used to produce the polymers. Phthalic anhydride (17 mol%) and maleic anhydride (83 mol%) which has a eutectic reaction temperature of 48 °C were used as crosslinking agents while benzyl dimethyl amine (BDMA) and ethylene glycol were used as the catalyst and initiator, respectively. The results showed that samples 100ELO and 80ELO20ESO could be used as a matrix in green composites because they demonstrated good mechanical properties.
TL;DR: In this paper, the fuel properties of camelina biodiesel were analyzed and tested in accordance with ASTM D6751, showing that it is comparable to that of sunflower biodiesel at the B20 level.
Abstract: Biodiesel derived from camelina as well as other feedstocks including palm, mustard, coconut, sunflower, soybean and canola were prepared via the conventional base-catalyzed transesterification with methanol. Fatty acid profiles and the fuel properties of biodiesel from different vegetable oils were analyzed and tested in accordance with ASTM D6751. Camelina biodiesel contains 10–12%, 37–40%, and 48–50% saturated, monounsaturated and polyunsaturated components, respectively. Some fuel properties of camelina biodiesel are comparable to that of sunflower biodiesel including kinematic viscosity (40 °C), flash point, cloud point, cold filter plugging point, and oil stability index. However, camelina biodiesel exhibited the poorest oxidative stability, highest distillation temperature and has the highest potential to form coke during combustion, all of which are attributed to the high amounts of n-3-fatty acids in camelina oil. While neat camelina biodiesel may exhibit undesirable fuel properties, it is very comparable with soybean biodiesel at the B20 level.
TL;DR: In this article, the authors evaluated the emulsifying properties of different modified sunflower lecithins in oil-in-water (O/W) emulsions, which were obtained by deoiling, fractionation with absolute ethanol (PC and PI enriched fractions), and enzymatic hydrolysis with phospholipase A2 from pancreatic porcine and microbial sources.
Abstract: Lecithins are a mixture of acetone-insoluble phospholipids and other minor substances (triglycerides, carbohydrates, etc.). The most commonly processes used for lecithin modification are: fractionation by deoiling to separate oil from phospholipids, fractionation with solvents to produce fractions enriched in specific phospholipids, and introduction of enzymatic and chemical changes in phospholipid molecules. The aim of this work was to evaluate the emulsifying properties of different modified sunflower lecithins in oil-in-water (O/W) emulsions. In this study, five modified sunflower lecithins were assessed, which were obtained by deoiling (deoiled lecithin), fractionation with absolute ethanol (PC and PI enriched fractions), and enzymatic hydrolysis with phospholipase A2 from pancreatic porcine and microbial sources (hydrolyzed lecithins). Modified lecithins were applied as an emulsifying agent in O/W emulsions (30:70 wt/wt), ranging 0.1–2.0% (wt/wt). Stability of different emulsions was evaluated through the evolution of backscattering profiles (%BS), particle size distribution, and mean particle diameters (D [3, 4], D [3, 2]). PC enriched fraction and both hydrolyzed lecithins presented the best emulsifying properties against the main destabilization processes (creaming and coalescence) for the analyzed emulsions. These modified lecithins represent a good alternative for the production of new bioactive agents.
TL;DR: In this article, the phospholipid (PL) fraction from egg yolk was isolated and purified using HPLC analysis using a Charged Aerosol Detector (CAD).
Abstract: The phospholipid (PL) fraction from egg yolk was isolated and purified. In the procedure applied (method 2) the egg yolk was extracted with ethanol, precipitated using acetone chilled to −20 °C and washed using acetone. The purity of the samples was checked by HPLC analysis using a Charged Aerosol Detector (CAD). The results were compared with those obtained for the phospholipid fraction isolated and purified by deoiling yolk before extraction and the precipitation of PL with acetone chilled to 4 °C (method 1). The use of acetone chilled to −20 °C to precipitate and wash the phospholipids yielded the phospholipid fraction with 100% purity (78.7 ± 0.2 of phosphatidylcholine and 21.3 ± 0.2 of phosphatidylethanolamine). When deoiling and the 4 °C purification process was used (method 1) 0.4 ± 0.1% cholesterol and some traces of triacylglycerols remained in the PL fraction.
TL;DR: In this article, the authors studied the adhesion properties of sodium bisulfite (NaHSO3)-modified canola protein and found that 3 g/L NaHSO 3 significantly improved handling and flowability of canola proteins adhesives.
Abstract: The objective of this research was to study the adhesion properties of sodium bisulfite (NaHSO3)-modified canola protein. Protein was extracted from canola meal through alkali solubilization and acid precipitation methods, then modified with different concentrations of NaHSO3 (0–15 g/L) during the isolation process. As NaHSO3 concentration increased, canola protein purities decreased. Amino acid profiles showed that the hydrophobic amino acids in canola protein constituted only 27% of total protein, indicating that canola protein is mostly hydrophilic. The reducing effects of NaHSO3 were exerted on canola protein through the breaking of disulfide bonds in both its cruciferin and napin components, as reflected by the protein electrophoresis profile, DSC data, and morphological images. The wet protein isolates were used as adhesives. The greatest wet shear strength of canola protein adhesive without modification was 3.97 MPa with 100% wood cohesive failure (WCF), observed at a curing temperature of 190 °C. NaHSO3 had slight weakening effects on the adhesion performance of canola protein. Canola protein modified with 3 g/L NaHSO3 exhibited wet shear strength similar to the control at 190 °C and higher strength at 150 and 170 °C. The NaHSO3 modification significantly improved handling and flowability of canola protein adhesives.
TL;DR: The medium pH and salt ions and their ionic strength can be manipulated to achieve selective solubility of napin and cruciferin of Brassicaceae seed meals.
Abstract: Seeds of six commercially produced Brassica juncea, Brassica napus and Sinapis alba varieties representing high-glucosinolate condiment-type and low-glucosinolate canola-type were studied for solubility characteristics of the predominant seed storage proteins (SSPs). The non-protein nitrogen components such as glucosinolates, nucleic acids, betaine, choline and sinapine contributed 3.1–5.2% and 7.9–10.8% for the total N content of low- and high-glucosinolate meals, respectively. The cruciferin and napin which are the predominant SSPs of crucifers were purified from these seeds and used to confirm soluble protein types under the conditions provided. The napins were soluble between pH 2 and 4 but not the cruciferins. Strong alkaline pH brought both cruciferin and napin into solution. In general, the SSP solubility was increased due to the presence of NaCl or CaCl2 salts in the medium. The effect of CaCl2 on solubility was more positive than NaCl for all the seed types except S. alba at neutral and alkaline pH. Presence of salts indeed reduced solubility of S. alba SSPs at alkaline pH. The medium pH and salt ions and their ionic strength can be manipulated to achieve selective solubility of napin and cruciferin of Brassicaceae seed meals.
TL;DR: In this article, a new 1H-NMR assay to determine the hydroperoxide amount in edible oils is presented, and the analytical performance of the method is similar to that of the commonly used peroxide value (PV) according to Wheeler.
Abstract: Within the course of lipid peroxidation, hydroperoxides are formed as primary products. They can be used as analytical markers to assess the deterioration status of oils and fats. Here a new 1H-NMR assay to determine the hydroperoxide amount in edible oils is presented. We were able to show that the analytical performance of the method is similar to that of the commonly used peroxide value (PV) according to Wheeler. A total of 290 edible oil samples were analyzed using both methods. For some oil varieties considerable discrepancies were found between the results obtained. In the case of black seed and olive oil, two substances could be identified that cause positive (black seed oil) and negative (olive oils) deviations from the theoretical PV expected from the NMR values.
TL;DR: Phenolic extracts from seven millet varieties, namely kodo, finger (Ravi), finger (local), proso, foxtail, little and pearl were evaluated for their inhibitory effects on lipid peroxidation in in-vitro copper-mediated human LDL cholesterol oxidation and several food model systems as discussed by the authors.
Abstract: Phenolic extracts from seven millet varieties, namely kodo, finger (Ravi), finger (local), proso, foxtail, little and pearl were evaluated for their inhibitory effects on lipid peroxidation in in-vitro copper-mediated human LDL cholesterol oxidation and several food model systems, namely cooked comminuted pork, stripped corn oil, and linoleic acid emulsion. The total phenolic content (TPC) and free radical scavenging activities were measured. The TPC ranged from 146 to 1156 μmol ferulic acid equiv (FAE)/g crude extract and the corresponding values based on defatted weight of grain ranged from 8.6 to 32.4 μmol FAE/g. At a final concentration of 0.05 mg/mL, millet extracts inhibited LDL cholesterol oxidation by 1–41%. All seven varieties exhibited effective inhibition of lipid oxidation in food systems used in this study and kodo millet exhibited superior inhibition of lipid peroxidation, similar to butylated hydroxyanisole at 200 ppm. Thus, millets may serve as a natural source of antioxidants in food applications and as a nutraceutical and functional food ingredient in health promotion and disease risk reduction.
TL;DR: In this article, the authors reported the full chemical and physical characterisation of Crambe abyssinica Hochst seed oil, which was extracted using n-hexane.
Abstract: This work was dedicated to reporting the full chemical and physical characterisation of Crambe abyssinica Hochst. seed oil. The oil from the seeds was extracted using n-hexane. The seeds contain about 30 % oil. Density, refractive index, colour, smoke point, viscosity, acidity, saponification value, iodine value, fatty acid methyl esters, the relative position of fatty acids in C1 and C3 carbon glycerol, sterols, tocopherols, peroxide value, \( \mathop E
olimits_{{1{\text{cm}}}}^{1\,\% } \) at 232 nm, and the susceptibility to oxidation measured by the Rancimat method were determined. The oil was found to contain high levels of unsaturated fatty acids, especially C22:1 (63.77 %). The dominant saturated acid was C22:0 (2.14 %). The oil was also found to contain high levels of β-sitosterol (51.93 %), campestanol (21.98 %), and brassicasterol (12.35 %). α-, γ-, and δ-Tocopherols were detected up to levels of 7.67, 125.04, and 3.99 mg/kg, respectively. The induction period (at 110 °C and 20 l/h) of the oil was 8.83 h. The relative position of fatty acids in C1 and C3 position was as follows: linoleic 0.45 %, oleic 8.84 %, and erucic 90.72 %. The thermal profile of the oil presented a single peak at −20.94 °C.
TL;DR: In this article, the peroxide formation rate was measured in sunflower and soybean oils exposed to increasing light intensity, from 0 to 8000 lx, at 10, 20 and 30 lx. At each lighting level, the Arrhenius equation was applied to develop a model predicting oil shelf life.
Abstract: The peroxide formation rate was measured in sunflower and soybean oils exposed to increasing light intensity, from 0 to 8000 lx, at 10, 20 and 30 °C. Results indicated that shelf life estimation of photosensitive foods under actual or accelerated conditions cannot be correctly achieved if the effect of light is not taken into account. At each lighting level, the Arrhenius equation was applied to develop a model predicting oil shelf life. Thermal activation energy was lower than 50 kJ/mol, indicating temperature to be a scarcely efficient accelerating factor. In contrast, the oxidation rate was significantly affected by light according to a power law equation, whose parameters describe the electromagnetic activation energy of the reaction. The model accounting for the effect of light on oxidation rate was merged with the Arrhenius equation to get a model predicting shelf life on the basis of the concomitant changes in both temperature and light.
TL;DR: Sesamin contents in the lines with a white seed coat color were significantly higher than in those samples with brown, yellow and black colors and potential genotypes for breeding high sesamin or sesamolin cultivars were identified.
Abstract: Sesame lignans, including mainly sesamin and sesamolin, has been reported to have multiple functions beneficial to health. This study analyzed sesamin and sesamolin contents by HPLC in 215 sesame lines from a core collection in China. The results showed the core sesame germplasm in China has a broad variation from 2.49 to 18.01 mg/g with average 8.54 mg/g in total of sesamin and sesamolin. On average, sesamin contents in the lines with a white seed coat color were significantly higher than in those samples with brown, yellow and black colors (P < 0.01). The lines with a black seed coat had the highest coefficient of variation followed by those with brown, yellow and white seed coats. The correlation coefficient between sesamin and sesamolin in the sesames with different seed coat colors ranked as white (R = 0.23) < yellow (R = 0.44) < brown (R = 0.72) < black (R = 0.77). The results of this study provide valuable background information on sesame germplasm in China and identified potential genotypes for breeding high sesamin or sesamolin cultivars.
TL;DR: In this article, a method for the quantitative determination of saturated F-acids in food is reported, which is based on accelerated solvent extraction, transesterification into methyl esters and silver ion chromatography (20% AgNO3 in silica, 1% deactivated).
Abstract: Furan fatty acids (F-acids) are valuable bioactive compounds found at low concentrations in food. A method for the quantitative determination of saturated F-acids in food is reported. The sample preparation is based on accelerated solvent extraction, transesterification into methyl esters and silver ion chromatography (20% AgNO3 in silica, 1% deactivated) of the resulting methyl esters. There then follows determination of the enriched F-acid methyl (or ethyl) esters by GC/EI-MS in the selected ion monitoring (SIM) mode. The 9-(3-methyl-5-pentylfuran-2-yl)-nonanoic acid ethyl ester (9M5-EE) was used as an internal standard for recovery checks. The limit of detection was 11 pg, and the recovery rate of the silver ion chromatography was 85% (n = 5). Further F-acid standards were used for evaluation of individual SIM-responses. Application of the method to various biological samples gave the following results: champignons (n = 2) contained 1.7 or 2.5 mg/100 g dry weight F-acids, while fish oil capsules (n = 5) contained between 18 and 234 mg/100 g oil F-acids distributed over up to seven F-acids. The concentrations and patterns were different to fresh fish. Accordingly, fish oil supplements seem to be a minor source for F-acids compared to (fresh) fish. Organic butter samples (n = 4) contained about twice the amount of F-acids when compared with conventional butter (n = 5).
TL;DR: In this article, the degree of interesterification was evaluated on the basis of TAG composition and solid fat content (SFC) for palm oil, palm olein and soft palm mid fraction.
Abstract: Interesterification is an important modification technique for fats and oils resulting in the redistribution of the fatty acids among the glycerol backbone and thus changing the physico-chemical properties of the modified fat. In this study palm oil, palm olein and soft palm mid fraction (PMF) were subjected to both enzymatic (batchwise) and chemical interesterification. The reaction products were characterized before, during and after interesterification by HPLC, pulsed NMR (p-NMR) and differential scanning calorimetry (DSC). Interesterification led to more uniform triacylglycerol (TAG) compositions with smaller differences in final physico-chemical properties between the studied substrates. The degree of interesterification was evaluated on the basis of TAG composition and solid fat content (SFC). Significant differences between both methods were observed. The degree of interesterification based on SFC is therefore a better tool to evaluate the rate constant of the reaction as the TAG composition method does not take into consideration the formation of positional isomers at the end of the enzymatic process.
TL;DR: In this article, a study was conducted to determine if foliar-applied trehalose (an osmoprotectant) could ameliorate the adverse effects of water shortage on maize seed oil composition and oil antioxidant potential.
Abstract: The present investigation was conducted to determine if foliar-applied trehalose (an osmoprotectant) could ameliorate the adverse effects of water shortage on maize seed oil composition and oil antioxidant potential. Drought stress significantly reduced the seed oil but increased oleic acid and linolenic acid contents of the oil with a concomitant decrease in linoleic acid content, which resulted in an increased oil oleic/linoleic ratio in both maize cultivars. Water stress also increased the seed oil α- γ- δ- and total tocopherols and flavonoids of both maize cultivars, however, oil phenolic content and oil antioxidant activity decreased. Exogenously applied trehalose positively influenced seed composition of both maize cultivars under non-stress and water stress conditions. Exogenous application of trehalose further increased the oil oleic and linolenic acid contents with a subsequent decrease in linoleic acid. Furthermore, exogenous application of trehalose increased the oil antioxidant activity in terms of oil DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity with an increase in oil tocopherols, total flavonoids and total phenolics contents.
TL;DR: In this paper, the effect of the molar ratio of glycerol to oil, enzyme concentration, and reaction temperature on MAG and DAG production was assessed, and the optimal temperature was in the range of 55-70 °C for production of both acylglycerols.
Abstract: Mono- (MAG) and diacylglycerols (DAG) are of nutritional interest. MAG and DAG containing eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids were produced in a solvent-free system via glycerolysis of menhaden oil catalyzed by Novozym 435. The effect of the molar ratio of glycerol to oil, enzyme concentration, and reaction temperature on MAG and DAG production was assessed. The optimal temperature was in the range of 55–70 °C for production of both acylglycerols. The increase in the substrates molar ratio led to a decrease in MAG and DAG content. The enzyme concentration was fixed at the lowest level evaluated (5%, by weight of substrates). High content of MAG (25% by weight) and DAG (41% by weight) containing, respectively, 12.46% EPA and 11.16% DHA, and 14.57% EPA and 13.70% DHA, were produced after 24 h at 70 °C, with 5% of lipase (by weight of substrate) and a glycerol-to-oil molar ratio of 1:1. For this reaction, a molar triacylglycerol (TAG) conversion of about 60% was achieved at equilibrium (10 h).
TL;DR: Aqueous extraction using subcritical water is an environmentally friendly alternative to extracting oil and protein from oilseeds with flammable organic solvents as discussed by the authors, and the effects of solids-to-liquid ratio (1:33-1:117), temperature (66-234°C), and extraction time (13-47min) were evaluated on the extraction of oil and proteins from soybean flakes and from extruded soybeans flakes with sub-critical water A central composite design (23) with three center points and six axial points was used Subcritical
Abstract: Aqueous extraction using subcritical water is an environmentally friendly alternative to extracting oil and protein from oilseeds with flammable organic solvents The effects of solids-to-liquid ratio (1:33–1:117), temperature (66–234 °C), and extraction time (13–47 min) were evaluated on the extraction of oil and protein from soybean flakes and from extruded soybeans flakes with subcritical water A central composite design (23) with three center points and six axial points was used Subcritical water extractions were carried out in a 1-L high-pressure batch reactor with constant stirring (300 rpm) at 003–386 MPa In general, oil extraction was greater for extruded soybean flakes than with soybean flakes More complete oil extraction for extruded soybean flakes was achieved at around 150 °C and extraction was not affected by solids-to-liquid ratios over the range tested, while oil extraction from soybean flakes was more complete at 66 °C and low solids-to-liquid ratio (1:117) Protein extraction yields from flakes were generally greater than from extruded flakes Protein extraction yields from extruded flakes increased as temperature increased and solids-to-liquid ratio decreased, while greater protein extraction yields from soybean flakes were achieved when using low temperatures and low solids-to-liquid ratio
TL;DR: In this article, the authors compared three treatments in the chemical hydrolysis reaction of bleached oil from carp (Cyprinus carpio) heads and to obtain polyunsaturated fatty acid concentrates by urea complexation.
Abstract: The aims of this study were to compare three treatments in the chemical hydrolysis reaction of bleached oil from carp (Cyprinus carpio) heads and to obtain polyunsaturated fatty acid concentrates by urea complexation. The three treatments were carried out with different oil:ethanol molar ratios. In the treatment with a 1:39 molar ratio, a higher yield of free fatty acids was found. These fatty acids were submitted to urea complexation (−10 °C for 20 h, and urea–fatty acid ratio of 4.5–1). There was a 31.4% increase in monounsaturated and polyunsaturated fatty acids (MUFA and PUFA) content and a 75% decrease in saturated fatty acids (SAF) content. An increase of 85.4% in the EPA + DHA content was found. The non-urea complexing fraction can be considered a rich source of MUFA and PUFA with a total amount of 88.9%.