Deacidification of black cumin seed oil by selective supercritical carbon dioxide extraction

The deacidification of high-acidity oils from Black cumin seeds (Nigella sativa) was investigated with supercritical carbon dioxide at two temperatures (40 and 60°C), pressures (15 and 20 MPa) and polarities (pure CO₂ and CO₂/10% MeOH). For pure CO₂ at a relatively low pressure (15 MPa) and relatively high temperature (60°C), the deacidification of a highacidity (37.7 wt% free fatty acid) oil to a low-acidity (7.8 wt% free fatty acid) oil was achieved. The free fatty acids were quantitatively (90 wt%) extracted from the oil and left the majority (77 wt%) of the valuable neutral oils in the seed to be recovered at a later stage by using a higher extraction pressure. By reducing the extraction temperature to 40°C, increasing the extraction pressure to 20 MPa, or increasing the polarity of the supercritical fluid via the addition of a methanol modifier, the selectivity of the extraction was significantly reduced; the amount of neutral oil that co-extracted with the free fatty acids was increased from 23 to 94 wt%.     

Castor oil dehydration kinetics

The dehydration reaction kinetics of castor oil was investigated with sodium bisulfate-sodium bisulfite mixture (SB-SB) or p-toluenesulfonic acid as catalyst. Reactions were carried out at 210, 220, and 230°C, and a kinetic model was determined for each case. The reactions with SB-SB catalyst at 210 and 220°C and with p-toluenesulfonic acid at 210°C followed second-order kinetics. A first-order rate equation showed the best fit to the experimental data for the reaction with SB-SB at 230°C. p-Toluenesulfonic acid-catalyzed reactions at 220 and 230°C were also first-order reactions. Additionally, some mathematical equations were derived between iodine value, refractive index, viscosity, and reaction time.     

Optimizing reaction parameters for the enzymatic synthesis of epoxidized oleic acid with oat seed peroxygenase

Peroxygenase is a plant enzyme that catalyzes the oxidation of a double bond to an epoxide in a stereospecific and enantiofacially selective manner. A microsomal fraction containing peroxygenase was prepared from oat (Avena sativa) seeds and the enzyme immobilized onto a hydrophobic membrane. The enzymatic activity of the immobilized preparation was assayed in 1 h by measuring epoxidation of sodium oleate (5 mg) in buffer-surfactant mixtures. The pH optimum of the reaction was 7.5 when t-butyl hydroperoxide was the oxidant and 5.5 when hydrogen peroxide was the oxidant. With t-butyl hydroperoxide as oxidant the immobilized enzyme showed increasing activity to 65°C. The temperature profile with hydrogen peroxide was flatter, although activity was also retained to 65°C. In 1 h reactions at 25°C at their respective optimal pH values, t-butyl hydroperoxide and hydrogen peroxide promoted epoxide formation at the same rate. Larger-scale reactions were conducted using a 20-fold increase in sodium oleate (to 100 mg). Reaction time was lengthened to 24 h. At optimized levels of t-butyl hydroperoxide 80% conversion to epoxide was achieved. With hydrogen peroxide only a 33% yield of epoxide was obtained, which indicates that hydrogen peroxide may deactivate peroxygenase.     

Kinetic evaluation of 3β-hydroxycholest-5-en-7-one (7-ketocholesterol) stability during saponification

To clarify conflicting information regarding 7-ketocholesterol (7-KC) recovery from saponification, we evaluated the stability of 7-KC in methanolic alkaline medium. We added 1 N alcoholic KOH to 7-KC or lard spiked with 7-KC and held the mixtures at 45, 55, 65, and 75°C for different times to simulate various saponification conditions. Gas-chromatographic determination of residual 7-KC with 5α-cholestane as the internal standard (IS) showed that the higher the saponification temperature, the greater the 7-KC degradation. Hot saponification at 75°C for 30 min caused extensive destruction and left only 31% 7-KC. 7-KC loss during saponification could be described by pseudo first-order kinetics, and the dependence of degradation rate on temperature (T, K) byk (h⁻¹)=(2.6×10¹⁷) exp (−1.36×10⁴/T). As predicted by the kinetic equation, 7-KC loss during room-temperature saponification (21°C) was practically negligible; following the exposure of 7-KC or lard spiked with 7-KC to 1 N alcoholic KOH for 18 h, about 97% 7-KC was recovered. 6-Ketocholestanol, when used as an IS, should be looked at carefully because of potential tautomerization, leading to the formation of two enol isomers when in extended contact with trimethylsilyl derivatization reagents.     

Lipase-catalyzed synthesis of monoacylglycerides by glycerolysis of campher tree seed oil and cocoa-butter

The lipase-catalyzed glycerolysis of Campher tree seed oil and Cocoa-butter in a solid-phase system was studied. Lipases from Pseudomonas cepacia (PCL) and Chromobacterium viscosum (CVL) were considered as suitable for the synthesis of monoacylglycerols (MAG). The glycerolysis of Campher tree seed oil was performed initially at 25°C followed by cooling to 7°C. This resulted in 86% (PCL) and 90% (CVL) MAG. Maximum concentration of MAG from Cocoa-butter was 89% with both lipases, when the reaction was performed at 25°C. Isolation of MAG was performed by extraction with chloroform at 4°C followed by purification via silica gel chromatography.     

Biosorption of a Basic Dye from Aqueous Solutions by Euphorbia rigida

Abstract

In this study, the biosorption of Basic Blue 9 (BB9) dye from aqueous solutions onto a biomass of Euphorbia rigida was examined by means of the initial biosorbate concentration, biosorbent amount, particle size, and pH. Biosorption of BB9 onto E. rigida increases with both the initial biosorbate concentration and biosorbent amount, whereas decreases with the increasing particle size. The experimental data indicated that the biosorption isotherms are well‐described by the Langmuir equilibrium isotherm equation at 20, 30, and 40°C. Maximum biosorption capacity was 3.28×10^?4 mol g^?1 at 40°C. The biosorption kinetics of BB9 obeys the pseudo‐second‐order kinetic model. The thermodynamic parameters such as ΔG°, ΔH° and ΔS° were calculated to estimate the nature of biosorption. These experimental results have indicated that E. rigida has the potential to act as a biosorbent for the removal of Basic Blue 9 from aqueous solutions.     

Effect of rosa mosqueta (Rosa rubiginosa) extract on the performance of chilean hazelnut oil (Gevuina avellana Mol.) at high temperature

The effect of the addition of rosa mosqueta husk extract (RME) on thermal oxidation of nontreated (HZO) and treated (THZO) Chilean hazelnut seed oil was evaluated at 180°C for 18 h. THZO to which was added 339 mg/kg of α-tocopherol was used as a comparison model because RME supplied 314 mg/kg of α-tocopherol. Formation of polar compounds and degradation of tocols and carotenoid, pigments were studied in these model systems. Degradation of trans-rubixanthin, trans-lycopene, and trans-β-carotene followed a pseudo first-order kinetics model. These pigments showed the same degradation rate in both HZO and THZO. The addition of RME to HZO and THZO decreased significantly (P<0.05) the formation of polar compounds, lead to less degradation of tocols, and improved their oxidative stability with respect to oils without RME. This behavior can be attributed to carotenoid-tocopherol interaction, suggesting that these pigments can protect tocols against degradation at high temperature.     

Equilibrium characteristics for the extraction of cobalt and nickel into di(2-ethylhexyl) phosphoric acid

The liquid-liquid extraction of cobalt and nickel from aqueous sulphate solutions into di(2-ethylhexyl) phosphoric acid, DZEHPA, has been investigated at 25°C and 60°C. The system studied was made up as follows: the aqueous phase-cobalt and nickel dphates; the organic phase-20% D2EHPA, 75% Esso solvent DX3641 and 5% tri-butyl phosphate. Analogies to vapour-liquid equilibria were made to develop three methods to correlate the binary equilibrium data, namely: 1) a delta Y method, 2) a method based on the correlation of solvent free mole fractions in both phases and 3) a “pseudo activity” coefficient or pseudo gamma method, γ_AB. The methods were evaluated as to their suitability for the prediction of binary isotherms. The delta Y and pseudo gamma methods were found to give the best results.     

Effect of temperature on linolenic acid loss and 18:3 Δ9-cis, Δ12-cis, Δ15-trans formation in soybean oil

Oil was extracted from soybeans, degummed, alkalirefined and bleached. The oil was heated at 160, 180, 200, 220 and 240°C for up to 156 h. Fatty acid methyl esters were prepared by boron trifluoride-catalyzed transesterification. Gas-liquid chromatography with a cyanopropyl CPSil88 column was used to separate and quantitate fatty acid methyl esters. Fatty acids were identified by comparison of retention times with standards and were calculated as area % and mg/g oil based on 17:0 internal standard. The rates of 18:3ω3 loss and 18:3 Δ9-cis, Δ12-cis, Δ15-trans (18:3c,c,t) formation were determined, and the activation energies were calculated from Arrhenius plots. Freshly prepared soy oil had 10.1% 18:3ω3 and no detectable 18:3c,c,t. Loss of 18:3ω3 followed apparent first-order kinetics. The first-order rate constants ranged from .0018±.00014 min⁻¹ at 160°C to .083±.0033 min⁻¹ at 240°C. The formation of 18:3c,c,t did not follow simple kinetics, and initial rates were estimated. The initial rates (mg per g oil per h) of 18:3c,c,t formation ranged from 0.0031±0.0006 at 160°C to 2.4±.24 at 240°C. The Arrhenius activation energy for 18:3ω3 loss was 82.1±7.2 kJ mol⁻¹. The apparent Arrhenius activation energy for 18:3c,c,t formation was 146.0±13.0 kJ mol⁻¹. The results indicate that small differences in heating temperature can have a profound affect on 18:3c,c,t formation. Selection of appropriate deodorization conditions could limit the amount of 18:3c,c,t produced.     

Solvent-free glycerolysis catalyzed by acetone powder of Nigella sativa seed lipase

The solvent-free glycerolysis of used sunflower oil catalyzed by acetone powder of Nigella sativa seeds was investigated. The highest partial acylglycerols yield was obtained at 60°C. The glycerolysis reactions, conducted at molar ratios of 1:1, 2:1, and 3:1 of oil to glycerol keeping the acetone powder content at 30% based on oil weight and the temperature at 60°C, approached equilibrium after 2 h. The highest partial acylglycerol content of the products was 66% (1:1 molar ratio) and 60% (2:1 molar ratio).     

Solvent-free glycerolysis catalyzed by acetone powder of Nigella sativa seed lipase

The solvent-free glycerolysis of used sunflower oil catalyzed by acetone powder of Nigella sativa seeds was investigated. The highest partial acylglycerols yield was obtained at 60°C. The glycerolysis reactions, conducted at molar ratios of 1:1, 2:1, and 3:1 of oil to glycerol keeping the acetone powder content at 30% based on oil weight and the temperature at 60°C, approached equilibrium after 2 h. The highest partial acylglycerol content of the products was 66% (1:1 molar ratio) and 60% (2:1 molar ratio).     

Poly(ethyl-n-butylsilylene): Structural,thermal, and flow properties of a liquid crystalline polysilane

Poly(ethyl-n-butylsilylene) (PEBS) was synthesized by sodium coupling of ethyl-n-butyldichorosilane and separated into fractions with differing molecular weights,M _w=1.4×10⁶ and 2.0×10⁴. Both fractions were studied by differential scanning calorimetry and by X-ray diffraction, UV spectroscopy, polarizing optical microscopy, and capillary rheometry, all as a function of temperature. Both samples adopt a hexagonal columnar liquid crystalline structure at room temperature and below. They undergo a weak endothermic transition at ?20°C and a first-order phase transition to a nematic liquid crystalline form at 90°C for the low and 170°C for the highM _w fraction. Melting to an isotropic liquid takes place at 106°C for the low and 185°C for the highM _w polymer. Both samples undergo two successive thermochromic transitions in the UV, one near the first-order exothermic transition and one near the ?20°C transition; the reasons underlying these thermochromic transitions are discussed. Flow properties of PEBS were investigated as a function of molecular weight.     

Effects of cooking and screw-pressing on functional properties of Cuphea PSR23 seed proteins

This investigation determined the effects of oil processing conditions on some functional properties of Cuphea PSR23 seed proteins to evaluate their potential for value-added uses. Flaked Cuphea seeds were cooked at 82°C (180°F) for 30, 75, or 120 min in the seed conditioner and then screw-pressed to extract the oil. Cooked flakes and press cakes were analyzed for proximate composition and protein functional properties. Results were compared with those of unprocessed ground, defatted Cuphea seeds. Protein from unprocessed Cuphea seeds had excellent emulsifying properties, poor foaming properties, poor solubility (10%) at pH 4–7, and much greater solubility at pH 2 and 10 (57 and 88%, respectively). Solubility profiles showed that cooking the flaked seeds to 82°C for 30 min resulted in a 50–60% reduction in soluble proteins. Cooking for 120 min gave <6% soluble proteins at all pH levels. Cooking for 75 min gave good oil yields but also resulted in <10% soluble proteins at pH 2–7 and 25% soluble proteins at pH 10. Seed cooking and screw pressing during oil extraction had significant detrimental effects on the solubility of Cuphea seed protein but generally improved its foaming capacity and emulsifying activity.     

The effect of temperature on lipid classes and their fatty acid profiles inLipomyces starkeyi

The effect of environmental temperature on fatty acid contents of major lipid classes was determined inLipomyces starkeyi at 30, 20, and 10°C. When the temperature was reduced from 30 to 20°C, the linolenic acid content increased in phosphatidylcholine but fell with further reduction to 10°C. The relative contribution of phosphatidylcholine and phosphatidylethanolamine that contained the next lowest-melting fatty acids, palmitoleic and linoleic acids, increased on lowering the temperature from 20 to 10°C and, concomitantly, the combined phosphatidylinositol and phosphatidylserine fraction decreased, and triacylglycerols were accumulated.     

Long-term preservation of high initial bioluminescence of lyophilized Photobacterium phosphoreum: Effect of skim milk and saccharose at various temperatures

A lyophilization method for long-term preservation of the initial bioluminescence of Photobacterium phosphoreum was investigated. The initial bioluminescence of lyophilized P. phosphoreum at different temperatures, −20 °C, 4 °C, room temperature (16–25 °C) and 45 °C, was monitored for 6 months with different additives. Saccharose, skim milk, and a mixture of saccharose and skim milk were tested. Skim milk showed the best protection for bioluminescence among the additives used. The initial bioluminescence remained high during 6 months at a wide range of storage temperatures, i.e., −20 °C, 4 °C, and room temperature, with skim milk as an additive. The average bioluminescence of lyophilized P. phosphoreum using skim milk as additive reached 33392 RLU within 30 min of regeneration. Bioluminescence increased slightly after 10 h of incubation.     

Temperature and cultivar effects on soybean seed oil and protein concentrations

The soybean [Glycine max (L.) Merr.] industry is interested in cultivar and climate effects on seed composition. These factors may underlie the known geographic variation in seed protein and oil concentrations. Regression analyses were used to test hypotheses of the effect of temperature and cultivar on oil and protein concentrations of soybean seed using a large data set from the U.S.A. Soybean Uniform Tests. The data set included 20 cultivars representing 10 maturity groups across 60 locations (latitude 29.4 to 47.5° N) for a total of 1863 cultivar by location by year observations. Temperature was determined for each observation as the average daily mean temperature from predicted first pod (first pod at least 5 mm long), using the SOYGRO phenology model, to observed maturity. The mean temperature ranged from 14.6 to 28.7°C among the observations. Linear, quadratic, and linear plateau regression models of oil and protein concentrations vs. temperature were evaluated. The quadratic model gave the best-adjusted R ² values for oil and protein with temperature, of 0.239 and 0.003, respectively. The analyses showed that the oil concentration increased with increasing temperature and approached a maximum at a mean temperature of 28°C. Unaccounted variation in the protein concentration may be from other factors such as photoperiod, water stress, or high temperatures during seed fill. Protein plus oil had a linear relationship with temperature (adjusted partial R ²=0.183). These data document the contribution of climate and cultivar to geographic variability of oil and protein concentrations in the United States.     

Absorption kinetics of ozone in aqueous O-cresol solutions

The kinetics of ortho-cresol ozonation in water has been studied using the film theory. At most experimental conditions investigated, the kinetic regime of the absorption has been fast pseudo first order with respect to ozone. At 30°C mass transfer plays an important role in controlling the absorption rate of ozone. The selfdecomposition reaction of ozone does not take place because of the great reactivity of o-cresol with ozone. Reaction rate constants have been determined at pH 7 for different temperatures below 30°C. The following Arrhenius equation was obtained: k_T = 2.2 × 10²³ exp(-11784/T), L/mol ? s At temperatures below 30°C there exists an ozone partial pressure value above which the ozone absorption kinetic regime changes to fast second order regardless of experimental conditions.     

Cholesterol oxidation in lard as affected by CLA during heating – A kinetic approach

The objectives of this study were to determine the effect of two CLAs , 9‐cis, 11‐trans CLA and 10‐trans, 12‐cis on cholesterol degradation and cholesterol oxidation products (COPs) formation in lard during heating for varied length of time. No CLAs and approximately 1770.1 µg/mL of cholesterol were detected in lard. Additionally, there was no significant change in the level of cholesterol and COPs in lard during heating at 100°C over a period of 240 min. But, at 150 or 200°C, the degradation of cholesterol was prominent with substantial amount of COPs being formed. Formation profiles of 7‐OOH, 7‐OH, and 7‐keto at 150°C as well as 5,6‐epoxides at both 150 and 200°C were fitted by a first‐order equation, while a pseudo‐second‐order model described the kinetic pathway of 7‐OH and 7‐keto formation at 200°C. The formation of 7‐OOH at 200°C were fitted as multiple first‐order formation and first‐order degradation curves as its level reached a peak at 60 min and declined to zero. Incorporation of 100 µg/mL CLA showed antioxidant activity, whereas a prooxidant activity was observed for CLA at 500 µg/mL. The outcome of this study demonstrated the potential of CLA to be an antioxidant in oil system.     

Simple dilatometer for polymer density and thermal expansivity measurements

A dilatometer is described to study the temperature dependence of density (ρ) of solid and semiliquid polymers and the following linear relations have been established. Atactic poly(vinylisobutyl ether) (25–90°C): ρ = 0.9166 ? 7.15 × 10^?4 × T. Isotactic poly(vinylisobutyl ether) (25–70°C): ρ = 0.9184 ? 7.13 × 10^?4 × T. Poly(n-butyl methacrylate) (90–150°C): ρ = 1.0622 ? 8.41 × 10^?4 × T. Poly(dimethyl siloxane) (30–51°C, using Lipkins pycnometer): ρ = 0.9846 ? 8.81 × 10^?4 × T; where ρ is in g.cm^?3, temperature T is in Celsius, and the linearity correlation coefficient r is better than 0.9998. Their volume–temperature plots are also linear. As the plots of polyn-butyl methacrylate curved slightly near its glass transition (20°C), the quadratic equation ρ = 1.0402 ? 4.79 × 10^?4 × T ? 1.46 × 10^?6 × T² (standard deviation = 1.57 × 10^?3) has been suggested for the entire range of 30–150°C scrutinized in this study. The data have been utilized to derive thermal expansivity and some equation-of-state parameters of the polymers at the reference temperature (ca. 20°C).     

Increase in the γ-linolenic acid content by solvent winterization of fungal oil extracted fromMortierella genus

The fungal oil extracted fromMortierella ramanniana var.angulispora (IFO 8187) was solvent winterized in order to raise the content of γ-linolenic acid (GLA). Effects of winterization conditions (solvent, oil concentration in the solvent and temperature) and changes of glyceride compositions were discussed. The fungal oil was separated into four diglycerides and 17 triglycerides (TG) with high performance liquid chromatography. The predominant species were POO, POP and LOP, whose contents were 24.4, 22.9 and 9.4% of the total TG, respectively. Ethanol at 4°C gave the highest GLA content of 10.5% in spite of lower yield than with acetone at −20°C. The highest separation efficiency for GLA (η_GLA) was 0.27 with acetone at −20°C and 10% oil concentration, resulting in 8.3% of GLA from the fungal oil at 5.7% LGA. In case of lower oil concentration at 5–20%, η_GLA showed higher in the following order: acetone (−20°C)>n-hexane (−20°C)>acetone (4°C)>petroleum ether (−20°C). The winterization process also proved to be effective for the separation of TG type, Sa₂U (Sa; saturated fatty acid; U, unsaturated fatty acid) into the crystallized fraction and SaU₂ into the liquid fraction. Acetone at −20°C showed higher separation efficiency for triunsaturated TG than the other solvents.