bluuebunny/crossref_metadata_2025 huggingface dataset:
Facile purification of tocopherols from soybean oil deodorizer distillate in high yield using lipase
Authors: Shimada Yuji , Nakai Seiichi , Suenaga Masaharu , Sugihara Akio , Kitano Motohiro , Tominaga Yoshio
Published: November 2006

Tocopherols have been purified from deodorizer distillate produced in the final deodorization step of vegetable oil refining by a process including molecular distillation. Deodorizer distillate contains mainly tocopherols, sterols, and free fatty acids (FFA); the presence of sterols hinders tocopherol purification in good yield. We found that Candida rugosa lipase recognized sterols as substrates but not tocopherols, and that esterification of sterols with FFA could be effected with negligible influence of water content. Enzymatic esterification of sterols with FFA was thus used as a step in tocopherol purification. High boiling point substances including steryl esters were removed from soybean oil deodorizer distillate by distillation, and the resulting distillate (soybean oil deodorizer distillate tocopherol concentrate; SODDTC) was used as a starting material for tocopherol purification. Several factors affecting esterification of sterols were investigated, and the reaction conditions were determined as follows: A mixture of SODDTC and water (4∶1, w/w) was stirred at 35°C for 24 h with 200 U of Candida lipase per 1 g of the reaction mixture. Under these conditions, approximately 80% of sterols was esterified, but tocopherols were not esterified. After the reaction, tocopherols and FFA were recovered as a distillate by molecular distillation of the oil layer. To enhance further removal of the remaining sterols, the lipase‐catalyzed reaction was repeated on the distillate under the same reaction conditions. As a result, more than 95% of the sterols was esterified in total. The resulting reaction mixture was fractionated to four distillates and one residue. The main distillate fraction contained 65 wt% tocopherols with low contents of FFA and sterols. In addition, the residue fraction contained high‐purity steryl esters. Because the process presented in this study includes only organic solvent‐free enzymatic reaction and molecular distillation, it is feasible as a new industrial purification method of tocopherols.
Low‐field1H nuclear magnetic resonance and chemometrics combined for simultaneous determination of water, oil, and protein contents in oilseeds
Authors: Pedersen Henrik Toft , Munck Lars , Engelsen Siren Balling
Published: November 2006

Prediction of the content of water, oil, and protein in rape and mustard seed was examined by a combination of low‐field1H nuclear magnetic resonance (LF‐NMR) and chemometrics, enabling utilization of the entire relaxation curves in the data evaluation. To increase the range of relative contents, the untreated seeds were wetted and dried; each treatment was followed by NMR analysis. The chemometric results are compared to traditional evoluation by multiexponential fitting of the relaxation curves. For this purpose a new jackKnife validation procedure was developed to evaluate the number of exponential components objectively. Classification of the two kinds of seeds was easily performed by LN‐NMR. Partial least squares regression to oil content in untreated rape and mustard seed yielded models with correlation coefficients ofr=0.88 and 0.89 with root mean square error of cross‐validation (RMSECV) of 0.84 and 0.45, respectively. The rapeseed model was based on one component, wheres the mustard seed model was based on two components. If the seeds were dried, the predictive performance improved tor=0.98 and RMSECV=0.38 for rapeseed and tor=0.95 and RMSECV=0.38 for mustard seed. Upon drying, prediction of protein content in mustard seed improved, whereas the prediction of protein for rapeseed deteriorated. Global models, including the combination of untreated, wet, and dry seeds, all resulted in a robust and good predictive performance with RMSECV in the range 0.8–1.3% to water, oil, and protein content. It was demonstrated that drying the seeds to simultaneously determine water and oil content was not necessary when chemometrics was applied on the relaxation curves.
Fatty acid triazoles: Novel corrosion inhibitors for oil well steel (N‐80) and mild steel
Authors: Quraishi M. A. , Jamal Danish
Published: November 2006

Three fatty acid triazoles, namely, 3‐undecane‐4‐aryl‐5‐mercapto‐1,2,4‐triazole (triazole 1), 3(heptadeca‐8‐ene)‐4‐aryl‐5‐mercapto‐1,2,4‐triazole (triazole 2), and 3(deca‐9‐ene)‐4‐aryl‐5‐mercapto‐1,2‐4‐triazole (triazole 3) were synthesized and their corrosion‐inhibiting action in 15% hydrochloric acid was evaluated by weight‐loss method and electrochemical techniques. Electrochemical polarization studies at room temperature indicated that all the triazoles are mixed‐type inhibitors, i.e., they inhibit both anodic and cathodic reactions. The adsorption of these compounds onto mild steel from 15% HCl followed Temkin's adsorption isotherm.
Solvent efficiency for oil extraction from spent bleaching clay
Authors: Lee C. G. , Seng C. E. , Liew K. Y.
Published: November 2006

Various alcohols and hydrocarbons were used as solvents to extract the residual oil in spent bleaching clay from palm oil refining. The content of oil and minor components in the spent clay was >40% by weight. The efficiencies of extraction by the polar alcohols, except for methanol, were higher but with a slower initial rate than the nonpolar hydrocarbons. The free fatty acids contents, the Totox values (anisidine value+2 x peroxide value), and the color of the alcohol‐extracted oil were also higher than that by the hydrocarbons resulting in poorer quality oils. All the extracted oils, irrespective of the solvent used, have poorer quality than crude palm oil. However, for regeneration of the residual spent clay, the polar alcohols should be more suitable as more of the impurities are removed.
Effect of adsorption and solvent extraction process on the percentage of carotene extracted from crude palm oil
Authors: Latip R. A. , Baharin B. S. , Che Man Y. B. , Rahman R. A.
Published: November 2006

Palm carotene was successfully concentrated from crude palm oil (CPO) by a batch adsorption process using a synthetic (polymer) adsorbent followed by solvent extraction. Carotene was concentrated to about 20,000 ppm, or about 33.3 times the original concentration in CPO. Carotene recovery varied from 16 to 74% depending on the process conditions. Adsorption times, isopropanol (IPA) extraction times, temperatures of adsorption and solvent extraction process, effect of agitation during IPA extraction process, and adsorbent lifespan were evaluated to determine their effects on the percentage of carotene extracted and carotene concentration. The minimum adsorption time required was 0.5 h. However, an adsorption time of 1.5 h gave a significantly higher carotene concentration than adsorption times of 0.5, 1.0, and 0.2 h. The IPA extraction time was determined based on the final carotene concentration desired. The suitable temperature for adsorption and solvent extraction process was 40°C. There was no significant difference in the percentage of carotene extracted and carotene concentration between the IPA extraction process with and without agitation.
Hydrogenation of vegetable oils using mixtures of supercritical carbon dioxide and hydrogen
Authors: King Jerry W. , Holliday Russell L. , List Gary R. , Snyder Janet M.
Published: November 2006

Hydrogenation of vegetable oils under supercritical conditions can involve a homogeneous one‐phase system, or alternatively two supercritical components in the presence of a condensed phase consisting of oil and a solid catalyst. The former operation is usually conducted in flow reactors while the latter mode is more amenable to stirred, batch‐reactor technology. Although many advantages have been cited for the one‐phase hydrogenation of oils or oleochemicals using supercritical carbon dioxide or propane, its ultimate productivity is limited by the oil solubility in the supercritical fluid phase as well as unconventional conditions that affect the hydrogenation. In this study, a dead‐end reactor has been utilized in conjunction with a head‐space consisting of either a binary fluid phase consisting of varying amounts of carbon dioxide mixed with hydrogen or neat hydrogen for comparison purposes. Reaction pressures up to 2000 psi and temperatures in the range of 120–140°C have been utilized with a conventional nickel catalyst to hydrogenate soybean oil. Depending on the chosen reaction conditions, a wide variety of end products can be produced having different iodine values, percentage trans fatty acid content, and dropping points or solid fat indices. Although addition of carbon dioxide to the fluid phase containing hydrogen retards the overall reaction rate in most of the studied cases, the majority of products have low trans fatty acid content, consistent with a nonselective mode of hydrogenation.
Selective extraction of phosphatidylcholine from lecithin by supercritical carbon dioxide/ethanol mixture
Authors: Teberikler Leyla , Koseoglu Sefa , Akgerman Aydin
Published: November 2006

Selective extraction of phosphatidylcholine (PC) from deoiled soybean lecithin using supercritical fluid (SCF) mixtures of carbon dioxide (CO2) and ethanol was studied at moderate pressures. Temperature was varied between 60 and 80°C at pressures of 17.2 and 20.7 MPa. Ethanol was added as co‐solvent to supercritical CO2 at the levels of 10 and 12.5 wt%. Constant rate of extraction of the individual phospholipids (PL) was observed for 150 min during which the extractions were carried out. Pressure and ethanol fraction had a positive effect on the selective extraction of PC, whereas temperature had a negative effect. Under all the conditions studied, the extracts were mainly composed of PC while the extraction of the other PL was very low. Extraction at 60°C and 20.7 MPa with 10 wt% ethanol/90 wt% CO2 SCF mixture resulted in 95% selectivity to PC.
Effect of refining of crude rice bran oil on the retention of oryzanol in the refined oil
Authors: Krishna A. G. Gopala , Khatoon Sakina , Shiela P. M. , Sarmandal C. V. , Indira T. N. , Mishra Arvind
Published: November 2006

The effect of different processing steps of refining on retention or the availability of oryzanol in refined oil and the oryzanol composition of Indian paddy cultivars and commercial products of the rice bran oil (RBO) industry were investigated. Degumming and dewaxing of crude RBO removed only 1.1 and 5.9% of oryzanol while the alkali treatment removed 93.0 to 94.6% of oryzanol from the original crude oil. Irrespective of the strength of alkali (12 to 20° Be studied), retention of oryzanol in the refined RBO was only 5.4–17.2% for crude oil, 5.9–15.0% for degummed oil, and 7.0 to 9.7% for degummed and dewaxed oil. The oryzanol content of oil extracted from the bran of 18 Indian paddy cultivars ranged from 1.63 to 2.72%, which is the first report of its kind in the literature on oryzanol content. The oryzanol content ranged from 1.1 to 1.74% for physically refined RBO while for alkali‐refined oil it was 0.19–0.20%. The oil subjected to physical refining (commercial sample) retained the original amount of oryzanol after refining (1.60 and 1.74%), whereas the chemically refined oil showed a considerably lower amount (0.19%). Thus, the oryzanol, which is lost during the chemical refining process, has been carried into the soapstock. The content of oryzanol of the commercial RBO, soapstock, acid oil, and deodorizer distillate were in the range: 1.7–2.1, 6.3–6.9, 3.3–7.4, and 0.79%, respectively. These results showed that the processing steps—viz., degumming (1.1%), dewaxing (5.9%), physical refining (0%), bleaching and deodorization of the oil—did not affect the content of oryzanol appreciably, while 83–95% of it was lost during alkali refining. The oryzanol composition of crude oil and soapstock as determined by high‐performance liquid chromatography indicated 24‐methylene cycloartanyl ferulate (30–38%) and campesteryl ferulate (24.4–26.9%) as the major ferulates. The results presented here are probably the first systematic report on oryzanol availability in differently processed RBO, soapstocks, acid oils, and for oils of Indian paddy cultivars.
Enzymatic esterification of (−)‐menthol with lauric acid in isooctane by sorbitan monostearate‐coated lipase from Candida rugosa
Authors: Babali Banu , Tuter Melek , Ustun Guldem
Published: November 2006

Esterification of (−)‐menthol and (±)‐menthol with lauric acid in isooctane was successfully catalyzed by a commercial nonioic surfactant (sorbitan monosterate)‐coated lipase from Candida rugosa (Lipase AY “Amano” 30) at the molar ratio of 1∶1 and at 35°C using 1.5 g enzyme/g (−)‐menthol and 0.1‐g molecular sieves. After 1 h, molar conversion of (−)‐menthol reached 81%. Equilibrium was reached after ca. 4 h, giving a (−)‐menthol molar conversion of 94%. Under the same conditions, native lipase catalyzed the esterification of (−)‐menthol and lauric acid to yield a molar conversion of 93% after 72 h. Coating the lipase with sorbitan monosterate increased the esterification rates of both (−)‐menthol and (±)‐menthol with lauric acid. After 6 h, the molar conversions of (−)‐menthol and (±)‐menthol were 94, and 62%, respectively.
Protection of α‐tocopherol in nonpurified and purified fish oil
Authors: Kul Elin , Ackman Robert G.
Published: November 2006

Menhanden oil was purified by column chromatography to remove minor components. The effect of α‐tocopherol (α TOH) (50–500 ppm) on the rate of formation of hydroperoxides in the original menahaden oil and in the purified menhaden triacylglycerol (TAG) fraction was studied at 30°C in the dark. An increase in the initial rate of formation of hydroper‐oxides was observed at αTOH concentrations above 100 ppm in both substrates. The original menhaden oil oxidized more rapidly than the purified menhaden, TAG at all antioxidant levels tested, and the presence of minor components in the menhaden oil was found to contribute only to a limited extent to the peroxidizing effect of αTOH. The αTOH did not display any prooxidant activity at either of the concentrations tested when the control oil was the purified menhaden TAG. Addition of ascorbyl palmitate eliminated the initial peroxidizing effect of αTOH, and this emphasizes the participation of the α‐toco‐pheroxyl radical in the reactions causing an accumulation of hydroperoxides at high concentrations of αTOH.
Antioxidant capacity of extra‐virgin olive oils
Authors: Ninfali Paolino , Aluigi Gianfranca , Bacchiocca Mara , Magnani Mauro
Published: November 2006

In this study, the oxygen radical absorbance capacity (ORAC) of vegetable oils was investigated using a spectrofluorometric method, which measures the protection of the phenolic substances of the oil on the β‐phycoerythrin fluorescence decay in comparison with Trolox. More than 97% of the phenolic substances was extracted from the oil using methanol, and the methanolic extract was then used for the ORAC and the total phenolics assay. We found a significant correlation between ORAC values of different olive oils and the total amount of phenolics. For extra‐virgin olive oils, maximal ORAC values reached 6.20±0.31 μmol Trolox equivalent/g, while refined and seed oils showed values in the 1–1.5 μmol Trolox equivalent/g range. Our method is useful to assess the quality of olive oils and to predict, in combination with the rancidity tests, their stability against oxidation.
Reproducibility of the bromthymol blue standards used for color specification of virgin olive oil
Authors: Melgosa M. , Prez M. M. , Hita E. , Heredia F. J. , Alba J. , Moyano M. J.
Published: November 2006

Three replicates were prepared for each of 60 BTB (bromthymol blue) standards, which are usually employed to determine the color of virgin olive and seed oils, and their colors were measured by spectrophotometric and spectroradiometric techniques on a monthly basis over a year. Although in principle both techniques are valid, their results are weakly correlated. The major color change of the BTB standards occurred soon after sample preparation; after 5 mon, the color stabilized at approximately 3.0 Commission Internationale de l’Éclairage 1976‐(L*a*b*) (CIELAB) units, with respect to the initial values. Therefore, after preparation, a certain waiting period would be advisable before using the BTB standards. The color of the BTB standards changes over time in the sense of becoming lighter, more saturated, and less greenish. In the monthly periods after the fifth month, the average color change of the BTB standards was negligible, being slightly lower than the average variability of the three replicates (which is around 1.5 CIELAB units).
Utilization of reaction medium‐dependent regiospecificity of Candida antarctica lipase (Novozym 435) for the synthesis of 1,3‐dicapryloyl‐2‐docosahexaenoyl (or eicosapentaenoyl) glycerol
Authors: Irimescu Roxana , Furihata Kiyomi , Hata Kazuhiko , Iwasaki Yugo , Yamane Tsuneo
Published: November 2006

A highly efficient enzymatic method for the synthesis of regioisomerically pure 1,3‐dicapryloyl‐2‐docosahexaenoyl glycerol (CDC) in two steps was established. 2‐Monoglyceride (2‐MG) formation by ethanolysis of tridocosahexaenoylglycerol (DDD) with immobilized Candida antarctica lipase (Novozym 435) as catalyst was the key step of the synthesis. CDC was finally obtained by reesterification of 2‐MG with ethylcaprylate (EtC) catalyzed by Rhizomucor miehei lipase (Lipozyme IM). The regiospecificity of Novozym 435 depended on the type of reaction and the initial composition of the reaction medium. It displayed strict 1,3‐regiospecificity for ethanolysis at a high excess of ethanol in the reaction mixture although it displayed no regiospecificity in transesterification and esterification reactions. The highest yield of CDC (85.4%) was obtained by ethanolysis at a 4∶1 weight ratio of ethanol/DDD for 6 h followed by reesterification at a 20∶1 molar ratio of EtC/initial DDD for 1.5 h. The regioisomeric purity of CDC was 100%. Good results were obtained also for the synthesis of 1,3‐dicapryloyl‐eicosapentaenoylglycerol (CEC) by the same method: 84.2% yield and 99.8% regioisomeric purity at the same reactant ratios as above. The yield of the reesterification step and the regioisomeric purity of the product were influenced by the molar ratio of the reactants for both CDC and CEC syntheses: higher excess of EtC favored higher yields and regioisomeric purity of the products.
An electronic nose to classify Iberian pig fats with different fatty acid composition
Authors: Carrapiso Ana I. , Ventanas Jesús , Jurado Ángela , García Carmen
Published: November 2006

Fatty acid analysis is frequently performed in fat and other raw materials to classify them according to their fatty acid composition, but the need to carry out online determinations has generated a growing interest in more rapid options. This research was done to evaluate the ability of a polymer‐sensor based electronic nose to classify Iberian pig fat samples with different fatty acid compositions. Significant correlations were found between individual fatty acids and sensor responses, proving that sensor response data were not fortuitously sorted. Significant correlations also appeared between some sensors and water activity, which was considered during the sample classification. Two supervised pattern recognition techniques were attempted to process the sensor responses: 85.5% of the samples were correctly classified by discriminant analysis, but the percentage increased to 97.8% using a one‐hidden layer back‐propagation artificial neural network. The electronic nose (specifically, sensor responses analyzed by a neural network) achieved success similar to that obtained using the more usual fatty acid analysis by gas chromatography.
Polyunsaturated fatty acid concentrates from borage and linseed oil fatty acids
Authors: Chen Tor‐Chern , Ju Yi‐Hsu
Published: November 2006

A modified low‐temperature solvent crystallization process was employed for the enrichment of polyunsaturated fatty acids (PUFA) in borage and linseed oil fatty acids. The effects of solvent, operation temperature, and solvent to free fatty acid (FFA) ratio on the concentration of PUFA were investigated. The best results were achieved when a mixture of 30% acetonitrile and 70% acetone was used as the solvent. With an operation temperature of −80°C and a solvent to FFA ratio of 30 mL/g, γ‐linolenic acid (GLA) in FFA of saponified borage oil can be raised from 23.4 to 88.9% with a yield of 62.0%. At a yield of 24.9%, α‐linolenic acid in linseed oil can be increased from 55.0 to 85.7%. The results of this work are comparable to the best results available in the literature.
Screening vegetable oil alcohol esters as fuel lubricity enhancers
Authors: Drown D. C. , Harper K. , Frame E.
Published: November 2006

Methyl and ethyl monoalkyl esters of various vegetable oils were produced for determining the effects of type of alcohol and fatty acid profile of the vegetable oil on the lubricity of the ester. Four methyl esters and six ethyl esters were analyzed for wear properties using the American Society for Testing and Materials method D 6079, Evaluating Lubricity of Diesel Fuels by the High‐Frequency Reciprocating Rig. Ethyl esters showed noticeable improvement compared to methyl esters in the wear properties of each ester tested. No correlation was found between lubricity improvement and fatty acid profile of the ester, except that esters of castor oil had improved lubricity over other oils with similar carbon chain‐length (C18) fatty acids.
Antioxidant activities of major components of γ‐oryzanol from rice bran using a linoleic acid model
Authors: Xu Zhimin , Godber J. Samuel
Published: November 2006

The change in hydroperoxides of linoleic acid incubated with constant micro air flow at 37°C was used to evaluate the antioxidant activities of three major components of γ‐oryzanol from rice bran (cycloartenyl ferulate, 24‐methylene cycloartanyl ferulate, and campesteryl ferulate) compared with α‐tocopherol and ferulic acid. The four hydroperoxide isomers of linoleic acid, 9‐hydroperoxy‐10‐trans, 12‐cis‐octadecadienoic acid [9HPODE(t,c)], 9‐hydroperoxy‐10‐trans, 12‐trans‐octadecadienoic acid, 13‐hydroperoxy‐9‐cis, 11‐trans‐octadecadienoic acid [13HPODE(c,t)], and 13‐hydroperoxy‐9‐trans, 11‐trans‐octadecadienoic acid, were measured using normal‐phase high‐performance liquid chromatography with an ultraviolet detector. The three components of γ‐oryzanol evidenced significant antioxidant activity when they were mixed with linoleic acid in a molar ratio of 1∶100 and 1∶250 but not in a molar ratio of 1∶500 (P<0.05). α‐Tocopherol and ferulic acid also demonstrated significant antioxidant activity at all three molar ratios (P<0.05). The highest molar ratio (1∶100) of α‐tocopherol, however, caused greater levels of 9HPODE(t,c) and 13HPODE(c,t) than the other two less concentrated treatments.
Characterization of extruded‐expelled soybean flours
Authors: Crowe Troy W. , Johnson Lawrence A. , Wang Tong
Published: November 2006

In recent years there has been widespread growth in extruding‐expelling (E‐E) facilities for small‐scale processing of soybeans. To compete in a highly competitive market, these E‐E operations are looking for ways to optimize production of their oil and meal products for values to their customers. The objective of this study was to determine the ranges of residual oil contents and protein dispersibility indices (PDI) possible with E‐E processing of soybeans. We also characterized the partially defatted meal for other factors important in food and feed applications. Residual oil and PDI values ranged from 4.7 to 12.7% and 12.5 to 69.1%, respectively. E‐E conditions significantly influenced residual lipase, lipoxygenase (L1–L3), and trypsin inhibitor activities. Chemical compositions were different for whole, dehulled, and reduced‐moisture soybeans, with dehulled soybeans tending to produce meals having higher residual oil contents at higher PDI values. It was possible to process soybeans with different characteristics (e.g., moisture content, whole, dehulled) to produce meals and flours with wide ranges of properties, providing E‐E operators with opportunities to market value‐added products.
Enzymatic process for extracting oil and protein from rice bran
Authors: Hanmoungjai P. , Pyle D. L. , Niranjan K.
Published: November 2006

Enzymatic extraction of oil and protein from rice bran, using a commercial protease (Alcalase), was investigated and evaluated by response surface methodology. The effect of enzyme concentration was most significant on oil and protein extraction yields, whereas incubation time and temperature had no significant effect. The maximal extraction yields of oil and protein were 79 and 68%, respectively. Further, the quality of oil recovered from the process in terms of free fatty acid, iodine value, and saponification value was comparable with solvent‐extracted oil and commercial rice bran oil, but the peroxide value was higher.
Adsorption of chromium(VI) and nickel(II) ions on acid‐ and heat‐activated deoiled spent bleaching clay
Authors: Seng C. E. , Lee C. G. , Liew K. Y.
Published: November 2006

De‐oiled spent bleaching clay was activated either by acid treatment followed by heat activation or by heat activation alone at temperatures between 200 and 800°C. The surface area of the heat‐activated clay attained a maximal value of ≈120 m2 g−1 at temperatures between 400 and 500°C while the acid‐heat‐treated clay attained maximal surface area of ≈140 m2 g−1. The adsorption capacities of chromium [Cr(VI)] for both series studied increased as the activation temperature increased until 300°C and decreased again at higher temperatures. At lower pH, more than 95% of the Cr(VI) was absorbed in a solution with initial concentration of 1 mg L−1 per gram of adsorbent activated at 300°C. The adsorption patterns followed Freudlich's isotherms. Two maximal values of adsorption capacities of nickel [Ni(II)] were observed at activation temperatures of 200 and 500°C for acid‐treated samples, whereas these were at 200 and 700°C for the nonacid‐treated samples. The amount of Ni(II) adsorbed increased with the pH of the solution for all samples studied. The maximal adsorption capacities of the adsorbents in solution containing initial Ni(II) concentration of 5 mg L−1 per 0.5 g of adsorbent and at pH 6 were found to be 44 and 42%, respectively, for the acid‐treated sample activated at 500°C and for the nonacid‐treated sample activated at 700°C. They all obeyed both the Langmuir's and Freundlich's isotherms.
Analytical characteristics of virgin olive oil from young trees (arbequina cultivar) growing under linear irrigation strategies
Authors: Tovar M. Jesús , Motilva M. José , Luna M. , Girona J. , Romero M. Paz
Published: November 2006

The effect of a linear (vs. effective crop coefficient, Kc), irrigation strategy applied to young olive trees (Arbequina cv.) on the qualitative and quantitative parameters of virgin olive oil quality was studied. Although linear irrigation strategy did not affect the quality indexes used to classify olive oil by commercial grades, it did influence other important parameters such as total phenol content, bitter index oxidative stability, and the sensorial appraisal. All of these of olive oil qualities were negatively associated with the amount of applied irrigation water. Pigment content of oils determined by carotenoid and chlorophylls also was negatively associated with the amount of water supplied. No consistent relation was found for α‐tocopherol and fatty acid content of olive oil in relation to these treatments.
Protein and lipid films at equilibrium at air‐water interface
Authors: Niño M. Rosario Rodríguez , Sánchez Cecilio Carrera , Fernández Marta Cejudo , Patino Juan M. Rodríguez
Published: November 2006

The surface activity of β‐casein, caseinate, and a whey protein isolate in aqueous solutions has been investigated over a range of protein concentrations (1·10−5to 5% w/w) at pH 5 and 7. The surface pressure data were determined by the Wilhelmy plate method. Surface pressure data at low protein concentration indicate a low surface activity that rises to a plateau as the monolayer is saturated at higher protein concentrations. The protein concentration and the surface pressure at the plateau depend on the pH and the type of protein in the aqueous phase. Protein‐monoglyceride interactions were investigated by spreading an insoluble monoglyceride (monopalmitin, monoolein, or monolaurin) on a film of protein previously adsorbed on the interface at equilibrium. The existence of protein‐monoglyceride interactions depends on the interfacial composition and on the protein/monoglyceride ratio. The surface activity of mixed protein‐monopalmitin and protein‐monoolein films is determined by the lipid as the surface pressure of the mixed film is the same as the monoglyceride equilibrium spreading pressure, and the monolayer is not saturated by the protein. However, the protein determines the surface activity of mixed protein‐monopalmitin and protein‐monoolein films as the protein saturates the monolayer. For protein and monolaurin mixed films, protein determines the surface activity over the range of protein‐monolaurin compositions due to monolaurin dissolution in the bulk aqueous phase.
Relationship of electronic nose analyses and sensory evaluation of vegetable oils during storage
Authors: Shen N. , Moizuddin S. , Wilson L. , Duvick S. , White P. , Pollak L.
Published: November 2006

Off‐flavors associated with oxidized oils make it difficult to recruit sensory panelists to evaluate the oils. Using an instrument called the “electronic nose” to monitor the formation of volatile compounds associated with off‐flavors could help to interpret oil oxidation studies in part to supplement human sensory panels. No published studies evaluate the correlation of oil oxidation sensory data and “electronic nose” analyses. Therefore, this project was designed to determine the correlation between sensory evaluation and “electronic nose” analyses. Canola, corn, and soybean oils were stored at 60°C in the dark until sufficiently oxidized. On days 0, 3, 6, 9, and 12, oils were evaluated for peroxide value, for volatile compounds by “electronic nose,” and for off‐flavor by sensory evaluation. The results suggest that the “electronic nose” is capable of measuring changes in volatile compounds associated with oil oxidation and could be used to supplement data obtained from sensory evaluations.
Oxidation of phytosterols in a test food system
Authors: Oehrl Lisa L. , Hansen Arthur P. , Rohrer Cynthia A. , Fenner Gregory P. , Boyd Leon C.
Published: November 2006

The oxidative stability of phytosterols in canola, coconut, peanut, and soybean oils was examined under simulated frying conditions of 100, 150, and 180°C for 20 h. The degree of oxidative decomposition was assessed by the loss of phytosterols, accumulation of phytosterol oxides, and the change in fatty acid profiles. The phytosterol oxides produced in the oils were identified using mass spectroscopy. Oils with higher levels of polyunsaturated fatty acids showed greater amounts of sterol loss; however, the sterol loss was less complete than in the more saturated oils. A greater variety of sterol oxides was observed at the lower temperatures of 100 and 150°C compared to 180°C. This study demonstrates that under conditions similar to frying, there is a loss of phytosterols and polyunsaturated fatty acids. The accumulation of phytosterol oxides may be temperature‐limited because of further break‐down into products not measurable by typical gas chromatography‐mass spectrometry techniques.
Effect of nitrogen and zinc fertilization and plant growth retardants on cottonseed, protein, oil yields, and oil properties
Authors: Sawan Zakaria M. , Hafez Saeb A. , Basyony Ahmed E.
Published: November 2006

The increase in the population in Egypt makes it imperative to explore promising approaches to increase food supply, including protein and oil, to meet the needs of the Egyptian people. Cotton is the principal crop of Egyptian agriculture. It is grown mainly for its fiber, but cottonseed products are also of economic importance. Cottonseed is presently the main source of edible oil and meal for livestock in Egypt. Field experiments were conducted in two successive seasons at the Agricultural Research Center (Giza, Egypt) on cotton (Gossypium barbadense L. cv. Giza 75) to determine the effect of nitrogen (N) fertilizer rate (107 and 161 kg of N/ha applied as ammonium nitrate containing 33.5% N in two equal doses at 6 and 8 wk after sowing), together with foliar applications of plant growth retardants (mepiquat chloride “Pix”, chloromequat chloride “Cycocel”, and daminozide “Alar”, each applied once at 288 g active ingredient/ha, after 75 d from sowing) and zinc (Zn) (applied in chelated form after 80 and 95 d from sowing at 48 g of Zn/ha) on seed, protein and oil yields and oil properties of cotton. The higher N‐rate, as well as the application of all growth retardants and Zn, resulted in an increase in cottonseed yield, seed protein content, oil and protein yields/ha, seed oil refractive index, unsaponifiable matter, and total unsaturated fatty acids (oleic and linoleic). These treatments tended to decrease oil acid value, saponification value, and total saturated fatty acids. The seed oil content tended to decrease as N‐rate increased and increased with the application of all growth retardants and Zn. There were some differences between Pix, Cycocel, and Alar regarding their effects on the studied characters. The highest increase in seed, oil, and protein yields/ha was found with Pix, followed by Cycocel. The Cycocel treatment gave the lowest total saturated fatty acids oil content, followed by Alar.
Esterification of glycerol with conjugated linoleic acid and long‐chain fatty acids from fish oil
Authors: Torres Carlos F. , Garcia Hugo S. , Ries Jason J. , Hill Charles G.
Published: November 2006

Free fatty acids from fish oil were prepared by saponification of menhaden oil. The resulting mixture of fatty acids contained ca. 15% eicosapentaenoic acid (EPA) and 10% docosahexaenoic acid (DHA), together with other saturated and monounsaturated fatty acids. Four commercial lipases (PS from Pseudomonas cepacia, G from Penicillium camemberti, L2 from Candida antarctica fraction B, and L9 from Mucor miehei) were tested for their ability to catalyze the esterification of glycerol with a mixture of free fatty acids derived from saponified menhaden oil, to which 20% (w/w) conjugated linoleic acid had been added. The mixtures were incubated at 40°C for 48h. The ultimate extent of the esterification reaction (60%) was similar for three of the four lipases studied. Lipase PS produced triacylglycerols at the fastest rate. Lipase G differed from the other three lipases in terms of effecting a much slower reaction rate. In addition, the rate of incorporation of omega‐3 fatty acids when mediated by lipase G was slower than the rates of incorporation of other fatty acids present in the reaction mixture. With respect to fatty acid specificities, lipases PS and L9 showed appreciable discrimination against esterification of EPA and DHA, respectively, while lipase L2 exhibited similar activity for all fatty acids present in the reaction mixture. The positional distribution of the various fatty acids between the sn‐1,3 and sn‐2 positions on the glycerol backbone was also determined.
Virgin olive oil: Free radical production studied with spin‐trapping electron paramagnetic resonance spectroscopy
Authors: Skoutas D. , Haralabopoulos D. , Avramiotis S. , Sotiroudis T. G. , Xenakis A.
Published: November 2006

Spin trapping using 5,5‐dimethyl‐1‐pyrroline N‐oxide (DMPO) has been used to detect and distinguish free radicals in samples of Greek extra virgin olive oils. A number of the samples examined immediately after the addition of the spin trap showed a spontaneous complex electron paramagnetic resonance (EPR) signal. The majority of DMPO‐radical adducts formed (80–90%) represented peroxyl and alkoxyl radical adducts. Similar spectra were recorded when DMPO was added in oxidized triolein and then treated with Fe2+, Fe3+, or Cu2+ or when EPR‐silent olive oil samples were treated with these metallic ions. Metal ion‐catalyzed decomposition of triolein hydroperoxides, as recorded by EPR signal intensity, increased with increasing metal ion concentration in the micromolar range. The relative concentration of alkoxyl‐DMPO adducts increased with increasing Fe2+ or Fe3+ concentration, whereas that of peroxyl‐DMPO species decreased. In contrast, the relative concentrations of alkoxyl and peroxyl species produced by Cu2+ were similar over the whole metal concentration range examined. Exposure of EPR‐silent virgin olive oil or oxidized triolein to ultraviolet light in the presence of DMPO resulted in the detection of a three‐line spectrum characterized by wide line widths.
Optimal tocopherol concentrations to inhibit soybean oil oxidation
Authors: Evans J. C. , Kodali D. R. , Addis P. B.
Published: November 2006

The optimal concentration for tocopherols to inhibit soybean oil oxidation was determined for individual tocopherols (α‐, γ‐, and δ‐tocopherol) and for the natural soybean oil tocopherol mixture (tocopherol ratio of 1∶13∶5 for α‐, γ‐, and δ‐tocopherol, respectively). The concentration of the individual tocopherols influenced oil oxidation rates, and the optimal concentrations were unique for each tocopherol. For example, the optimal concentrations for α‐tocopherol and γ‐tocopherol were ∼100 and ∼300 ppm, respectively, whereas δ‐tocopherol did not exhibit a distinct concentration optimum at the levels studied (P<0.05). The optimal concentration for the natural tocopherol mixture ranged between 340 and 660 ppm tocopherols (P<0.05). The antioxidant activity of the tocopherols diminished when the tocopherol levels exceeded their optimal concentrations. Above their optimal concentrations, the individual tocopherols and the tocopherol mixture exhibited prooxidation behavior that was more pronounced with increasing temperature from 40 to 60°C (P<0.05). A comparison of the antioxidant activity of the individual tocopherols at their optimal concentrations revealed that α‐tocopherol (∼100 ppm) was 3–5 times more potent than γ‐tocopherol (∼300 ppm) and 16–32 times more potent than δ‐tocopherol (∼1900 ppm).
Friction and adsorption properties of normal and high‐oleic soybean oils
Authors: Biresaw G. , Adhvaryu A. , Erhan S. Z. , Carriere C. J.
Published: November 2006

The steel/steel boundary friction properties of soybean oil (SBO) and high‐oleic soybean oil (HOSBO) are compared. HOSBO is significantly more saturated than SBO and more oxidatively stable. Changes in degree of unsaturation affect lateral interactions of adsorbate molecules, which in turn affects their adsorption and, hence, their boundary lubrication properties. To investigate this possibility, the free energies of adsorption (ΔGads) of SBO, HOSBO, and methyl laurate (ML) were determined from the analysis of friction‐derived adsorption isotherms using the Langmuir and Temkin adsorption models. The results showed a stronger adsorption for the vegetable oils than for ML, an indication of multiple interactions between the ester groups of the triglycerides and the steel surface. The result also showed no difference in the ΔGads values of SBO and HOSBO obtained using either the Langmuir or Temkin models. This was interpreted as an indication of the lack of appreciable net lateral interaction between triglyceride adsorbates.
Solvent‐based fatty alcohol synthesis using supercritical butane: Flowsheet analysis and process design
Authors: Brands D. S. , Pontzen K. , Poels E. K. , Dimian A. C. , Bliek A.
Published: November 2006

The liquid‐phase hydrogenolysis of fatty esters to fatty alcohols is an important step in the industrial manufacture of surfactants and detergents. High operating pressures are necessary, due to the low solubility of hydrogen in fatty esters feeds. In principle, these high operating pressures might be overcome by use of a suitable solvent, but only at the expense of large solvent recycle and cumbersome product‐solvent separation. The employ of supercritical solvents may resolve these drawbacks, as an elegant solvent‐product separation is possible by reverting to the subcritical regime. In the present work the hydrogenolysis of methyl palmitate in supercritical butane is investigated by simulation. Operating conditions are analyzed on the basis of vapor liquid equilibrium data and chemical equilibrium considerations. Separation and recycle problems are evaluated and discussed on the basis of a flowsheet analysis. It is demonstrated that an efficient hydrogenolysis process may be developed by using supercritical butane as solvent. A moderate operating pressure (9 MPa) and temperature (470 K) lead to high conversion levels and high product purity. A hydrogen to ester molar ratio of 4∶1 in the feed is achievable, which compares favorably to existing liquid‐and gas‐phase processes, and allows recycle streams to be reduced.
Effects of physical refining on contents of waxes and fatty alcohols of refined olive oil
Authors: Tubaileh Rana M. , Garrido‐Fernández Antonio , Victoria Ruiz‐Méndez M. , León‐Camacho Manuel , Graciani‐Constante Enrique
Published: November 2006

Changes in the contents of waxes and fatty alcohols during deodorization/physical refining of bleached olive oil were studied. Experiments were carried out with 1.85% acidity oil, which was physically refined in a discontinuous deodorizer of 250‐kg maximum capacity using nitrogen as stripping gas instead of steam. The variables studied were load and temperature of oil in the deodorizer as well as N2 flow. Analyses of waxes and alcohols were carried out at different operation times. The maximum content of wax was always observed when the oil reached the deodorization temperature. The variation in the wax content depended on temperature and N2 flow. Wax decomposition started and continued during the operating time, and a progressive decrease, which was pronounced between 3 and 4 h, was observed. Small changes in waxes were observed between 4 and 5 h. Total content of fatty alcohols diminished throughout the operating time, and changes did not depend on the variables studied.
Analysis of free and esterified sterols in vegetable oils
Authors: Verleyen T. , Forcades M. , Verhe R. , Dewettinck K. , Huyghebaert A. , De Greyt W.
Published: November 2006

In vegetable oils, phytosterols occur as free sterols or as steryl esters. Few analytical methods report the quantification of esterified and free sterols in vegetable oils. In this study, esterified and free sterols were separated by silica gel column chromatography upon elution with n‐hexane/ethyl acetate (90∶10 vol/vol) followed by n‐hexane/diethyl ether/ethanol (25∶25∶50 by vol). Both fractions were saponified separately and the phytosterol content was quantified by GC. The analytical method for the analysis of esterified and free sterols had a relative standard deviation of 1.16% and an accuracy of 93.6–94.1%, which was comparable to the reference method for the total sterol analysis. A large variation in the content and distribution of the sterol fraction between different vegetable oils can be observed. Corn and rapeseed oils were very rich in phytosterols, which mainly occurred as steryl esters (56–60%), whereas the majority of the other vegetable oils (soybean, sunflower, palm oil, etc.) contained a much lower esterified sterol content (25–40%). No difference in the relative proportion of the individual sterols among crude and refined vegetable oils was observed.
Effect of relative humidity on the oxidative and physical stability of encapsulated milk fat
Authors: Hardas N. , Danvirivakul S. , Foley J. L. , Nawar W. W. , Chinachoti P.
Published: November 2006

Milk fat was used in this work as a model to study the effects of humidity and physical properties on lipid oxidation. Although milk fat is considered a relatively stable fat because of its low content of unsaturated FA, it can oxidize significantly under certain conditions, as observed, for example, in the case, of dairy‐based powders. Humidity and physical properties have a profound influence on the oxidative stability of powders, containing fat, and these factors affect the surface and encapsulated fractions of the fat differently. To examine these effects, encapsulated milk fat powders were stored under conditions of controlled relative humidity. Oxidation of the encapsulated fat as assessed by measurements of PV, losses of FA, and hexanal production increased, with increasing relative humidity (RH). At higher RH, moisture penetrates into the hydrophilic wall, interacting with and plasticizing the components, thereby making them less effective as moisture and oxygen barriers. Total oxidation of the powders was strongly influenced by the extent of oxidation in the encapsulated fraction (>98% of total lipids) although the surface fat fraction was oxidized more rapidly. Better protection against oxidation was obtained when fats were encapsulated and stored at 14 and 44% RH than at 52% RH.
Conjugated linoleic acid production from linoleic acid by lactic acid bacteria
Authors: Kishino Shigenobu , Ogawa Jun , Omura Yoriko , Matsumura Kenji , Shimizu Sakayu
Published: November 2006

After screening 14 genera of lactic acid bacteria, Lactobacillus plantarum AKU 1009a was selected as a potential strain for CLA production from linoleic acid. Washed cells of L. plantarum with high levels of CLA production were obtained by cultivation in a nutrient medium with 0.06% (wt/vol) linoleic acid (cis‐9,cis‐12‐octadecadienoic acid). Under the optimal reaction conditions with the free form of linoleic acid as the substrate, washed cells of L. plantarum produced 40 mg CLA/mL reaction mixture (33% molar yield) from 12% (wt/vol) linoleic acid in 108 h. The resulting CLA was a mixture of two CLA isomers, cis‐9,trans‐11 (or trans‐9,cis‐11)‐octadecadienoic acid (CLA1, 38% of total CLA) and trans‐9,trans‐11‐octadecadienoic acid (CLA2, 62% of total CLA), and accounted for 50% of the total FA obtained. A higher yield (80% molar yield to linoleic acid) was attained with 2.6% (wt/vol) linoleic acid as the substrate in 96 h, resulting in CLA production of 20 mg/mL reaction mixture [consisting of CLA1 (2%) and CLA2 (98%)] and accounting for 80% of total FA obtained. Most of the CLA produced was associated with the cells (ca. 380 mg CLA/g dry cells), mainly as FFA.
Epoxidation of soybean oil by the methyltrioxorhenium‐CH2Cl2/H2O2 catalytic biphasic system
Authors: Gerbase Annelise E. , Gregório José R. , Martinelli Márcia , Brasil Márcia C. , Mendes Ana N. F.
Published: November 2006

We studied the methyltrioxorhenium (MTO)‐CH2Cl2/H2O2 biphasic system for epoxidizing soybean oil. The reactions were optimized (reactant ratio, time, and temperature), which resulted in a better performance (higher conversion and selectivity) than those described in the literature. Total doublebond conversion and 95% selectivity were obtained in 2 h at room temperature. Furthermore, it was possible to reach desired epoxidation degrees by changing the oxidant and MTO amounts. The rhenium‐epoxidized soybean oil remained stable in the absence of stabilizers for up to 30 d when stored at mild conditions.