bluuebunny/crossref_metadata_2025 huggingface dataset:
Total fatty acid analysis of vegetable oil soapstocks by supercritical fluid extraction/reaction
Authors: King Jerry W. , Taylor Scott L. , Snyder Janet M. , Holliday Russell L.
Published: May 2007

Soapstock from vegetable oil refining operations is a value‐added by‐product that finds further industrial use based on its fatty acid content. Since the fatty acid content of soapstock can vary according to its vegetable oil source or method of refining, determination of its total fatty acid (TFA) by an accurate analytical method is of key importance to purchasers of this refinery by‐product. Traditionally, the TFA content of soapstock has been determined by the AOCS Official Method G3‐53 based on a gravimetric assay. Unfortunately, this gravimetric‐based assay requires considerable time and incorporates a considerable quantity of organic solvent per assay. In this study, the authors have applied supercritical fluid extraction (SFE) with an enzymatic‐based reaction (SFR), in the presence of supercritical carbon dioxide (SC‐CO2), to determine the TFA content of soapstocks. The SFE/SFR sequence was conducted using two commercially available extractors using an in situ supported lipase in the extraction cell to form fatty acid methyl esters (FAME). Gas chromatographic (GC) determination of the individual FAME, followed by quantitation based on the calculated sum of all the fatty acids from the GC analysis, allowed a precise determination to be made of the soapstock’s TFA content. The TFA contents of three different soapstocks determined by this method were slightly higher than the values derived from Official Method G3‐53. The reported method takes less than one‐half of the time of Official Method G3‐53 and reduces organic solvent use from 575 mL to under 2 mL of solvent by using SC‐CO2.
Characterization of fatty acid isomers in dehydrated castor oil by gas chromatography and gas chromatography‐mass spectrometry techniques
Authors: Ramamurthi Suresh , Manohar Venkat , Mani V. V. S.
Published: May 2007

Fatty acid isomers present in dehydrated castor oil were analyzed by gas chromatography and gas chromatography‐mass spectrometry (GC‐MS) of their dimethyl oxazoline derivatives. Conjugated linoleic acid 9,11 and 10,12 isomers were identified by GC based on equivalent chainlengths. Segmental peak analysis of GC‐MS total ion chromatogram mass fragmentation pattern revealed the presence of 7,9 and 8,10 conjugated linoleic acids along with 9,11 and 10,12 conjugated linoleic acids. Interestingly, a reverse elution of trans, trans‐conjugated linoleic acids was observed, viz. 10,12 was followed by 9,11, which was in turn followed by the 8,10 and 7,9 isomers. The observed reverse order of elution was in contrast to the conventional elution pattern of both nonconjugated and conjugated cis,cis‐, cis,trans‐ and trans,cis‐isomers.
Chemical composition of commercial cornicabra virgin olive oil from 1995/96 and 1996/97 crops
Authors: Salvador M. D. , Aranda F. , Fregapane G.
Published: May 2007

The chemical composition of commercial Cornicabra virgin olive oils (n=65) was studied, as was its relationship with oil quality and the influence of the extraction method and production year. The main characteristics of these olive oils were: oxidative stability 53 ± 24 h, mean polyphenol content 162 ± 57 mg/kg (as gallic acid), oleic acid 80.8 ± 0.9%, linoleic acid 4.6 ± 0.6%, and campesterol 4.3 ± 0.1%, which is peculiar to this variety. No clear differences in composition were observed with respect to the different extraction systems (dual‐phase/triple‐phase decanters and pressure), although oils produced by the dual‐phase decanter showed higher oxidative stability and polyphenol content. There were significant differences in major fatty acids and sterols according to the production year.
Autoxidation of the furan fatty acid ester, methyl 9,12‐epoxyoctadeca‐9,11‐dienoate
Authors: Sehat N. , Yurawecz M. P. , Roach J. A. G. , Mossoba M. M. , Eulitz K. , Mazzola E. P. , Ku Y.
Published: May 2007

The objective of this study was to identify autoxidation products of methyl 9,12‐epoxyoctadeca‐9,11‐dienoate (F9,12). Previous work has shown that F9,12 is a product both of autoxidation and singlet oxygen oxidation of the methyl ester derivative of conjugated linoleic acid (CLA). F9,12, 95% pure, was synthesized from methyl ricinoleate. The synthetic F9,12 was heated at 50°C in sealed tubes containing air. Each tube contained 6 mg F9,12 and 1 mg methyl stearate as an internal standard. Samples were taken at 4.5, 7, 23, 46.5, 69.5, and 93 h. The oxidized F9,12 was dissolved in isooctane and analyzed by gas chromatography (GC), GC‐direct deposition‐Fourier transform infrared spectroscopy, and GC‐electron ionization mass spectrometry. CLA methyl ester was oxidized in a similar manner. Under these conditions, the half‐lives of CLA and F9,12 were 40 and 35 h, respectively. Oxidation products of F9,12 that were identified included: 5‐hexyl‐2‐furaldehyde (I), methyl 8‐oxooctanoate (II), methyl 13‐oxo‐9,12‐epoxytrideca‐9,11‐dienoate (III), methyl 8‐oxo‐9,12‐epoxy‐9,11‐octadecadienoate (IV), and methyl 13‐oxo‐9,12‐epoxy‐9,11‐octadecadienoate (V).
Concerns for the determination of free fatty acid in cottonseed
Authors: Wan P. J. , Pakarinen D. R. , Wakelyn P. J.
Published: May 2007

The official AOCS method for the determination of free fatty acid (FFA) in cottonseed requires dehulling the seed, grinding the meats with a 12‐blade food processor, and extracting the ground meats in a butt tube with three portions of room‐temperature petroleum ether. The extracted oil, after desolventization, is then titrated with NaOH to the end point of phenolphthalein in a mixed solvent of isopropanol and hexane. Our study showed that this procedure tends to underestimate the amount of FFA present in the oil of cottonseed by as much as 11.5%. It was also found that to obtain consistent and accurate FFA content, a desirable particle size is smaller than 10 mesh (preferably <14 mesh), minimum extraction temperature should be no less than 40°C (preferably greater than 50°C), and the extraction time should be longer than 2 h in a Soxhlet extractor.
Synthesis of polyunsaturated fatty acid‐enriched triglycerides by lipase‐catalyzed esterification
Authors: Cerdán L. Esteban , Medina A. Robles , Giménez A. Giménez , González M. J. IbáɁez , Grima E. Molina
Published: May 2007

This paper reports on the synthesis of triglycerides by enzymatic esterification of polyunsaturated fatty acids (PUFA) with glycerol. A PUFA concentrate obtained from cod liver oil was used to optimize the reaction to favor triglyceride synthesis with lipases. The type and amount of lipase and organic solvent, glycerol content, temperature, water content, and amount and time of addition of molecular sieves were studied. The optimal reaction mixture and conditions were: 9 mL hexane, 60°C, 0.5% (vol/vol) water, 1 g molecular sieves added after 24 h of reaction, glycerol/fatty acid molar ratio 1:3 and 100 mg of Novozym 435 (Novo Nordisk A/S) lipase. Under these conditions, an enriched triglyceride yiedl of 84.7% containing 27.4% eicosapentaenoic acid and 45.1% docosahexaenoic acid was obtained from a cod liver oil PUFA concentrate.
Enzymatic interesterification of lard and high‐oleic sunflower oil with Candida antarctica lipase to produce plastic fats
Authors: Seriburi Vimon , Akoh Casimir C.
Published: May 2007

Lard and high‐oleic sunflower oil (Trisun® Extra) were interesterified at 55°C for 24 h with SP435 lipase from Candida antarctica to produce plastic fats. As the amount of trisun increased, percentage free fatty acid, unsaturated fatty acid/saturated fatty acid value, oxidizability, and the amount of 18:1 found at the sn‐2 position of triglyceride products increased. Differential scanning calorimetry showed that the low‐melting components in the product contained more 18:1 than the high‐melting components. A 60:40 (w/w) ratio of lard to trisun had the widest plastic range (3–26°C). The scaled‐up reaction to produce this blend resulted in a product that had 60.1% 18:1 at the sn‐2 position compared to 44.9% for the physical blend. The solid fat content of the 60:40 interesterified mixture resembled soft‐type margarine oil.
Modification of butterfat by selective hydrolysis and interesterification by lipase: Process and product characterization
Authors: Balcão Victor M. , Kemppinen Asmo , Malcata F. Xavier , Kalo Paavo J.
Published: May 2007

Butterfat was chemically modified via combined hydrolysis and interesterification, catalyzed by a commercial lipase immobilized onto a bundle of hydrophobic hollow fibers. The main goal of this research effort was to engineer butterfat with improved nutritional properties by taking advantage of the sn‐1,3 specificity and fatty acid specificity of a lipase in hydrolysis and ester interchange reactions, and concomitantly decrease its level of long‐chain saturated fatty acid residues (viz., lauric, myristic, and palmitic acids) and change its melting properties. All reactions were carried out at 40°C in a solvent‐free system under controlled water activity, and their extent was monitored via chromatographic assays for free fatty acids, esterified fatty acid moieties, and triacylglycerols; the thermal behavior of the modified butterfat was also assessed via calorimetry. Lipase‐modified butterfat possesses a wider melting temperature range than regular butterfat. The total saturated triacylglycerols decreased by 2.2%, whereas triacylglycerols with 28–46 acyl carbons (which contained two or three lauric, myristic, or palmitic acid moieties) decreased by 13%. The total monoene triacylglycerols increased by 5.4%, whereas polyene triacylglycerols decreased by 2.9%. The triacylglycerols of interesterified butterfat had ca. 10.9% less lauric, 10.7% less myristic, and 13.6% less palmitic acid residues than those of the original butterfat.
Enzymatic glycerolysis of soybean oil
Authors: Noureddini H. , Harmeier S. E.
Published: May 2007

Enzymatic glycerolysis of soybean oil was studied. Of the nine lipases that were tested in the initial screening, Pseudomonas sp. resulted in the highest yield of monoglycerides. Lipase from Pseudomonas sp. was further studied for the influence of temperature, thermal stability, enzyme/oil ratio, and glycerol/oil ratio. A full factorial optimization approach was performed. The following conditions were tested over the specified ranges: temperature (30–70°C), thermal stability (30–70°C), enzyme/oil ratio (0.05–0.2 g enzyme/10 g oil), glycerol/oil ratio (1:1–3:1 glycerol/oil molar ratio) and 1 h reaction time. The stability of the enzyme at the reaction temperature was also incorporated as a separate variable. At temperatures above 40°C enzyme denaturation offset the higher activity. The optimal conditions were selected to be the basis for a continuous process: 40°C, a glycerol/oil molar ratio of 2:1, and an enzyme/oil ratio of 0.1 g enzyme/10 g oil. A definition for glycerolysis activity was adopted. The glycerolysis activity (1 GU) was defined as the amount of enzyme necessary to consume 1 µmol of substrate (glycerol and oil) per minute. This research is intended to explore the reaction parameters that are important in a continuous enzymatic glycerolysis process.
γ‐Linolenic acid in zygomycetous fungi: Syzygites megalocarpus
Authors: Weete J. D. , Shewmaker F. , Gandhi S. R.
Published: May 2007

The fatty acids of over 150 species and isolates of zygomycetous fungi were analyzed, and it was found that γ‐linolenic acid (GLA) composed 35 to 62% of the total fatty acids in several species, i.e., Circenella simplex, Mucor indicus, Syzygites megalocarpus (ATCC 18025), and Zygorhynchus moellierie A (UAMH 1556). Further study of S. megalocarpus showed that the total lipid content of the mycelium could be increased from 9.8% of the dry biomass to 20 to 25% when grown in a medium with a high carbon/nitrogen ratio. Under these conditions, the GLA content of the triacyglycerols increased during culture development, even during the stationary phase, but remained relatively constant in the phospholipid fraction. Nonsaponifiable lipid represented 4% of the total lipid, and the major sterol among 14 others detected was ergosterol at 52% of the total. Phospholipids composed 7% of the total lipid with phosphatidylethanol‐amine and phosphatidylcholine representing 53 and 39% of the total, respectively.
Effect of pro‐oxidants on the occurrence of 2‐pentyl pyridine in soy protein isolate
Authors: Boatright W. L. , Crum A. D. , Lei Q.
Published: May 2007

Levels of 2‐pentyl pyridine in hexane‐defatted soybean flours prepared from Burlison, Stressland, and Probst varieties and a variety null for lipoxygenase 1, 2, and 3 were determined using an internal standard of deuterium‐labeled 2‐pentyl pyridine. These defatted flours contained from 0.06 to 0.51 ppm 2‐pentyl pyridine. The flours from lipoxygenase‐null and Stressland varieties of soybeans contained the lowest levels. Control freeze‐dried soy protein isolates (SPI) prepared from defatted‐flours all contained from 0.16 to 0.18 ppm 2‐pentyl pyridine.

Adding pro‐oxidants (FeCl3, CuCl2) or exposing the protein slurries to ultraviolet light during SPI processing increased the level of 2‐pentyl pyridine in the protein isolates by up to 1256 percent above the control Burlison, Stressland, and Probst SPI. The CuCl2 and/or UV treatment contributed the largest increase in each case. The same pro‐oxidant and UV treatments contributed no significant increases in the level of 2‐pentyl pyridine in the protein isolates from the lipoxygenase null SPI.
Key odorants of french fries
Authors: Wagner Robert K. , Grosch Werner
Published: May 2007

Twenty‐one compounds, which had been screened in preceding experiments as potent odorants of french fries prepared in palm oil (PO), were quantified by stable isotope dilution assays. Nineteen odorants were dissolved in sun‐flower oil in concentrations equal to those in PO. The flavor profile of the model obtained was close to that of a real sample of PO. A comparison of the complete model with models lacking one or more compounds indicated the following key odorants of PO: 2‐ethyl‐3,5‐dimethylpyrazine, 3‐ethyl‐2,5‐dimethylpyrazine, 2,3‐diethyl‐5‐methylpyrazine, 3‐isobutyl‐2‐methoxypyrazine, (E,Z)‐ and (E,E)‐2,4‐decadienal, trans‐4,5‐epoxy‐(E)‐2‐decenal, 4‐hydroxy‐2,5‐dimethyl‐3(2H)‐furanone, methylpropanal, 2‐ and 3‐methylbutanal, and methanethiol. Replacement of palm oil by coconut fat led to a coconut note in the profile of french fries. γ‐Octalactone was identified as a major contributor to this note.
Effect of vacuum frying on the oxidative stability of oils
Authors: Shyu Shyi‐Liang , Hau Lung‐Bin , Hwang Lucy Sun
Published: May 2007

The purpose of this study was to evaluate frying oil quality with different assessment methods during vacuum frying of carrot slices. In six consecutive days, palm oil, lard, and soybean oil were fried under vacuum at 105°C for 20 min each hour in an 8‐h shift. Peroxide value, acid value, carbonyl value, total polar components, dielectric constant (Food Oil Sensor reading), viscosity, and fatty acid composition were used to evaluate the quality of these oils. Results showed that palm oil and lard possess greater thermal stability than soybean oil. The decrease in C18:2/C16:0 ratio was greater for soybean oil than the other two oils. Of the assessment methods used, peroxide value, carbonyl value, total polar components, and dielectric constant all showed good correlation with frying time and between each other. Viscosity was suitable to assess vacuum‐fried lard and soybean oil, but not palm oil. The measurement of dielectric constant, on the other hand, appeared to be unsuitable to assess vacuum‐fried soybean oil.
The influence of carotenoids and tocopherols on the stability of safflower seed oil during heat‐catalyzed oxidation
Authors: Henry L. K. , Catignani G. L. , Schwartz S. J.
Published: May 2007

The stability and antioxidant effects of carotenoids and tocopherols in safflower seed oil were evaluated under thermal (75°C) and oxidative conditions and the oxidative stability index (OSI) determined. The antioxidant capability of butylated hydroxytoluene (BHT) was also compared with that of β‐carotene in a model system. Lycopene and β‐carotene (1 to 2000 ppm) were heated (75°C) and exposed to air (2.5 psi) in an oxidative stability instrument. β‐Carotene had no antioxidant effect at concentrations below 500 ppm, because it did not alter the induction time. Lycopene increased the induction time only slightly at low concentrations. However, at concentrations greater than 500 ppm, both β‐carotene and lycopene acted as prooxidants, significantly decreasing the induction period. At the highest concentration, 2000 ppm, lycopene was more prooxidative than β‐carotene. α‐ and γ‐Tocopherol (concentration, 1000 ppm) delayed the induction time by 16 and 26 h, respectively. There was no cooperative interaction between α‐tocopherol and β‐carotene in delaying the onset of oxidation. Furthermore, BHT was significantly more antioxidative than β‐carotene. Thus, under thermal and oxidative conditions, β‐carotene could not delay the onset of oxidation. The tocopherols and BHT were effective in suppressing the onset of oxidation, as determined by the oxidative stability measurement.
Urea complexation for the rapid, ecologically responsible fractionation of fatty acids from seed oil
Authors: Hayes Douglas G. , Bengtsson Ylva C. , Van Alstine James M. , Setterwall Fredrik
Published: May 2007

Urea complex formation is a classic method for fractionating fatty acids from seed and other oils. The method’s simplicity, ease of scaling, and ecological friendliness suggest its reevaluation in regard to modern fractionation challenges. In keeping with this, a simple, quick, inexpensive, robust, and environmentally friendly procedure was developed for reducing the saturated free fatty acid (FFA) content of saponified low‐erucic acid rapeseed oil (LEAR). The process involves formation of a homogeneous 65°C solution of FFA and urea in 95% ethanol (5% water), followed by cooling of the resultant urea complex slurry to room temperature. The urea complex and liquid phases are separated by gravity filtration, and the urea isolated in each phase is removed by extraction with 60°C water. Saturated LEAR oil FFA preferentially formed urea complexes easily separated from the noncomplexed, mostly unsaturated FFA, the main product of interest. The effects of single‐ vs. double‐stage fractionations and several other variables (component mass or volume ratios, temperature, ethanol solvent to water ratio) were preliminarily evaluated. Results demonstrated the robustness, reproducibility, and simplicity of the method.
Pretreatment of corn oil for physical refining
Authors: Antoniassi Rosemar , Esteves Walter , de Almeida Meirelles Antonio José
Published: May 2007

Crude corn oil that contained 380 ppm of phosphorus and 5% of free fatty acids was degummed, bleached, and winterized for physical refining. The pretreatment and the steam‐refining conditions were studied in pilot plant scale (2 kg/batch). The efficiency of wet degumming and of the total degumming processes, at different temperatures, was evaluated. TriSyl silica was tested as an auxiliary agent in the reduction of the phosphorus content before bleaching. The experimental conditions of the physical refining were: temperature at 240 or 250°C; 8 to 18 mbar vacuum, and distillation time varying from 1 to 3 h. Degumming at 10 or 30°C resulted in the removal of more phosphorus than at 70°C. Water degumming was more efficient than the processes of total degumming or acid degumming. Corn oil, degummed at 10 or 30°C, after bleaching passed the cold test, irrespective of the degumming agent used. Degumming and winterization took place simultaneously at these temperatures. The pretreatment was able to reduce the phosphorus content to less than 5 ppm. The amount of bleaching earth was reduced by carrying out dry degumming or by using silica before bleaching. Corn oil acidity, after physical refining, varied from 0.49 to 1.87%, depending on the residence time. Contrary to alkali refining, physical refining did not promote color removal due to the fixation of pigments present in the crude corn oil.
Commercial production of chia in Northwestern Argentina
Authors: Coates Wayne , Ayerza (h) Ricardo
Published: May 2007

The economy of northwestern Argentina depends heavily on sugar and tobacco. Depressed prices for these crops in recent years have caused significant economic problems, and alternative crops are actively being sought. Chia (Salvia hispanica L.), a source of industrial oil for the cosmetics industry and θ‐3 α‐linolenic acid for the food industry, is one new crop that could help diversify the local economy. A project to develop chia as a commercial crop was initiated in 1991. In 1996, 13 fields were commercially grown in two provinces of northwestern Argentina. Biomass production and seed yields were affected by weather, location, and production practices. Average seed yield was 606 kg/ha. Oil content and fatty acid composition varied between fields.
Recovery of γ‐oryzanol from rice bran oil with silica‐based continuous chromatography
Authors: Saska Michael , Rossiter Gordon J.
Published: May 2007

A simulated moving bed chromatography separator was tested for recovery of γ‐oryzanol from degummed and dewaxed rice bran oil that contained 1.2 to 1.6% γ‐oryzanol. A crude product with 12–15% of γ‐oryzanol was obtained and a 90 to 95% pure product was recovered from the concentrate by crystallization from heptane. With the recycling of the crystallization liquor, an overall γ‐oryzanol recovery of 85 to 90% is feasible and is potentially higher than the recovery in the conventional soapstock‐based process.
Extraction of oil from meadowfoam flakes
Authors: Carlson Kenneth D. , Phillips Bliss S. , Isbell Terry A. , Nelsen Terry C.
Published: May 2007

As part of a program to improve meadowfoam seed processing, the authors examined the effects of seed moisture, seed temperature, and flaking roll opening on oil extraction efficiency in meadowfoam flakes. Flakes were prepared using a Wolf Mill with dual horizontal, unheated 12‐in. diameter rolls. Roll openings of 0.005, 0.013, and 0.020 in. (0.127, 0.330, and 0.508 mm, respectively) gave average flake thicknesses of 0.013, 0.021, and 0.031 in., respectively (0.330, 0.533, and 0.787 mm). Seed moistures of 9, 12, and 15% and seed temperatures of 65, 190, and 210°F (18, 88, and 99°C) chosen for flaking were known to provide a range of conditions suitable for enzyme inactivation during seed cooking prior to flaking. Experimental flakes were examined for extractable oil content (petroleum ether extraction); this was compared to total oil content (31.5%) determined on finely ground flakes. Roll opening was the dominant variable determining flake thickness, the primary parameter affecting oil extraction efficiency. Thus, the thinnest flakes at 0.013 in. were only slightly less extractable (29.8%) than finely ground flakes (31.5%), but intermediate (0.021 in.) and thick (0.031 in.) flakes were significantly less extractable (28.0 and 26.0%, respectively). There was a slight but significant (P<0.01) trend toward thicker flakes with increasing seed moisture (15>12>9%) during flaking. A similar trend to thicker flakes with increasing temperature was significant (P<0.01) only for the thickest flakes produced at the largest roll opening (0.020 in.). Lower seed moisture and higher seed temperature significantly impacted extractable oil content of the thickest flakes, but negligibly affected extractability of the thinnest flakes. The authors conclude that meadowfoam flakes must be as thin as possible (e.g., <0.015 in.) for efficient oil extraction. Further, seed cooking temperatures >190°F at moistures >10% and <15% that are adequate for efficient enzyme inactivation in the whole seed are also suitable for seed flaking.
Deacidification of a synthetic oil with an anion exchange resin
Authors: Eychenne Valérie , Mouloungui Zéphirin
Published: May 2007

Esters of trimethylolpropane were prepared by reaction of trimethylolpropane with erucic acid. Unreacted erucic acid was eliminated by fixation on an anion exchange resin to produce an oil with a low free fatty acid content. The authors describe the deacidification of the reaction product by Lewatit MP500A and MP600 resins in a fixed‐bed reactor or in a stirred reactor. The discontinuous process gave the best results with the Lewatit MP600 resin in a stirred reactor with a 99% yield. The acid value was below 0.1 after less than 1 h of contact.
Comparison of four accelerated stability methods for lard and tallow with and without antioxidants
Authors: Liang Chao , Schwarzer Koen
Published: May 2007

The oxidative stability of lard and tallow with and without antioxidants was evaluated by four accelerated stability methods, the active oxygen method (AOM), the oxygen bomb test, the Rancimat method, and the Schaal oven test. The results indicated that the oxidative stability of animal fats and the relative effectiveness of an antioxidant in the fats could have different mechanisms. When the protective index was used to demonstrate the relative effectiveness of the antioxidants, the results suggested that the Rancimat Method may be the least reliable method compared with AOM, oxygen bomb test, and Schaal oven test. More than one accelerated stability method is recommended for evaluating the effectiveness of an antioxidant or the oxidative stability of fats.
Calculating the lodine value for marine oils from fatty acid profiles
Authors: Ham Bryan , Shelton Robert , Butler Boyce , Thionville Paul
Published: May 2007

The iodine values of marine oils were directly calculated from fatty acid profiles by using reacting ratios (calculation factors) between I2 (iodine) and either the fatty acids bound to a triglyceride or the free fatty acids. A total of 20 factors were incorporated from C14:1 to C24:1, placed into an Excel® spreadsheet, and used to calculate the iodine values. The calculated values were then compared to the oil’s iodine value obtained by the traditional titration method. The results indicate that this method can be used to obtain the iodine value of marine oils directly from the oil’s fatty acid composition, thus giving two results from one analysis.
Ultrasonic attenuation of edible oils
Authors: Chanamai Ratjika , McClements D. Julian
Published: May 2007

The frequency dependence (1–60 MHz) of the ultrasonic attenuation coefficient of canola oil, corn oil, olive oil, peanut oil, safflower oil, soybean oil, and sunflower oil was measured at 25°C. The attenuation coefficient of all the oils could be described by the relation: α ∼ Afn(with A between 6 and 40 × 10−12, and n between 1.74 and 1.86).
Occurrence of conjugated linoleic acid isomers in beef
Authors: Fritsche Sonja , Fritsche Jan
Published: May 2007

The amounts of Δ9,Δ11‐conjugated linoleic acid (CLA) isomers were determined in loin‐associated fat samples of bulls (n=6) and steers (n=7) by capillary gas chromatography of fatty acid methyl ester (FAME) derivatives. The main CLA‐isomer—18:2 c9,t11—provided approximately 0.76 ± 0.15% and 0.86 ± 0.15% of total FAME in bulls and steers, respectively. No differences (P>0.05) were observed between the CLA isomer distribution of bulls (t9,c11, 0.026 ± 0.014%; c9,c11, 0.015 ± 0.008%; and t9,t11, 0.029 ± 0.003%) and steers (t9,c11, 0.027 ± 0.014%; c9,c11, 0.015 ± 0.005%; and t9,t11, 0.030 ± 0.007%).
Optical resolution of (±)‐Threo‐9,10,16‐trihydroxy hexadecanoic acid using (−)brucine
Authors: Malkar Navdeep B. , Kumar V. G.
Published: May 2007

The optical resolution of (±)threo‐9,10,16‐trihydroxy hexadecanoic acid was achieved by fractional crystallization using (−)brucine. Formation of an estolide during decomposition of the (−)brucine complex was observed to interfere with the separation of the optically pure material. This was corrected by converting the estolide to (+)‐threo‐9,10,16‐trihydroxy hexadecanoic acid via alcoholic alkaline hydrolysis followed by neutralization. Enantiomeric purity was determined by chiral lanthanide nuclear magnetic resonance shift reagent.
On the use and misuse of the avrami equation in characterization of the kinetics of fat crystallization
Authors: Marangoni Alejandro G.
Published: May 2007

The Avrami model is widely used in the analysis of crystallization kinetic data. Unfortunately, the use of the original model has been abandoned in favor of modified versions. The modifications are largely arbitrary and create a dependence between the Avrami constant and the Avrami exponent. From a curve‐fitting point of view, no advantages exist in using the modified over the original form of the Avrami model. The order of a polynomial fit to crystallization data is not equivalent to the Avrami exponent. The use of turbidity measurements for the quantitative characterization of crystallization kinetics is not valid.
Flavor components of olive oil—A review
Authors: Kiritsakis A. K.
Published: May 2007

The unique and delicate flavor of olive oil is attributed to a number of volatile components. Aldehydes, alcohols, esters, hydrocarbons, ketones, furans, and other compounds have been quantitated and identified by gas chromatography‐mass spectrometry in good‐quality olive oil. The presence of flavor compounds in olive oil is closely related to its sensory quality. Hexanal, trans‐2‐hexenal, 1‐hexanol, and 3‐methylbutan‐1‐ol are the major volatile compounds of olive oil. Volatile flavor compounds are formed in the olive fruit through an enzymatic process. Olive cultivar, origin, maturity stage of fruit, storage conditions of fruit, and olive fruit processing influence the flavor components of olive oil and therefore its taste and aroma. The components octanal, nonala, and 2‐hexenal, as well as the volatile alcohols propanol, amyl alcohols, 2‐hexenol, 2‐hexanol, and heptanol, characterize the olive cultivar. There are some slight changes in the flavor components in olive oil obtained from the same oil cultivar grown in different areas. The highest concentration of volatile components appears at the optimal maturity stage of fruit. During storage of olive fruit, volatile flavor components, such as aldehydes and esters, decrease. Phenolic compounds also have a significant effect on olive oil flavor. There is a good correlation between aroma and flavor of olive oil and its polyphenol content. Hydroxytyrosol, tyrosol, caffeic acid, coumaric acid, and p‐hydroxybenzoic acid influence mostly the sensory characteristics of olive oil. Hydroxytyrosol is present in good‐quality olive oil, while tyrosol and some phenolic acids are found in olive oil of poor quality. Various off‐flavor compounds are formed by oxidation, which may be initiated in the olive fruit. Pentanal, hexanal, octanal, and nonanal are the major compounds formed in oxidized olive oil, but 2‐pentenal and 2‐heptenal are mainly responsible for the off‐flavor.
Volatile compounds in heated oleic acid‐esterified propoxylated glycerol
Authors: Mahungu Symon M. , Hansen Steven L. , Artz William E.
Published: May 2007

Static headspace and capillary gas chromatography, in combination with infrared and mass spectrometry, were used to collect, separate, identify, and quantitate the oxidative and thermal decomposition products in two heated model compound triacylglycerols, oleic acid‐esterified propoxylated glycerol (EPG‐08 oleate) and triolein. The EPG‐08 oleate and triolein were each heated in a deep‐fat fryer at 192±8°C for 12 h each day until the oil contained ≥20% polymeric material. Most of the volatile compounds identified in heated triolein and EPG‐08 oleate were associated with the oxidative and thermal decomposition of oleates, such as short‐chain alkanes, aldehydes, and alcohols. The major volatile compounds (concentration >20 ppm) in heated EPG‐08 oleate and triolein were heptane, octane, heptanal, octanal, trans‐2‐decenal, nonanal, and trans‐2‐undecenal. However, a few minor volatile compounds, not previously found in heated fats and oils, were identified in the heated EPG‐08 oleate samples. These compounds included 1,2‐propanediol, 1‐hydroxy‐2‐propanone (hydroxyacetone), 1‐acetoxy‐2‐propanone (acetoxyacetone), 2‐ethyl‐4‐methyl‐1,3‐dioxolane, 2,2,4‐trimethyl‐1,3‐dioxolane, 2‐heptyl‐4‐methyl‐1,3‐dioxolane, and 4‐methyl‐2‐octyl‐1,3‐dioxolane. Alkyl‐substituted dioxolanes have been found in heated methyl linoleate.
Immobilized lipase‐catalyzed ethanolysis of sunflower oil in a solvent‐free medium
Authors: Selmi Boulbada , Thomas Daniel
Published: May 2007

The ethanolysis of sunflower oil (SFO) with Lipozyme (immobilizéd 1,3‐specific Mucor miehei lipase) in a medium solely composed of substrates was investigated. The effects of oil/ethanol molar ratio, temperature, added water content, and amount of enzyme were analyzed. The optimal values were, respectively, 1:3, 50°C, 0% (vol/vol), and 0.4 g of Lipozyme per 5.7 mmol of SFO. The use of immobilized lipase made the reuse of enzyme feasible, and the enzyme could be recovered easily from the reaction mixture and recycled to reduce the cost of catalyst. In the last three consecutive runs of enzyme reuse, the final conversion yield of SFO from ethanolysis with added silica gel support was higher than that obtained from ethanolysis under standard conditions. The lipase‐catalyzed alcoholytic reaction is potentially useful in the production of alkyl esters of specific interest.
Lipase‐catalyzed modification of borage oil: Incorporation of capric and eicosapentaenoic acids to form structured lipids
Authors: Akoh Casimir C. , Moussata Charment O.
Published: May 2007

Two immobilized lipases, nonspecific SP435 from Candida antarctica and sn‐1,3 specific IM60 from Rhizomucor miehei, were used as biocatalysts for the restructuring of borage oil (Borago officinalis L.) to incorporate capric acid (10:0, medium‐chain fatty acid) and eicosapentaenoic acid (20:5n‐3) with the free fatty acids as acyl donors. Transesterification (acidolysis) reactions were carried out in hexane, and the products were analyzed by gas‐liquid chromatography. The fatty acid profiles of the modified borage oil were different from that of unmodified borage oil. Higher incorporation of 20:5n‐3 (10.2%) and 10:0 (26.3%) was obtained with IM60 lipase, compared to 8.8 and 15.5%, respectively, with SP435 lipase. However, SP435 lipase was able to incorporate both 10:0 and 20:5n‐3 fatty acids at the sn‐2 position, but the IM60 lipase did not. Solvents with log P values between 3.5 and 4.5 supported the acidolysis reaction better than those with log P values between −0.33 and 3.0.
Two‐step enzymatic reaction for the synthesis of pure structured triacylglycerides
Authors: Soumanou Mohamed M. , Bornscheuer Uwe T. , Schmid Rolf D.
Published: May 2007

Structured triacylglycerides with medium‐chain fatty acids (caprylic acid) in sn1‐ and sn3‐positions and a long‐chain unsaturated fatty acid (oleic or linoleic acid) in the sn2‐position of glycerol (MLM) were synthesized by lipase catalysis in a two‐step process. First, pure 2‐monoacylglycerides (2‐MG) were synthesized by alcoholysis of triacylglycerides (triolein, trilinolein, or peanut oil) in organic solvents with 1,3‐regiospecific lipases (from Rhizomucor miehei, Rhizopus delemar, and Rhizopus javanicus). The 2‐MG were purified by crystallization and obtained in up to 71.8% yield. These 2‐MG were esterified in a second reaction with caprylic acid in n‐hexane to form almost pure MLM. For 2‐MG obtained from peanut oil, the final product contained more than 90% caprylic acid in the sn1‐ and sn3‐positions, whereas the sn2‐position was composed of 98.5% unsaturated long‐chain fatty acids. Reaction conditions for both steps were optimized with respect to source and immobilization of lipase, water activity, and solvent.
Enzymatic interesterification of triolein and tristearin: Chemical structure and differential scanning calorimetric analysis of the products
Authors: Seriburi Vimon , Akoh Casimir C.
Published: May 2007

The structural composition and thermal properties of the products of enzymatic interesterification of triolein and tristearin were investigated. The biocatalyst for the reaction was an immobilized Candida antarctica lipase, SP435. Enzyme load of 10% (w/w reactants) produced 72% of desired total products. Oleoyl‐distearoyl triglycerides (SSO, OSS) had higher melting points than dioleoyl‐stearoyl triglycerides (OOS, SOO) because the sample contained larger amounts of stearic acid than oleic acid residues. SOS and OSO were hardly produced (0.2 to 1.2%), which indicates that SP435 acted as a nonspecific lipase when catalyzing the interesterification of triolein and tristearin. The maximal yield of OSS and SSO (46.9%) was achieved with a 1.2 mole ratio of triolein to tristearin. As the proportion of tristearin was increased, the production of SOO and OOS decreased, the melting profile of the interesterified triglycerides shifted toward higher melting forms, and the solid fat content increased, indicating formation of hard fats.
Microbial conversion of palmitoleic acid to 9,12‐hexadecadienoic acid (16:2ω4) by Trichoderma sp. AM076
Authors: Shirasaka Norifumi , Umehara Takuya , Murakami Tetsuo , Yoshizumi Hajime , Shimizu Sakayu
Published: May 2007

Trichoderma sp. AM076, isolated from a freshwater sample, was found to accumulate 9,12‐cis‐hexadecadienoic acid (16:2ω4), when grown with palmitoleic acid (16: 1ω7). Methyl myristate was the best carbon source for the conversion of palmitoleic acid to 16:2ω4. The mycelial 16:2ω4 content reached 17.4 mg/g dry mycelia (443 mg/L) when the fungus was grown in a medium that contained 2.0% methyl myristate, 1.5% yeast extract, and 2.0% methyl palmitoleate, pH 6.0, for 5 d at 28°C with shaking. In both nonpolar and polar lipids from the mycelia, 16:2ω4 was detected as one of the major fatty acids when 16:1ω7 was added. It is probable that 16:1ω7 is converted to 16:2ω4 through the Δ12 desaturation reaction.
Effect of fruit storage conditions on olive oil quality
Authors: Kiritsakis A. , Nanos G. D. , Polymenopulos Z. , Thomai T. , Sfakiotakis E. M.
Published: May 2007

“Koroneiki” olive fruit from trees grown in Crete were stored under five different conditions (0°C, air; 5°C, air; 5°C, 2% O2+5% CO2; 7.5°C, air; 7.5°C, 2% O2+5% CO2). Oil was obtained from fruit immediately after harvest and after fruit storage for 30 and 60 d. Olive oil quality was evaluated by determining acidity, peroxide value, absorption coefficients (K232, K270), phenol and chlorophyll content, fatty acid composition, and the resistance to oxidation by oven test. Olives stored at 7.5°C, even for 30 d, deteriorated from fungus development, and the obtained oil was of inferior quality with high acidity, peroxide value, and absorption coefficients. The same oil had high chlorophyll and phenol content, resulting in good oil resistance to oxidation. Olive oil from fruit stored at 0 or 5°C for 30 d had acceptable acidity, peroxide value, and absorption coefficients, but showed low resistance to oxidation, which was attributed to low chlorophyll and phenol content. This condition is further attributed to chilling injury caused by low storage temperatures. During storage, all treatments resulted in an increase of oleic acid, partly as a result of linoleic acid oxidation.
General properties and the fatty acid composition of the oil from the mophane caterpillar,Imbrasia belina
Authors: Motshegwe S. M. , Holmback J. , Yeboah S. O.
Published: May 2007

A preliminary investigation of the bulk properties of the oil from the edible mophane caterpillar (phane),Imbrasia belina, showed a significant difference in the iodine values of the oils from mature and young phane. Detailed analysis of the fatty acid composition of the two oil samples was thus carried out by capillary gas chromatography (GC) and complemented with1H and13C nuclear magnetic resonance (NMR) studies to investigate the degree of unstauration in the two oil samples. While these studies showed that the oil samples from the mature and young mophane caterpillar were much the same in fatty acid composition, the data revealed a significant divergence from a literature report on phane oil. This earlier report puts the ratio of total saturated to total unsaturated fatty acids at approximately 1:1 (48.2:48.8, in percentages) and estimates the fatty acid composition for the major fatty acids as 16:0 (31.9%), 18:0 (15.2%), 18:1 (20.4%), 18:2 (9.9%), and 18:3 (19%). The data collected from the present work, however, showed the fatty acid composition for total saturated and total unsaturated fatty acids to be 40.5 and 57.0%, respectively. This work estimated the fatty acid composition for the major fatty acids as 16:0 (27.2%), 18:0 (12.3%), 18:1 (16.1%), 18.2 (10.7%), and 18:3 (29.0%). Thus, linolenic acid was the most abundant fatty acid in the phane oil. The GC results of the present analysis were largely corroborated by studies of the composition of fatty acid classes in the phane oil estimated from integrals of1H and13C NMR signals. Oils from other edible Lepidoptera larvae are also known to be much richer in unsaturated than saturated fatty acids.
Effect of xanthan gum on enhancing the foaming properties of soy protein isolate
Authors: Xie Y. R. , Hettiarachchy N. S.
Published: May 2007

The foaming properties of soy protein isolate (SPI) in the presence of xanthan gum (XG) were investigated. The XG solution alone did not exhibit any foaming ability. The optimal foaming properties were obtained from the SPI‐XG dispersion that contained 0.1% SPI and 0.2% XG. This SPI‐XG dispersion gave higher foaming capacity than that of SPI or egg white (P<0.05). The foam stability of SPI‐XG dispersion was nine times higher than that of SPI and egg white (P<0.05). The SPI‐XG foams were stable over wide ranges of ionic strength (0.1 to 1.0 M NaCl) and pH (4.5 to 9.0), and when heated (85°C, 1 h).
Concentration and stabilization of n‐3 polyunsaturated fatty acids from sardine oil
Authors: Ganga Angélica , Nieto Susana , Sanhuez Julio , Romo Claudio , Speisky Hernán , Valenzuela Alfonso
Published: May 2007

A simple and relatively inexpensive procedure to obtain 90% eicosapentaenoic acid + docosahexaenoic acid concentrates from sardine oil involved a two‐step winterization of the oil (10 and 4°C), followed by saponification and selective precipitation of saturated and less unsaturated free fatty acids by an ethanolic solution of urea. Antioxidant effects of butylated hydroxytoluene, dl‐α‐tocopherol, and two natural antioxidants, quercetin and boldine, added to the concentrate (0.5% wt/vol), were compared in the Rancimat at 60°C. dl‐α‐Tocopherol was unable to inhibit concentrate oxidation. Butylated hydroxyanisole and butylated hydroxytoluene had induction periods of 1.7–1.8 h compared to the control (1.0 h). A mixture of quercetin + boldine (2:1 w/w) significantly increased the induction period to 4.5 h.
Quality and compositional studies of some edible leguminosae seed oils in Botswana
Authors: Ketshajwang K. K. , Holmback J. , Yeboah S. O.
Published: May 2007

Seed oils were extracted with n‐hexane from three edible Leguminosae seeds: Tylosema esculentum, Xanthocercis zambesiaca, and Bauhinia petersiana, giving yields of 48.2, 17.6, and 20.8% (w/w), respectively. Some physical and chemical parameters were determined to ascertain the general characteristics of the oils. The saponification and iodine values indicated that all three oil samples could be classified among the olive group of oils. This inference was supported by the results of the detailed fatty acid composition of the oils as determined by capillary gas chromatography. The ratio of total unsaturated to total saturated fatty acids in all three oil samples was approximately 70:30, with either oleic or linoleic acid being the dominant fatty acid. These results were in agreement with a proton nuclear magnetic resonance analysis of the fatty acid classes in the seed oils. Thus, the analysis served to justify the use of the three Leguminosae seed oils in food preparations. The work has further indicated that, with their attractive properties, the seed oils from T. esculentum, X. zambesiaca, and B. petersiana are good candidates for further studies to evaluate their future commercial prospects in the Southern African region.
Preparation of monoglycerides by guanidine‐catalyzed processes
Authors: Aguiar Leila M. Guimarães , Vargas Rogério Matheus
Published: May 2007

Glycerolysis of methyl stearate and tristearin has been carried out in the presence of alkylguanidines—strong nonionic bases—as catalysts. When applied at 10 mol%, 1,5,7‐triazabicyclo [4.4.0]dec‐5‐ene, 1,2,3‐tricyclohexylguanidine, and 1,3‐dicyclohexyl‐2‐n‐octylguanidine give monoglycerides in more than 90% selectivity, in a maximum of 6 h reaction time.
Properties of rapeseed oil for use as a diesel fuel extender
Authors: McDonnell K. , Ward S. , Leahy J. J. , McNulty P.
Published: May 2007

Chemical and thermal analyses were carried out on degummed and filtered (5 µm) rapeseed oil (referred to as SRO, i.e., semirefined rapeseed oil) to determine its suitability as a diesel fuel extender. The upper rate for inclusion of SRO with diesel fuel is 25%. This fuel blend had a phosphorus level of 2.5 ppm, which was comparable to rape methyl esters (1.0 ppm phosphorus). Thermogravimetric analyses were used to estimate the cetane ratings of the fuels. A 25% SRO/diesel blend had an estimated cetane index of 32.4 compared to 38.1 for diesel fuel only. Differential scanning calorimetry and thermogravimetric analyses were used to compare the volatility ranges of the fuels. SRO needed higher temperatures for volatilization (i.e., 70–260°C for diesel fuel vs. 280–520°C for SRO). This indicated poorer cold‐starting performance of SRO compared with diesel fuel. SRO fuel is a low‐sulfur, high‐oxygen fuel giving SRO a more favorable emissions profile than pure diesel fuel.
Transesterification of heated rapeseed oil for extending diesel fuel
Authors: Mittelbach M. , Enzelsberger H.
Published: May 2007

Fatty acid methyl esters are well established as an alternative fuel called “biodiesel.” For economic reasons, used frying oil is an interesting alternative feedstock for biodiesel production. The chemical changes that occur during heating of rapeseed oil, especially the formation of polymers, were investigated. Heated rapeseed oil samples were transesterified with methanol and analyzed by size‐exclusion chromatography. During heating, the amount of polymers in the starting oil increased up to 15 wt%, but only up to 5 wt% in the transesterified samples. So during transesterification, dimeric and trimeric triglycerides in the starting oil were mainly converted into monomeric and dimeric fatty acid methyl esters. The amount of polymeric fatty acid methyl esters had a negative influence on fuel characteristics. After 6 h of heating, the amount of Conradson carbon residue and after 16 h the viscosity exceeded that of the existing specifications for biodiesel. Therefore, the amount of polymers in waste oil is a good indicator for the suitability for biodiesel production.
Preparation of fatty epoxy alcohols using oat seed peroxygenase in nonaqueous media
Authors: Piazza George J. , Foglia Thomas A. , NuɁez Alberto
Published: May 2007

Peroxygenase is an enzyme of higher plants that is capable of using hydroperoxide and hydrogen peroxide for oxidation of a double bond to an epoxide. A microsomal fraction was prepared from dry oat (Avena sativa) seeds. The peroxygenase activity of this fraction was tested using fatty acid hydroperoxide 2a [13(S)‐hydroperoxy‐9(Z), 11(E)‐octadecadienoic acid] and its methyl ester 2b as sources of peroxygen. These were prepared by the action of soybean lipoxygenase on linoleic acid. A high‐performance liquid chromatographic assay was used to differentiate between peroxygen cleavage and peroxygen cleavage with accompanying double‐bond oxidation Higher activity was obtained with 2b compared to 2a, and peroxygen cleavage activity was observed in both aqueous and organic solvent media. Double‐bond oxidation activity was high only in aqueous media and nonpolar organic solvents. Structural elucidation of the epoxidized product showed it to be the oxylipid, methyl cis‐9,10‐epoxy‐13(S)‐hydroxy‐11(E)‐octade‐cenoate 4b, demonstrating specificity for epoxidation of the cis double bond. Trihydroxy product was not detected, demonstrating that the epoxide was not hydrolyzed.