bluuebunny/crossref_metadata_2025 huggingface dataset:
Production of alkyl ester as biodiesel from fractionated lard and restaurant grease
Authors: Lee Ki‐Teak , Foglia Thomas A. , Chang Kyu‐Seob
Published: November 2006

Methyl or ethyl esters were produced from lard and restaurant grease by lipase‐ or base‐catalyzed reactions. Before esterifying, some renewable substrates (lard and restaurant grease) should be manipulated through acetone fractionation or on a chromatography column packed with an adsorbent to obtain maximal reaction rate. Because lipase activity was hindered by excess amounts (more than 1 mol) of methanol, each 1 M methanol was added sequentially after 24 h of reaction. Through a three‐step reaction, 74% conversion to tallow‐methyl ester was obtained. However, a porous substance, such as silica gel, improved the conversion when more than 1 M methanol was used as reaction substrate. When a 1∶3 (fractionated lard/methanol, mole ratio) substrate was used, the conversion rates (i.e., extent of conversion) were 2.7 (24 h) and 2.8% (48 h). However, with 10% silica gel in the reaction mixture, the conversion rates increased to 25 and 58%, respectively. Regenerated restaurant grease (FFA removed through column chromatography) was further converted to esters by alkali‐catalyzed methanolysis. After 24 h of reaction, 96% conversion was obtained, while only 25% conversion was observed from crude grease. Alkyl esters produced in this study could be used for fuels, potentially as biodiesel.
Plasticization of soy protein polymer by polyol‐based plasticizers
Authors: Mo Xiaoqun , Sun Xiuzhi
Published: November 2006

Soy protein isolate (SPI) was mixed with four polyol‐based plasticizers and molded into plastics using a hot press. The plasticized SPI powder was evaluated for denaturation temperatures and denaturation enthalpies. The SPI plastics were studied for mechanical properties, glass transition temperatures, storage modulus, morphology, and water absorption. Thermal properties of the SPI plastics with propylene glycol were depressed to the largest degree, and the plastics with glycerol showed the largest strain at break, whereas plastics with 1,3‐butanediol gave the highest tensile strength. The morphology of the fractured surface on the SPI plastics changed from brittle fracture for the unplasticized SPI to ductile fracture for the plasticized SPI. Water absorption of all the plasticized SPI plastics was lower than that of the unplasticized SPI plastics.
Effect of gallic acid on the aroma constituents of soymilk and soy protein isolates
Authors: Boatright W. L.
Published: November 2006

Volatile compounds from soymilk were analyzed by gas chromatography/olfactometry/mass spectrometry (GCO/MS) with direct injection of various volumes of static headspaces. The most powerful odorants, determined by the minimum headspace volume required to detect by olfactometry, were (i) hexanal, (ii) acetaldehyde, (iii) methanethiol, (iv) dimethyl trisulfide (DMTS), and (v) 2‐pentyl furan. Analyses of soymilk prepared with the addition of 100 ppm gallic acid revealed that the only two detectable odorants were hexanal and acetaldehyde. Sensory analyses of the soymilk treated with 100 ppm gallic acid produced a significantly lower score (P=0.0006) for overall odor intensity compared with the control soymilk. Aqueous slurries of soy protein isolates (SPI) prepared with the addition of 100 ppm gallic acid also had lower odor intensities than the control SPI (P<0.0001). GCO/MS analyses of headspace volatiles revealed that the gallic acid treatment had removed all detectable levels of methanethiol and DMTS while having no significant effect on the level of hexanal (P=0.81).
Lipase‐catalyzed acidolysis of perilla oil with caprylic acid to produce structured lipids
Authors: Kim In‐Hwan , Kim Hakryul , Lee Ki‐Teak , Chung Soo‐Hyun , Ko Soon‐Nam
Published: November 2006

Structured lipids were synthesized by acidolysis of perilla oil and caprylic acid using two lipases, Lipozyme RM IM from Rhizomucor miehei and Lipozyme TL IM from Thermomyces lanuginosa. Effects of molar ratio, reaction time, reaction temperature, enzyme load, and solvent content on acidolysis reactions were studied. The solvent content ranged from 0.0 (solvent‐free) to 85.3%. The results showed that the incorporation increased in parallel with solvent content to 49.0% with Lipozyme RM IM and to 63.8% with Lipozyme TL IM. After 24 h incubation in n‐hexane, caprylic acids were incorporated to 48.5 mol% with Lipozyme RM IM and to 51.4 mol% with Lipozyme TL IM, respectively, whereas linolenic acid content was reduced from 61.4 to 31.5 mol% with Lipozyme RM IM and to 28.4 mol% with Lipozyme TL IM, respectively. Lipozyme TL IM showed a higher acyl migration rate than Lipozyme RM IM when acidolysis was performed in the reaction system containing n‐hexane as a solvent, whereas the difference in acyl migration between the two lipases in the solvent‐free system was negligible.
Impact of extraction method on yield of lipid oxidation products from oxidized and unoxidized walnuts
Authors: Crowe Tammy D. , Crowe Troy W. , Johnson Lawrence A. , White Pamela J.
Published: November 2006

The objective of this study was to measure and compare differences in oxidized products of oil extracted from unoxidized and oxidized walnuts using five different extraction methods: (i) mechanical pressing, or solvent extraction with (ii) hexane, (iii) methylene chloride, (iv) chloroform/methanol, or (v) supercritical carbon dioxide (SC−CO2). Of the extraction methods evaluated, only chloroform/methanol and methylene chloride provided reasonable results for all parameters measured (total lipid yield, FA profile, PV, conjugated dienes, FFA content, and volatile content); however, chloroform/methanol extracted significantly greater levels of volatile compounds. The SC−CO2 extraction with purified gas was simple and accurate for all data except collection of volatile compounds, as these materials are lost during the lipid extraction. Pressing was neither quantitative nor qualitative, and hexane extraction retrieved significantly lower levels of volatiles than the other methods, except for SC−CO2.
Effects of pH and ferric ions on the antioxidant activity of olive polyphenols in oil‐in‐water emulsions
Authors: Paiva‐Martins Fátima , Gordon Michael H.
Published: November 2006

The effects of four phenolic compounds occurring in olives and virgin olive oil, namely, oleuropein, hydroxytyrosol, 3,4‐dihydroxyphenylethanol‐elenolic acid (3,4‐DHPEA‐EA) and 3,4‐dihydroxyphenylethanol‐elenolic acid dialdehyde (3,4‐DHPEA‐EDA), on the oxidative stability of stripped olive oil‐in‐water emulsions were studied at three pH values in the presence or absence of ferric chloride at 60°C. In the stability test, the addition of phenolic compounds in emulsions at pH 5.5 significantly extended the induction time of lipid oxidation, and the activities in decreasing order were 3,4‐DHPEA‐EA> 3,4‐DHPEA‐EDA>hydroxytyrosol>α‐tocopherol∼oleuropein ≫control. The effect of concentration, iron, and pH on the antioxidant activity of the phenolic compounds in stripped olive oil‐in‐water emulsions was analyzed by response surface methodology. Oleuropein and hydroxytyrosol enhanced the prooxidant effect of ferric chloride at pH 3.5 and pH 5.5 but not at pH 7.4. The 3,4‐DHPEA‐EDA reduced the prooxidant effect of ferric chloride at pH 5.5 and pH 7.4, but at pH 3.5 prooxidant effects were evident at higher phenol concentration. The 3,4‐DHPEA‐EA reduced the prooxidant effect of ferric ions at all pH values tested. Differences in activity of the phenols may be explained by consideration of their free radical scavenging activity and ferric reducing capacity.
Changes in the main components and quality indices of virgin olive oil during oxidation
Authors: Gutiérrez F. , Villafranca M. J. , Castellano J. M.
Published: November 2006

This work reports on changes in the major and minor components of virgin olive oil during oxidation, details modifications found in the standardized quality indices, and analyzes the most significant relationships between the components of the oil and its oxidative stability. During the induction period or slow phase of oxidation, polyphenols, tocopherols, and pigments undergo the most important alterations. Other compounds, such as FA or volatiles, suffer significant modifications only during the rapid or exponential phase of oxidation when the natural antioxidant systems fall to minimal values. Among the quality indices, PV and the specific extinction coefficients K232 and K270 increase markedly from the earliest stages of oxidation, whereas titratable acidity does not change appreciably during the induction period. The evolution of the different compounds and parameters analyzed suggests that the tocopherol and orthodiphenol contents are the best indices to determine the average life of the oils.
Exhaust emissions and health effects of particulate matter from agricultural tractors operating on rapeseed oil methyl ester
Authors: Krahl Jürgen , Bünger Jürgen , Schröder Olaf , Munack Axel , Knothe Gerhard
Published: November 2006

Exhaust emissions and their effects on the environment and human health, such as mutagenicity of particulate matter (PM) and ozone‐forming potential, must be considered when using an alternative fuel. In the present work, a test engine and two agricultural tractors ran on rapeseed oil methyl ester (biodiesel) or conventional diesel fuel as well as blends thereof. The objective was to detect any disproportionately positive or negative effects depending on blend levels, because conventional diesel fuel and biodiesel can be blended in every ratio. Generally, emissions of regulated compounds changed linearly with the blend level. The known positive and negative effects of biodiesel varied accordingly. Overall, no optimal blend was found. Increasing biodiesel content of the fuel caused a linear increase in benzene emissions in the agricultural five‐mode engine test, an effect that may be explained from previous studies on precombustion chemistry. In using the test engine, it was found that PM from biodiesel significantly reduced mutagenic potential compared with that from diesel fuel, although in this work PM masses were found to be reproducibly higher for biodiesel from rapeseed oil compared with conventional diesel fuel. Ozone precursors increased 10–30% when using biodiesel compared with conventional diesel fuel. Emissions of aldehydes and alkenes are mainly responsible for this effect. N2O emissions increased when using a catalytic converter.
Dynamic mechanical and thermal behavior of epoxy resins based on soybean oil
Authors: Gerbase Annelise E. , Petzhold Cesar L. , Costa Ana Paula O.
Published: November 2006

Mechanical and thermal properties of materials prepared by curing epoxidized soybean oil with various cyclic acid anhydrides in the presence of tertiary amines were investigated by dynamic mechanical thermal analysis and thermogravimetry. All samples presented thermoset material characteristics that were dependent upon the type of anhydride, the anhydride/epoxy molar ratio, and epoxy group content. The thermosets obtained from anhydrides with rigid structures as such phthalic, maleic, and hexahydrophthalic showed higher glass transition temperatures (Tg) and cross‐linking densities. As expected, the Tg decreased as the anhydride/epoxy ratio decreased. The influence of the degree of epoxidation of soybean oil on the mechanical properties and Tg was also investigated. It was found that the higher the epoxy group amount, the higher the Tg and hardness. Cured resins exhibited thermal stability up to 300°C, except for those prepared with dodecenyl succinic anhydride, which began to decompose at lower temperature. They presented excellent chemical resistance when immersed in 1% wt/vol NaOH and 3% wt/vol H2SO4 solutions but poor chemical resistance in the presence of organic solvents.
Extraction of oil from ground corn using ethanol
Authors: Kwiatkowski J. R. , Cheryan M.
Published: November 2006

Corn oil was extracted from whole ground corn using ethanol as the solvent. The yield of oil was measured as a function of temperature, time of extraction, solvent‐to‐solids ratio, and ethanol concentration. Optimal conditions were a solvent‐to‐solids ratio of 4 mL/g corn, an ethanol concentration of 100%, 30 min of extraction time, and a temperature of 50°C. Under these conditions, a single batch extraction yielded ≈3.3 g oil/100 g corn, equivalent to 70% extraction efficiency. A three‐stage extraction, where the same corn was exposed to fresh ethanol, resulted in a yield of ≈4.5 g/100 g corn (2.5 lb/bu of corn), equivalent to 93% recovery of the oil in corn. When anhydrous ethanol was used to repeatedly extract fresh corn, moisture was absorbed linearly by ethanol from the corn in successive stages, which, in turn, decreased oil yield and increased nonoil components in the extract.
Structure indices in FA chemistry. How relevant is the iodine value?
Authors: Knothe Gerhard
Published: November 2006

Most common analytical methods in FA chemistry can be categorized as yielding either structure or quality indices. Quality indices often describe components in fats and oils arising from processing, storage, and naturally occurring, nonfatty materials. Common structure indices are the iodine value (IV), the saponification value, and the hydroxyl value. Although modern analytical methods yield more detailed and reliable information, structure indices are still widely used. The IV, which indicates total unsaturation, has even been included in some standards for industrial products such as biodiesel. However, the IV index is too general to allow the correlation of physical and chemical properties with FA composition. The IV is treated in a theoretical fashion regarding biodiesel‐ and oxidative stability‐related issues. That the concept of IV as a structure index is unsatisfactory is shown by the development of a quaternary composition diagram (QCD). The QCD demonstrates the derivation of a specific IV from varying FA compositions. Improved correlations are possible among the structure indices. Alternative indices for the IV are developed. Possible alternatives are the allylic position equivalent (APE) and the bisallylic position equivalent (BAPE) which better relate structure and amount of common component FA in vegetable oils to observed properties. The APE and BAPE indices are based on the number of reactive positions in oxidation.
Camelina oil and its unusual cholesterol content
Authors: Shukla V. K. S. , Dutta P. C. , Artz W. E.
Published: November 2006

The oil in Camelina sativa L. Crantz has a combined linolenic and linoleic acid content that is greater than 50% and a relatively low saturated FA content (∼10%). Although the FA composition has been reported, no information is available on the sterol composition of camelina oil. The derivatized plant sterols were separated and quantified with capillary GC and their identity confirmed with GC‐MS. The refined camelina oil sample contained approximately 0.54 wt% unsaponifiables, and over 80% of the unsaponifiables were desmethylsterols. Perhaps the most unusual characteristic of camelina oil is its relatively high content of cholesterol, particularly for a vegetable oil, since it contains several times the cholesterol found in other “high‐cholesterol” vegetable oils. Camelina oil also contains relatively large amounts of another unusual sterol, brassicasterol. The major sterols identified in the camelina oil included cholesterol (188 ppm), brassicasterol (133 ppm), campesterol (893 ppm), stigmasterol (103 ppm), sitosterol (1,884 ppm), and Δ5‐avenasterol (393 ppm).
Validation of the oxygen radical absorbance capacity (ORAC) parameter as a new index of quality and stability of virgin olive oil
Authors: Ninfali Paolino , Bacchiocca Mara , Biagiotti Enrica , Servili Maurizio , Montedoro Gianfrancesco
Published: November 2006

The induction period (IP), determined using accelerated methods such as the Rancimat test, is a parameter that has been used to predict the shelf life of virgin olive oil. The oxygen radical absorbance capacity (ORAC) has recently been proposed as a quality index of virgin olive oil because it measures the efficiency of phenolic compounds in the protection against peroxyl radicals. This study aims to investigate relationships between the ORAC and IP values and proposes ORAC as a new parameter of virgin olive oil stability. The concentrations of phenolics, o‐diphenols, tocopherol, β‐carotene, lutein, and ORAC and IP values were determined in 33 virgin olive oils. Regression analyses showed that both ORAC and IP values correlate with total phenols and o‐diphenols with highly significant indices, whereas the correlations of both ORAC and IP with tocopherols, β‐carotene, and lutein were not significant. The ORAC values correlate with the IP values with low but significant indices (R=0.42; P<0.02). The results confirm the key role of phenolic compounds in accounting for the shelf life of virgin olive oil and suggest that the ORAC parameter may be used as a new index of quality and stability.
Riboflavin‐photosensitized singlet oxygen oxidation product of vitamin D2
Authors: King Joan M. , Min David B.
Published: November 2006

The riboflavin‐photosensitized singlet oxygen oxidation of vitamin D2 in a model system of 12% water and 88% acetone was studied to understand the possible oxidation of fortified vitamin D in milk. Only the samples containing vitamin D2 and riboflavin under light storage showed two new peaks in the HPLC chromatogram, indicating that singlet oxygen oxidation of vitamin D2 had occurred. UV analysis indicated that a new compound was formed from the reaction of the triene of vitamin D2 with oxygen. The mass spectrum showed that one of the two compounds had a molecular ion at m/z=412, which was an increase of the mass of vitamin D2 by the mass of exactly one oxygen. The IR spectrum suggested the presence of a hydroxyl group and no carbonyl group in the product. The combned information from UV, MS, and FTIR spectra and the chemical mechanisms of singlet oxygen oxidation of vitamin D2 indicated that a 5,6‐epoxide of vitamin D2 was formed from vitamin D2 in the presence of riboflavin under light.
Characterizing cocoa butter seed crystals by the oil‐in‐water emulsion crystallization method
Authors: Hindle Scott A. , Povey Malcolm J. W. , Smith Kevin W.
Published: November 2006

Unambiguous quantitative evidence for the catalytic action of seed crystals in cocoa butter is presented. We used an ultrasound velocity technique to determine the isothermal growth of solid fat content in cocoa butter oil‐in‐water emulsions, in which the probability of finding a seed crystal in any one droplet was around 0.37 at 14.2°C. The upper limit for the size of seed crystals in West African cocoa butter was around 0.09 μm, the Gibbs free energy for nucleation was 0.11 mj m−2, and the concentration of seed crystals was in the range of 1016to 1017m−3. X‐ray diffraction measurements showed that emulsified cocoa butter crystallizes in the α polymorph and does not appear to transform to the β′ form within the first 25 min of crystallization. Primary nucleation events in cocoa butter emulsions are accounted for by seed crystals. Collision‐mediated nucleation, a secondary nucleation mechanism, in which solid droplets (containing seed crystals) catalyze nucleation in liquid droplets, is shown to account for subsequent crystallization. This secondary nucleation mechanism is enhanced by stirring.
Characterization of olive oil classes using a Chemsensor and pattern recognition techniques
Authors: Peña F. , Cárdenas S. , Gallego M. , Valcárcel M.
Published: November 2006

Classification is an important component of food quality assurance, as methods to guarantee authenticity of food products are widely demanded by food producers, processors, consumers, and regulatory bodies. The objective of this work was to develop a rapid classification method in order to discriminate virgin olive oil, olive oil, and „orujo” olive oil, the prices of which differ dramatically in the market on a ccount of the high quality level of the former. For these purposes, new ChemSensor equipment that combines a headspace autosampler with a mass‐selective detector and Pirouette data evaluation software was used. To take into account the large number of samples analyzed (50 samples repeated 10 times), as well as the wide interval ofm/zratios scanned (41–170), chemometric approaches were necessary. Cluster analysis, principal component analysis, K‐nearest neighbors, and soft independent modeling of class analogy (SIMCA) were applied to model the different oil classes. The results indicated good classification and prediction abilities, with SIMCA affording the best results (viz. 97% specificity).
Monitoring milk fat fractionation: Effect of agitation, temperature, and residence time on physical properties
Authors: Vanhoutte Bert , Dewettinck Koen , Vanlerberghe Brecht , Huyghebaert André
Published: November 2006

With the use of two central composite designs, the effects of agitation rate, fractionation temperature, and residence time on the thermal properties of the stearin and olein milk fat fractions were investigated. The main function of agitation during fat fractionation was suspending the crystal aggregates and enhancing the heat transfer. For the experimental conditions described here, crystal aggregation did not seem to be affected by agitation. The effect of fractionation temperature on the physical properties of the olein fraction was very significant. Triangle diagrams were shown to be a useful tool for monitoring and designing fractionation processes. They illustrate that oleins with similar melting properties can be produced over a range of yields of stearin, which is important from an industrial point of view. Crystallizer residence time, which influences production costs, clearly affects both stearin yield and olein melting properties. For any fractionation temperature, stearin fractions with virtually identical melting properties and yields can be obtained over a range of olein melting properties. Manipulation of both the fractionation temperature and residence time allows the fractionation process to be adapted to meet changing market demands for fractions with different melting properties.
Comparison of a low‐linolenic and a partially hydrogenated soybean oil using pan‐fried hash browns
Authors: Soheili Kambiz C. , Tippayawat Preeyanooch , Artz William E.
Published: November 2006

Hash browns (HB) were fried (Teflon‐coated pan, ∼180°C) with low‐linolenic acid (LL‐SBO) and creamy partially hydrogenated soybean oils (PH‐SBO). High‐performance size‐exclusion chromatography of the oil extracted before heating indicated a relatively low polymer content (LL‐SBO, 3.8%; PH‐SBO, 1.6%), although the oil remaining in the pan after frying had a much greater polymer content (38.8%, LL‐SBO; 17.5%, PH‐SBO). The percentage of altered TAG in the LL‐SBO sample (extracted from HB) was 34.4% after frying, whereas the PH‐SBO had 33.2% altered TAG (as determined by supercritical fluid chromatography). In the LL‐SBO pan‐fried HB samples (not the extracted oil), 2‐pentanone, hexanal, 2‐hexenal, trans‐2‐heptenal, 2‐pentylfuran, and trans‐2‐octenal were found, whereas the major volatile compounds in the HB fried with PH‐SBO included hexanal, trans‐2‐hexenal, and trans‐2‐heptenal. Hexanal was the most abundant volatile compound in both HB samples (LL‐SBO, 2.7 ppm; PH‐SBO, 0.3 ppm). There were significant differences in the polymer content, hexanal content, p‐anisidine values, and Foodoil sensor readings between LL‐SBO and PH‐SBO (P<0.05). The PH‐SBO sample was more stable than the LL‐SBO sample. Moreover, the LL‐SBO oil sample in the pan after frying had the greater increase in polymer content.
Composition and sensory qualities of minimum‐refined soybean oils
Authors: Wang Xi , Wang Tong , Johnson Lawrence A.
Published: November 2006

Commodity (normal) and high‐oleic soybean oils extracted by extrusion‐expelling (E‐E) were minimally processed using water degumming and adsorptive deacidification to produce edible oil. Degummed and deacidified oils were deodorized at 150°C for 1 h by purging with N2, CO2, or steam. They were also conventionally deodorized for quality comparisons. Generally, the oxidative stability of the properly gas‐purged commodity oils was better than that of the conventionally deodorized oils. Total tocopherols, FFA contents, and colors of the deodorized oils were not significantly different among the treatments. Sensory analysis of the oils showed that the toasty/nutty flavors of the gas‐purged oils, especially for the degummed oils, were more intense than those of the conventionally deodorized oils. The beany flavors of gas‐purged oils were not significantly different from those of conventionally deodorized oils, although the flavor intensities tended to be slightly higher in gas‐purged oils. The overall flavor intensities of the gas‐purged oils were similar to those of conventionally deodorized oils. Therefore, E‐E soybean oil has the potential to be minimally refined to produce edible oil with good compositional and sensory qualities.
Particle size effects on supercritical CO2 extraction of oil‐containing seeds
Authors: del Valle José M. , Uquiche Edgar L.
Published: November 2006

Rosehip seeds were milled, sieved, and extracted with 26.3 g/g substrate/h of supercritical carbon dioxide (CO2) at 40°C and 300 bar. The extraction kinetics were characterized by an initial solubility‐controlled period (8.78 g oil/kg CO2 at 40°C and 300 bar), followed by a transition period to a final mass transfer‐controlled process. The integral yield of oil approached an asymptotic value that was dependent on the particle size of the substrate: 57.1 g oil/kg dry oil‐free substrate (large particles), 171.0 g/kg (medium‐size particles), or 391.5 g/kg (small particles). Based on gravimetric determinations and microscopic analysis, our size‐classification process segregated seed parts having different oil contents. Particles ≥0.85 mm were mainly composed of tough, lignified testa fragments devoid of oil, whereas particles ≤0.425 mm contained mostly brittle, oil‐rich germ fragments. The segregation of seed in fractions with different oil contents may be a common occurrence in supercritical extraction experiments, especially for seeds with thick and/or hard testa and small germ, whose fractions can be separated by sieving.
FA and unsaponifiable composition of five Amazonian palm kernel oils
Authors: Bereau Didier , Benjelloun‐Mlayah Bouchra , Banoub Joseph , Bravo René
Published: November 2006

The kernel oils of five different palm species native to the Amazon basin and French Guyana were studied. Those studied were Acrocomia lasiospatha Wall., Astrocaryum vulgare C. Mart., Bactris gasipaes H.B.K., Elaeis oleifera (Kunth) Cortés, and Maximiliana maripa Drude. Lauric and myristic acids were found in all of the oils. Analysis of the unsaponifiable contents, especially the sterol and triterpene alcohol determinations, revealed the preponderance of sitosterol and the presence of two triterpene alcohols (cycloartenol and 24‐methylenecycloartanol). Antioxidant (vitamin E) levels were present in small amounts, with the levels being more similar to olive than to palm oil.
Tocopherols in sea buckthorn (Hippophaë rhamnoides L.) berry oil
Authors: Zadernowski R. , Naczk M. , Amarowicz R.
Published: November 2006

The free tocopherol content in whole berries of six sea buckthorn cultivars grown in northeastern Poland and Belorussia was determined with HPLC. The total free tocopherol content in oil from whole berries was 101.4–128.3 mg/100 g of oil. α‐Tocopherol was the predominant tocopherol of sea buckthorn berries, and only traces of γ‐tocopherol were detected in the oil. α‐ and δ‐Tocopherols constituted 62.5–67.9% and 32.1–37.5% of total tocopherol, respectively. The total free tocopherol content in oil of sea buckthorn cv. Nadbaltycka increased during maturation from 40.4 to 109.8 mg/100 g of oil. Green berries contained a marked amount of γ‐tocopherol, but its content rapidly declined to traces when the color of berries turned from green to olive‐yellow.
Chemical composition and antioxidant activity of extracts from Daphne gnidium L.
Authors: Deiana M. , Rosa A. , Casu V. , Cottiglia F. , Bonsignore L. , Dessì M. A.
Published: November 2006

Members of the Daphne genus have been of interest owing to their excellent medicinal value. In this work, we describe the results of phytochemical analysis and the antioxidant activity of the methanol extracts from leaves and stems of D. gnidium L. grown wild in Sardinia, Italy. Four coumarins (daphnetin, daphnin, acetylumbelliferon, and daphnoretin), nine flavonoids (apigenin, luteolin, quercetin, orientin, isoorientin, luteolin 7‐O‐glucoside, apigenin 7‐O‐glucoside, genkwanin, and 5‐O‐β‐d‐primeverosyl genkwanine), and α‐tocopherol were isolated. We investigated the ability of the two extracts and five pure compounds (daphnetin, daphnoretin, apigenin, luteolin, and α‐tocopherol) to protect linoleic acid against free radical attack in simple in vitro systems by autoxidation and iron‐ or EDTA‐mediated oxidation. Pure compounds were the most active antioxidants. During autoxidation, daphnetin, luteolin, and α‐tocopherol were effective at a molar ratio of 1∶1600, 1∶2500, and 1∶2000, respectively. Daphnoretin was active only at high concentrations. During the iron‐catalyzed oxidation of linoleic acid, all the materials tested showed activity in the following order: luteolin>daphnetin>α‐tocopherol >leaf extract>stem extract>daphnoretin. Apigenin was not active in any of the experimental systems used.
Production of FAME from acid oil, a by‐product of vegetable oil refining
Authors: Haas Michael J. , Michalski Paul J. , Runyon Stan , Nunez Alberto , Scott Karen M.
Published: November 2006

Simple alkyl FA esters have numerous uses, including serving as biodiesel, a fuel for compression ignition (diesel) engines. The use of acid‐catalyzed esterification for the synthesis of FAME from acid oil, a by‐product of edible vegetable oil refining that is produced from soapstock, was investigated. Soybean acid oil contained 59.3 wt% FFA, 28.0 wt% TAG, 4.4 wt% DAG, and less than 1% MAG. Maximum esterification occurred at 65°C and 26 h reaction at a molar ratio of total FA/methanol/sulfuric acid of 1∶15∶1.5. Residual unreacted species under these conditions, as a fraction of their content in unesterified acid oil, were FFA, 6.6%; TAG, 5.8%; and DAG, 2.6%. This corresponds to estimated concentrations of FFA, 3.2%; TAG, 1.3%; and DAG, 0.2%, on a mass basis, in the ester product. In an alternative approach, the acylglycerol species in soapstock were saponified prior to acidulation. High‐acid (HA) acid oil made from this saponified soapstock had an FFA content of 96.2 wt% and no detectable TAG, DAG, or MAG. Optimal esterification conditions for HA acid oil at 65°C were a mole ratio of FFA/methanol/acid of 1∶1.8∶0.17, and 14 h incubation. FAME recovery under these conditions was 89% of theoretical, and the residual unesterified FFA content was approximately 20 mg/g. This was reduced to 3.5 mg/g, below the maximum FFA level allowed for biodiesel, by washing with NaCl, NaHCO3, and Ca(OH)2 solutions. Alternatively, by subjecting the unwashed ester layer to a second esterification, the FFA level was reduced to less than 2 mg/g. The acid value of this material exceeded the maximum allowed for biodiesel, but was reduced to an acceptable value by a brief wash with 0.5 N NaOH.
Structural characterization of triacylglycerols using electrospray ionization‐MSn ion‐trap MS
Authors: Marzilli Lisa A. , Fay Laurent B. , Dionisi Fabiola , Vouros Paul
Published: November 2006

Structural analysis of mixtures of TAG requires the determination of the M.W. of each compound, the characterization of the structure(s) of the individual FA substituents, and identification of the relative disposition of the acyl groups on the glycerol backbone (regiospecificity). In this study we demonstrated that ion‐trap MS in combination with electrospray ionization provides an easy and detailed characterization of the TAG structure. We showed that electrospray mass spectra are characterized by intense molecular ion adducts and that the acyl group disposition on the TAG backbone can be determined on the basis of relatively well‐defined quantitative differences of fragment ions produced from MS2 data. Moreover, additional spectral data can be generated by MS3 experiments on moieties containing individual acyl ion fragments. When hyphenated with chromatographic separations ion‐trap electrospray MS might become a routine and powerful way to analyze TAG mixtures.
Detection of olive oil adulteration using principal component analysis applied on total and regio FA content
Authors: Dourtoglou V. G. , Dourtoglou Th. , Antonopoulos A. , Stefanou E. , Lalas S. , Poulos C.
Published: November 2006

Principal component analysis (PCA) has been used to establish a new method for the detection of olive oil adulteration. The data set, composed of values obtained from the determination of the mole percentage of total FA and their regiospecific distribution in positions 1 and 3 in TG of oils (pure or mixtures) by GC analysis, was subjected to PCA. 3‐D scatter plots showed clearly that it is possible to distinguish the pure oils from the mixtures. Moreover it is possible to discriminate the different types of seed oil used for the adulteration.
TAG composition of ewe's milk fat. Detection of foreign fats
Authors: Goudjil Hanane , Fontecha Javier , Fraga Ma Jesús , Juárez Manuela
Published: November 2006

The TAG composition of 45 samples of ewe's milk, collected throughout the year from five Spanish breeds, was analyzed according to their carbon number by using short capillary column GC. The TAG content had a bimodal distribution with maxima at C38 (12.8%) and C52 (8.4%). The TAG composition did not vary significantly with respect to the time of year of sampling but was affected by the breed. Multiple regression equations based on TAG content are proposed to detect foreign fats in ewe's milk fat. Analysis of known mixtures of lard, palm oil, and cow's milk fat with ewe's milk fat have experimentally confirmed the accuracy of the equations.
Physical analyses of gel‐like behavior of binary mixtures of high‐ and low‐melting fats
Authors: Higaki K. , Sasakura Y. , Koyano T. , Hachiya I. , Sato K.
Published: November 2006

Gel‐like fat mixtures of high‐melting (HM) and low‐melting (LM) fats were formed by means of rapid cooling and subsequent heating. No “non‐fat” ingredients such as emulsifiers, water, or waxes were added to the mixtures. The gel‐like fats having solid fat content (SFC) values below 2.0 wt% formed crystal networks of HM‐fats that entrapped the liquid oil fraction of LM‐fats. In a search for optimal fat combinations exhibiting gel‐like behavior, fully hydrogenated rapeseed oil with a high amount of behenic acid (FHR‐B), fully hydrogenated rapeseed oil with a high amount of stearic acid (FHR‐S), tristearoylglycerol (SSS), triarachidonoyl‐glycerol (AAA), and tribehenoylglycerol (BBB) were examined as the HM‐fats. For LM‐fats, sal fat olein (SFO), cocoa butter (CB), palm super olein (PSO), and olive oil were examined. The following results were obtained: (i) the gel‐like behavior was observed in mixtures of FHR‐B/SFO and FHR‐B/CB with initial concentrations of FHR‐B of 1.5–4.0 wt%. (ii) Rapid cooling to Tc (crystallization temperature) from 70°C and subsequent heating to Tf (final temperature) were necessary to reveal the gel‐like behavior, whereas simple cooling without a cooling/heating procedure did not form the gel‐like fat mixture. (iii) Optimal values of Tc and Tf were related to the m.p. of the LM‐fat and HM‐fat, respectively. (iv) Temperature variations of SFC as well as X‐ray diffraction spectra showed that the melt‐mediated transformation from α to β of the HM‐fat crystals was a prerequisite to reveal the gel‐like behavior. Consequently, the fat mixture revealing the gel‐like behavior might be called β‐fat gel.
Purification of FAME by rice hull ash adsorption
Authors: Özgül‐Yücel Sevil , Türkay Selma
Published: November 2006

Rice hull ash (RHA) and silica gel were used for purification of FAME by adsorption of FFA at atmospheric conditions. Studies demonstrated that silica gel is a better adsorbent than RHA in purifying FAME. However, both adsorbents were effective in reducing FFA levels from FAME extracts. The FFA adsorption efficiency increased with high FAME concentration and high adsorbent dosage. But FAME adsorption also increased with larger doses of adsorbent. The adsorption isotherms of FFA were determined with both adsorbents. FFA adsorption displayed Freundlich‐type isotherms.
Ternary phase diagram of soybean phosphatidylcholine‐water‐soybean oil and its application to the water degumming process
Authors: Lei Ling , Ma Yue , Kodali Dharma R. , Liang Jingmei , Davis H. Ted
Published: November 2006

Crude soybean oil contains phospholipids (2.5 wt%) that must be removed from oil during processing. A common method is the water‐degumming process. A ternary phase diagram of soybean oil‐water‐soybean PC, a major component of phospholipids, was established. From this diagram, phase transitions and compositions of phases can be determined. A theoretical model describing the relationship between aggregation curvature and the amount of water added is presented to explain the phase transitions. The amount of water absorption by the lamellar phase should be larger than the critical value of 34 wt% based on the total weight of water and PC. Below this critical amount, phospholipids tend to form liposomes. Above the critical point and below the saturation point, larger aggregates of particles form and can be easily separated. When more water is added to reach the water adsorption limit, about 40 wt% based on the total weight of water and PC, a phase transition boundary is observed, beyond which a third phase, water, appears and the particle size falls dramatically. In between the critical line predicted by the model and the water adsorption saturation line observed experimentally, there is an operation window on the ternary phase diagram for the water‐degumming process.
Effect of crop season on the composition of virgin olive oil with protected designation of origin “Les garrigues”
Authors: Romero M. Paz , Tovar M. Jesús , Ramo Tomas , Motilva M. José
Published: November 2006

In recent years a growing demand for agricultural produce with an identifiable geographical origin has developed. The aim of this work was to study differences in quality and composition of virgin olive oils produced over four consecutive crop seasons in the region of the protected designation of origin “Les Garrigues” (Catalonia, Spain), taking the harvesting period and the climatic conditions of the year into consideration. The results obtained in this study indicate that virgin olive oil composition is greatly influenced by climatic conditions, mainly the cumulative rainfall in the case of FA composition and phenolic compounds, and the minimum temperatures during harvest period in the case of chlorophyll, carotenoid pigments, and α‐tocopherol content. The harvest period influenced most of the parameters analyzed, apart from the PV and FFA content. Prediction models for carotenoid pigment content, oxidative stability, and bitter index were found.
An experimental approach to structure‐activity relationships of caffeic and dihydrocaffeic acids and related monophenols
Authors: Nenadis Nikolaos , Boyle Susanne , Bakalbassis Evangelos G. , Tsimidou Maria
Published: November 2006

The importance of a catechol moiety to the radical‐scavenging activity of p‐hydroxycinnamic derivatives is widely accepted, whereas the role of the carbon side chain remains controversial. Extension of the conjugation to this chain is a molecular feature that requires some attention. Differences in the activity of caffeic and dihydrocaffeic acids were examined using a series of experimental procedures: assays using free radicals [1,1‐diphenyl‐2‐picrylhydrazyl (DPPH•) and 2,2′‐azino‐bis(3‐ethylbenzthiazoline‐6‐sulfonic acid) (ABTS•+)]; assays based on redox reactions; and accelerated tests in bulk oils and dispersed systems. To reinforce observations on the role of the side chain, a group of related monophenols, differing in one double bond and/or its position in the chain, was also examined. Extended conjugation was essential for the rapid scavenging of free radicals and for effectiveness in dispersed systems (both liposomes and emulsions). In the case of bulk oils, the contribution of conjugation remained unclear. Information based on redox reactions was not useful for the aim of our study. The experimental conditions may mask or enhance the effect of the chain characteristics on the activity, so the size and the order of activity may be influenced. Thus, structure‐activity relationships should be drawn with caution.
Pan‐frying stability of NuSun oil, a mid‐oleic sunflower oil
Authors: Kiatsrichart Sudatip , Susan Brewer M. , Cadwallader Keith R. , Artz William E.
Published: November 2006

Pan‐frying is a popular frying method at home and in many restaurants. Pan‐frying stabilities of two frying oils with similar iodine values (IV)—mid‐oleic sunflower oil (NuSun oil; IV=103.9) and a commercial canola oil (IV=103.4)—were compared. Each oil sample was heated as a thin film on a Teflon‐coated frying pan at ∼180°C to a target end point of ≥20% polymer. High‐performance size‐exclusion chromatography analysis of the mid‐oleic sunflower and canola oil samples indicated that the heated samples contained 20% polymer after approximately 18 and 22 min of heating, respectively. The food oil sensor values increased from zero to 19.9 for the canola sample and from zero to 19.8 for the mid‐oleic sunflower sample after 24 min of heating. The apparent first‐order degradation rate for the mid‐oleic sunflower sample was 0.102±0.008 min−1, whereas the rate for the canola sample was 0.092±0.010 min−1. The acid value increased from approximately zero prior to heating to 1.3 for the canola sample and from zero to 1.0 for the mid‐oleic sunflower sample after 24 min of heating. In addition, sensory and volatile analyses of the fried hash browns obtained from both oils indicated there were no significant differences between the two fried potato samples.
Analysis of the polyethylene glycol glucosides and FA esters thereof by atmospheric‐pressure ionization MS
Authors: Jin Xin , Yang Jinzong , Tang Bingtao , Zhu Minggui , Yu Ning , Liu Yi
Published: November 2006

Polyethylene glycol (PEG) glucosides (PEGG) and the PEGG esters of lauric acid were analyzed by atmospheric‐pressure ionization MS (API‐MS) with electrospray ionization. Straightforward mass characterization of the complex mixtures could be achieved without prior chromatographic separation. The constituents were identified on the basis of quasi‐molecular ions. Individual components could be observed as protonated molecular ions [M+H]+and/or as their NH4+, Na+, or K+adducts in positive ion mode. The mass spectrometric investigation showed that mixtures of PEGG consisted of monoglucoside, diglucoside, polyglucoside, and free PEG. The esterification product is a mixture of two types of nonionic surfactants: PEG‐laurates and PEGG‐laurates. The reasons for distortion of the quasi‐molecular ion intensities and the stabilization of adduct ions were discussed. The rapid and highly sensitive API‐MS analysis technique proposed here is well suited for direct characterization of complex mixtures and suitable for development as a routine analytical method.
DSC determination of thermally oxidized olive oil
Authors: Vittadini E. , Lee J. H. , Frega N. G. , Min D. B. , Vodovotz Y.
Published: November 2006

The feasibility of using DSC as an analytical method to evaluate the autoxidation of olive oil at 50°C and thermal oxidation at 93 and 180°C in 10‐mL airtight vials was studied. DSC peak enthalpy and peak crystallization temperatures were compared with headspace oxygen depletion and headspace volatiles in oxidized oil samples. A single crystallization peak was found in olive oil. The crystallization peak shifted to lower temperatures, and the enthalpy associated with this phase transition decreased as the exposure time increased at 93 and 180°C. DSC peak enthalpy in olive oil at 50, 93, and 180°C showed correlations of 0.84, 0.91, and 0.95, respectively, with headspace oxygen depletion in sample bottles. Correlation of DSC initial peak temperature with headspace oxygen depletion was 0.53, 0.87, and 0.95 at 50, 93, and 180°C, respectively. Correlations of DSC peak enthalpy and initial peak temperature with headspace volatiles at 180°C were 0.95 and 0.97, respectively. These results indicate that DSC is a good analytical method to determine the oxidative stability of olive oil at frying temperature.
Determination of degree of oxidation of methyl linoleate and linolenate by weighing method
Authors: Matikainen Jorma , Laantera Matti , Kaltia Seppo
Published: November 2006

Autoxidation of methyl linolenate and linoleate was investigated at room temperature in the light and dark during a period of 2 mon using a weighing method accompanied with 1H NMR measurements. In the light, the increase in weight, or autoxidation process, of the two compounds began immediately after the start of the experiment. In the dark, the weight of methyl linolenate began to increase after a delay of 1 wk, and the weight of methyl linoleate after 40 d. The maximal increases in the weights of the compounds were somewhat greater in the dark than in the light; the weight of methyl linolenate in the dark increased by 22.3% and in the light by 20.8%. The corresponding values for methyl linoleate were 16.9 and 14.4%, respectively. Results of the NMR measurements were compared to the weighing results, and a table was constructed representing the correlation between selected multiplets and corresponding weight increments.
Novel method for rapid monitoring of lipid oxidation by FTIR spectroscopy using disposable IR cards
Authors: Russin Ted A. , van de Voort Frederick R. , Sedman Jacqueline
Published: November 2006

A new FTIR approach was investigated for assessing edible oil oxidative stability with the use of polymer IR (PIR) cards as sample holders. This approach allows oil oxidation to be monitored at moderate temperatures owing to the fairly rapid rate at which unsaturated oils oxidize on the PIR cards. To assess the FTIR/PIR card method, pure TAG—triolein, trilinolein, and trilinolenin—were loaded onto cards and placed in a chamber where warm air (55°C) flowed over them continuously to facilitate oxidation. At periodic intervals, individual cards were removed and their FTIR spectra scanned, after which they were replaced in the aeration chamber. All spectra were normalized to compensate for variations in PIR card path lengths or oil loadings, and for each card the initial spectrum recorded (t=0) was subtracted from all subsequent spectra taken over time to produce differential spectra. With the use of a peak‐find algorithm, the absorbance minimum in the cis region (3017–3000 cm−1) and the absorbance maxima in the hydroperoxide (3550–3200 cm−1), isolated trans (977–957 cm−1), and conjugated trans regions (995–983 cm−1) were measured in the differential spectra and plotted as a function of time. For all three TAG, the loss of cis double bonds was linearly related to the development of hydroperoxides and isolated trans bonds for much of the oxidation process, whereas for the polyunsaturated TAG a similar relationship also existed for conjugated trans species. Based on experimentally determined hydroperoxide (ROOH) absorbance slope factor (0.06 mAbs/PV), ROOH absorbance changes were converted to PV, allowing direct PV monitoring as a function of time using the PIR cards. Trilinolenin, trilinolein, and triolein attained a PV of 100 mequiv/kg oil after, 43,98, and 2889 min, respectively, their relative reaction rates being similar to ratios published in the literature. The assessment of the FTIR/PIR card method using TAG indicates that it may be a practical and rapid means of oxidizing lipids and tracking their oxidative state in terms of PV so as to provide a measure of their oxidative stability.