bluuebunny/crossref_metadata_2025 huggingface dataset:
Survey of soybean oil and meal qualities produced by different processes
Authors: Wang Tong , Johnson Lawrence A.
Published: November 2006

Soybean oil and meal produced by extruding‐expelling (E‐E) are believed to have unique characteristics compared with products produced by solvent extraction (SE). A survey was conducted to compare quality characteristics of the oils and meals produced from different types of soybean processing methods. Soybean oil and meal samples were collected three different times within a 1‐yr period from 13 E‐E mills, 8 SE plants, and 1 continuous screwpress (SP) plant. Properties of oil and meal varied considerably between different types of plants and among plants of the same type and sampling times. In general, settled crude E‐E and SP oils had significantly greater peroxide values than those of SE oils. E‐E oils contained less free fatty acid and phosphorus than did SE and SP oils. The oxidative stability (AOM) of E‐E oil was less than that of SE oil, and that of SP oil was intermediate. E‐E and SP meals had higher oil and lower protein and moisture contents than those of SE meals. Protein dispersibility indices were lower for E‐E and SP meals. Protein solubilities in KOH were similar for E‐E and SE meal, but higher than that of SP meal (62%). Rumen bypass protein values were higher for the SP meal.
Encapsulated carotenoid preparations from high‐carotenoid canola oil and cyclodextrins and their stability
Authors: Basu Hemendra N. , Del Vecchio Anthony
Published: November 2006

Cyclodextrin complexes were prepared using 1∶1 and 1∶0.5 molar ratios of cyclodextrins and high‐carotenoid canola oil. β‐Cyclodextrin formed powdered complexes with a molar ratio of 1∶0.5, cyclodextrin/high‐carotenoid canola oil. With a 1∶1 molar ratio, the complex was clumpy. In the case of α‐cyclodextrin, powdery complexes were formed with either 1∶1 or 1∶0.5 molar ratio. The triglyceride oil present in the complexes varied between 28.87 and 48.2%, and there, was no segregation of the triglyceride oil during complex formation. The stability of carotenoids and tocopherols was also the same in brown bottles whether the complexes were kept under nitrogen or under oxygen. In clear glass vials, the amounts of α‐and β‐carotene went down, but there was very little change in tocopherols. With respect to sterols, more than 90% of the sterols present in the degummed oil were present in the α‐cyclodextrin complexes, thereby indicating a higher affinity of the sterols in the cyclodextrin cavity.
Wax analysis of vegetable oils using liquid chromatography on a double‐adsorbent layer of silica gel and silver nitrate‐impregnated silica gel
Authors: Hénon G. , Recseg K. , Kovari K.
Published: November 2006

A chromatographic method is described to measure the crystallizable wax content of crude and refined sunflower oil. It can also be applied to any other vegetable oil. The preparative liquid chromatography step on a glass column containing a silica gel adsorbent superimposed upon a silver nitrate‐impregnated silica gel support is used to isolate a wax fraction which is then analyzed by gas chromatography. The recovered wax fraction contains, in addition to the crystallizable waxes, hydrocarbons and other compounds with gas chromatographic retention times corresponding to waxes with chain lengths C34−C42. These compounds are short‐chain saturated waxes in fruit oils, such as grapeseed and pomace. In seed oils such as sunflower, soybean or peanut, the compounds initially referred to as “soluble esters” are identified as monounsaturated waxes, esters of long‐chain saturated fatty acids, and a monounsaturated alcohol, mainly eicosenoic alcohol. Such waxes are absent from corn or rice bran oils.
Method for determining oxidation of vegetable oils by near‐infrared spectroscopy
Authors: Yildiz Gülgün , Wehling Randy L. , Cuppett Susan L.
Published: November 2006

Use of near‐infrared (NIR) transmittance spectroscopy for rapid determination of the oxidation level in soybean oils (SBO) was investigated, and calibrations were developed for quantitative determination of peroxide value (PV), conjugated diene value (CD), and anisidine value (AV) of SBO. Partial least squares (PLS) regression and forward stepwise multiple linear regression were used to develop calibration models from spectral data in log 1/T, first derivative and second derivative of log 1/T formats for both 1‐ and 2‐mm path lengths. The models were validated by comparing NIR results from independent sample sets to the values obtained by official methods. The spectral region from 1100 to 2200 nm was best for measuring oxidation when using a 2‐mm path length. PLS regression using first‐derivative spectra gave the best results for PV. For the validation sets, linear relationships were obtained for PV (r=0.99), and CD (r=0.95), compared with accepted reference procedures. However, measurement of AV by NIR was less successful than measurement of the other two indices of oxidation, especially for an external validation sample set. Results obtained in this study indicate that NIR spectroscopy is a useful technique for measuring oxidation in soybean oil.
Oil viscosity measurement by ultrasonic reflectance
Authors: Saggin Raffaella , Coupland John N.
Published: November 2006

Pulses of shear‐mode ultrasound (center frequency 10 MHz) are reflected from the surface of a series of vegetable and synthetic high‐viscosity calibration oils at a range of temperatures (5–50°C). For all samples and temperatures there is a single negative correlation between the magnitude of the echo from the interface between the delay‐line and the sample and the viscosity of the sample. Similar experiments with longitudinal ultrasonic waves show the amount of sound reflected decreased with increasing viscosity, but there is no single correlation for all samples.
Purification and characterization of antioxidative peptides from protein hydrolysate of lecithin‐free egg yolk
Authors: Park Pyo‐Jam , Jung Won‐Kyo , Nam Kyung‐Soo , Shahidi F. , Kim Se‐Kwon
Published: November 2006

The protein extracted from lecithin‐free egg yolk, normally discarded by lecithin processing plants, was hydrolyzed with the aid of Alcalase, a commercial enzyme. The hydrolysate was separated through a series of ultrafiltration membranes with molecular weight cutoffs of 10, 5, and 1 kDa; and three types of permeates including 10 K (permeate from 10 kDa), 5 K (permeate from 5 kDa), and 1 K (permeate from 1 kDa) were obtained. The antioxidative efficacy of hydrolysates so obtained was investigated and compared with α‐tocopherol. Furthermore, two different peptides showing strong antioxidative activity were isolated from the hydrolysates by using consecutive chromatographic methods including ion exchange chromatography on a SP‐Sephadex C‐25 column, gel filtration on a Sephadex G‐25 column, and high‐performance liquid chromatography on an octadecylsilane column. The purity of the peptides was identified using capillary electrophoresis. The isolated peptides were composed of 10 and 15 amino acid residues, and both contained a leucine residue at their N‐terminal positions.
Inhibition of cholesterol autoxidation by the nonsaponifiable fraction in rice bran in an aqueous model system
Authors: Kim Joo‐Shin , Godber J. S. , King J. M. , Prinyawiwatkul W.
Published: November 2006

The inhibition of cholesterol autoxidation by nonsaponifiable fraction from rice bran oil (700, 1400, and 2100 ppm) was studied in an aqueous model system for 16 h at pH 5.5 and 80°C. Antioxidant effectiveness was investigated by following the loss of cholesterol and the formation of 7‐keto‐cholesterol. The changes in levels of vitamin E vitamers and γ‐oryzanol in the system were determined during cholesterol autoxidation. The 2100 ppm treatment produced a 92% reduction of 7‐ketocholesterol, 1400 ppm an 82% reductions and 700 ppm a 64% reduction after 16 h, whereas without the nonsaponifiable fraction, the samples showed almost complete degradation of cholesterol. Vitamin E vitamers decreased (P<0.05) in all treatments, but γ‐oryzanol was not significantly (P<0.05) reduced in the 2100 ppm treatment.
11‐selenadodecylglyceryl‐1‐ether in lipid autoxidation
Authors: Yanishlieva N. , Raneva V. , Marinova E. , Houte H. , Partali V. , Sliwka H. ‐R.
Published: November 2006

The effect of 11‐selenadodecylglyceryl‐1‐ether (11‐SeDGE) at concentrations of 5 × 10−4 and 1 × 10−2 M on the autoxidation of sunflower oil with a natural content of 0.06% tocopherols at 100°C and at room temperature in the dark and of pure triacylglycerols of sunflower oil (TGSO) at 100°C was studied. The process was followed by peroxide concentration (peroxide value) determination and by ultraviolet (UV) spectroscopy. It was found that 11‐SeDGE acted synergistically with the tocopherols in sunflower oil in a dose‐dependent manner to delay oxidation at 100°C. The results from the UV spectra indicated that 11‐SeDGE decomposed the initiators of the process, the hydroperoxides, into inactive products. During oxidation of pure TGSO (i.e, depleted of tocopherols) at 100°C, 11‐SeDGE retarded the process without a pronounced induction period. At room temperature, 11‐SeDGE showed a slight prooxidative effect on sunflower oil oxidation. Taking into account the established prooxidative effect of the two hydroxy groups in a molecule such as 11‐SeDGE, it was recommended to study the lipid autoxidation in the presence of selenium compounds that do not contain such prooxidative groups.
Preparation and functional properties of soy hull pectin
Authors: Monsoor M. A. , Proctor A.
Published: November 2006

Soy hulls (400 g), a co‐product of the soybean processing industry, were used as a source of pectin which was extracted by0.05 N hydrochloric acid and precipitated with alcohol. The effect of various ratios of hull to extraction solvent (1∶10, 1∶15, 1∶20, and 1∶25) on the yield and purity of soy hull pectin was measured. The soy hull pectin extracts contained 63.07 to 68.72% galacturonic acid at various hull/solvent ratios. The pectin yield increased from 7.68 to 13.73% as the hull/solvent ratio increased from 1∶10 to 1∶15. Changes in pectin yield for higher hull/solvent ratio were insignificant (16.31–13.28% for 1∶20–1∶25 ratio, respectively). The hull/extraction solvent ratio did not significantly affect the pectin content and degree of esterification. Diffuse reflectance Fourier transform infrared spectroscopy of soy hull pectin revealed a similar surface structure to commercial‐and analytical‐grade pectins. The solubility of soy hull pectins was independent of solvent extraction ratios and pH. Rheology studies showed that pectin solution viscosity increased as the ratio of extraction solvent to hull decreased.
Determining the regioselectivity of immobilized lipases in triacylglycerol acidolysis reactions
Authors: Chandler Ian C.
Published: November 2006

Lipase regioselectivity is the ability to distinguish between primary (i.e., sn‐1,3) and secondary (sn‐2) ester functionalities in a triacylglycerol molecule, which is of importance in the manufacture of structured lipids. Unlike existing methods of assessment, which utilize hydrolysis reactions, an alternative technique to assess the regioselectivity of lipases in triacylglycerol transesterification reactions has been developed. An acidolysis reaction is performed between triolein and decanoic, lauric, or stearic acids under conditions that minimize acyl migration, and products are analyzed by silver‐ion complexation liquid chromatography, enabling detection of specific triacylglycerol positional isomers. From the rate of formation of these isomers the relative selectivity of the lipase for sn‐2 and sn‐1,3 ester bonds is determined. With lipases known to lack regioselectivity, the rate of reaction at sn‐2 was similar to that at sn‐1,3 from the start of the reaction. With sn‐1,3 selective lipases, the formation of triacylglycerol isomers with decanoic acid in the secondary position was not detected at any point in the reaction. Regioselectivity as a function of reaction progress was monitored. Two lipases from the genus Pseudomonas exhibited activity toward all positions, but the rate at sn‐2 was much reduced, and no incorporation of decanoic acid into this position was detectable until a high degree of conversion had been achieved.
Determination of oil color by image analysis
Authors: Fengxia Sun , Dishun Zhao , Zhanming Zhou
Published: November 2006

An image analysis method was developed to determine oil color based on Lovibond‐red according to Chinese standard GB5528‐85. For one hue, one feature of image analysis, a negative correlation with the red reading of the Lovibond tintometer (r>0.995) was found. Mathematical models were designed to measure oil color based on image analysis. Fortynine oil samples including peanut oil, soybean oil, fragrant sesame oil, rapeseed oil and cottonseed oil were evaluated to assess the performance of the image analysis models. Good agreement, r2=0.999, between image analysis values and visual color measurement by using the Lovibond Color Scale was obtained.
Twin‐screw extrusion texturization of extruded‐expelled soybean flour
Authors: Crowe Troy W. , Johnson Lawrence A.
Published: November 2006

Texturized soy proteins (TSP) have been produced from hexane‐extracted soy flours having a narrow range of characteristics. The objective of this study was to determine the influence of protein dispersibility index (PDI) and residual oil content on extrusion texturization of partially defatted soy flours produced by extruding‐expelling (E‐E). Ten E‐E processed soy flours having residual oil contents and PDI values of 5.5–12.7% and 35.3–69.1%, respectively, were texturized using a twin‐screw extruder. Water‐holding capacities were greater for TSP prepared from E‐E processed soy flours with lower residual oil contents. Bulk densities were significantly lower for TSP prepared from E‐E processed soy flours compared with a commercial product made from hexane‐extracted soy flour. The texture characteristics of extended ground beef patties containing texturized E‐E processed soy flour were similar to that of 19% fat ground beef. Flavor acceptability was directly correlated (R=0.761) with residual oil content of the E‐E processed soy flours. However, lower residual oil and higher PDI flours exhibited better texturization and extrudate qualities.
Effects of hydrophobic emulsifier additives on crystallization behavior of palm mid fraction in oil‐in‐water emulsion
Authors: Awad Tarek , Sato Kiyotaka
Published: November 2006

Ultrasonic velocity measurements and X‐ray diffraction were employed to monitor the crystallization behavior of palm mid fraction (PMF) in oil‐in‐water emulsions (20 vol%). Three hydrophobic emulsifiers—sucrose oligoesters (SOE) containing palmitic acid (P‐170) and stearic acid (S‐170) moieties and a polyglycerine ester (DAS‐750) containing a stearic acid moiety—were added to PMF in an attempt to increase the rate and extent of crystallization of PMF, which are otherwise suppressed owing to emulsification of the oil phase into many droplets. The results revealed that the hydrophobic emulsifiers accelerate the nucleation of PMF in the emulsion system, while retarding the rate of crystal growth. As a results, the crystallization temperature (Tc) of PMF increased with increasing concentrations of the hydrophobic emulsifiers. The effects of the three additives were different; in particular the addition of DAS‐750 remarkably enhanced crystallization at low concentrations. By adding the emulsifiers at higher concentrations, the polymorphic behavior of PMF crystallization was also modified to different degrees, depending on the type of emulsifier. With addition of SOE, PMF crystallized predominantly in the β′ form; with addition of DAS‐750, the extent of β′ nucleation was reduced by comparison with that observed with SOE. The results were explained in terms of adsorption of the hydrophobic emulsifier additives at the oil‐water interface, which provides a template for acceleration of surface heterogeneous nucleation of PMF in the emulsion system.
Preparation, characterization, and surface and biological properties of N‐stearoyl amino acids
Authors: Sivasamy A. , Krishnaveni M. , Rao P. G.
Published: November 2006

Several lipoamino acids were synthesized, in which n‐octadecanoic acid (stearic acid) was coupled with the α‐amino group of an amino acid. The products were characterized and their identities confirmed by advanced analytical techniques like Fourier transform infrared 1H nuclear magnentic resonance spectroscopy, and differential scanning, calorimetry. Their surface properties, such as critical micelle concentration (CMC) and foaming properties, biodegradability, and antimicrobial activity were also evaluated. The N‐stearoyl amino acids (NSA) had low CMC values, and some of them showed good foaming properties. They were screened for antimicrobial activity against the gram‐positive bacteria Staphylococcus aureus, Micrococcus luteus, and Bacillus cerceus, the gram‐negative bacteria Escherichia coli and Pseudomonas aeruginosa, and the yeast Candida albicans. All the compounds inhibited at least one of these organisms. N‐Stearoyl proline was the most effective, the order of antimicrobial activity being aromatic NSA> acidic NSA>basic NSA. However, the effective inhibition by all the compounds indicates the desirability of more thorough investigation and suggests that some of these compounds may have potential utility as biostatic additives in commercial products. All NSA are highly biodegradable and can readily be removed under conditions of normal secondary sewage treatment.
Effect of row space and irrigation on seed composition of Turkish sesame (Sesamum indicum L.)
Authors: Alpaslan M. , Boydak E. , Hayta M. , Gerçek S. , Simsek M.
Published: November 2006

The effect of row space (RS) and irrigation (IR) on total protein, total oil, and fatty acid composition of Harran‐grown sesame seed was studied. Total oil content of sesame varied from 46.4 to 51.5%. The oil and protein contents were significantly different among treatments (P<0.01) in 1998 and 1999. IR affected oil content significantly (P<0.01) in both years, and RS had no significant effect. The protein content was significantly influenced by RS and IR at P<0.05 and P<0.01, respectively. RS 70 cm had the highest protein content followed by RS 60, 50, and 40 cm, respectively. IR every 24th day resulted in the highest level of protein, followed by 18th‐, 12th‐, and 6th‐day irrigation, respectively. Correlation coefficients between protein and oil content were −0.34 in 1998 and −0.59 in 1999. RS (P<0.05) and IR (P<0.01) influenced oleic and linoleic acid contents significantly. Interactions of RS and IR were also found to be significant (P<0.05) over the oleic and linoleic acid levels.
Gas chromatographic analysis of diels‐alder adducts of geometrical and positional isomers of conjugated linoleic acid
Authors: Reaney Martin J. T. , Liu Ya‐Dong , Taylor Wesley G.
Published: November 2006

This research demonstrates the gas chromatographic analysis of the 4‐methyl‐1,2,4‐triazoline‐3,5‐dione (MTAD) adducts derived from standards of cis,trans‐9,11‐octadecadienoic acid, trans,trans‐9,11‐octadecadienoic acid, and cis,cis‐9,11‐octadecadienoic acid. Methyl cis,trans‐9,11‐octadecadienoate and methyl trans,trans‐9,11‐octadecadienoate formed Diels‐Alder addition products with MTAD to produce adducts with similar mass spectral fragmentation patterns but different retention times determined by gas chromatography/ mass spectrometry. Methyl cis,cis‐9,11‐octadecadienoate reacted slowly and produced two adducts with similar fragmentation patterns and different retention times. These results were comparable to those reported for an analogous series of conjugated hexadienes. Based on hexadiene reactions, methyl cis,trans‐9,11‐octadecadienoate produced a trans adduct as a major product while methyl trans,trans‐9,11‐octadecadienoate formed a cis adduct. Methyl cis,cis‐9,11‐octadecadienoate reacted slowly under the conditions used leaving mostly unreacted material. Of the adducts observed from this isomer, a major trans adduct and a minor cis adduct were formed.
Application of arrhenius kinetics to evaluate oxidative stability in vegetable oils by isothermal differential scanning calorimetry
Authors: Tan C. P. , Che Man Y. B. , Selamat J. , Yusoff M. S. A.
Published: November 2006

In this study, 10 different vegetable oils were oxidized at four different isothermal temperatures (383, 393, 403, and 413 K) in a differential scanning calorimeter (DSC). The protocol involved oxidizing vegetable oils in a DSC cell with oxygen flow. A rapid increase in evolved heat was observed with an exothermic heat flow appearing during initiation of the oxidation reaction. From this resulting exotherm, the onset of oxidation time (To) was determined graphically by the DSC instrument. In our experimental data, linear relationships were determined by extrapolation of the log (To) against isothermal temperature. The rates of lipid oxidation were highly correlated with temperature. In addition, based on the Arrhenius equation and activated complex theory, reaction rate constants (k), activation energies (Ea), activation enthalpies (ΔH‡), and activation entropies (ΔS‡) for oxidative stability of vegetable oils were calculated. The Ea′, ΔH‡, and ΔS‡ for all vegetable oils ranged from 79 to −104 kJ mol−1, from 76 to −101 kJ mol−1, and from −99 to −20 J K−1 mol−1, respectively. Based on the results obtained, differential scanning calorimetry appears to be a useful new instrumental method for kinetic analysis of lipid oxidation in vegetable oil.
Improved oil treatment conditions for soft degumming
Authors: Choukri A. , Kinany M. A. , Gibon V. , Tirtiaux A. , Jamil S.
Published: November 2006

“Soft degumming” is a new physicochemical degumming process. It involves the complete elimination of phospholipids by using a chelating agent, EDTA, in the prescence of an emulsifying additive. To study the optimal cost of the process, a laboratory study was undertaken to find a method based on substituting the emulsifying additive by endogenous phospholipids. The phospholipids were first extracted from the oil by an initial hot‐water treatment. In a second stage, a solution containing a chelating agent was incorporated. The mixture was then vigorously stirred to form an emulsion. The degummed oil was obtained after centrifugation. A comparative study carried out on several oils provided an indication of the efficiency of this alternative procedure. The phospholipid content of the processed oils was about 5 ppm phosphorus.
Fatty acid composition of spanish shortenings with special emphasis on trans unsaturation content as determined by fourier transform infrared spectroscopy and gas chromatography
Authors: Alonso L. , Fraga M. J. , Juárez M. , Carmona P.
Published: November 2006

A Fourier transform infrared spectroscopic procedure was used to analyze 34 edible fats (22 shortenings and 12 vegetable margarines) as neat fats (IRNF) to determine their total trans fatty acid (TFA) content. The sloping baseline was corrected with a reference spectrum based on a nonprocessed olive oil. The calibration was done using seven partially hydrogenated fats with an individual TFA content previously determined by the combination of gas chromatography (GC) with argentation thin‐layer chromatography. Taking into account the different absorptivities of various trans isomers, different correction factors were calculated using the calibration standards (0.83 and 1.71 for single trans bonds in both diethylene and triethylene and for trans, trans‐diethylene fatty acids, respectively) and applied to calculate the total TFA of samples. Moreover, the samples were converted to their methyl esters and reanalyzed following the same procedure (IRFAME). Differences in TFA content of fats were not found when a t‐test was used to compare the results obtained by IRNF vs. either IRFAME or GC, suggesting that IR of neat fats could be used, thus avoiding the need to prepare sample solutions in organic solvents and to prepare fatty acid methyl esters. The mean TFA content (determined by IRNF) of a representative group of Spanish shortenings (22 samples) that varied widely in terms of fat sources, processes, and purposes (bakery, sandwiches, ice cream, coatings, chocolate coverings) was 6.55±11.40%, although more than 54% contained <3% of TFA. Fatty acid composition of shortenings by direct GC using a 100‐m polar cyanopolysiloxane capillary column indicated that the mean trans‐18∶2 isomer content was 0.58%, ranging from 0.9 to 3.4%. Small amounts of trans‐18∶3 isomers (<0.3%) were observed in 18 of the 22 shortenings studied; the maximal value was <2%. The mean value of the fraction saturated+TFA of shortenings was high (59.95±12.73%), including two values higher than 83%.
Milled rice surface lipid measurement by diffuse reflectance fourier transform infrared spectroscopy (DRIFTS)
Authors: Gangidi Rahul Reddy , Proctor Andrew , Meullenet Jean‐François
Published: November 2006

Diffuse reflectance Fourier transform infrared spectroscopy was investigated as a method for rice surface lipid determination. Long‐ and medium‐grain rice was milled at four degrees of milling to obtain samples with various levels of residual bran, and total lipids were determined by solvent extraction. Fourier transform infrared spectra were collected between 4000 and 400 cm−1. Weighted regression analysis identified changes in surface chemical functional groups with bran removal. Groups typical of lipids increased with bran content whereas those typical of carbohydrates and protein decreased. Partial least squares (PLS) regression analysis showed a high degree of correlation between the spectra in the 4000–400 cm−1 range and extracted lipids of long‐grain rice (R2=0.96) and medium‐grain rice (R2=0.96); a high degree of correlation was also observed when long‐ and medium‐grain rice data were combined (R2=0.96). There was a high positive correlation between the spectra and extracted lipids in the 1300–1000 cm−1 range for the long‐grain rice (R2=0.98), medium‐grain rice (R2=0.98), and combined long‐/medium‐grain rice data (R2=0.94). PLS selected spectral regions that correlated positively with functional groups of lipid/lipid oxidation products and negatively with functional groups of protein and carbohydrates.
The effect of fatty acid composition on the acrylation kinetics of epoxidized triacylglycerols
Authors: Scala John La , Wool Richard P.
Published: November 2006

Epoxidized oils, epoxidized triacylglycerols, and epoxidized fatty acid methyl esters were made by reaction with performic acid formed in situ. The extent of epoxidation was ca. 95% for all of the epoxidized samples, as determined by 1H nuclear magnetic resonance. The epoxidized samples were reacted with an excess of acrylic acid for different reaction times. The acrylation reaction was found to have a first‐order dependence on the epoxide concentration for all oils, pure triacylglycerols, and fatty acid methyl esters. However, the rate constant of acrylation was found to depend on the composition of the epoxidized material. The acrylation rate constant for 9,10‐epoxystearic acid was 96 L2/(mol2·min). The rate constant of acrylation for the epoxides on 9,10,12,13‐diepoxystearic acid was 60 L2/(mol2·min). The acrylation rate constant for the epoxides on 9,10,12,13,15,16‐triepoxystearic acid was 50 L2/(mol2·min). Thus, the rate constant of acrylation increased as the number of epoxides per fotty acid decreased. Multiple epoxides per fatty acid decrease the reactivity of the epoxides because of steric hindrance effects, and the oxonium ion, formed as an intermediate during the epoxyacrylic acid reaction, is stabilized by local epoxide groups. These results were used to derive an acrylation kinetic model that predicts rate constants from fatty acid distributions in the oil. The predictions of the model closely match the experimentally determined rate constants.
The effects of intercepted solar radiation on sunflower (Helianthus annuus L.) seed composition from different head positions
Authors: Santalla E. M. , Dosio G. A. A. , Nolasco S. M. , Aguirrezábal L. A. N.
Published: November 2006

The effect of intercepted solar radiation during fruit filling on seed weight and oil content from seeds of three sectors of the head in two sunflower (Helianthus annuus L.) hybrids of low and high potential oil percentage was investigated. Seed weight in each sector depended on both the level of radiation intercepted (modified by shading and thinning plants) and the genotype grown. A higher level of intercepted solar radiation increased seed weight in each sector. Central seeds of shaded plants showed the lowest weight. The seed and kernel oil content hierarchy among the three sectors was modified only in the hybrid with high potential oil content. For each head sector, variations in seed oil content associated with changes in the level of intercepted radiation could be accounted for by changes in the kernel oil content, not in the kernel/seed ratio. Significant relationships were found between seed oil and kernel oil contents when analyses between treatments (R>0.86) and sectors (R>0.92) were carried out. These relationships together with the growing conditions of plants during seed filling, the genotype, and the seed position on the head are essential factors that should be taken into account when selecting seeds in sunflower breeding programs since they affect the commercial/industrial quality of seeds.
A kinetic study of oil deterioration during frying and a comparison with heating
Authors: Houhoula Dimitra P. , Oreopoulou Vassiliki , Tzia Constantina
Published: November 2006

The thermooxidative alterations of cottonseed oil during frying of potato chips without oil turnover, in a temperature range of 155–195°C, were studied. The results showed that the content of polar compounds, conjugated dienes, conjugated trienes, and p‐anisidine value (p‐AV) increased linearly with the time of frying at a rate depending on temperature. The rate constants showed a significant but low increase with temperature, except for the rate constant of conjugated trienes that was not correlated to frying temperature. The alterations induced by heating the oil were also measured and compared with those observed in frying at the same temperature. The major difference observed between frying and heating was related to the p‐AV increase, which presented a considerably higher rate during heating. The FA content, as a function of process time during frying at 185°C, showed a significant increase in palmitic acid (C16∶0) and a significant decrease in linoleic acid (C18∶2). Oleic acid (C18∶1) also showed a small but significant decrease. The same results were obtained for the oil heated at 185°C. Examination of p‐AV or conjugated dienes with polar compounds showed that both p‐AV and conjugated dienes had a linear relationship with total polar compounds, with correlation coefficients of 0.946 and 0.862, respectively.
Influence of moisture content and cooking on screw pressing of crambe seed
Authors: Singh K. K. , Wiesenborn D. P. , Tostenson K. , Kangas N.
Published: November 2006

The cooking and drying conditions for oilseeds preparatory to screw pressing are some of the most important factors that influence screw‐press performance. Screw‐press oil recovery, residual oil, pressing rate, and oil sediment content were measured for uncooked crambe seed and crambe seed cooked at 100°C for 10 min, pressed at six moisture contents ranging from 9.2 to 3.6% dry basis. Oil recovery significantly increased (P≤0.01) from 69 to 80.9% and 67.7 to 78.9% for cooked and uncooked seeds, respectively, as moisture content decreased. Residual oil significantly decreased (P≤0.01) from 16.3 to 11.1% and 16.9 to 11.9%, respectively, as moisture content decreased. The reduced oil loss due to only drying the seed from 9.2 to 3.6% was 32% for cooked seed, whereas cooking contributed only 3.6 to 7% reduced oil loss. Pressing rate decreased from 5.81 to 5.17 kg/h and 6.09 to 5.19 kg/h for cooked and uncooked seeds, respectively, whereas sediment content increased from 0.9 to 7.8% and 1.1 to 5.4%, respectively, as moisture content decreased. The effects of moisture content on pressing rate and sediment content were significant at P≤0.05. All relationships of screw‐press performance to moisture content were fitted to a second‐order polynomial.
Rheological characterization of egg yolk processed by spray‐drying and lipid‐cholesterol extraction with carbon dioxide
Authors: Miranda J. , Partal P. , Cordobes F. , Guerrero A.
Published: November 2006

The present work studies the rheological properties of avian egg yolks processed by spray‐drying and by lipid‐cholesterol extraction with CO2 under near‐critical conditions. The results have been compared with those obtained from native egg products in order to analyze the effect of processing on the microstructure and rheological properties of egg yolks. The rheological study included linear viscoelasticity measurements by means of dynamic oscillatory shear and creep tests, which provided information about the unperturbed structure of the material, as well as steady‐state flow measurements. The thermal denaturation of proteins, which was produced during the spray‐drying of egg yolk, was responsible for the dramatic change from fluid to gel‐like behavior. The thermal denaturation of proteins promotes the formation of a gel‐like network, which may be attributed to exposure of internal hydrophobic groups that favor protein aggregation. Lipid (and cholesterol) extraction from yolk increased the viscoelasticity functions and flow properties due to the increased protein concentration.
Effect of synthetic antioxidants on cholesterol stability during the thermal‐induced oxidation of a polyunsaturated vegetable oil
Authors: Valenzuela Alfonso , Sanhueza Julio , Nieto Susana
Published: November 2006

As a molecule with an unsaturated bond, cholesterol is prone to oxidation. Cholesterol oxidation products (COP) are found in many common foods and have been shown to be atherogenic, cytotoxic, mutagenic, and possibly carcinogenic. Efforts to reduce the formation of oxidation products are considered important during the manufacture and processing of foods. The effect of synthetic antioxidants on cholesterol oxidation has not been extensively studied. We assayed the effect of five commonly used antioxidants—BHT, BHA, the n‐propyl ester of 3,4,5‐trihydroxy benzoic acid (PG), TBHQ, and 6‐ethoxy‐1,2‐dihydro‐2,4‐trimethylquinoline (EQ)—on cholesterol stability when oxidation is induced in a Rancimat 679 instrument by bubbling air through the sample at 150°C. The sample consisted of 200 mg cholesterol dispersed in 100 g of a polyunsaturated vegetable oil (soybean oil). Formation of six COP was measured at the induction period, and at the 50 and 100 μS conductivity values. Under the experimental conditions, BHT and TBHQ were the most effective inhibitors of cholesterol oxidation. BHA and EQ were less effective, and PG was unable to prevent cholesterol oxidation. Synthetic antioxidants were more effective in preventing COP formation at the nucleus of the cholesterol structure than at the lateral chain.
Phenolic acids of borage (Borago officinalis L.) and evening primrose (Oenothera biennis L.)
Authors: Zadernowski R. , Naczk M. , Nowak‐Polakowska H.
Published: November 2006

The composition of phenolic acids, both free and liberated from esters and glycosides, was determined in evening primrose and borage seeds by GC and MS. The free phenolic acid fraction was predominant in these seeds. Protocatechuic acid was the principal phenolic acid of the free and esterified phenolic acids in evening primrose seeds. Ferulic acid represented a high proportion of the free phenolic acids, but hydroxycaffeic acid was the major constituent of phenolic acids liberated from esters of borage seeds.
Use of nitrogen to improve stability of virgin olive oil during storage
Authors: Di Giovacchino L. , Mucciarella M. R. , Costantini N. , Ferrante M. L. , Surricchio G.
Published: November 2006

Experiments were carried out to study the possibility of improving the stability of extra virgin olive oil by using nitrogen as a conditioner gas during storage. With this aim, virgin olive oil samples, obtained from Leccino and Coratina cultivars, were stored in the dark, in closed bottles conditioned with air or nitrogen at 12–20 and 40°C. Results indicated that the FFA percentage increased over 1% only when oils were stored at 40°C. The PV and the K232 value (light absorbance at 232 nm) of oils increased over the limit value allowed by European Union law when the bottles were only partly filled and air was the conditioner gas. The use of nitrogen as conditioner gas helped to avoid this risk during 24 mon of storage at 12–20°C. The total phenolic content of both cultivars oils decreased during storage because their oxidation protected the oils from autoxidation. The content of total volatile compounds in oils decreased continuously during storage at 12–20°C, whereas it increased over 10 (Coratina cv.) and 15 (Leccino cv.) mon and then diminished when the storage temperature was 40°C. The same behavior, i.e., increase then decrease, was ascertained for trans‐2‐hexenal. The hexanal content of oils increased continuously during storage because this compound is formed by the decomposition of the 13‐hydroperoxide of linoleic acid.
Determination of MG and TG phase composition by time‐domain NMR
Authors: van Duynhoven John , Dubourg Isabelle , Goudappel Gert‐Jan , Roijers Eli
Published: November 2006

The feasibility of time‐domain NMR curve‐fitting methodology for the quantitative determination of TG blend phase compositions was investigated. By studying a range of TG in their different crystal forms, it was shown that the transverse NMR relaxation characteristics of TG differ for the respective crystal polymorphs {α,β,β′}. This enables the TG polymorphism in fat blends to be quantitatively determined by curve fitting. If a liquid phase is present in the blend, curve fitting is able to determine the solid fat content, and the results compare well with those of the accepted NMR methods. The curve‐fit method is less hindered by some of the disadvantages of these accepted methods, such as the use of a calibration factor.
Effect of roasting temperature and time on the chemical composition of rice germ oil
Authors: Kim In‐Hwan , Kim Chul‐Jin , You Jeung‐Mi , Lee Kwang‐Won , Kim Chong‐Tai , Chung Soo‐Hyun , Tae Beom‐Seok
Published: November 2006

Compositional changes of rice germ oils prepared at different roasting temperatures (160–180°C) and times (5–15 min) from rice germ were evaluated and compared with those of unroasted rice germ oil. The color development and phosphorus content of oils increased significantly as roasting temperature and time increased, whereas the FA compositions of rice germ oils did not change with roasting temperature and time. Four phospholipid classes, i.e., PE, PI, PA and PC, were identified. PE had the lowest stability under roasting conditions. There were no significant differences in γ‐oryzanol levels of rice germ oils prepared at different roasting temperatures and times. Four tocopherol isomers (α−, β−, γ−, and δ‐tocopherol) and three tocotrienol isomers (α−, γ−, and δ‐tocotrienol) were identified, but no β‐tocotrienol was detectable. The content of α− and γ−tocopherol in rice germ oil gradually increased as roasting temperature and time increased.
Effects of emulsifiers on the oxidative stability of soybean oil TAG in emulsions
Authors: Kubouchi Hiroaki , Kai Hideto , Miyashita Kazuo , Matsuda Koji
Published: November 2006

The effects of two types of commercial emulsifiers, sucrose FA esters and polyglycerol FA esters, on the oxidation of soybean oil TAG‐in‐water emulsions were studied. Both emulsifiers influenced the oxidative stability of soybean oil TAG in the emulsion, but they had little effect on the oxidation of TAG in bulk phase. When the TAG were dispersed with sucrose esters having the same FA composition, the oxidative stability increased as their hydrophilic‐lipophilic balance (HLB) increased. On the other hand, when the HLB was the same, the oxidative stability increased with increasing acyl chain length of the FA esterified on sucrose ester. However, the effect of the polyglycerol ester could not be explained by the relationship with HLB or the acyl composition. When the stability of TAG in emulsion was compared under the same concentrations of TAG, emulsifier, and oxidation inducer, the TAG dispersed with sucrose esters were oxidatively less stable than with polyglycerol esters. Analysis of the emulsion droplet size suggested that the lower oxidative stability of TAG dispersed with sucrose esters was partly due to their relatively smaller droplet sizes.
Relationship between crystallization behavior, microstructure, and mechanical properties in a palm oil‐based shortening
Authors: Litwinenko J. W. , Rojas A. M. , Gerschenson L. N. , Marangoni A. G.
Published: November 2006

In this study, the effects of cooling rate, degree of supercooling, and storage time on the microstructure and rheological properties of a vegetable shortening composed of soybean and palm oils were examined. The solid fat content vs. temperature profile displayed two distinct regions: from 5 to 25°C, and from 25°C to the end of melt at 45–50°C. A peak melting temperature of 42.7°C was determined by DSC. Discontinuity in the crystallization induction time (determined by pulsed NMR) vs. temperature plot at 27°C also suggested the existence of two separate groups of crystallizing material. Isothermal crystallization kinetics were characterized using the Avrami and Fisher‐Turnbull models. In using DSC and powder X‐ray diffraction, the α polymorph formed upon fast cooling (>5°C/min), and the β′ form predominated at lower cooling rates (<1°C/min). An α to β′ transition took place upon storage. Fractal dimensions (Df) obtained by microscopy and image analysis showed no dependence on the degree of supercooling sinceDfremained constant (∼1.89) at crystallization temperatures of 5, 22, and 27°C. Crystallization at 22°C at 1°C/min and 15°C/min yieldedDfvalues of 1.98 and 1.93, respectively. Differences in microstructure were observed, and changes in particle properties increased the parameter λ at higher degrees of supercooling.
An efficient method for a numerical description of virgin olive oil color with only two absorbance measurements
Authors: Escolar Daniel , Haro María R. , Ayuso Jesús
Published: November 2006

Four polynomial expressions are obtained that provide a good approximation and an easy, rapid calculation of the chromatic coordinates and the chroma—L*, a*, b*, and C—for the illuminant C and the standard observer, for a virgin or extra virgin olive oil; absorbance is measured at only 480 and 670 nm. These are as follows: L*=0.556458(A480)2−2.51145A480+0.55504(A670)2−8.53016A670+98.4089; a*=0.177372(A480)2+2.1363A480+1.43254(A670)2−0.789231A670−13.9246; b*=−16.0277(A480)2+79.8932A480−5.06558(A670)2+3.36169A670+31.9405; C=−15.8439(A480)2+78.9312A480−5.26784(A670)2+3.56917A670+33.3927. These give acceptable results, making the method a practical alternative to the extremely laborious Commission Internationale d’Eclairage (CIE) L*a*b* system, by which 391 absorbance values must be measured individually, nanometer by nanometer, before applying more complex equations. The validity of the proposed method has been confirmed by comparison, using a set of 20 sample oils different from the set of 25 oils used to generate the order of the equations. The variations between the values provided by the proposed and standard methods, respectively, had a mean of 0.00 for each of the chromatic variables—L*, a*, b*, and C; SD were moderate (0.71, 0.52, 1.22, and 1.22, respectively); the root mean square and the R2‐terms also confirmed the validity of the method.
Study of TAG ethanolysis to 2‐MAG by immobilized Candida antarctica lipase and synthesis of symmetrically structured TAG
Authors: Irimescu Roxana , Iwasaki Yugo , Hou Ching T.
Published: November 2006

Regiospecific ethanolysis of homogenous TAG with immobilized Candida antarctica lipase (Novozym 435) was studied using trioleoylglycerol (TO) as a model substrate. Optimization of the reactant weight ratio revealed that the 2‐MAG reaction yield increased when a larger amount of ethanol was used. These results suggested that Novozym 435 showed strict regiospecificity in an excess amount of ethanol. The process optimization (reaction temperature and reactant molar ratio) and a study of lipase specificity for various substrates were performed. Under the optimized conditions (ethanol/TO molar ratio=77∶1 and 25°C), 2‐monooleoylglycerol (2‐MO) was obtained in more than 98% content among glycerides of the reaction mixture and approximately 88% reaction yield in 4 h. The above reaction conditions were applied for ethanolysis of tridocosahexaenoylglycerol, trieicosapentaenoylglycerol, triarachidonoylglycerol, tri‐α‐linolenoylglycerol, and trilinoleoylglycerol. Reaction yields ranging from 71.9 to 93.7% were obtained in short reaction times (2.5 to 8 h). Purified (>98%) 2‐MO and 2‐monodocosahexaenoylglycerol (2‐MD) were reesterified with caprylic acid by immobilized Rhizomucor miehei lipase (Lipozyme IM) to afford symmetrical structured TAG. At a stoichiometric ratio of 2‐MAG/caprylic acid, 25°C and 2–5 mm Hg vacuum, the glyceride composition of the esterification mixture was approximately 95% 1,3‐dicapryloyl‐2‐oleoylglycerol (COC) at 4 h, and 96% 1,3‐dicapryloyl‐2‐docosahexaenoylglycerol (CDC) at 4 h, and 96% 1,3‐dicapryloyl‐2‐docosahexaenoylglycerol (CDC) at 8 h. The regioisomeric purity of both COC and CDC was 100%.
Antiradical activity of extracts of almond and its by‐products
Authors: Siriwardhana Subhashinee S. K. W. , Shahidi Fereidoon
Published: November 2006

Antioxidant activities of ethanolic extracts of whole almond seed, brown skin, and green shell cover were evaluated using different free radical trapping assays. Trolox equivalent antioxidant capacity assay revealed that the total antioxidant capacities of brown skin and green shell cover extracts were 13 and 10 times greater than that of the whole seed extract at the same extract concentration. The free radical‐scavenging activity of extracts of brown skin and green shell cover also exceeded that of the whole seed. The scavenging activity of superoxide radical by different almond extracts ranged from 76 to 97% at 100 ppm and 85 to 99% at 200 ppm. The corresponding reduction of hydrogen peroxide concentration was 59–66% (100 ppm) and 86–91% (200 ppm). The hydroxyl radical‐scavenging capacities at 100 and 200 ppm were 16 and 42% for whole seed, 57 and 100% for brown skin, and 40 and 56% for green shell extracts, respectively. A 100% scavenging activity of the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical was observed for brown skin and green shell extracts at 100 and 200 ppm concentrations, respectively, and whole seed extracts scavenged 21 (at 100 ppm) and 73% (at 200 ppm) of the DPPH radical.
Oxidative stability of structured lipids produced from borage (Borago officinalis L.) and evening primrose (Oenothera biennis L.) oils with docosahexaenoic acid
Authors: Namal Senanayake S. P. J. , Shahidi Fereidoon
Published: November 2006

This study utilized γ‐linolenic acid (18∶3n−6; GLA)‐rich borage oil (BO) and evening primrose oil (EPO) for the synthesis of structured lipids (SL) and compared the oxidative stability of the products with those of unmodified BO and EPO as controls. Immobilized Novozym 435 lipase from Candida antarctica was used as the biocatalyst for SL production. BO or EPO eas enzymatically modified with docosahexaenoic acid (22∶6n−3; DHA), as the acyl donor, to produce SI. The SI were characterized and their oxidative stabilities evaluated. Among the oils examined, SL gave rise to higher quantities (P≤0.05) of conjugated dienes, TBARS, and headspace volatiles as compared to their unmodified counterparts. Results indicated that modified oils were less stable than their unmodified counterparts. The double bond index (DBI) and methylene bridge index (MBI) of oils decreased (P<0.05) during oxidation in the more unsaturated oils. An attempt was made to correlate various parameters of oxidation with DBI and MBI of oils; correlation coefficients (−r) were within the range of 0.574–0.973. This suggests that indicators such as DBI and MBI can reflect oxidative stability of oils.