bluuebunny/crossref_metadata_2025 huggingface dataset:
Borago officinalis oil: Fatty acid fractionation by immobilized Candida rugosa lipase
Authors: Schmitt‐Rozieres Murielle , Vanot Guillaume , Deyris Valérie , Comeau Louis‐Claude
Published: May 2007

γ‐Linolenic acid (Z,Z,Z‐6,9,12‐octadecatrienoic acid), a very important polyunsaturated fatty acid is found in the free fatty acid fraction prepared by the hydrolysis of borage oil. Our aim was to enrich this fraction in γ‐linolenic acid using selective esterification. Candida rugosa lipase was used as catalyst after immobilization on the following ion‐exchange resins: Amberlite IRC50, IRA35, IRA93, and Duolite A7, A368, A568. In every case, immobilization modified the lipae's specificity: palmitic, stearic, oleic, and linoleic acids were preferentially esterified compared to γ‐linolenic acid, thus allowing a γ‐linolenic acid enrichment of 3.0.
Enzymatic synthesis of structured lipids from single cell oil of high docosahexaenoic acid content
Authors: Iwasaki Yugo , Han Jeong Jun , Narita Miho , Rosu Roxana , Yamane Tsuneo
Published: May 2007

The lipase‐catalyzed acidolysis of a single‐cell oil (SCO) containing docosahexaenoic acid (DHA) and docosapentaenoic acid (DPA) with caprylic acid (CA) was investigated. The targeted products were structured lipids containing CA residues at the sn‐1 and ‐3 positions and a DHA or DPA residue at the sn‐2 position of glycerol. Rhizomucor miehei lipase (RML) and Pseudomonas sp. KWI‐56 lipase (PSL) were used as the biocatalysts. When PSL was used > 60 mol% of total SCO fatty acids (FA) were exchanged with CA, with DHA and DPA as well as the other saturated FA being exchanged. The content of the triacylglycerols (TG) containing two CA and one DHA or DPA (number of carbon atoms = 41, i.e., C41) residue was high (36%), and the isomer with the desired configuration (unsaturated FA residue at the sn‐2 position) represented 77–78% of C41. In the case of RML, CA content reached only 23 mol% in the TG. A large amount of DHA and DPA residues remained unexchanged with RML, so that the resulting oil was rich in TG species containing two or three DHA or DPA residues (46%). TG C41 amounted to 22%, almost all of which had the desired configuration. This result suggested that the difference in the degree of acidolysis by the two enzymes was due to their different selectivity toward DHA and DPA, as well as the difference in their positional specificities.
Immobilization of lipase on poly(N‐vinyl‐2‐pyrrolidone‐co‐2‐hydroxyethyl methacrylate) hydrogel for the synthesis of butyl oleate
Authors: Basri M. , Wong C. C. , Ahmad M. B. , Razak C. N. A. , Salleh A. B.
Published: May 2007

Lipase from Candida rugosa was immobilized by entrapment on poly(N‐vinyl‐2‐pyrrolidone‐co‐2‐hydroxyethyl methacrylate) [poly(VP‐co‐HEMA)] hydrogel, cross‐linked with ethylene glycol dimethacrylate (EDMA). The immobilized enzyme was used in the esterification of oleic acid with butanol in hexane. The activities of the immobilized enzyme preparations and the leaching of the enzyme from the hydrogel supports with respect to composition were investigated. The thermal, solvent, and storage stability of the immobilized preparations also were determined. Increasing the percentage VP from 0 to 90, which corresponds to the increase in the hydrophilicity of the hydrogels, increased the activity of the immobilized enzyme. Lipase immobilized onto VP(%):HEMA(%), 90:10 hydrogel had the highest activity. Increasing the hydrophobicity of the hydrogel (increasing the percentage HEMA) seemed to decrease leaching of the enzyme from the support. Immobilized lipase on 100% HEMA hydrogel indicated highest entrapment and lowest leaching by hexane washing. The lipase immobilized on VP(%):HEMA(%), 50:50 hydrogel showed highest thermal, solvent, and storage stability compared to lipase immobilized on other hydrogel compositions as well as the native lipase.
Milk fat fractionation by solid‐layer melt crystallization
Authors: Peters‐Erjawetz Sandra , Ulrich Joachim , Tiedtke Michaela , Hartel Richard W.
Published: May 2007

The layer crystallization process has the potential to produce the same milk fat fractions as can be obtained by the suspension crystallization process. That is, milk fat fractions with solid fat content melting profiles similar to those obtained by suspension fractionation can be produced with this technique. The fatty acid profiles as well as the melting enthalpies of the different fractions confirm the separation of milk fat by the layer technique. Furthermore, there is potential to improve the results of separation presented in the first part of this paper. The two sources of improvement, temperature control of the process and controlled nucleation, lead to (i) a smooth crystalline layer with a low amount of entrapped mother liquor, contrary to the layers composed of agglomerated needles, and (ii) a good quality of attachment of the crystalline layer to the cooled surface. Moreover, the product quality can be increased using sweating as a postcrystallization step. “Sweating by warm gas” seems to have a better outlook concerning handling and controlling the process than “sweating by warm tube” because sloughing of the crystal layers can be avoided. Further investigations of the mass ratio of sweating fraction and amount of product as well as the aspect of energy consumption will determine the technical feasibility of solid‐layer crystallization for fractionation of milk fat.
Crystallization and pressure filtration of anhydrous milk fat: Mixing effects
Authors: Patience D. B. , Hartel R. W. , Illingworth D.
Published: May 2007

Melt crystallization of anhydrous milk fat and subsequent filtration of the slurry is a common process for obtaining milk fat fractions with different physical and chemical properties. The crystallization mechanism is very complex and little is known about how the crystallizer conditions and the crystal size distribution (CSD) affect the filtration process. The objective of this study was to characterize the fractionation process and determine which geometric parameters of the crystallizer affect the filtration step. Two scales of fractionation were studied, 0.6 L and 3.6 L, with crystallization at 28°C. The slurry was pressure‐filtered after 24 h at 500 kPa in a 1‐L chamber. Impeller diameters and speeds were varied for both scales. Photomicroscopy and spectrophotometry were used to characterize the crystallization process, and filtration rates were measured by weighing the amount of filtrate passing through the filter. Filtration resistance values, calculated using the constant pressure filtration equation, as well as photomicroscopy results indicated that the agglomerates and crystals that formed had different morphological characteristics for the different mixing and flow regimes in the crystallizer. Crystallization conditions that provide an optimal filtration time, a solid fraction with minimal liquid entrainment, and a CSD with an intermediate range of sizes (80–500 µm) having good packing properties for filtration were found.
Crystal packing of a homologous series β′‐stable triacylglycerols
Authors: van Langevelde Arjen , van Malssen Kees , Sonneveld Ed , Peschar René , Schenk Henk
Published: May 2007

From a homologous series of CnCn+2Cn (n = even) triacylglycerols which are β′‐stable, Guinier X‐ray powder diffraction photographs were used to determine cell parameters and space groups. The powder diffraction patterns are consistent with a pseudo‐orthorhombic unit cell with space group lc2a. Only one axis is changing as a function of chain lengthening. The experimental results were used to propose a β′‐crystal packing for triacylglycerols. In contrast to earlier proposed β′‐crystal structures, the acyl chains of this structure are not tilted with respect to the methyl‐end group plane. Furthermore, with only one molecule in the asymmetric unit, overall orthogonal chain packing is obtained when the intramolecular acyl zigzag planes are parallel.
Determination of olive oil free fatty acid by fourier transform infrared spectroscopy
Authors: Bertran Enriqueta , Blanco Marcelo , Coello Jordi , Iturriaga Hortensia , Maspoch Santiago , Montoliu Ivan
Published: May 2007

A new procedure for determining free fatty acids (FFA) in olive oil based on spectroscopic Fourier transform infrared‐attenuated total reflectance spectroscopy measurements is proposed. The range of FFA contents of samples was extended by adding oleic acid to several virgin and pure olive oils, from 0.1 to 2.1%. Calibration models were constructed using partial least‐squares regression (PLSR). Two wavenumber ranges (1775–1689 cm−1 and 1480–1050 cm−1) and several pretreatments [first and second derivative; standard normal variate (SNV)] were tested. To obtain good results, splitting of the calibration range into two concentration intervals (0.1 to 0.5% and 0.5 to 2.1%) was needed. The use of SNV as a pretreatment allows one to analyze samples of different origins. The best results were those obtained in the 1775–1689 cm−1 range, using 3 PLSR components. In both concentration ranges, at a confidence interval of α = 0.05, no significant differences between the reference values and the calculated values were observed. Reliability of the calibration vs. stressed oil samples was tested, obtaining satisfactory results. The developed method was rapid, with a total analysis time of 5 min; it is environment‐friendly, and it is applicable to samples of different categories (extra virgin, virgin, pure, and pomace oil).
Influence of ecological cultivation on virgin olive oil quality
Authors: Gutiérrez Francisca , Arnaud Teresa , Albi Miguel A.
Published: May 2007

The quality of oil extracted from ecologically cultivated olives of the Picual variety was compared with oil extracted from Picual olives cultivated using conventional methods. Olive trees were grown in a two‐section plot. Fruits from each plot were harvested at various stages of ripeness, and acidity value, peroxide index, ultraviolet absorption at 232 and 270 nm, stability to oxidation, sensory analysis, fatty composition, and contents of tocopherols, phenolic compounds, and sterols were determined on oil extracted from each treatment. The results showed that the organic virgin olive oil was of a superior quality to the conventional virgin olive oil in all the quality parameters analyzed.
Classification of virgin olive oils of the two major cretan cultivars based on their fatty acid composition
Authors: Stefanoudaki E. , Kotsifaki F. , Koutsaftakis A.
Published: May 2007

Fatty acid composition was determined for 105 virgin olive oil samples of the two dominant Cretan olive cultivars, Koroneiki and Mastoides, harvested from different producing areas at different maturity stages. The oils of the Koroneiki cultivar were characterized by lower concentrations of oleic and decaheptanoic and higher concentrations of linoleic and palmitic acids. Oils obtained from high‐altitude locations were rich in monounsaturated fatty acids, while oils obtained from low‐altitude locations had higher content of saturated fatty acids. Palmitic and palmitoleic acids increased with increasing altitude in both cultivars examined. The statistical analysis of the compositional data showed significant potential for the classification of the samples according to cultivar and location of origin.
Frying performance of genetically modified canola oils
Authors: Petukhov I. , Malcolmson L. J. , Przybylski R. , Armstrong L.
Published: May 2007

The frying performance of low linolenic and high oleic canola oils was compared to regular and hydrogenated canola oils. The antifoaming agent dimethylpolysiloxane (2 ppm) was added to all frying oils. Potato chips were fried in the four oils over a 5‐d period for a total of 40 h of frying. Oil samples were collected each day and analyzed for conjugated dienoic acids, free fatty acids, polymers, oxidation products, and polar components. Polar components were determined by the gravimetric method and by thin‐layer chromatography with flame‐ionization detection. The initial quality of the four oils was similar except in the amount of tocopherols present. All oils deteriorated after 5 d of frying but differences were not as anticipated, possibly as a result of observed differences in tocopherol levels.
Antioxidant effect of the constituents of susabinori (Porphyra yezoensis)
Authors: Nakayama Reiko , Tamura Yoshiyuki , Kikuzaki Hiroe , Nakatani Nobuji
Published: May 2007

The antioxidant activities of several extracts from Susabinori (Porphyra yezoensis) were measured by the ferric thiocyanate method and the thiobarbituric acid method. The methanol, acetone, ethyl acetate, and hexane extracts, and the chloroform‐soluble and water‐soluble fractions from the chloroform‐methanol extract exhibited higher activities than α‐tocopherol. The hot water extract showed little activity. Thin‐layer chromatography analysis of the active extracts suggested the existence of several antioxidants. The activity of the chloroform soluble fraction was due to chlorophyll analogs. A strong antioxidant was isolated from the methanol extract, accompanied by several amino acids such as leucine and phenylalanine. This compound was identified as usujilene, a kind of mycosporine‐glycine like amino acid.
Recent advances in assessment of marine lipid oxidation by using fluorescence
Authors: Aubourg Santiago P.
Published: May 2007

Lipid changes during food processing are important because of their impact on the final product quality. Lipid damage detection is limited because of the ability of lipid oxidation products (i.e., hydroperoxides and carbonyl compounds) to produce interaction compounds by reacting with nucleophilic food constituents. Fluorescence quantification at a single excitation/emission maximum of these interaction compounds has been employed in a qualitative way as a complementary tool for food quality assessment. The present work reviews recent research where simultaneous detection at different excitation/emission maxima was employed to assess lipid oxidation and quality changes during fish processing. A fluorescence shift towards a higher wavelength maxima was detected as a result of lipid damage; the shift was calculated as the ratio (δF) between two of the maxima tested (393/463 nm and 327/415 nm) and was investigated along different fish processes (freezing and frozen storage, refrigerated storage, cooking, and canning) and in complementary model systems where the influence of different factors (time and temperature of processing, amine and aldehyde composition and content, formaldehyde presence, and pH value of the medium) was checked. Determination of the δF value provided better results for quality change assessment in fish products than most of the lipid quality indices, in addition to being rapid and sensitive.
Influence of used frying oil quality and natural tocopherol content on oxidative stability of fried potatoes
Authors: Ruiz G. Márquez , Polvillo M. Martín , Jorge N. , Ruiz Méndez M. V. , Dobarganes M. C.
Published: May 2007

Sunflower oil (SO) and high‐oleic sunflower oil (HOSO) were used to prepare fried potatoes by either discontinuous or continuous laboratory frying. Fried potatoes that had been fried in oils of differing quality were stored at 60°C for up to 30 d and evaluated for polar compounds, polymers, peroxide value, oil stability index, and α‐tocopherol content. Results obtained through the various methods applied were consistent and indicated that the length of the induction period could not be explained only on the basis of the degree of unsaturation or polar compound levels in fried potatoes before storage. α‐Tocopherol content also had a significant influence as potatoes fried in HOSO, with 16% polar compounds and only 10 mg/kg α‐tocopherol at the starting point of storage, were oxidized more rapidly than potatoes fried in SO with a comparatively higher degradation level, 19% polar compounds, and 100 mg/kg α‐tocopherol.
Contribution of chemical components of cornicabra virgin olive oils to oxidative stability. A study of three successive crop seasons
Authors: Salvador M. D. , Aranda F. , Fregapane G.
Published: May 2007

Oxidation is the primary cause of virgin olive oil quality deterioration. This paper presents a correlation between oxidative stability, as determined by the Rancimat method, and some chemical components involved in the oxidation process of a set of 74 Cornicabra virgin olive oils obtained from three successive crop seasons (94/95 to 96/97). Results showed a clear influence of total polyphenols on virgin olive oil stability, with linear regression coefficients which were similar for the three seasons studied, and a much lower contribution of α‐tocopherol and unsaturated fatty acids, mainly linoleic acid. A significant effect dependent on the crop season was also observed.
Structural changes of sinapic acid and sinapine bisulfate during autoclaving with respect to the development of colored substances
Authors: Cai R. , Arntfield S. D. , Charlton J. L.
Published: May 2007

Structural changes in sinapic acid during autoclaving were studied using spectral analysis, thin‐layer chromatography, high‐performance liquid chromatography, nuclear magnetic resonance (NMR), and mass spectroscopy. Color properties of sinapic acid and its derivatives were studied by determining the transmittance spectrum, calculating the Commission Internationale de l’Eclairage 1931 tristimulus values and converting to Hunter L a b values. It was found that the colorless sinapic acid aqueous solution (100 µg/mL) turned yellow after 15 min in an autoclave at 121°C and 0.1 MPa. Filtering the yellow aqueous solution through a 0.45‐µm filter removed a brown solid consisting of at least three undetermined colored substances and left a yellow liquid. A newly developed yellow substance, syringaldehyde, was identified in the liquid phase by comparing the NMR and mass spectra of the unknown with those of authentic syringaldehyde. Thomasidioic acid was also found in the liquid phase. Under the same autoclaving conditions, sinapine bisulfate showed no evidence of any structural or color changes.
Assessment of lipase‐ and chemically catalyzed lipid modification strategies for the production of structured lipids
Authors: Willis Wendy M. , Marangoni Alejandro G.
Published: May 2007

The purpose of the present study was to devise a two‐step reaction to produce partial glycerides, which would subsequently be used as substrates in both lipase‐catalyzed and chemically catalyzed esterification reactions with caprylic acid. The yields and kinetics of these two‐step reactions were compared to established lipase‐catalyzed acidolysis and transesterification as well as to chemical transesterification reactions. Acyl migration did not occur during the hydrolysis or short‐path distillation steps in the preparation of free fatty acid‐free partial glycerides for esterification reactions. No significant differences in final yields (59.9% to 82.8% w/w of total triacylglycerols) of new structured lipids were detected among lipase‐catalyzed (24 h) and chemically catalyzed (5 h) reactions; however, the yield of new structured triacylglycerols (TAG) after 2 h was lower for acidolysis than for the other lipase‐catalyzed reactions (P≤0.05). Since no differences in final yields were detected among the reactions, chemical esterification using hydrolyzed oil could represent the best synthetic option, since it offers the advantage of positional distribution control associated with lipase‐catalyzed reactions as well as rapid reaction times associated with chemically catalyzed reactions. Attempts to evaluate the positional distribution of caprylic acid using allyl magnesium bromide (Grignard reagent) were hampered by production of unknown species, which prevented accurate determination of the concentration of some key fatty acids.
Production of a very low saturate oil based on the specificity of Geotrichum candidum lipase
Authors: Diks R. M. M. , Lee M. J.
Published: May 2007

Lipase B (GCB) produced by the fungus Geotrichum candidum CMICC 335426 is known for its high specificity towards cis‐Δ9 unsaturated fatty acids. The wild‐type lipase (not genetically modified) as well as the lipase obtained by heterologous expression of the corresponding gene in Pichia pastoris (genetically modified) were studied in a process aiming to produce an oil containing very little saturated fatty acids (SAFA). The approach described in this paper is based on the selective hydrolysis of sunflower oil (12% SAFA) using the G. candidum type B (GCB) lipases. Depending on the lipase input, up to 60% w/w degree of hydrolysis was obtained within 6–8 h. Because of the high specificity of the GCB lipases (specificity factor ∼30), the level of unsaturates in the free fatty acid fraction was >99% w/w. In contrast with literature data, no loss of specificity was observed, even at the highest degree of hydrolysis obtained. Though both GCB lipases are stable at 30°C, the rate of hydrolysis decreased considerably during the process. Product inhibition as well as time‐dependent deactivation (half‐life ≈2 h) were shown to be involved. After separation of the oil phase, the unsaturated free fatty acids were recovered from the mixture by evaporation and reconverted to triglycerides by enzymatic esterification with glycerol. Because the GCB lipases have a very low efficiency for esterification, this reaction was carried out with immobilized Rhizomucor miehei lipase. Under continuous removal of the water generated during the process, >95% triglycerides were obtained in less than 24 h. Standard deodorization resulted in an odorless, colorless, and tasteless oil with less than 1% SAFA.
Effect of genetic modification on the distribution of minor constituents in canola oil
Authors: Abidi S. L. , List G. R. , Rennick K. A.
Published: May 2007

Oil derived from different lines of genetically modified canola varieties was analyzed for phospholipids, tocopherols, and phytosterols by various chromatographic techniques. As observed previously in genetically modified soybean oils, there was a decrease in the content and composition of phosphatidic acid in three of the modified canola oils derived from the 12 varieties investigated. Normal‐phase high‐performance liquid chromatographic (HPLC) analyses showed small variations in the phospholipid content of major classes, despite few differences in their composition. Reversed‐phase HPLC data indicated that the molecular species distribution of phosphatidylethanolamine was significantly altered by genetic modification when compared to phosphatidylcholine. Impact of oilseed modification on the tocopherol content was variable, with greater variation in the concentration of α‐ and γ‐tocopherols than δ‐tocopherol. Phytosterol composition was markedly affected by genetic modification. Brassicasterol, campesterol, and β‐sitosterol levels were consistently lowered in one genotype, whereas increased brassicasterol content was observed in the other variety. In general, genetic modification of canola seeds led to changes in the distribution of phospholipids, tocopherols, and phytosterols.
The seed fatty acid composition and the distribution of Δ5‐olefinic acids in the triacylglycerols of some taxares (Cephalotaxus and Podocarpus)
Authors: Wolff Robert L. , Pédrono Frédérique , Marpeau Anne M. , Gunstone Frank D.
Published: May 2007

The fatty acid compositions of the seeds from four Cephalotaxus species or varieties (plum yews; Cephalotaxaceae) and two Podocarpus species (podocarps; Podocarpaceae) have been established. These compositions were compared with those previously published for some Taxaceae species (Taxus and Torreya). Cephalotaxaceae, Podocarpaceae, and Taxaceae belong to the Taxares suborder. Δ5‐Olefinic acids are present in the seed lipids from all species analyzed. In Cephalotaxus, Podocarpus, and Torreya, the prominent Δ5‐olefinic acid that occurs is the trienoic acid 5,11,14–20:3 (sciadonic) acid, comprising from 6.7 to 26.4% of total fatty acids. In these species, the Δ5,11 structure is largely favored over the Δ5,9 structure: the 5,9–18:2 (taxoleic) and 5,9,12–18:3 (pinolenic) acids are at the limit of detection, in contrast to Taxus and most Pinaceae species, where these two Δ5‐olefinic acids generally predominate. 14‐Methylhexadecanoic acid, an habitual though minor component of Pinaceae and Ginkgo biloba seed lipids, could not be detected in Cephalotaxus species studied here and was tentatively identified in trace amounts only in one Podocarpus species. In addition to sciadonic acid, Cephalotaxus and Podocarpus seeds are characterized by unusually high amounts of 11,14–20:2 acid, in the range of 3.1–12.0%. This contrasts with most of the 170 species of conifers analyzed so far (from the families Pinaceae, Cupressaceae, Taxodiaceae, Taxaceae, and Sciadopityaceae, which belong to the Pinares suborder), where this acid is generally ≤2%. A close resemblance between Torreya grandis and three of the Cephalotaxus species analyzed might be indicative of some phyletic relationship between the families Cephalotaxaceae and Taxaceae. 13C nuclear magnetic resonance spectroscopy of the seed oils from C. drupaceae and P. andinus has shown that Δ5‐olefinic acids are apparently excluded from the internal position of triacylglycerols, which is a characteristic common to all Coniferales species analyzed so far, and consequently of great antiquity.
Composition of muscle tissue lipids of silver carp and bighead carp
Authors: Vujković Gordana , Karlović Đerđ , Vujković Ivan , Vörösbaranyi István , Jovanović Branislava
Published: May 2007

Lipids have a complex role in the nutritional value of food. Some polyunsaturated fatty acids, characterized as essential, are extremely important for human health. This is primarily related to α‐linolenic acid (18:3n‐3), eicosapentaenoic acid (20:5n‐3) and docosahexaenoic acid (22:6n‐3). Content of polyunsaturated n‐3 fatty acids is usually much higher in lipids of marine fish than in freshwater fish. Previous investigations have shown that muscle tissue of silver carp and bighead carp from fish farms may be a rich source of essential fatty acids. Because of that, the objective of this work was to examine contents and composition of fatty acids and total lipids in the muscle tissue of silver and bighead carp, with the aim to find out whether there are significant differences in this respect between the two species and to what extent the harvest season can influence the composition of lipids in these freshwater fish. This study showed that there is no significant difference either in the content of polyunsaturated n‐3 and n‐6 fatty acids, or in the n‐6/n‐3 fatty acid ratio in these two fish species. The lipids of both the silver and bighead carp from the spring harvest have significantly higher contents of the n‐3 acids and a significantly lower n‐6/n‐3 ratio than fish from the autumn harvest.
A simple method for regiospecific analysis of triacylglycerols by gas chromatography
Authors: Angers Paul , Arul Joseph
Published: May 2007

A simple method for regiospecific analysis of triglycerides was developed. It consists of partial deacylation of triglycerides by ethylmagnesium bromide followed by derivatization of monoglycerides with n‐butyryl chloride, and direct analysis of dibutyrate derivatives of monoglycerides by gas chromatography. The chromatographic conditions were carried out with monoglycerides of C12 to C20 fatty acids and resulted in separation of dibutyrate derivatives between those bearing the medium‐ or long‐chain fatty acid in the sn‐1(3) and sn‐2 positions of glycerol. Beef tallow and grapeseed and cotton seed oils were analyzed using this new method, and their regiospecific distributions were compared with literature data. The method does not require separation of products by thin‐layer chromatography or special analytical equipment other than a standard gas chromatograph, and it can thus be used for routine regiospecific analysis of triglycerides.
Determination of free fatty acids in crude palm oil and refined‐bleached‐deodorized palm olein using fourier transform infrared spectroscopy
Authors: Che Man Y. B. , Moh M. H. , van de Voort F. R.
Published: May 2007

A rapid direct Fourier transform infrared (FTIR) spectroscopic method using a 100 µ BaF2 transmission cell was developed for the determination of free fatty acid (FFA) in crude palm oil (CPO) and refined‐bleached‐deodorized (RBD) palm olein, covering an analytical range of 3.0–6.5% and 0.07–0.6% FFA, respectively. The samples were prepared by hydrolyzing oil with enzyme in an incubator. The optimal calibration models were constructed based on partial least squares (PLS) analysis using the FTIR carboxyl region (C=O) from 1722 to 1690 cm−1. The resulting PLS calibrations were linear over the range tested. The standard errors of calibration (SEC) obtained were 0.08% FFA for CPO with correlation coefficient (R2) of 0.992 and 0.01% FFA for RBD palm olein with R2 of 0.994. The standard errors of performance (SEP) were 0.04% FFA for CPO with R2 of 0.998 and 0.006% FFA for RBD palm olein with R2 of 0.998, respectively. In terms of reproducibility (r) and accuracy (a), both FTIR and chemical methods showed comparable results. Because of its simpler and more rapid analysis, which is less than 2 min per sample, as well as the minimum use of solvents and labor, FTIR has an advantage over the wet chemical method.
Rapid determination of cis and trans content, iodine value, and saponification number of edible oils by fourier transform near‐infrared spectroscopy
Authors: Li H. , van de Voort F. R. , Sedman J. , Ismail A. A.
Published: May 2007

Fourier transform near‐infrared (FT‐NIR) spectroscopy was evaluated as a means of simultaneously determining the cis and trans content, iodine value (IV), and saponification number of neat fats and oils. Reference values for these parameters were obtained from oils using a previously developed mid‐FTIR Edible Oil Analysis Package. Two partial least squares calibrations were developed for a 5‐mm heated flow cell, the first a process calibration based on hydrogenated soybean samples and the second a more generalized calibration based on an oil samplematrix containing many oil types and designed to remove any correlations among the parameters measured. Each calibration performed well with its own validation samples; however, only the noncorrelated calibration was able to analyze oil samples accurately from a variety of sources. It was found that NIR analysis maintained the internal consistency between cis/trans and IV, and the accuracy and reproducibility of the predictions were on the order of ±1.5 and ±1.0 units, respectively, for all parameters evaluated. FT‐NIR is shown to be a very workable means of determining cis/trans/IV values and saponification number for edible fats and oils, and it provides a rapid alternative to the commonly used chemical and physical methods presently employed in the industry.
Modulated temperature differential scanning calorimetry for examination of tristearin polymorphism: I. Effect of operational parameters
Authors: Singh Satish K. , Jalali Ali Fathe , Aldén Maggie
Published: May 2007

The transformations of tristearin were examined by modulated temperature differential scanning calorimetry (MTDSC) in order to study the effect of operational parameters on the nature of information obtained from this technique. Tristearin has been used as a model polymorphic system showing metastable phases and complicated transformation routes occurring at relatively slow rates. The parameters examined were underlying heating/cooling rates and the amplitude of modulation. The first conclusion is that MTDSC enables overlapping α‐melting and β‐crystallization events to be separated, thus increasing the information obtained compared to normal thermal analysis. Other general conclusions are that observation of reversible processes is strongly influenced by the underlying heating rate; low to moderate heating rates are recommended. Amplitude of modulation has a complicated effect on the phenomenon being studied; when studying systems that exhibit metastable or polymorphic transitions, it is recommended that a range of amplitudes be tested to enable confirmation of whether an observed ‘recrystallization’ effect is a new phase or the same phase as the one melting. Cooling with modulation disturbs the crystallization process, possibly leading to smaller or imperfect crystals; however, the phases obtained are not different compared to normal DSC. The usefulness of MTDSC in analyzing these types of complicated systems is primarily qualitative at the moment. Some recommendations have been made as to the combinations of parameters for studying such systems.
Optimizing production of ethyl esters of grease using 95% ethanol by response surface methodology
Authors: Wu W. H. , Foglia T. A. , Marmer W. N. , Phillips J. G.
Published: May 2007

Previous research suggested that ethyl esters derived from recycled restaurant grease might be a potential source of biodiesel. Accordingly, response surface methodology (RSM) was employed to optimize reaction parameters—temperature, time, level of lipase, mole ratio of reactants—in the PS‐30 lipase‐catalyzed transesterification reaction of grease to ethyl esters using 95% ethanol. The regression equation obtained by a modified central composite design of RSM predicted optimal reaction conditions of 38.4°C, 2.47 h, 13.7 wt% lipase (PS‐30), and a mole ratio of grease to ethanol of 1:6.6. Under these conditions the predicted optimal percentage ethyl ester yield was 85.4%. Subsequent experiments using the predicted parameter combinations indicated a trend where experimental percentage yields of ethyl ester were consistently lower than predicted values. In an effort to improve the experimental yield of esters, a second portion of PS‐30 lipase was added without success; however, the addition of 5% SP435 one hour after the start of the initial reaction increased the yield of esters to >96%. Neither lipase PS‐30 nor lipase SP435 alone, however, gave the RSM‐predicted yield of ethyl esters.
In‐line and off‐line trapping of lipids extracted from chicken liver by supercritical carbon dioxide
Authors: Li Shufen , Maxwell Robert J. , Lightfield Alan R.
Published: May 2007

This supercritical fluid extraction study determined the retentive properties of neutral alumina sorbent as an in‐line trap for lipids in the dynamic state over a pressure range of 490–680 bar and temperatures of 40 and 80°C. Lipids were extracted from a chicken liver matrix using supercritical carbon dioxide over a 40‐min period at a flow rate of 3 L/min (expanded gas), then were quantified by high‐performance liquid chromatography using an evaporative light‐scattering detector. Approximately 30 and 18%, respectively, of the total extracted lipids were trapped on the in‐line alumina sorbent bed at 40°C as the operating pressure increased from 490 to 680 bar, while the remaining lipids were trapped off‐line after CO2 decompression. The major lipid classes trapped in‐line were fatty acids and cholesterol, whereas only minor amounts of the less polar lipid classes such as sterol esters and triacylglycerols were retained. At 80°C and 680 bar, less than 1.5% of the extracted total lipids was trapped in‐line, indicating the lack of adsorptive selectivity for lipids by alumina under these conditions.
Isothermal crystallization of hydrogenated sunflower oil: II. growth and solid fat content
Authors: Herrera M. L. , Falabella C. , Melgarejo M. , AɁón M. C.
Published: May 2007

Isothermal crystallization of sunflower seed oil hydrogenated under two different conditions was studied by means of pulse nuclear magnetic resonance (pNMR) and optical microscopy. Solid fat content (SFC) curves showed two different shapes depending on supercooling. When supercooling was high, hyperbolic curves were found, whereas with low supercooling sigmoidal curves were obtained. Curves were interpreted with the modified Avrami equation. Photographs of the crystals were taken from the beginning of crystallization, every 15 s until 15 min and every 5 min until 60 min. Samples which exhibited hyperbolic curves showed a slight increase in crystal number, and crystals were needle‐shaped in all cases. Samples which had sigmoidal crystallization curves showed a marked increase in crystal number with time, and crystals were spherical in shape. Crystallization behavior was also in agreement with the chemical composition of the samples. Samples which had the highest content of high‐melting triacylglycerols (especially trielaidin) showed only hyperbolic curves. Supercooling is a very important parameter that defines the way nucleation occurs. Depending on the initial number of nuclei, two different growth mechanisms were found: a uniform linear growth of the nuclei for a small initial number (sigmoidal curves) and an aggregate of the nuclei for a high initial number (hyperbolic curves).
The difference between cocoa butter and salatrim® lies in the microstructure of the fat crystal network
Authors: Narine Suresh S. , Marangoni Alejandro G.
Published: May 2007

The solid fat content of Salatrim® at 22°C is 9% higher than that of cocoa butter; however, its storage modulus, G′ (1 Hz), or solid‐like character, is one order of magnitude lower (2.5 MPa vs. 52 MPa). This difference may be explained by structural differences in the microstructure of the fat crystal network of the respective fat systems. Polarized light micrographs of these two confectionery fats show that cocoa butter forms a fat crystal network characterized by discrete crystalline particles which aggregate to large microstructures which then form a three‐dimensional network, while Salatrim®’s network is composed of randomly arranged noncrystalline, translucent platelets. Rheological measurements on both fat networks yielded fractal dimensions of 2.37 for cocoa butter and 2.90 for Salatrim®. Image analysis of the microstructure of cocoa butter yielded a fractal dimension of 2.31; however, the microstructure of Salatrim® does not lend itself to fractal analysis via image analysis. It was observed that the microstructure of Salatrim® is random instead of fractal. The proposition is made that the macroscopic mechanical properties of Salatrim® are related to the mechanical properties of the platelets that make up the network and the nature of the links between the platelets. Furthermore, the random spatial distribution of the platelets does not provide an indication of the strength of the network. For cocoa butter, the macroscopic mechanical properties are integrally related to the fractal spatial distribution of the solid mass in the network, the nature of the links between the microstructures, and the strength of the microstructures.
Determination of peroxide value in thermally oxidized crude palm oil by near infrared spectroscopy
Authors: Moh M. H. , Che Man Y. B. , van de Voort F. R. , Abdullah W. J. W.
Published: May 2007

A near infrared (NIR) spectroscopic method was developed to measure peroxide value (PV) in crude palm oil (CPO). Calibration standards were prepared by oxidizing CPO in a fermentor at 90°C. A partial least squares (PLS) calibration model for predicting PV was developed based on the NIR spectral region from 1350 to 1480 nm with reference to single‐point baseline at 1514 nm. The optimization of calibration factors was guided by the predicted residual error sum of squares test. The standard error of calibration obtained was 0.156 over the analytical range of 2.17–10.28 PV and the correlation coefficient (R2) was 0.994. The method was validated with an independent set of samples which was prepared in the same manner on a different day. A linear relationship between the American Oil Chemists’ Society and the NIR methods was obtained with R2 of 0.996 and standard error of performance of 0.17. This study has demonstrated that the prediction of PV in the NIR region is possible. The method developed is rapid, with total analysis time less than 2 min, is environmentally friendly, and its accuracy is generally good for quality control of CPO.
Development of calibration equations to predict oil content and fatty acid composition in brassicaceae germplasm by near‐infrared reflectance spectroscopy
Authors: Velasco Leonardo , Goffman Fernando D. , Becker Heiko C.
Published: May 2007

The use of nondestructive analytical methods is critical for the evaluation of very small seed samples such as those from germplasm collections. The objective of this study was to evaluate the potential of near‐infrared reflectance spectroscopy (NIRS) for the simultaneous analysis of seed oil content and concentration of major fatty acids in intact‐seed samples of the family Brassicaceae. A total of 495 samples from 56 genera and 128 species were analyzed by NIRS. The fatty acid composition of the seed oil was determined in all the samples by gas‐liquid chromatography (GLC). The total seed oil content was determined by solvent extraction in 129 samples from 22 genera. Calibration equations for oil content (n=97) and individual fatty acids (n=410) were developed and tested through external validation with the samples not included in the calibration sets. The calibration equations for oil content (r2=0.97 in validation) and concentrations of C18:1 (r2=0.93), C18:3 (r2=0.95), and C22:1 (r2=0.94) showed very good performance and provided reliable estimations of these traits in the samples of the validation set. The calibration equations for C16:0, C18:0, and C18:2 content were less reliable, with r2 from 0.67 to 0.73. There was practically no response of NIRS to differences in C20:1 (r2=0.31). These results demonstrated that the oil content and concentrations of C18:1, C18:3, and C22:1 can be estimated reliably within the family Brassicaceae by using NIRS calibration equations integrating broad taxonomic variability.
Changes in flax (Linum usitatissimum L.) seed lipids during germination
Authors: Wanasundara P. K. J. P. D. , Wanasundara U. N. , Shahidi F.
Published: May 2007

Flax (Linum usitatissimum L.) seeds were germinated for 8 d under laboratory conditions, and changes in their lipid fraction were studied by various chemical and chromatographic methods. Total lipid content of the seeds was reduced fourfold at the end of the 8‐d germination period as compared to ungerminated seeds on a fresh weight basis. The neutral lipids comprised the major fraction of seed lipids, and triacylglycerols predominated over all other lipid components even during the germination period. Both the spectrophotometric and thin‐layer chromatography‐flame‐ionization detection methods of quantification showed a considerable increase in the content of free fatty acids. The glycolipid fraction of lipids increased, but the phospholipid fraction exhibited only minor changes. Lipase activity of flaxseed increased at the beginning of germination and then remained constant until the fifth day. Phosphatidylcholine was the major phospholipid of flaxseed lipids, and its content was reduced during the germination. The contents of lysophosphatidylcholine and phosphatidic acid increased from negligible amounts to 46% of the total phospholipids. Linolenic, linoleic, and oleic acids, respectively, were the predominant fatty acids of all the lipid fractions of flaxseed, and remained unchanged during the germination period. The glycolipid fraction had the lowest content of polyunsaturated fatty acids. Fatty acids C14:0, C20:0, C24:0, C20:1, C22:1, and C20:5 appeared after d 2 of germination in neutral, glyco‐ and phospholipid fractions.
Separation and characterization of peanut phospholipid molecular species using high‐performance liquid chromatography and fast atom bombardment mass spectrometry
Authors: Singleton J. A. , Ruan M. , Sanford J. H. , Haney C. A. , Stikeleather L. F.
Published: May 2007

Total lipid extracts from peanut seed were separated on a silica column into a triacylglycerol fraction and a polar lipid fraction by high‐performance liquid chromatography (HPLC). The polar fraction containing the phospholipids was retained on the precolumn, and the triacylglycerol fraction was eluted to a waste flask by a special valve arrangement. Phospholipids were eluted from the precolumn and separated into various classes on a silica analytical column. Each phospholipid class was manually collected and subsequently subjected to reversed‐phase HPLC in tandem with a fast atom bombardment mass spectrometer. Phosphatidylethanolamine was separated into five molecular species. Phosphatidylinositol and phosphatidylcholine were each separated into six molecular species.
Characterization of phospholipids from glyphosate‐tolerant soybeans
Authors: List G. R. , Orthoefer F. , Taylor N. , Nelsen T. , Abidi S. L.
Published: May 2007

The phospholipids from three control and two glyphosate‐tolerant soybean cultivars were isolated by extraction of soy flakes with hexane and characterized after separation by high‐pressure liquid chromatography. In addition, several lots of commercial fluid lecithin were analyzed and the results were compared to values published in the literature. Phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, and phosphatidic acid were identified as major components in these cultivars and in the commercial lecithin samples. The results showed that glyphosate‐tolerant soybeans yield lecithin comparable and equivalent to conventional soybean cultivars.
Lecithin gum rheology and processing implications
Authors: Lambourne David , Covey Geoff H. , Chai Eugene , Dunstan David
Published: May 2007

The rheology of canola, sunflower, and soybean lecithin gum was examined by studying samples of different moisture contents produced in a batch evaporator (70°C, 0.1 atm). Soybean lecithin was found to have the lowest viscosity, approximately 10 poise (100 s−1, 70°C), compared to canola and sunflower lecithin with viscosities of approximately 90 and 90,000 poise, respectively. The high sunflower viscosity was attributed to the presence of long‐chain waxes. Lecithin gum was shown to change from a Bingham (water continuous phase) to a pseudoplastic (oil continuous phase) type fluid as the moisture content of the lecithin gum decreased. The viscosity maxima occurred between 6.9 and 19.3% moisture content (100 s−1), with the variation found to be related to the oil/water ratio of the system. Rheological results indicated that vertical scraped surface evaporator design could be optimized through the addition fluidizing of agents prior to the evaporator and/or increased heating at the evaporator outlet.
Deodorization of vegetable oils. Part I: Modelling the geometrical isomerization of polyunsaturated fatty acids
Authors: Hénon G. , Kemény Zs. , Recseg K. , Zwobada F. , Kovari K.
Published: May 2007

Laboratory‐scale treatments of canola oils similar to deodorization were carried out by applying the following conditions: reduced pressure with nitrogen or steam stripping at different temperatures ranging from 210 to 270°C for 2–65 h. The formation of the group of trans linolenic acid isomers follows a first‐order reaction and the kinetic constant varies according to the Arrhenius’ law. Similar results were observed for the trans isomerization of linoleic acid. Based on these experiments, a mathematical model was developed to describe the isomerization reaction steps occurring in linoleic and linolenic acids during deodorization. The calculated degrees of isomerization are independent of the composition of the oil but related to both time and temperature of deodorization. The degree of isomerization of linolenic acid is unaffected by the decrease of this acid content observed during the deodorization. Deodorization at about 220–230°C appears to be a critical limit beyond which the linolenic isomerization increases very strongly. The newly established model can be a tool for manufacturers to reduce the total trans isomer content of refined oils, and was applied to produce a special selectively isomerized oil for a European Nutritional Project.