bluuebunny/crossref_metadata_2025 huggingface dataset:
Crystallization of sunflower oil waxes
Authors: Martini S. , Añón M. C.
Published: November 2006

Activation free energies of nucleation (ΔGc) were calculated using induction times of crystallization measurements. Results showed that ΔGc decreased exponentially as wax concentration increased at a constant crystallization temperature (Tc). In contrast, for a constant supersaturation, ΔGc increased from 12 to 22°C but decreased between 22 and 35°C. Melting behavior of purified waxes and solutions of purified waxes in sunflower oil were studied by DSC after crystallization at fast and slow cooling rates (20 and 1°C/min, respectively). Low supercooling temperatures (Tc>65°C) showed an increase in the onset temperature (T0) as Tc increased for both fast and slow cooling rates. Broader peaks were obtained for samples crystallized at a slow cooling rate at the same Tc. Regarding the solutions of waxes in sunflower oil, the wax concentration (supersaturation of the system) controlled crystallization as well as Tc. As Tc increased, the enthalpy (ΔH) decreased at a constant wax concentration. When wax concentration decreased, ΔH decreased at a constant Tc. For a low driving force, a small shoulder was obtained in the DSC diagrams owing to some type of fractionation. These results showed that wax crystallization is affected by different experimental parameters, such as Tc and cooling rate, depending on the wax concentration of the sample.
Variability in soy flour composition
Authors: Porter Michael A. , Jones Alison M.
Published: November 2006

Soy flour is commonly used as a protein source in industrial fermentations. As an essentially natural product, the composition of soy flour can vary from year to year as a result of changes in growing conditions. The composition of soy flour from a single manufacturing plant was determined over an 8‐yr period. Protein concentration varied from 51.2% in the 1997 crop to 53.2% in the 1998 crop, but overal amino acid composition was relatively constant. The concentrations of valine, isoleucine, tyrosine, and alanine showed significant variation between years. Crude fat levels were steady, but the fat by acid hydrolysis (FAH) levels varied, suggesting changes in the level of phospholipids. The difference between the crude fat and FAH analyses (a proxy for phospholipids) had a strong positive correlation (P<0.001) with the total phosphorus concentration, consistent with this interpretation. FA distribution varied year to year with linoleic acid providing the most dramatic effect. Fe and P concentrations showed significant variation, but Al, Ca, Cu, K, Mg, Mn, Mo, Ni, and Zn did not vary significantly. Although P concentration had a significant correlation with proxy phospholipid levels, there was not a significant correlation between P concentration and phytic acid concentrations
Lipid hydrolysis and oxidation on the surface of milled rice
Authors: Lam Henry S. , Proctor Andrew
Published: November 2006

The changes in milled rice FFA content and composition and in conjugated diene (CD) content and bacterial, yeast, and mold counts were determined at 24, 37, and 50°C and 70% RH over 50 d. There was a rapid rate of FFA formation during the first few days of storage, which was optimal at 37°C, but that slowed after 2, 4, and 5 d at 37, 24, and 50°C, respectively. There was a second increase in FFA after about day 12 that increased with increasing temperature, indicating nonlipase hydrolysis. Linoleic and oleic acids were the main components of the total FFA produced on the surface of milled rice. The pattern of CD development followed that of FFA increase. Bacterial growth correlated with increased FFA levels after 12 d of storage, suggesting that bacterial lipase rather than bran lipase may be responsible for rice lipid hydrolysis
Oxidative stability of walnut oils extracted with supercritical carbon dioxide
Authors: Crowe Tammy D. , White Pamela J.
Published: November 2006

Supercritical carbon dioxide (SC‐CO2) was used to partially defat walnuts, and the oxidative stability of the extracted walnut oils was assessed. The SC‐CO2‐extracted oils were less stable during accelerated storage in the dark than was pressed walnut oil, as determined by PV, headspace analysis by solid‐phase microextraction, and sensory methods. The SC‐CO2‐extracted oils, however, exhibited greater photo‐oxidative stability than did pressed walnut oil by all of these methods, possibly because of the presence of chlorophyll in the pressed oil. Oxidative stability indices and tocopherol contents were significantly lower in the SC‐CO2‐extracted oils than in pressed oil.
Tocol levels in milling fractions of some cereal grains and soybean
Authors: Ko Soon‐Nam , Kim Chul‐Jin , Kim Hakryul , Kim Chong‐Tai , Chung Soo‐Hyun , Tae Beom‐Seok , Kim In‐Hwan
Published: November 2006

Tocol levels in the milling fractions of rice, barley, corn, wheat, and soybeans were analyzed by HPLC with a fluorescence detector. Among all milling fractions tested in this study, rice germ had the highest total tocol levels. In the four milling fractions of barley, except pearling flour, all eight tocol isomers were detected, and they were more uniformly distributed than in any other cereal grains measured in this study. The total tocol and α‐tocopherol levels of wheat germ were significantly (P<0.05) higher than the other wheat milling fractions. A significantly (P<0.05) higher proportion of γ‐tocopherol was obtained from corn germ (71.5%) and endosperm (50.3%) than from corn hulls. Only four tocol isomers (α‐, β‐, γ‐, and δ‐tocopherol) were detected in soybean milling fractions; no tocotrienol isomers were detected. The δ‐tocopherol level of soybean endosperm, although minor, was significantly higher than those in milling fractions of other cereal grains in this study.
Determination of hexane residues in vegetable oils with FTIR spectroscopy
Authors: Mirghani M. E. S. , Che Man Y. B.
Published: November 2006

The FTIR spectroscopy method was developed for the determination of hexane residues in palm and groundnut (peanut) oils. The method was based on horizontal attenuated total reflectance with a ZnSe crystal at 45° at room temperature, and partial least squares (PLS) statistics were used to derive calibration models. The accuracy of the method was comparable to that of the AOCS Method Ca 3b‐87, with coefficients of determination (R2) of 0.9866 and 0.9810 for palm and groundnut oils, respectively, and SE of calibration of 3.83 and 4.91, respectively. The calibration models were validated, and the R2 of validation and the SE of prediction computed. The SD of the difference for repeatability for the method was comparable to that for the standard AOCS method when used for palm and groundnut oils. With its speed and ease of data manipulation by computer software, FTIR spectroscopy has an advantage over present chemical methods, which require preparation of the oil using toxic solvents before GC.
Inhibitive effect of FA derivatives on mild steel corrosion in the presence of formic acid
Authors: Quraishi M. A. , Ansari Farhat A.
Published: November 2006

The influence of selected long‐chain FA hydrazides and thiosemicarbazides on the corrosion inhibition of mild steel in the presence of 20% formic acid was studied. The inhibition efficiency of these compounds varied with concentration, temperature, and immersion time. All the FA derivatives in the formic acid solution followed Temkin's adsorption isotherm. The activation energies and free energies of adsorption of all the hydrazides and thiosemicarbazides also were calculated. Potentiodynamic polarization studies indicated that all the tested compounds were of mixed type. Electrochemical impedance spectroscopy was also used to investigate the mechanism of corrosion inhibition.
Preparation of fatty 3,5‐disubstituted isoxazole compounds from FA esters
Authors: Kenar James A. , Wetzel Amanda R.
Published: November 2006

Long‐chain fatty compounds containing an isoxazole heterocyclic ring system substituted at the 3‐ and 5‐ring positions were prepared in moderate to good yields (40–64%) in one pot by condensing FA esters such as methyl palmitate, stearate, oleate, or linoleate with the lithiated anion of N‐(isopropylidene)isopropylamine followed by dehydrative cyclization. This approach allows readily available FA esters to be utilized and incorporated into the construction of the isoxazole ring system. These novel products were isolated then characterized by NMR, IR spectroscopy, GC‐MS, and m.p. Mass spectra of the fatty isoxazole compounds, derived utilizing EI ionization, showed distinctive cleavage patterns that occurred uniformly along the fatty alkyl chain allowing the position of double bonds to be readily located. Two prominent ions at m/z 97 and 110 were common to all the fatty isoxazole compounds examined and were presumably from a McLafferty rearrangement and a cyclization displacement reaction, respectively.
An efficient method for the purification of arachidonic acid from fungal single‐cell oil (ARASCO)
Authors: Vali Shaik Ramjan , Sheng Huei Ya , Ju Yi‐Hsu
Published: November 2006

PUFA, such as arachidonic acid (AA), have several pharmaceutical applications. An efficient method was developed to obtain high‐purity arachidonic acid (AA) from ARASCO, a single‐cell oil from Martek (Columbia, MD). The method comprises three steps. In the first step, AA was enriched from saponified ARASCO oil by low‐temperature solvent crystallization using a polar, aprotic solvent, which gave a FA fraction containing 75.7% AA with 97.3% yield. The second step involved enriching AA content via lipase‐catalyzed selective esterification of FA with lauryl alcohol. When a mixture of 1 g FA/lauryl alcohol (2∶1 mol/mol), 50 mg Candida rugosa lipase, and 0.33 g water was incubated at 50°C for 24 h with stirring at 400 rpm, the AA content in the unesterified FA fraction was as much as 89.3%, with ca. 90% yield. Finally, a solvent extraction procedure, in which acetonitrile was the extracting solvent, was used to enrich AA from FA fraction dissolved in n‐hexane. The best results were obtained when 2 g FA was dissolved in 80 mL hexane and extracted twice, each time with 20 mL acetonitrile at −20°C, by allowing 2 h storage. This step gave a FA fraction containing 95.3% AA with 81.2% yield. By using this three‐step process the AA content in the saponified single‐cell oil (ARASCO) was increased from 38.8 to 95.3% with a total yield of ca. 71%.
Oxidative instability of CLA concentrate and its avoidance with antioxidants
Authors: Lee Junsoo , Lee Seon‐Mi , Kim In‐Hwan , Jeong Jae‐Hong , Rhee Chul , Lee Kwang‐Won
Published: November 2006

This study evaluated the effectiveness of antioxidants, such as BHA, BHT, TBHQ, propyl gallate (PG), α‐tocopherol (α‐1), green tea extract (GTE), and rosemary extract (RE) on oxidative stability of CLA concentrate. Stability of CLA concentrate stored in air at 45°C up to 44 d was assessed by PV. During the storage period, the PV of the control CLA concentrate sample increased from 0.20 (fresh oil) to 1654 meq/kg (oxidized oil). On the other hand, the PV for CLA concentrates treated with 200 ppm of the single synthetic antioxidants, BHA, BHT, TBHQ, and PG, increased from 0.20 to 81, 107, 78, and 101 meq/kg, respectively. Also, the PV of CLA concentrate with the addition of 200 ppm single natural antioxidants α‐T, GTE, and RE lowered the final PV to 122, 140, and 110 meq/kg, respectively. Under our experimental conditions, the protective effect of 200 ppm antioxidant was in the order of TBHQ>BHA>PG>BHT>RE>α‐T> GTE. These results suggest that the appropriate use of antioxidants prolongs the oxidative stability of CLA concentrate.
Preparation and properties of lubricant basestocks from epoxidized soybean oil and 2‐ethylhexanol
Authors: Hwang Hong‐Sik , Adhvaryu Atanu , Erhan Sevim Z.
Published: November 2006

Synthetic lubricant basestocks were prepared from epoxidized soybean oil (ESO) and 2‐ethylhexanol (2‐EH) to be used alone or with polyalphaolefin (PAO). Sulfuric acid‐catalyzed reaction of ESO with 2‐EH involves a ring‐opening reaction at the epoxy group followed by transesterification at the ester group. Reaction with other catalysts including p‐toluenesulfonic acid, Dowex 50W‐8X, boron trifluoride, and sodium methoxide was also examined. Pour points of the products were observed as lows as −21 and −30°C without and with 1% of pour point depressant, respectively. When the hydroxy groups in the products were esterified with an acid anhydride, lower pour points were observed. Pour point depression of the product by adding PAO has been tested. Oxidative stability of the product was examined using pressurized DSC and compared with those of synthetic lubricant basestocks, PAO, and a synthetic ester.
Hydrolysis of mono‐ and diepoxyoctadecanoates by alumina
Authors: Piazza George J. , Nuñez Alberto , Foglia Thomas A.
Published: November 2006

In this study it is shown that the epoxide derivative of oleic acid, methyl 9,10‐epoxyoctadecanoate, is readily hydrolyzed to a diol when exposed to a commercial preparation of neutral alumina. Comparison of 1H and 13C NMR spectra of the diol with those of standards showed that the product was the threo isomer. When methyl 9, 10–12,13‐diepoxyocta‐decanoate was treated with alumina, a mixture of dihydroxy‐tetrahydrofuran regioisomers, methyl 9,12‐epoxy‐10,13‐dihydroxystearate and methyl 10,13‐epoxy‐9,12‐dihydroxystearate, was obtained. These results show that alumina is an unsuitable support for epoxidation catalysts. However, alumina‐catalyzed hydrolysis of fatty epoxides is an efficient way to synthesize polyhydroxy materials, and these materials are suitable for several industrial applications.
Transesterification of phytosterol and edible oil by lipase powder at high temperature
Authors: Negishi Satoshi , Hidaka Ichiro , Takahashi Isamu , Kunita Shigeru
Published: November 2006

Phytosterol, which is hardly soluble in edible oil, was solubilized at a high concentration by converting it to FA esters by lipase‐catalyzed transesterification at temperatures higher than 100°C using powdered Lipase QLM (Meito Sangyo Co., Ltd., Nagoya, Japan). Transesterification was conducted, in sunflower oil containing 10% phytosterol, without adding water or solvent, at 100°C. The conversion rate was 97.1% after 7 h of reaction. The effect of temperature on the conversion rate was also examined. Maximum enzyme activity occurred in the 100–120°C range, and 20% of the maximum activity was retained even at 130°C. When the lipase was recovered by filtration and recycled for repeated reactions at 90°C, the half‐life of lipase activity was 260 h. Thus, edible oils with nutritional value could be produced by blending the phytosterol‐containing sunflower oil into other edible oils.
Separation of EPA and DHA in fish oil by lipase‐catalyzed esterification with glycerol
Authors: Halldorsson Arnar , Kristinsson Bjorn , Glynn Caroline , Haraldsson Gudmundur G.
Published: November 2006

The objective of this study was to investigate the use of lipases as catalysts for separating EPA and DHA in fish oil by kinetic resolution based on their FA selectivity. Esterification of FFA from various types of fish oils with glycerol by immobilized Rhizomucor miehei lipase under water‐deficient, solvent‐free conditions resulted in a highly efficient separation of EPA and DHA. Reactions were conducted at 40°C with a 10% dosage of the lipase preparation under vacuum to remove the coproduced water, thus rapidly shifting the reaction toward the products. The bulk of the FA, together with EPA, were converted into acylglycerols, whereas DHA remained in the residual FFA. As an example, when FFA from tuna oil comprising 5% EPA and 25% DHA were esterified with glycerol, 90% conversion into acylglycerols was obtained after 48 h. The residual FFA contained 78% DHA and only 3% EPA, in 79% DHA recovery. EPA recovery in the acylglycerol fraction was 91%. The type of fish oil and extent of conversion were highly important parameters in controlling the degree of concentration.
Chemometric classification of olive cultivars based on compositional data of oils
Authors: Brescia Maria Antonietta , Alviti Giovanna , Liuzzi Vitantonio , Sacco Antonio
Published: November 2006

European Union regulations provide important guidelines for maintaining the Protected Designation of Origin (PDO) of olive oil and other foods. This includes characterization of foods based on variety (cultivar) and geographical origin, as this may be used as a criterion for determining authenticity and quality. Therefore, analytical method standards need to be established to ensure these criteria. This study describes how cultivar differences can be established between Italian oils, obtained from single varieties, based on acid, sterol, and TAG differences determined by chemometrics. TAG and FA composition provided the best basis for differentiation of olive oils among cultivars. The results were compared with those obtained using 13C NMR analysis, and a similar differentiation between oils of different cultivars was achieved. 13C NMR provides useful information on the acyl composition and on the positional distribution of the glycerol moiety and can be used for classification of cultivars based on oil composition. Furthermore, the advantages of this technique come from the rapidity with which information can be obtained and from the very simple preparation procedure required for analysis.
Dispersed phase destabilization in table spreads
Authors: Rousseau D. , Zilnik L. , Khan R. , Hodge S.
Published: November 2006

Commercially available butter, regular‐fat margarine, and a fat‐reduced margarine (38% fat w/w) were stored between 10 and 35°C for up to 4 d to elaborate on the relationship between droplet size and solid fat content (SFC) that exists in these spreads. At 10°C, the mean volume‐weighted droplet size for butter was 4.22±0.40 μm followed by margarine (6.22±0.10 μm) and fat‐reduced margarine (12.62±0.28 μm). At higher temperatures, as a result of decreasing SFC, the mean droplet size increased as did the droplet size distribution, leading to eventual coalescence and destabilization in all spreads. In butter, the critical SFC was ∼9%, whereas in margarine notable coalescence occurred at ∼5% SFC. The fat‐reduced margarine destabilized at lower temperatures than the other spreads (∼20°C vs. ∼30°C), at an SFC of ∼6.5%. In these spreads, two different mechanisms influenced dispersed phase stability: (i) steric stabilization against coalescence via fat crystals located at the droplet interface, known as Pickering stabilization, and (ii) stabilization against droplet sedimentation (and droplet encounters) due to the presence of the fat crystal network.
Cholesterol oxidation in some processed fish products
Authors: Pickova Jana , Dutta Paresh C.
Published: November 2006

Numerous foods of animal origin are reported to contain considerable levels of cholesterol oxidation products (COP); however, very few reports are available on fish products. Levels of COP were assessed in samples of fish roe, fish oil, and fish meal. Among the fish roe samples, the smoked cod roe had the highest amount of COP, 93 μg/g lipids. Refined and bleached menhaden oil had 8 μg/g, and two experimental alkali‐refined, bleached, and deodorized herring fish oil samples contained similar amounts of COP. The range of total COP in the three fish meal samples ranged from 50 to 78 μg/g fish meal. Generally, processed fish roe contained high amounts of COP compared with refined fish oils, which had very low amounts of COP. Fish meal samples had very high amounts of COP.
Do antioxidants improve the oxidative stability of oil‐in‐water emulsions?
Authors: Cuvelier Marie‐Elisabeth , Lagunes‐Galvez Laura , Berset Claudette
Published: November 2006

Oil‐in‐water emulsions were prepared with 30% stripped sunflower oil, stabilized by 20 g/L BSA and homogenized under high pressure to obtain a mean droplet size near 0.5 μm. The emulsions were shown to be physically stable during storage in a shaker at 47°C for 5 d. Such a medium was suitable to test the efficiency of different types of antioxidants. Oxidation of control emulsions appeared rapidly without a lag phase, and the contents of conjugated dienes and hexanal reached a plateau after around 20 h. In the presence of EDTA, the oxidation was strongly inhibited, suggesting that some metallic ions present in the oil or the protein solution act as inducers. Ascorbic acid and ascorbyl palmitate were inactive. Isoeugenol was found to be a powerful antioxidant, better than eugenol, α‐tocopherol, and Trolox.
Stability of spray‐dried encapsulated carotenoid pigments from rosa mosqueta (Rosa rubiginosa) oleoresin
Authors: Robert P. , Carlsson R. M. , Romero N. , Masson L.
Published: November 2006

Oleoresin of rosa mosqueta (Rosa rubiginosa) was encapsulated with starch or gelatin by spray‐drying. Stability of the powders was studied at 25, 40, and 55°C in the dark. Degradation of trans‐rubixanthin, trans‐lycopene, and trans‐β‐carotene followed a pseudo‐first‐order kinetic model for both encapsulating agents. The gelatin matrix provided a greater protective effect over the main carotenoid pigments, as shown by the lower degradation rate constants and the longer half‐life values at 21°C. In contrast, the carotenoid pigments showed the same degradation rate in starch, but trans‐β‐carotene was more stable in gelatin. The kinetic compensation effect obtained according to the calculated thermodynamic parameters suggests that the carotenoids are degraded by the same mechanism.
Electrochemical hydrogenation of canola oil using a hydrogen transfer agent
Authors: Mondal Kanchan , Lalvani Shashi B.
Published: November 2006

A novel low‐temperature process for the electrochemical hydrogenation of canola oil is described. An emulsion of oil and water containing formic acid and a nickel hydrogenation catalyst, placed in the cathode compartment of an electrolysis cell and subjected to an electrical current, underwent hydrogenation at temperatures as low as 45°C. At these low temperatures of hydrogenation, the trans FA content of the hydrogenated canola oil was very low as compared with that of the edible oils hydrogenated by commercial processes using high temperature and high partial pressure of hydrogen gas. Because of its adverse health effects, a high trans FA content in edbile oils is viewed as undesirable. In addition to the commercially available nickel supported on silica, amorphous nickelphosphorus alloys supported on a variety of substrates were also used. Amorphous alloys are generally very corrosion resistant because of the absence of grain boundaries. A mechanism for hydrogenation using the hydrogen transfer agent of formic acid and its continuous regeneration at the cathode was evoked to explain the experimental data.
Adsorption isotherms in bleaching hazelnut oil
Authors: Bayrak Yuksel
Published: November 2006

Adsorption isotherms in bleaching hazelnut oil were determined to investigate the applicability of the Langmuir and Freundlich equations and to elucidate the adsorption characteristics of oil on bentonite EY‐09 (Bensan Co. Ltd., Edirne, Turkey). The degree of bleaching was monitored spectrophotometrically. Absorbance measurements were carried out to investigate the adsorption force of clay during bleaching of hazelnut oil with 0.3, 0.5, 0.7, and 0.9 wt% clay at 50, 60, 70, 80, and 90°C. Bentonite EY‐09 was used as the bleaching clay (adsorbent). Plots of log(x/m) vs. log Xe (for the Freundlich isotherm) and Xe/(x/m) vs. Xe (for the Langmuir isomtherm) were made (where x is the amount of pigment removed per unit mass of the adsorbent, m, and Xe is the equilibrium concentration of the pigment). The Freundlich constants were found to increase with temperature for a given oil/bleaching agent ratio, showing the formation of more active sites on the adsorbent with a rise in temperature. Since the heat evolved during adsorption (0.32–1.03 kJ mol−1) was less than 20 kJ mol−1, the forces between the adsorbent and adsorbate appeared to be van der Waals forces. This type of adsorption is defined as physical or van der Waals adsorption. The results obtained show good agreement with the Freundlich isotherm, indicating that the adsorption of the pigment from the oil proceeds by monolayer formation on the surface of the adsorbent.
Simulation modeling of the phase behavior of palm oil‐supercritical carbon dioxide
Authors: Lim C. S. , Manan Z. A. , Sarmidi M. R.
Published: November 2006

The phase behavior of crude palm oil (CPO) with supercritical CO2 was successfully modeled in an Aspen Plus® 10.2.1 commercial simulator (Aspen Technology Inc., Cambridge, MA) using the Redlich‐Kwong‐Aspen (RKA) equation of state thermodynamic model. The modeling procedure involved estimating pure component vapor pressures and critical properties and computing a regression of phase equilibrium behavior. The interaction parameters for the RKA model were obtained from the regression of experimental phase equilibrium data for a binary system of palm oil components‐supercritical CO2 available in the literature. The distribution coefficients and solubilities of palm oil components obtained from this simulation showed good agreement with experimental data obtained from the literature. The model provides an efficient and cost‐effective alternative for the preliminary design and optimization of a supercritical fluid extraction process involving a complex CPO‐supercritical CO2 system.
NIR reflectance spectroscopic analysis of the FA composition in sesame (Sesamum indicum L.) seeds
Authors: Sato Tetsuo , Maw Aye Aye , Katsuta Masumi
Published: November 2006

The feasibility of using NIR reflectance spectroscopy to estimate the FA composition of sesame seed (Sesamum indicum L.) samples from the National Institute of Crop Science of Japan and from Myanmar was examined. Multiple linear‐regression analyses of NIR sepctral data and chemical data for whole seeds were carried out to develop calibration equations for predicting the proportion of each of the four major FA in sesame seeds from the total FA composition. The SE of prediction (SEP) was 0.616% for palmitic acid, 0.348% for stearic acid, 1.051% for oleic acid, and 0.826% for linoleic acid. This NIR method provides a simple, rapid, and nondestructive means of estimating the FA composition of sesame seeds for breeding selection, regardless of the color of the sesame seed coats. However, the proportions of palmitic and stearic acids could not be reliably measured because their SEP were almost as great as the SD of their concentrations in the set of prediction samples. The relationship between NIR spectral patterns and the FA composition of sesame seeds also was examined. The correlation coefficient calculated for the standardized second‐derivative NIR spectral readings at 1708 nm and the percentages of linoleic acid was −0.830. A rough estimate of the proportion of linoleic acid in the total FA composition of sesame seeds could be obtained even with single sesame seeds, except for those with a black coat, based on NIR spectral pattern analysis using the wavelength assignments of linoleic acid.
Production of cocoa butter‐like fats by the lipase‐catalyzed interesterification of palm oil and hydrogenated soybean oil
Authors: Abigor Roland D. , Marmer William N. , Foglia Thomas A. , Jones Kerby C. , DiCiccio Robert J. , Ashby Richard , Uadia Patrick O.
Published: November 2006

Cocoa butter‐like fats were prepared from refined, bleached, and deodorized palm oil (RBD‐PO) and fully hydrogenated soybean oil (HSO) by enzymatic interesterification at various weight ratios of substrates. The cocoa butter‐like fats were isolated from the crude interesterification mixture by fractional crystallization from acetone. Analysis of these fat products by RP‐HPLC in combination with ELSD or MS detection showed that their TAG distributions were similar to that of cocoa butter but that they also contained MAG and DAG, which were removed by silica chromatography. The optimal weight ratio of RBD‐PO to HSO found to produce a fat product containing the major TAG component of cocoa butter, namely, 1(3)‐palmitoyl‐3(1)‐stearoyl‐2‐monoolein (POS), was 1.6∶1. The m.p. of this purified product as determined by DSC was comparable to the m.p. of cocoa butter, and its yield was 45% based on the weight of the original substrates.
Lipase‐catalyzed incorporation of n−3 PUFA into palm oil
Authors: Fajardo A. Ramírez , Akoh Casimir C. , Lai O. M.
Published: November 2006

Two immobilized lipases, IM60 from Rhizomucor miehei and QLM from Alcaligenes sp., were used as biocatalysts for the modification of the FA composition of palm oil by incorporating n−3 PUFA. Acidolysis and interesterification reactions were conducted with hexane as organic solvent, and the products were analyzed by using GLC. After a 24‐h incubation in hexane, there was an average incorporation of 20.8% EPA and 15.6% DHA into palm oil, respectively, while the percentages of palmitic and oleic acids in palm oil decreased by 28.8 and 11.8%, respectively. Higher EPA and DHA incorporation was obtained when EPAX (fish oil concentrate high in n−3 PUFA) was used in the ethyl ester form (interesterification reaction) than in the free acid form (acidolysis) in the presence of Lipozyme (IM60 lipase. Lipase QLM was found to discriminate against EPA, and it showed slightly better catalytic activity for DHA in the free acid form than in the ethyl ester form. Generally, as the mole ratio of the acyl donor to TAG increased, the percentage incorporation of EPA and DHA increased; however, reactions catalyzed by Lipozyme IM60 did not show increases in the incorporation beyond a TAG/EPAX mole ratio of 3. When limitations due to mass transfer were not a factor, an increase in the reactant amount also gave an increase in the percentage incorporation of the n−3 PUFA. Palm oil containing EPA and DHA was successfully produced and may be beneficial in certain food and nutritional applications.
A computational study of the structure‐activity relationships of some p‐hydroxybenzoic acid antioxidants
Authors: Vafiadis Anastasios P. , Bakalbassis Evangelos G.
Published: November 2006

Equilibrium structures of all derivatized systems of p‐hydroxybenzoic acid, 3,4‐dihydroxybenzoic acid, 3‐methoxy‐4‐hydroxybenzoic acid, and 3,5‐dimethoxy‐4‐hydroxybenzoic acid and calculated structural and energetic molecular descriptors were determined at the B3LYP/6‐31+G(d) density functional theoretical level in an attempt to study their structure‐activity relationships (SAR). The theoretical antioxidant activity trend, derived in terms of hydrogen‐donating capacity against radicals in lipid systems, is in excellent agreement with the experimental one. The lower antioxidant activity of benzoates, experimentally found relative to the homologous cinnamates, could be due to (i) their lower spin delocalization, (ii) their higher calculated heats of formation values in forming radicals (ΔHOF), and (iii) the much stronger electron‐withdrawing effect of the‐COOH group than‐CH=CHCOOH. The low calculated dipole moment values of the global minimum structures of the antioxidants could facilitate their solubilities in nonpolar solvents, hence the ease of hydrogen abstraction. However, highest occupied molecular orbital (HOMO) eigenvalues can neither predict antioxidant activity nor differentiate the same activity between two series of structurally related compounds. Again, density functional theory calculations provide a good molecular descriptor, ΔHOF, to correlate with the antioxidant activity in molecules showing similar structural characteristics.
Multivariate sensory characteristics of low and ultra‐low linolenic soybean oils displayed as faces
Authors: Su Caiping , Gupta Monoj , White Pamela
Published: November 2006

The effects of linolenic acid (18∶3) concentration, combined with IBHQ addition, temperature, and storage time, on the flavor stability of soybean oils (SBO) were evaluated. A descriptive panel was trained to evaluate the overall oil quality and the intensity of individual flavors of SBO during 12 mon of storage under fluorescent light at both 21 and 32°C. Chernoff faces were used to achieve a simplified and integrated interpretation of the multivariate sensory data and to facilitate the interpretation of the vast amount of the data. In early storage, SBO with low 18∶3 (2.2% 18∶3, LLSBO) showed better flavor stability than did SBO with ultra‐low 18∶3 (1.0% 18∶3, ULSBO). This trend disappeared during storage. During 10‐ to 12‐mon storage, a painty flavor became predominant in all oils, which may have made it difficult for panelists to detect differences in treatment effect on flavor characteristics of SBO. During early storage, oils with TBHQ addition had poorer overall oil quality and stronger beany, painty, and fishy flavors than did oils without TBHQ addition. This trend disappeared as storage time progressed to 10 mon. Oils storedat 32°C had poorer overall oil quality and stronger painty, fishy, and beany flavors than did oils stored at 21°C starting from 2‐mon storage.
Extracting long‐chain fatty acids from a fermentation medium
Authors: Lalman Jerald A. , Bagley David M.
Published: November 2006

Several solvents were evaluated for extracting free long‐chain FA (LCFA) from a fermentation medium. Chloroform, chloroform/methanol (1∶1), hexane, and hexane/methyl tert‐butyl ether (MTBE) (1∶1) were evaluated as alternative extraction solvents. Parameters considered for optimizing LCFA recoveries included pH and ionic strength. Maximal LCFA recoveries were obtained by adding 2 mL of the hexane/MTBE (1∶1) solvent mixture, 80 μL of 50% H2SO4, and 0.05 g NaCl to 1 mL of the aqueous sample and mixing for 15 min at 200 rpm. This method quantified saturated LCFA [capric acid (C10∶0) to stearic acid (C18∶0)] and unsaturated LCFA with 18 carbons [linoleic acid (C18∶2) and oleic acid (C18∶1)] with a 98 to 100% recovery. Caproic (C6∶0) and caprylic (C8∶0) acids were characterized by 27 and 76% recoveries, respectively.
Fatty acid composition and oxidation of lipids in Korean catfish
Authors: Hwang K. T. , Kim J. E. , Kang S. G. , Jung S. T. , Park H. J. , Weller C. L.
Published: November 2006

This study determined the lipid content and FA composition of muscle and a mixture of muscle and viscera from Korean catfish as well as lipid oxidation and hydrolysis. Lipid content and FA compositions in Korean catfish, which were purchased every month or two during September 1999–July 2000, were analyzed. Lipid oxidation and hydrolysis were determined as PV, thiobarbituric acid value, and FFA in the muscle and the mixture during storage at 2°C for 12 d and −14°C for 9 wk. Lipid contents of the muscle and the mixture were 3.2 (w/w) and 5.4%, respectively. Oleic acid was the most abundant FA in the catfish lipids, constituting 28.0% (w/w) of total FA in the muscle and 25.6% in the mixture, followed by palmitic acid and linoleic acid, amounting to 20.2 and 12.2%, respectively, in the muscle and 20.2 and 12.5% in the mixture. EPA and DHA were 3.2 and 6.8%, respectively, in the muscle and 3.5 and 8.1% in the mixture. Seasonal variation in lipid contents and FA composition was minimal in catfish. Lipids in minced catfish oxidized and hydrolyzed readily at 2°C. Inclusion of viscera into the muscle increased lipid oxidation and hydrolysis. Frozen storage at −14°C and addition of ascorbic acid both reduced lipid oxidation. Frozen storage retarded lipid hydrolysis in catfish.
Fatty acid (FA) composition and contents of trans unsaturated FA in hydrogenated vegetable oils and blended fats from Pakistan
Authors: Bhanger Muhammad Iqbal , Anwar Farooq
Published: November 2006

This study presents the FA composition and trans FA (TFA) contents of different hydrogenated vegetable oils and blended fats marketed in Pakistan. Thirty‐four vanaspati (vegetable ghee), 11 shortenings, and 11 margarines were analyzed. The contents of saturated FA, cis monounsaturated FA, and cis PUFA were in the following ranges: vanaspati 27.8–49.5, 22.2–27.5, 9.3–13.1%; vegetable shortenings 37.1–55.5, 15.8–36.0, 2.7–7.0%; and margarines 44.2–55.8, 21.7–39.9, 2.9–20.5%, respectively. Results showed significantly higher amounts of TFA in vanaspati samples, from 14.2 to 34.3%. Shortenings contained TFA proportions of 7.3–31.7%. The contents of TFA in hard‐type margarines were in the range of 1.6–23.1%, whereas soft margarines contained less than 4.1% TFA.
Immobilized lipase‐catalyzed ethanolysis of sunflower oil
Authors: Yesiloglu Yesim
Published: November 2006

The ethanolysis of sunflower oil catalyzed by an immobilized 1,3‐specific porcine pancreatic lipase in a medium composed solely of substrates was investigated. The effects of the oil/ethanol molar ratio, temperature, amount of added water, and amount of enzyme used [respectively, 1∶3, 45°C, 0% (vol/vol), and 0.5 g of lipase, i.e., 10% w/w of total substrate]. To investigate the reusability of the lipase, the four‐step ethanolysis process was repeated by transferring the immobilized lipase to a substrate mixture. As a result, the percentage of conversion after the first usage decreased markedly.
Estimating soybean seed protein and oil concentration before harvest
Authors: Yaklich R. W. , Vinyard B. T.
Published: November 2006

Temperature and precipitation during the growing season have been shown to influence the protein and oil composition of the soybean [Glycine max L. Merr.] seed. A method based on these parameters was developed to estimate protein and oil concentrations of the seed before harvest. This method was developed with protein and oil data and temperature and precipitation data from the Uniform Soybean Tests, Southern Region, for the years 1975 to 1983. Classification and regression “tree‐based” analyses were used to determine the month and numeric value (“splitting point”) of the environmental variable that correctly classified the variation from median protein and oil composition for the 126 location‐years. Temperature in September was most influential in determining the splitting point for three of the four variables. Oil concentrations from the location‐years were separated into low vs. high median‐based boundary categories most readily by the September sum of minimum temperatures. Total protein and oil concentrations from the location‐years were classified best by September growing degree days. Protein‐to‐oil ratios were best separated by the September mean minimum temperature. The August mean maximum temperature best separated protein concentration. These data demonstrate that temperature during specific months of the crop year were useful in estimating the final concentration of protein and oil in the seed and could be used by seed processors to estimate seed composition before harvest.
Rheometry and polymorphism of cocoa butter during crystallization under static and stirring conditions
Authors: Toro‐Vazquez Jorge F. , Pérez‐Martínez David , Dibildox‐Alvarado Elena , Charó‐Alonso Miriam , Reyes‐Hernández Jaime
Published: November 2006

In this work the association between polymorphism and the crystal network structure developed by the TAG of cocoa butter (CB) was investigated under static and stirring crystallization conditions using a dynamic mechanical spectrometer. The results obtained showed that parameters obtained through oscillatory rheometry (i.e., phase shift angle, δ) followed the polymorphism of CB during static crystallization. Although standard DSC was not capable of differentiating the α to β′ phase transformation from the direct β′ crystallization from CB melt, δ rheograms measured these two processes separately. Additionally, through oscillatory rheometry, we followed the dimensionality of the crystal network during CB crystallization. Within this context, the pre‐exponential term (In γ) from the weak‐link regime equation for colloidal dispersions was much more sensitive than the fractal dimension (D) to differences in crystal size, spatial distribution of the crystal network, and melting temperature of the β′ phase of CB. On the other hand, torque measurements obtained during CB crystallization under stirring conditions showed a shear rate effect that favored TAG development in the β phase at temperatures of 19, 22, and 26.5°C, particularly at shear rates of 120 and 400 rpm. In contrast, under static conditions CB did not develop in the β phase at any of the crystallization temperatures investigated (i.e., 18 to 26.5°C).
Proposal of a uniform color scale for virgin olive oils
Authors: Melgosa M. , Huertas R. , Hita E. , Roa J. M. , Heredia F. J. , Alba J. , Moyano M. J.
Published: November 2006

A new color scale was developed from a broad data set of 1700 virgin olive oil samples over four crop seasons, which can be considered highly representative of the whole color range of virgin olive oils available in Spain. This color scale provides a new set of 60 color standards, improving the results achieved by the old 60‐color standards proposed by the bromthymol blue method. Seeking the greatest possibility of including a near match between colors of virgin olive oils and proposed standards, we developed our new color scale using a recent uniform color space, with standards placed in a regular rhombohedral lattice like the one employed by the Uniform Color Scales of the Optical Society of America. The average color difference between each of the 1700 virgin olive oils and its nearest standard is reduced from 8.17 CIELAB units, using the bromthymol blue standards, to 3.99 CIELAB units using the new standards. Within a color tolerance of 7.0 CIELAB units, 93.2% of our virgin olive oils can be classified with the new standards, but only 59.1% with the bromthymol blue ones. In the interest of future adoption, the performance of the new color standards should be tested by industry and researchers.
Investigation of soy protein‐kymene®adhesive systems for wood composites
Authors: Li Kaichang , Peshkova Svetlana , Geng Xinglian
Published: November 2006

This study investigated a new adhesive system, consisting of soy protein isolate (SPI) and Kymene®557H (simply called Kymene) (a commercial wet‐strength agent for paper), that was prepared by mixing SPI and Kymene. Wood composites bonded with SPI‐Kymene adhesive preparations had shear strengths comparable to or higher than those bonded with commercial phenol formaldehyde resins. Wood composites bonded with the new adhesive system had high water resistance and retained relatively high strength even after they had undergone a boiling‐water test. The new adhesive system is formaldehyde‐free, easy to use, and environmentally friendly. Kymene was proposed to serve as a curing agent in SPI‐Kymene adhesives.
Measurement of fat content of food with single‐sided NMR
Authors: Guthausen Andreas , Guthausen Gisela , Kamlowski Andreas , Todt Harald , Burk Wolfgang , Schmalbein Dieter
Published: November 2006

Fat content is one of the important parameters of quality control in many food products. Several techniques are used to determine the amount of fat in a given product. In this work, the applicability of a portable dedicated nuclear magnetic resonance (NMR) analyzer to measure the fat content in a packaged product without destruction of the material was examined. Two different low‐field NMR methods, namely, a ratio method and a relaxation time method, were applied and discussed. The processed NMR signal was linearly correlated with the fat content obtained by reference methods. The linear correlation allowed the application of single‐sided NMR for fat measurements.
Quantification of sphingolipids in soybeans
Authors: Gutierrez Elizabeth , Wang Tong , Fehr Walter R.
Published: November 2006

Soybean is believed to be a rich source of sphingolipids, a class of polar lipids with desirable biological activities. Analytical methods for sphingolipids vary, and quantitative data for sphingolipids in foods, including soybeans, are scarce. the objectives of this study were to establish a method for quantification of sphingolipids in soybeans and to determine whether genotype, stage of maturity, and growing location affect sphingolipid content in soybeans. Separation of neutral lipids and interfering polar lipids from sphingolipids by saponification, transesterification, and solvent partition was studied. Solvent partition accompanied by TLC purification was determined to be the most accurate sample preparation method for HPLC quantification of cerebroside. There were significant differences in cerebroside concentration among genotypes, with a range of 142 to 492 nmol/g seed (dry wt basis). The differences in cerebroside concentration between immature and mature seeds of one genotype and between two seed production locations of one genotype were considerable but not statistically significant.
Modification of margarine fats by enzymatic interesterification: Evaluation of a solid‐fat‐content‐based exponential model with two groups of oil blends
Authors: Zhang Hong , Pedersen Lars Saaby , Kristensen Dorther , Adler‐Nissen Jens , Christian Holm Hans
Published: November 2006

Lipozyme TL IM‐catalyzed interesterification for the modification of margarine fats was carried out in a batch reactor at 70°C with a lipase dosage of 4%. Solid fat content (SFC) was used to monitor the reaction progress. Lipase‐catalyzed interesterification, which led to changes in the SFC, was assumed to be a first‐order reversible reaction. Accordingly, the change in SFC vs. reaction time was described by an exponential model. The model contained three parameters, each with a particular physical or chemical meaning: (i) the initial SFC (SFC0), (ii) the change in SFC (ΔSFC) from the initial to the equilibrium state, and (iii) the reaction rate constant value (k). SFCo and ΔSFC were related to only the types of blends and the blend ratios. The rate constant k was related to lipase activity on a given oil blend. Evaluation of the model was carried out with two groups of oil blends, i.e., palm stearin/coconut oil in weight ratios of 90∶10, 80∶20, and 70∶30, and soybean oil/fully hydrogenated soybean oil in weight ratios of 80∶20, 65∶35, and 50∶50. Correlation coefficients higher than 0.99 between the experimental and predicted values were observed for SFC at temperatures above 30°C. The model is useful for predicting changes in the SFC during lipase‐catalyzed interesterification with a selected group of oil blends. It also can be used to control the process when particular SFC values are targeted.
“Well Intended Liberal Slop”: Allegories of Race in Spiegelman's Maus
Authors: LOMAN ANDREW
Published: November 2006

In a 1992 interview, Art Spiegelman described the genealogy of Maus, his acclaimed comic-book treatment of the Holocaust. He was inspired to write Maus, he stated, when asked to contribute to a commix anthology called Funny Aminals; the only restriction on his creativity was that the story must somehow involve anthropomorphized animals. “At the time I was trying to figure this out,” Spiegelman reports,
I went to sit in on some classes of a friend of mine, Ken Jacobs, a filmmaker and very wonderful teacher at SUNY Binghamton, who was showing some old animated cartoons in his class with cats and mice romping around, and then he was showing some racist cartoons from the same period, and it became clear that there was a connection between the two, that Al Jolson was Mickey Mouse without the ears. At that point I said, “I have it: I'll do a comic-book story about the Ku Klux Kats, and a lynching of some mice, and deal with racism in America using cats and mice as the vehicle.” And that lasted about ten minutes before I realized that I just didn't have enough background and knowledge to make this thing happen well, that it would just come across as well intended liberal slop. And instantly the synapses connected, and I realized that I had a metaphor of oppression much closer to my own past in the Nazi Project. (Spiegelman CD-ROM)