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Showing papers in "Journal of the American Oil Chemists' Society in 1991"


Journal ArticleDOI
TL;DR: In this paper, the chlorophyll and carotenoid content of virgin olive oils from five varieties harvested at varying degrees of ripeness were determined from the chromatic ordinates L*, a*, b* of the absorption spectrum.
Abstract: The chlorophyll and carotenoid content of virgin olive oils from five varieties harvested at varying degrees of ripeness were determined. Colors were evaluated from the chromatic ordinates L*, a*, b* of the absorption spectrum. Oil color changes for different varieties or stages of ripeness are directly related to pigment content and a* and b* values. The statistical study made on both series of parameters proves that there is a good correlation between them. The carotenoid content and b* have one of the best correlation coefficients (r) and is easily measured. This methodology evaluates chlorophyll and carotenoid content, an additional attribute for evaluation of virgin olive oil quality.

492 citations


Journal ArticleDOI
TL;DR: In this paper, the total polar fraction and individual phenols present in virgin olive oil were tested for their antioxidant effect in refined olive oil, and the results showed that the phenols had little or no effect on the stability of the oil.
Abstract: The total polar fraction and individual phenols present in virgin olive oil were tested for their antioxidant effect in refined olive oil. Hydroxytyrosol and caffeic acid showed protection factors greater than BHT. Protocatechuic and syringic acid were also found to have antioxidant activity. Tyrosol, p-hydroxyphenylacetic acid, o-coumaric acid, p-coumaric acid, p-hydroxybenzoic acid and vanillic acid had very little or no effect, and their contribution to the stability of the oil is negligible.

347 citations


Journal ArticleDOI
TL;DR: Phenolic compounds were degraded as a consequence of their antioxidant activity and their degradation rate was positively correlated to their antioxidant efficacy, and Polar substituents at the para position, such as in caffeic acid and oleuropein, were correlated with higher hydroxyl radical quenching ability.
Abstract: The autoxidation of linoleic acid dispersed in an aqueous media and the antioxidant effect of hydroxytyrosol, oleuropein, caffeic acid and tyrosol were studied. Linoleic acid autoxidation rate was estimated by the increase of conjugated diene level and by the decrease of linoleic acid content in the samples. The phenolic compounds exhibited an antioxidant activity which increased in the order: tyrosol < caffeic acid < oleuropein < hydroxytyrosol. The analysis of the hydroperoxide isomers pointed out that hydroxytyrosol, oleuropein and caffeic acid at a concentration of 10−4M inhibited the formation oftrans- trans isomers in the increasing order: caffeic acid < oleuropein < hydroxytyrosol. This inhibition could be related to the ability of phenolic compounds to scavenge peroxyl radical. Tyrosol did not inhibit the formation oftranstrans isomers. Phenolic compounds were degraded as a consequence of their antioxidant activity and their degradation rate was positively correlated to their antioxidant efficacy. These phenolic compounds, at a concentration of 6 × 10−3M, also scavenged hydroxyl radical, with an efficiency which increased in the order: tyrosol < hydroxytyrosol < oleuropein < caffeic acid. Polar substituents at the para position, such as in caffeic acid and oleuropein, were correlated with higher hydroxyl radical quenching ability.

309 citations


Journal ArticleDOI
TL;DR: In this paper, the antioxidant properties of methanol extracts of oregano, dittany, thyme, marjoram, spearmint, lavender and basil were tested in lard stored at 75°C.
Abstract: The antioxidant activities of methanol extracts of oregano, dittany, thyme, marjoram, spearmint, lavender and basil were tested in lard stored at 75°C. The concentration of extracts in lard varied from 0.01 to 0.20%. Oregano extract was found to be the most effective in stabilizing lard, followed by thyme, dittany, marjoram and lavender extracts, in a decreasing order. The induction period of lard increased with antioxidant concentration. After the induction period, peroxide formation proceeded rapidly, following pseudo-zero order reaction kinetics. The rate of the reaction decreased slightly with increasing plant extract concentration. Combined addition of plant extracts in lard showed a low synergistic action between thyme extract and spearmint extract.

275 citations


Journal ArticleDOI
TL;DR: By varying culture carbon source, lipid content in mycelium of Thraustochytrium aureum ATCC 34304 varied widely in the range 1–25% of biomass weight, which was optimal at an initial culture pH of 6.0.
Abstract: By varying culture carbon source, lipid content in mycelium ofThraustochytrium aureum ATCC 34304 varied widely in the range 1–25% of biomass weight. Docosahexaenoic acid (DHA) content of mycelium lipid was higher (65–76%) when biomass lipid content was very low (1–2%) and lower (40–50%) when biomass contained a high lipid content (14–18%). DHA yields from glucose, starch and maltose were 270, 325 and 334 mg/L, respectively. DHA yield and content of biomass was optimal at an initial culture pH of 6.0. During the culture cycle ofT. aureum, DHA content in lipids remained relatively constant with optimal DHA yield being observed after six days. Biomass, lipid content in biomass, DHA content in biomass and DHA yield were all optimal at a cultivation temperature of 28°C. However, the proportion of DHA in lipids declined with increase in temperature. Biomass, lipids in biomass and DHA yields were 13%, 42% and 47% higher, respectively, din light-exposed cultures as compared to dark cultures. A maximum yield of DHA of 511 mg/L was observed in light- exposed cultures containing 2.5% starch, where lipids accounted for over 20% of biomass dry weight.

181 citations


Journal ArticleDOI
TL;DR: In this article, a batch system with magnetic stirring was used without the addition of any solvents or emulsifiers, and a mixture of mono-, di- and triglycerides was obtained.
Abstract: Several triglyceride fats and oils were reacted with glycerol using lipase as catalyst. A batch system with magnetic stirring was used without the addition of any solvents or emulsifiers. In all cases a mixture of mono-, di- and triglycerides was obtained. However, the yield of monglyceride (MG) depended strongly on the reaction temperature: at higher temperatures approximately 30% MG was produced at equilibrium while at lower temperatures a yield of 65%–90% MG was obtained for most of the fats examined. The upper temperature limit below which a high MG yield could be attained was designated the critical temperature (Tc). The value of Tc depended on the fat type and was found to vary between 30°C and 46°C for naturally occurring hard fats. A high MG yield could not be obtained for fully hydrogenated tallow and lard under the conditions described here. Of the three liquid oils examined, rapeseed oil and olive oil had a Tc of 5°C and 10°C respectively whereas a high yield of MG could not be obtained with corn oil at 5°C or greater. The maximum yield of MG below Tc also depended on the fat type: the highest yields being obtained for olive oil (90%), palm stearin and milk fat (80%) and the lowest yield for palm oil (67%). In all cases a high yield of MG was accompanied by solidification of the reaction mixture. The effect of enzyme type on MG production was examined for palm oil and palm stearin and the effect of water concentration was examined for palm oil.

144 citations


Journal ArticleDOI
TL;DR: Extrusion can improve the digestibility of proteins, while reducing gossypol, proteinase inhibitors, allergens, aflatoxins, and other undesirable compounds as mentioned in this paper.
Abstract: Cooking extruders process high-protein materials into palatable foods. New applications have been developed for protein extrusion during the past decade. Improvements in functional characteristics of proteins may be achieved through modification of temperature, screw speed, moisture content, and other extrusion parameters. Flavors and odors may be removed during expansion at the extruder die. Extrusion can improve the digestibility of proteins, while reducing gossypol, proteinase inhibitors, allergens, aflatoxins, and other undesirable compounds. In the future the use of extruders as chemical reactors for both animal and plant proteins will provide new food ingredients as well as novel, nutritious foods.

127 citations


Journal ArticleDOI
TL;DR: In this paper, the compositions of positionssn-1, 2 and 3 of triacylglycerols can be determined by partial hydrolysis with ethyl magnesium bromide, derivatization of the total products with (S)-(+)-1-(1-naphthyl)ethyl isocyanate and isolation of the diacyl-sn-glycerol urethane derivatives by chromatography on solid-phase extraction columns containing an octadecylsilyl phase.
Abstract: The compositions of positionssn-1, 2 and 3 of triacylglycerols can be determined by partial hydrolysis with ethyl magnesium bromide, derivatization of the total products with (S)-(+)-1-(1-naphthyl)ethyl isocyanate and isolation of the diacyl-sn-glycerol urethane derivatives by chromatography on solid-phase extraction columns containing an octadecylsilyl phase. The diastereomericsn-1,2-and 2,3-diacylglycerol derivatives are separated by high-performance liquid chromatography on silica for determination of their fatty acids by gas chromatography. Each step in the process has been evaluated rigorously. The compositions of all three positions can be calculated with good accuracy from the analyses of these compounds and that of the total triacylglycerols. Although the 1,3-sn-diacylglycerol derivatives can also be isolated easily, they do not give reliable results for the composition of positionsn-2 because acyl migration occurs during their generation. The stereospecific analysis procedure has been applied to some plant and animal triacyl-sn-glycerols of commercial and scientific interest, containing predominantly C16 and C18 fatty acids,i.e. safflower, sunflower, olive and palm oils, tallow, egg and rat adipose tissue. The method is not at present suited to the analysis of more complex triacylglycerols, such as milk fat or fish oils, and problems associated with these are discussed.

119 citations


Journal ArticleDOI
TL;DR: Three approaches were used in an effort to increase the yield of monoglycerides (MG) during the lipase catalyzed reaction of glycerol with triglyceride fats and oils and temperature programming was found to be the most effective.
Abstract: Three approaches were used in an effort to increase the yield of monoglycerides (MG) during the lipase catalyzed reaction of glycerol with triglyceride fats and oils: i) various commercially available lipases were screened for ability to catalyze MG synthesis; ii) mixtures of lipases were compared with single lipases; and iii) two-step temperature programming was applied during the reaction. Of these, temperature programming was found to be the most effective. With an initial temperature of 42°C for 8–16 hr followed by incubation at 5°C for up to 4 days, a yield of approximately 90 wt% MG was obtained from beef tallow, palm oil and palm stearin. When the second incubation temperature was greater than 5°C, the yield of MG was progressively lower with increasing temperature. In the case of screening of newly available commercial lipase preparations, lipases fromPseudomonas sp. were found to be most effective, giving a yield of approximately 70 wt% MG at 42°C from tallow. Lipases fromGeotrichum candidum, Penicillium camembertii (lipase G) andCandida rugosa were inactive. A mixture of lipases fromPenicillium camembertii andHumicola lanuginosa was found to be more effective than either enzyme alone, giving a yield of approximately 70 wt% MG using beef tallow or palm oil. A mixture ofPenicillium camembertii lipase with eitherPseudomonas fluorescens lipase orMucor miehei lipase was not more effective thanPseudomonas fluorescens orMucor miehei lipase alone.

119 citations


Journal ArticleDOI
TL;DR: In this paper, the authors measured and characterized the NIR spectra of pure triglycerides and compared them with those of other types of fat and oils, and then reconstructed them by summation of the triglyceride spectra, which are multiplied by factors corresponding to the fatty acid composition of the sample determined by gas chromatography.
Abstract: A near infrared (NIR) spectral pattern of oil contains information about fatty acid composition, because NIR absorption bands around 1600–1800 nm and 2100–2200 nm are due to the straight carbon chain andcis double bonds, respectively. This study was undertaken to build a foundation for the rapid determination of the fatty acid composition in oil by an NIR method. First, NIR spectra of pure triglycerides were measured and characterized. Fatty acid compositions could be estimated roughly by comparing the spectra of fats and oils (butter fat, pig milk fat, soybean oil and palm oil) with those of pure triglycerides. Secondly, the NIR spectra of these fats and oils were reconstructed by summation of the triglyceride spectra, which are multiplied by factors corresponding to the fatty acid composition of the sample determined by gas chromatography. The calculated spectra agree with the originals, especially for that of soybean oil. However, in order to reconstruct spectra precisely, it may be necessary to reevaluate the loading weight of each triglyceride, which was equal in this study.

118 citations


Journal ArticleDOI
TL;DR: In this article, the yields and isomer ratios of the chloropropandiols and dichloropropanols formed are interpreted in terms of reaction mechanisms for their formation, which involve preferential nucleophilic substitution by the chloride anion at positions activated by neighboring ester groups.
Abstract: Chloropropanols are formed in protein hydrolysates by the reaction of hydrochloric acid with residual lipids associated with the proteinaceous materials used in their production. The products formed from glycerol, triolein, 1,2-diacyl-sn-glycero-3-phosphorylcholine and soya meal have been analyzed by thin-layer and gas chromatography. The yields and isomer ratios of the chloropropandiols and dichloropropanols formed are interpreted in terms of reaction mechanisms for their formation, which involve preferential nucleophilic substitution by the chloride anion at positions activated by neighboring ester groups. These provide anchimeric assistance and govern regioselectivity through steric and electronic effects.

Journal ArticleDOI
TL;DR: In this article, eight separate solvent systems were used with groats and hulls of several lines of oats to determine which system resulted in the most effective, rapid extraction of antioxidants.
Abstract: Eight separate solvent systems were used with groats and hulls of several lines of oats to determine which system resulted in the most effective, rapid extraction of antioxidants. Antioxidant activity at room temperature was estimated by using thin-layer chromatography (TLC) along with a β-carotene spray. The greatest antioxidant activities were obtained with methanolic antioxidant extracts derived from Noble and Ogle oats and hulls. These extracts were added to soybean oil (SBO) and their effectiveness was compared with that of butylated hydroxytoluene (BHT), tertiary butyl hydroquinone (TBHQ) and a control (no additives) at 32°C, 60°C and 180°C. A petroleum ether extract of Noble oats also was tested in SBO at 180°C. Peroxide values (PV) for oils with added antioxidants during storage at 32°C and 60°C showed that the Ogle oat extract was more effective than the other oat and hull extracts or the control. There were no significant differences in effectiveness among the extracts and the control at 60°C. At 180°C, the stability of each oil was determined by measuring conjugated dienoic acid values (CD) and the relative amounts of the unoxidized fatty acid methyl esters (FAME) 18:2, 18:3 and 18:2/16:0. All oils with added oat and hull extracts had significantly lower CD and significantly higher 18:2/16:0 than oils with added BHT, TBHQ or the control during 14 days at frying temperature. Phenolic and hydroxy-phenolic antioxidant compounds with acids, alcohols, sugars or glycerides attached were tentatively identified in the oat and hull extracts by using TLC and Chromatographic sprays.

Journal ArticleDOI
TL;DR: In this article, supercritical fluid extraction with carbon dioxide has been employed as an alternative method to recover evening primrose oil (EPO), which was performed over the pressure range of 20-70 MPa and at temperatures from 40 to 60°C, with a CO2 mass flow rate of 18 g/min.
Abstract: The oil extracted from the seeds ofOenothera biennis L. (evening primrose) is a major commercial source of gamma-linolenic acid, a fatty acid having potential therapeutic value in the treatment of several diseases. This fatty acid is prone to oxidation and thermal rearrangement; therefore, the conventional recovery of the oil via mechanical expression and hexane extraction must be carried out under very mild and controlled conditions. In this study, supercritical fluid extraction with carbon dioxide has been employed as an alternative method to recover evening primrose oil (EPO). Extractions were performed over the pressure range of 20–70 MPa and at temperatures from 40 to 60°C, with a CO2 mass flow rate of 18 g/min. The experimental data permitted the determination of EPO solubility in supercritical CO2 at the tested extraction conditions. Supercritical fluid Chromatographic analysis of fractions collected during the extraction showed a subtle shift in the triglyceride composition. Fatty acid methyl ester analysis on similar fractions indicated that the fatty acid content was invariant with respect to extraction time.

Journal ArticleDOI
TL;DR: In this article, the ethanolic extract of sage (Salvia officinalis L.) was separated into five fractions through reextraction with supercritical CO2 and further fractionation of the most active antioxidant fractions by means of liquid chromatography, with silicic acid as absorbent, yielded 2H-10,4α-(epoxy methano)-phenantren-12-one-1,1,3,4,9, 10,10,10αhexahydro-5, 6-dihydroxy-9α-eth
Abstract: The ethanolic extract of sage(Salvia officinalis L.) was separated into five fractions through reextraction with supercritical CO2. Further fractionation of the most active antioxidant fractions by means of liquid chromatography, with silicic acid as absorbent, yielded 2H-10,4α-(epoxy methano)-phenantren-12-one-1,3,4,9,10,10αhexahydro-5, 6-dihydroxy-9α-ethoxy-1,1-dimethyl-7-(1methylethy), (rosmanol-9-ethyl ether). The same compound was isolated from the alcoholic extract of the hyssop(Hyssopus officinalis L.). Rosmanol-9-ethyl ether was shown to be one of the active antioxidant components in sage and hyssop, with activity much greater than butylated hydroxytoluene (BHT).

Journal ArticleDOI
TL;DR: In this paper, the authors investigated commercial frying practices and frying conditions at 62 restaurants or fast-food outlets and the quality of their discarded frying oils was evaluated by several standard laboratory methods: total polar components (TPC), free fatty acids (%FFA), p-anisidine and peroxide values, color, viscosity, C18:2/C16:0, absorbance at 232 and 268 nm, and five quick test methods (Foodoil sensor, Oxifrit (RAU-Test), Fritest, Veri-Fry-TAM 150
Abstract: Commercial frying practices and frying conditions at 62 restaurants or fast-food outlets were investigated and the quality of their discarded frying oils was evaluated by several standard laboratory methods: total polar components (TPC), free fatty acids (%FFA), p-anisidine and peroxide values, color, viscosity, C18:2/C16:0, absorbance at 232 and 268 nm, and five quick test methods (Foodoil sensor, Oxifrit (RAU-Test), Fritest, Veri-Fry-TAM 150, and Veri-Fry-FFA 500). Frying techniques varied from primitive traditional practice at traditional shops to modern sophisticated frying procedures at some franchise restaurants. Discarded oils appeared to be heat-damaged to a varying extent according to the degree of quality control applied by the corresponding restaurants. Test methods were shown to possess different statistical correlations. Highly significant correlations were found between TPC and Foodoil sensor (c.f=0.93) and between Oxifrit and Fritest (c.f=0.94), each of which were also correlated relatively well to the TPC. Peroxide value followed by %FFA did not significantly (p<0.05) correlate with the TPC. Significant linear relationships (p⊕0.05) were found between the TPC and each of the other indicators but %FFA and peroxide value.

Journal ArticleDOI
TL;DR: In this article, the solubility isotherms for oleic acid and methyl oleate as well as mono-, di-, and trioleylglycerol (MO, DO, and TO) in supercritical fluid CO2 at 50 and 60°C are reported.
Abstract: Solubility isotherms for oleic acid and methyl oleate as well as mono-, di-, and trioleylglycerol (MO, DO, and TO) in supercritical fluid CO2 at 50 and 60°C are reported. Partition coefficients for quaternary (MO-DO-TO-CO2) mixtures were obtained at 60°C at pressures ranging from 172 to 309 bar. Data indicate that diolein, and especially monoolein, exhibit positive deviation from ideal behavior, possibly due to intermolecular hydrogen bonding. Supercritical fluid CO2 appears to be a good media for removal of mono- and diacylglycerol by-products from synthetic triglyceride reaction mixtures at moderate temperatures.

Journal ArticleDOI
TL;DR: A new compound, 7,10-dihydroxy-8(E)-octadecenoic acid (DOD), was produced from oleic acid at a yield of greater than 60% by bacterial strain PR3 which was isolated from a water sample in Morton, IL as discussed by the authors.
Abstract: Sixty-two cultures from the Agricultural Research Service (ARS) Culture Collection and 10 cultures isolated from soil and water samples in Illinois were screened for their ability to convert agricultural oils to value-added industrial chemicals. A new compound, 7,10-dihydroxy-8(E)-octadecenoic acid (DOD), was produced from oleic acid at a yield of greater than 60% by bacterial strain PR3 which was isolated from a water sample in Morton, IL. To our knowledge, DOD has not been previously reported. The optimum time, pH and temperature for the production of DOD were 2 days, 7.0, and 30°C, respectively. The production of DOD is unique in that it involves hydroxylation at two positions and rearrangement of the double bond of the substrate molecule.

Journal ArticleDOI
TL;DR: In this paper, the same authors used a reversed phase C18-column and gradient elution with water/acetonitrile/methanol/isopropanol.
Abstract: Triglycerides, together with nine synthetic phenolic antioxidants most commonly used to prevent oxidation of edible oils and fats, as well as the natural antioxidants tocopherols andα-tocopherol acetate, were separated by high performance liquid chromatography by means of a reversed phase C18-column and gradient elution with water/acetonitrile/methanol/isopropanol. Besides dilution of the oil with isopropanol/hexane, no further example preparation was required. UV detection was applied. The synthetic antioxidants propyldodecylgallate, octyldodecylgallate, dodecylgallate, 3-tert-butyl-4-hydroxyanisol,tert-butylhydroquinone, 3,5-di-terf-butyl-4-hydroxytoluene, 2,6-di-tert-butyl-4-hydroxymethyl-phenol, 2,4,5-trihydroxybutyrophenone and nordihydro-quaiaretic acid, as well asα- andδ-tocopherol andα-tocopherol acetate were base-line separated;β- andγ-tocopherol, however, eluted together. The triglycerides, detected at λ = 215 nm, were separated according to then-partition number. The absorption at λ = 215 nm revealed saturated and unsaturated triglycerides. The absorption at λ = 280 nm indicated triglycerides with conjugated unsaturation, relating information about refining and heat treatment of the oil. Oxidized unsaturated triglycerides showed absorption at γ = 230 nm. Triglycerides of ricinoleic acid, a hydroxymonoun-saturated acid, gave identical UV spectra. The simultaneous detection of antioxidants and triglycerides may be used to study inhibition effects by antioxidants in oils.

Journal ArticleDOI
TL;DR: In this paper, the authors examined the polymorphic behavior of 1,3-rac-palmitoyl-stearoy 1-2-oleoylglycerol, 99.9% purity (POS) by X-ray diffraction (XRD), differential scanning calorimetry (DSC), solubility measurements and optical microscopy.
Abstract: Polymorphic behavior of 1,3-rac-palmitoyl-stearoy 1-2-oleoylglycerol, 99.9% purity (POS) was examined by X-ray diffraction (XRD), differential scanning calorimetry (DSC), solubility measurements and optical microscopy in comparison with 1,3-dipalmitoyl-2-oleoylglycerol (POP) and 1,3-distearoyl-2-oleoylglycerol (SOS). Melt crystallization and solvent crystallization were examined for the occurrence of metastable and stable polymorphs. The number of independent polymorphs was four; α,δ, pseudoβ′ andβ. The lowest melting form, α, was identical to that commonly observed in POP and SOS lowest melting forms. As to the highest melting form,β, the XRD shortspacing pattern was identical toβ1 of POP and SOS. This is consistent with crystal habit:β single crystals of POS showed the same shape as those of β1 of POP and SOS. However, the melting point ofβ (POS), 35.9°C, was lower than those ofβ1 of POP, 36.7°C, and of SOS, 43.0°C. Correspondingly, solubility ofβ of POS was lower than that of β1 of POP below about 13°C, but higher above 13°C. POS did not possessβ2, which is the second stable form in POP and SOS. Two forms of6 and pseudoβ′ occurred, the latter being more stable. The structural properties ofδ showed thatδ is not identical toγ previously observed in POP and SOS. Transformation behavior from the metastable to stable polymorphs of POS showed some differences from those of POP and SOS.

Journal ArticleDOI
TL;DR: In this article, the antioxidative effects of spermine, spermidine and putrescine were determined by measurement of primary and secondary oxidation products of polyunsaturated fatty acids, using gas and liquid chromatography as well as spectrophotometric recordings.
Abstract: The antioxidative effects of spermine, spermidine and putrescine were determined by measurement of primary and secondary oxidation products of polyunsaturated fatty acids, using gas and liquid chromatography as well as spectrophotometric recordings. It was demonstrated that polyamines inhibit the oxidation of polyunsaturated fatty acids,α-tocopherol and carotenoid pigments. Both linear and nonlinear dose/response relationships have been observed. The efficiency of a given polyamine was correlated with the number of amine groups in the molecule. Spermine was, thus, more efficient than spermidine, which in turn had a higher efficiency than putrescine. The relative antioxidative effect was as follows: spermine (100.0), spermidine (61.0), putrescine (23.0), ethoxyquin (27.6), ascorbyl palmitate (18.3), octyl gallate (7.9), tert butylhydroquinone (6.3), butylated hydroxyanisole (3.6) andα-tocopherol (3.4).

Journal ArticleDOI
TL;DR: Three methods were attempted for EPA concentration and arachidonic acid removal from the oil of this alga and resulted in an EPA concentrate of 97% purity and an AA concentrate of 80% purity.
Abstract: The polyunsaturated fatty acid eicosapentaenoic acid (EPA) has attracted increased attention due to its pharmaceutical properties. The main source is marine fish oil which contains approximately 15% EPA. However, pharmaceutical applications of EPA will probably require higher concentrations, perhaps as high as 90%. The red microalgaPorphyridium cruentum is a potential source, because its EPA content approaches 44.1% of the total fatty acids. Three methods were attempted for EPA concentration and arachidonic acid (AA) removal from the oil of this alga. Separation of the glycolipids, formation of a urea inclusion complex and reverse phase chromatography on C-18 Sep-Pak filters resulted in an EPA concentrate of 97% purity. Similar methods resulted in an AA concentrate of 80% purity.

Journal ArticleDOI
TL;DR: Differential scanning calorimetry (DSC) measurements of the crystallization and melting phenomena of pure forms of the three principal triglycerides present in cocoa butter and related confectionery fats are presented in this article.
Abstract: Differential scanning calorimetry (DSC) measurements of the crystallization and melting phenomena of pure forms of the three principal triglycerides present in cocoa butter and related confectionery fats are presented. The results are used to exhibit the usefulness of the DSC technique for potential application in quality control of these types of material, but also as a warning of the difficulties in interpretation of data. The results also serve as a reference for future use in DSC studies of similar materials.

Journal ArticleDOI
TL;DR: The wax ester yield was found to be directly dependent upon the alcohol concentration that was used to modulate the outcome of the reaction towards either the wax or the partial glycerides, and the process was applied to the synthesis of waxes from high erucic acid rapeseed oil.
Abstract: The lipase (triacylglycerol acylhydrolase, E.C. 3.1.1.3) catalyzed synthesis of wax esters has been investigated via two different approaches. All studies were performed using an immobilized 1,3-specific lipase [Lipozyme from Novo Industries (Montreal, Quebec, Canada)]. The first approach involves reacting stoichiometric amounts of a fatty acid and stearyl alcohol in the presence of lipase. The medium is solvent-free, which allows for high substrate concentrations (1.55 M) and use of 5% (w/w) Lipozyme. In this reaction, maximum wax ester synthesis was found to be dependent upon the efficient removal of the water produced by the reaction. Under optimal conditions, yields of 100% were routinely reached after only 2 hr. The medium was then exclusively composed of the wax and the enzyme, no purification was required. The second method involves alcoholysis of a triglyceride, in this case triolein, with stearyl alcohol to produce 1,2-diolein, 2-monoolein and the wax ester of oleic acid. Again, no organic solvent was used. The wax ester yield was found to be directly dependent upon the alcohol concentration that was used to modulate the outcome of the reaction towards either the wax or the partial glycerides. The process was applied to the synthesis of waxes from high erucic acid rapeseed oil.

Journal ArticleDOI
TL;DR: In this article, the foaming capacity and foam stability of denatured soy protein concentrate obtained from toasted flour were improved by proteolysis with fungal or bacterial proteases.
Abstract: Solubility, foaming capacity and foam stability of denatured soy protein concentrate obtained from toasted flour were improved by proteolysis with fungal or bacterial proteases. Emulsifying capacity was unchanged, but emulsion stability decreased; bacterial protease highly improved oil absorption. Also, the bacterial protease was able to solubilize more protein and gave products which foamed more than those obtained with the fungal enzyme. However, the stabilizing properties of the bacterial modified soy protein concentrate at the air/water or oil/water interface were inferior. By limited hydrolysis up to degree of hydrolysis 10% most functional properties were improved without greatly reducing emulsion stability and water absorption.

Journal ArticleDOI
TL;DR: In this paper, individual and combined effects of ascorbic acid and δ-tocopherol on the autoxidation of fish oil have been evaluated with the induction period monitored by Rancimat.
Abstract: Individual and combined effects of ascorbic acid andδ-tocopherol on the autoxidation of fish oil have been evaluated with the induction period monitored by Rancimat. The antioxidative efficiency of them was found to increase with increasing concentration.δ-Tocopherol and ascorbic acid acted highly synergistic with each other. Whenδ-tocopherol content was varied at a fixed content of ascorbic acid, the synergistic efficiency was generally 100% or more. On the other hand, when ascorbic acid content was varied at a fixed content ofδ-tocopherol, the synergistic efficiency rose sigmoidally with increasing concentration. We concluded that at least 0.01–0.02% ascorbic acid is required to obtain a considerable synergistic effect withδ-tocopherol in stabilizing fish oil.

Journal ArticleDOI
TL;DR: In this paper, the feasibility and technical merits of supercritical fluid extraction (SFE) as a potential alternative to molecular distillation for enriching tocopherols effectively from soybean sludge were examined.
Abstract: Supercritical fluid extraction (SFE) has been widely applied as a promising alternative to current extraction processes used in the food and pharmaceutical industries. SFE has some advantages over conventional separation processes such as liquid-liquid extraction, distillation, and adsorption. The most important advantage of utilizing SFE is the easy separation of the solvent from the extracted material without solvent residue. Further, supercritical fluids provide lower mass transfer resistance than those in conventional separation processes. A number of references dealing with the basic principles and applications of SFE are now available [1-3]. The objective of this study is therefore to examine the feasibility and technical merits of SFE as a potential alternative to molecular distillation for enriching tocopherols effectively from soybean sludge. In this regard, the solubilities of both sterol-removed soybean sludge and esterified soybean sludge in SC-CO2 were determined by a flow-through SFE system at temperature and pressure ranges f 35–70∘C and 200–400 bar, respectively. The tocopherol content in the extracts collected continously at equilibrium conditions up to the approximate 70 wt% extraction rate of the feed was checked by HPLC at each interval. The results of these initial feasibility experiments could provide fundamental information for the suitable application of a continous-type SFE for concentrating tocopherols.

Journal ArticleDOI
TL;DR: In this article, the antioxidant effect of phospholipids on the oxidation of refined perilla oil was investigated by measuring weight-gains and by the oven test at 37°C.
Abstract: Antioxidant effect of phospholipids on the oxidation of refined perilla oil (PO;α-18:3, 54.5%; 16:0, 7.2%; 18:0, 2.6%; 18:1, 18.6%; 18:2, 15.5%), tocopherol-free (POF) and tocopherol-enriched (POR) perilla oil were investigated by measuring weight-gains and by the oven test at 37°C. The oxidative stability of PO was especially increased by additions of phosphatidylethanolamine (PE) and phosphatidylserine (PS), but phosphatidylcholine (PC) scarcely showed an antioxidant effect. The oxidative stability of POF was markedly low, and none of the phospholipids (PC, PE, PS) showed an antioxidant effect on the oxidation of POF. The stability of POR was lower than that of PO regardless of its higher tocopherol contents. However, the oxidation of POR was significantly suppressed by additions of PE and PS, as was observed with PO. PC showed a small antioxidant effect on the oxidation of POR. Therefore, it seems that the antioxidant effects of phospholipids, especially of PE and PS, was due to the presence of tocopherols in the perilla oil.

Journal ArticleDOI
TL;DR: In this paper, a high-speed, high-resolution approach to silver-complexation chromatography of triacylglycerols in vegetable fats and cocoa butter equivalents is described.
Abstract: A high-speed, high-resolution approach to silvercomplexation chromatography of triacylglycerols in vegetable fats and cocoa butter equivalents is described. Trisaturated and major isomeric unsaturated species with up to five double bonds are eluted within 12 min. A simple change of solvent composition enables elution of species with up to nine double bonds within the same time-frame. Throughput is three samples/hr (70 samples/24 hr with an automatic system). Short-term reproducibility of analytical data for the system gives standard deviations similar to those obtained in practice for high-resolution capillary gas chromatography of triacylglycerols, and quantitative accuracy is good. Details of column preparation, solvent gradient and system operation are given.

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TL;DR: In this paper, triacylglycerols from North Atlantic herring (Clupea harengus) were separated according to the degree of unsaturation by high performance liquid chromatography (HPLC) in the silver ion mode.
Abstract: Triacylglycerols from North Atlantic herring (Clupea harengus) were separated according to the degree of unsaturation by high performance liquid chromatography (HPLC) in the silver ion mode. Each of the eleven fractions collected was then separated by reversed- phase HPLC, which in these circumstances separated the molecules according to the combined chain- lengths of the fatty acyl residues only. One hundred thirty fractions were obtained for fatty acid analysis. Almost 50% of the triacylglycerol molecules had six or more double bonds in their fatty acyl residues. Saturated-dimonoenes and disaturated- monoenes, 18.9% and 10.4%, respectively, were the most plentiful fractions of the more saturated species. Such a complex mixture of molecules was present that the most abundant subfractions from reversed- phase HPLC represented less than 5% of the total. Indeed, the largest single molecular species [16:0- 22:l- 22:6(n− 3)] represented only 2.8% of the total. These sequential analyses by complementary techniques made it possible to obtain a considerable amount of information on the composition of molecular species, but it was still not possible to identify all components.

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TL;DR: In this article, the effects of carotenoids on photooxidation of soybean oil in methylene chloride were studied by measuring peroxide values and conjugated diene content.
Abstract: The effects of 0, 1.0 × 10”−5, 2.5 × 10−5, and 5.0 × 10−5 M β-apo-8'-carotenal, β-carotene, and canthaxanthin on the photooxidation of soybean oil in methylene chloride containing 3.3 × 10−9 M chlorophyll b were studied by measuring peroxide values and conjugated diene content. β-Apo-8'-carotenal, β-carotene, and canthaxanthin contain 10,11, and 13 conjugated double bonds, respectively. The peroxide values and conjugated diene contents of oils containing the carotenoids were significantly lower (P<0.05) than those of control oil containing no carotenoid. As the number of conjugated double bonds of the carotenoids increased, the peroxide values of soybean oils decreased significantly (P<0.05). The quenching mechanisms and kinetics of the carotenoids in the photosensitized oxidation of soybean oil were studied by measuring peroxide values. The steady-state kinetics study showed that carotenoids quenched singlet oxygen to reduce chlorophyll-sensitized photooxidation of soybean oil. The singlet-oxygen quenching rate constants ofβ- apo-8'-carotenal, β-carotene, and canthaxanthin were 3.06 × 109, 4.60 × 109, and 1.12 × 1010 M−1sec−1, respectively.