Determination of tocopherols and sterols by capillary gas chromatography

Slover, Hal T.; Thompson, Raymond H.; Merola, George V.

doi:10.1007/bf02666576

Cited by 113 publications

(46 citation statements)

References 6 publications

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“…Hewlett-Packard HP 5890 A gas chromatograph was used under the following operating conditions: column, 0,53 mm X 5 m coated with DB-1 phase in a film thickness of 1,0 micron; column temperature, 200-280°C with a rate of 4°C/min; injection and detector temperature, 290°C, and carrier gas was helium at flow rate of 8,0 ml/min. Preparation of pure sterols mixture and their silyl derivatives, and gas chromatographic analysis were conducted according to Slover et al (33) and El-Shami (34).…”

Section: Methodsmentioning

confidence: 99%

Studies on the lipid constituents of grape seeds recovered from pomace resulting from white grape processing

El-Shami¹,

El-Mallah²,

Mohamed³

1992

Grasas y Aceites

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RESUMENEstudios sobre los constituyentes lipidíeos de semillas de uva recuperadas de la pulpa resultante del procesado de uva blanca Se han realizado estudios sobre los constituyentes lipidiaos de semillas de uva producidas como subproducto del procesado de uva blanca. La cromatografía gas-líquido se usó para determinar la composición de esteres metílicos de ácidos grasos y silil derivados esteróles del aceite. Se observó que el aceite contenía cantidades apreciables de ácidos grasos insaturados, principalmente ácidos oleico y linoleico, no siendo sin embargo detectado el ácido linolénico. Se encontraron en cantidades razonables ácidos grasos saturados, principalmente, palmítico y esteári-co. Como componentes minoritarios se detectaron los ácidos mirístico, palmitoleico, eicosanoico y eicosadienoico. El isofucosterol apareció junto a otros esteróles, principalmente, campesterol, estigmasterol y beta-sitosterol. El análisis por HPLC del aceite para la determinación de tocoferoles, mostró la presencia de alfa-y gamma-tocotrienoles, y alfa-y gamma-tocoferoles en cantidades de 53'2, 28'6, 16'4 y 1'8 respectivamente. El contenido en tocoferoles totales del aceite fue de 470 ppm. En la harina desgrasada de semillas de uva se vio un contenido del 24'6% en proteína, con amplias proporciones de todos los aminoácidos esenciales, determinados mediante analizador de aminoácidos. PALABRAS-CLAVE: Composición iipfdica -Proceso tecnológico -Semilla de uva -Subproducto. SUMMARY Studies on the lipid constituents of grape seeds recovered from pomace resulting from white grape processingStudies on the lipid constituents of grape seeds, produced as by-product from white grape processing, were carried out. Gas liquid chromatography was used to determine the composition of fatty acid methyl esters and sterol silyl derivatives of the oil. The oil was found to contain appreciable amount of unsaturated fatty acids, namely, oleic and linoleic acids, however, linolenic acid was not detected. Saturated fatty acids, namely, palmitic and stearic were found to be present in reasonable amounts. Myristic, palmitoleic, eicosanoic and eicosadienoic acids were detected as minor components. Isofucosterol was found among the other sterol constituents namely, campesterol, stigmasterol and beta-sitosterol. HPLC analysis of the oil for determination of tocopherols, showed the presence of alpha-and gamma-tocotrienols, and alpha-and gamma-tocopherols to the extent of 53.2, 28.6, 16,4 and 1,8% respectively. The total tocopherols content of the oil was 470 ppm. The defatted meal of grape seeds was found to contain 24,6% protein which contained large proportions of all the essential amino acids as determined by amino acid analyzer. By-product • nological process. KEY-WORDS:

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Section: Methodsmentioning

confidence: 99%

Studies on the lipid constituents of grape seeds recovered from pomace resulting from white grape processing

El-Shami¹,

El-Mallah²,

Mohamed³

1992

Grasas y Aceites

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“…These were analyzed according to the procedures described by Sanchez Casas, Osorio Bueno, Montano Garcia, and Martinez Cano (2004) who modified the method of Slover, Thompson, and Merola (1983). The oil sample was saponified with ethanolic potassium hydroxide solution.…”

Section: Sterol Determinationmentioning

confidence: 99%

Chemical characterization of traditional varietal olive oils in East of Spain

Cortés

Salazar‐García

Velázquez‐Martí

et al. 2013

Food Research International

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The aim of this work has been to characterize the chemical composition of the eight most emblematic varietal olive oils from the West of the Mediterranean Sea. These were classified into two groups according to the International Olive Council (IOC norms): Sweet oils (Farga, Morruda and Serrana) which were compared with Arbequina as standard of the Spanish sweet oils; and bitter-spicy oils (Alfafara, Blanqueta, and Villalonga) that were compared with Picual, considered as the standard of the bitter-spicy olive oils. For the study, sampled trees were chosen in their geographically separated originating areas. They were cultivated in the traditional conditions. The variety of each sampled tree was previously identified by the International Union for the Protection of new Varieties for Plants (UPOV TG/99/4). We have attempted to find differences between these varieties based on their fatty acid and sterol components. Although our results of only the sterols in olive oils suggested that stigmasterol could allow the segregation of the varieties, our experience indicates that analysis of the main fatty acids (palmitic, oleic and linoleic), together with a PCA applied to all fatty acids and sterols, can be used to validate the varietal determinations with enough precision. In addition, α-tocopherol can be used as differentiator in bitter-spicy oils.

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“…Known amounts of pure α-and δ-tocopherol standards (500 and 200 ppm, respectively) were added to anhydrous milk fat. This fat was chosen as matrix because it is known to contain low tocopherol levels (20-50 ppm) [7].Compared to similar studies of Slover et al [8] and Ulberth et al [9], a lower but still acceptable recovery of 92 % was obtained for α-tocopherol (Tab. 1).…”

mentioning

confidence: 88%

“…The recovery of δ-tocopherol was even better (102 %), which was not evident. According to literature, this homologue is the most difficult to extract after saponification, probably due to the presence of soaps in the saponification mixture [8]. A distinct explanation for the observed differences in recovery is not readily available.…”

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confidence: 95%

Analysis of tocopherols by gas-liquid and high-performance liquid chromatography: a comparative study

Greyt¹,

Petrauskaitè

Kellens³

et al. 1998

Fett/Lipid

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Analyse von Tocopherolen mittels Gas-Flüssigkeits-und Hochleistungsflüssigchromatographie: eine vergleichende Untersuchung. Ausgewählte Normalphasen-HPLC-und gaschromatographische Methoden wurden für die Analyse von Tocopherolen in pflanzlichen Ölen untersucht. Wiederholbarkeit, Genauigkeit und/oder Wiederfindung wurden für beide Methoden bestimmt und mit Daten der offiziellen Methodik verglichen. Die größte Genauigkeit wurde mittels der Normalphasen-HPLC-Technik, basierend auf der AOCS-Methode Ce 8-89, erzielt, was wahrscheinlich durch die kurze und einfache Probenaufbereitung erklärt werden kann. Es wurden Tocopherolgehalte von sechzehn voll raffinierten Pflanzenölen mit sowohl GLC als auch HPLC bestimmt. Die Regressionsanalyse zeigte, daß Tocopherolgehalte, die mittels GLC ermittelt worden sind, um 6,1% höher waren als die vergleichbaren HPLC-Daten. Obwohl die ermittelte Wiederfindungsrate der GLC-Methode gut ist, scheint es, daß bei der Probenaufbereitung zusätzlich eine Auftrennung mittels Dünnschichtchromatographie eingeführt werden sollte, um eine Überlappung der Peaks zwischen Tocopherolen und einigen störenden Substanzen der unverseifbaren Fraktion zu vermeiden.a Department of Food Technology and Nutrition, University of Ghent, Gent, Belgium. b De Smet Engineering N. V., Edegem, Belgium.vents and reagents used were analytical or HPLC grade and purchased from Acros Organics (Geel, Belgium). Gas liquid chromatographySample preparation: The selected GLC procedure was based on the AOCS official method Ce 3-74 [6]. 5-7 g of oil were saponified in the presence of 0.15 % butylhydroxytoluene as antioxidant [5]. Tocopherols and sterols were not separated by thin-layer chromatography prior to GLC analysis. Derivatization was accomplished by the addition of 1 ml acetic acid anhydride, keeping the mixture 10 min at 140 °C. After cooling, 1 µl was injected in the gas chromatograph.Gas-chromatographic conditions: Analyses were carried out on a Carlo Erba 4160 chromatograph equipped with a flame-ionization detector (FID) and a split injector (split ratio 1:40) (Carlo Erba, Milano, Italy). A fused silica capillary column coated with a nonpolar stationary phase (CP TM Sil 5CB, 25 m × 0.25 mm internal diameter; 0.25 µm film thickness, Chrompack, The Netherlands) was selected. The oven temperature was kept constant at 290 °C. Injector and detector were maintained at 340 °C. All tocopherol homologues eluted within 15 min. The total analysis time was set at 30 min to assure the elution of all sterols.Identification of the individual tocopherols was realized with pure standards as reference compounds.Quantification: Correction factors were determined for all tocopherols by analyzing different mixtures of the tocopherol standards and an internal standard (3-octadecyloxy-1,2-propanediol). Quantitative analyses were performed with a Shimadzu RC3A integrator. High-performance liquid chromatographyPrinciple: The selected NP-HPLC procedure was based on the previously mentioned IUPAC method 2.432 [5] and the AOCS official method Ce ...

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Determination of tocopherols and sterols by capillary gas chromatography

Cited by 113 publications

References 6 publications

Studies on the lipid constituents of grape seeds recovered from pomace resulting from white grape processing

Studies on the lipid constituents of grape seeds recovered from pomace resulting from white grape processing

Chemical characterization of traditional varietal olive oils in East of Spain

Analysis of tocopherols by gas-liquid and high-performance liquid chromatography: a comparative study

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