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  • 1
    Electronic Resource
    Electronic Resource
    MODIFICATION OF BUTTER OIL: EFFECTS OF SUPERCRITICAL CARBON DIOXIDE EXTRACTION AND INTERESETERIFICATION (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food lipids 1 (1994), S. 0 
    Details
    ISSN: 1745-4522
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Physical properties of lipid fractions isolated from anhydrous butter oil under various experimental conditions using supercritical carbon dioxide (SC-CO2) extraction, intereseterification or their combination, together with thermal modification were assayed in terms of triacylglycerol and fatty acid profiles. SC-CO2 process, at 35C and 2000 psi, preferentially extracted the low-molecular-weight triacylglycerols, did not result in any separation of cholesterol and extracted an approximately constant fraction (7%) of the material in each 2h interval. Combination of SC-CO2 extraction with thermal fractionation yielded a butter oil fraction with improved spreadability at refrigerator temperatures. At higher pressure and longer extraction time SC-CO2 resulted in decreased solvent selectivity without increased extraction yield. The triacylglycerol and fatty acid profiles of high pressure 6000 psi extracts were remarkably similar to those of the butter itself. Chemical interesterification of butter oil randomized the constituent fatty acids, giving products which contained higher proportions of the middle-range constituents. Thermal fractionation of interesterified butter yielded products only slightly enriched in higher molecular weight triacylglycerols, but interesterification of a solid obtained from thermal fractionation of butter gave a product greatly enriched in these compounds. Thus, modified lipid samples with distinct triacylglycerol and fatty acid compositions were prepared which may be used in different industrial applications.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1745-4522.1994.tb00247.x
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  • 2
    Electronic Resource
    Electronic Resource
    FURTHER DEVELOPMENT IN THERMAL MODIFICATION OF BUTTER OIL (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food lipids 1 (1993), S. 0 
    Details
    ISSN: 1745-4522
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Anhydrous butter oil was modified by acetone or n-hexane crystallization (10–20% w/w) over a temperature range of 29–17C without agitation, producing solid fractions with higher proportions of C44–C54 triacylglycerols vis-a-vis fractions obtained by classical thermal modification of butter oil. Similarly, recrystal-lization of a mixture of thermally isolated butter oil solids (S.25–S. 17C) in organic solvents at various temperatures yielded butter lipid fractions with significantly distinct chemical and physical properties. These lipid fractions showed to contain higher and lower proportions of C44–C54 and C26–C36 triacylglycerol respectively vis-a-vis solid fractions isolated via thermal modification of butter oil in organic solvents as the starting material(S.25–S. 17C) contained more of the former and less of the latter triacylglycerols than butter oil.Extraction of low molecular weight lipidsfrom solid fractions obtained by classic thermal modification of butter oil using acetone left a white powderous lipid which produced one sharp melting peak (53 C) in its DSC thermogram. The acetone treated fraction was enriched in C44–C52 triacylglycerols with a 2 to 6-fold reduction in C4–C10 fatty acids content.Recrystallization of a mixture of solid butter fractions isolated according to classical procedures at 29–21 C, over a temperature range of 35–21 C, yielded discrete fractions with profound differences in fatty acid and triacylglycerol profiles having very distinct physical properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1745-4522.1993.tb00240.x
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  • 3
    Electronic Resource
    Electronic Resource
    Chromatographic optimization for the determination of traces of selenonium and arsonium cations by HPLC with on-line detection by AAS (1991)
    Springer
    Chromatographia 31 (1991), S. 481-488 
    Details
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Selenonium and arsonium cations ; AAS detection ; Chromatographic optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Optimal mobile phase compositions were determined for the separation of selenonium ions [trimethylselenonium, (2-hydroxyethyl)dimethylselenonium and (2-acetoxyethyl)dimethylselenonium] and, separately, for arsonium ions (tetramethylarsonium, arsenobetaine, and arsenocholine) by HPLC with detection by atomic absorption spectrometry (AAS). Surface response methodologies were used to predict the variations in detector response (peak area), capacity factors, and selectivities as a function of the mobile phase composition. For selenonium analytes, a mixture of triethylammonium and trimethylsulfonium ions in the methanol-1% acetic acid mobile phase provided a compromise between resolving power and chromatographic efficiency. By contrast, optimum chromatography of the arsonium analytes was obtained by replacing onium additives in the mobile phase by picrylsulfonic acid. For both selenonium and arsonium analytes, the dominant interaction with the stationary phase was with residual silanols and improvements to the chromatographic performance of these analytes resulted in appreciable decreases in their limits of detection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02262393
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    Paper (German National Licenses)
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