Institut für Lebensmittelchemie

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Browsing Institut für Lebensmittelchemie by Classification "660"

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    Furan fatty acid amounts and their occurrence in triacylglycerols of white asparagus (Asparagus officinalis) from the German market
    (2023) Müller, Franziska; Bauer, Vanessa; Vetter, Walter
    Vegetables including asparagus contain a wide range of fatty acids, mainly stored in triacylglycerols. One class of interesting minor fatty acids is the family of furan fatty acids (FuFAs) because of their antioxidant properties. Since FuFAs have not been studied previously in asparagus (Asparagus officinalis L.), we developed and applied a simplified method for their analysis in 20 fresh and three preserved samples. Four FuFAs were detected with clear dominance of the dimethyl‐substituted FuFAs (D‐FuFAs) 11D5 and 9D5 as well as small amounts of the monomethyl‐substituted FuFAs (M‐FuFAs) 11M5 and 9M5. The total amounts of FuFAs in fresh white asparagus ranged from 1.4 to 4.6 mg/100 g dry weight (mean 3.0 mg/100 g dry weight). Subsequent LC‐Q‐Orbitrap‐HRMS measurements enabled the detection of 22 different FuFA‐containing TAGs. These were predominantly found together with one or two polyunsaturated fatty acid.
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    LC‐Orbitrap‐HRMS determination of two novel plastochromanol homologues
    (2023) Hammerschick, Tim; Graf, Jana; Vetter, Walter
    Scope: The antioxidant plastochromanol-8 (PC-8) is a tocochromanol which differs from γ-tocotrienol in having an unsaturated side chain of eight instead of three isoprene units. The recent isolation of PC-8 from flaxseed oil indicates the additional presence of lower shares of two previously unknown homologues, plastochromanol-7 (PC-7) and plastochromanol-9 (PC-9), which feature seven and nine isoprenoid units respectively on the γ-chromanol backbone. Here, a fast LC-Orbitrap-HRMS method is applied for the determination of PC-7 and PC-9 in seven plant oils and a plant extract. Methods and results: The presence of PC-7, PC-8, and PC-9 is confirmed in all eight investigated samples by LC-Orbitrap-HRMS analysis after saponification. PC-8 amounts of ≈315–350 mg kg−1 in two flaxseed oils, ≈75 mg kg−1 in rapeseed oil, ≈38 mg kg−1 in camelina oil, ≈80–120 mg kg−1 in two mustard oils, ≈90 mg kg−1 in candle nut oil, and ≈900 mg kg−1 dry weight in Cecropia leaves are determined by quantification. Semi-quantification of PC-7 and PC-9 indicated the presence of ≈0.1–1% of PC-7 and PC-9 in varied relative ratios. Conclusion: The novel plastochromanol homologues are of particular interest to researchers with focus on vitamin E and other tocochromanols because of their unexplored bioactivity.
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    Silver ion chromatography enables the separation of 2‐methylalkylresorcinols from alkylresorcinols
    (2023) Hammerschick, Tim; Vetter, Walter
    Alkylresorcinols (∑ARs) is the generic term for a highly varied class of lipids found mainly in cereals. These bioactive compounds consist mainly of 5‐alkylresorcinols (ARs), which differ in length, unsaturation, and substituents on the alkyl side chain on C‐5. In addition, 2‐methyl‐5‐alkylresorcinols (mARs) are scarcely studied minor compounds that are supposed to exist with the same structural diversity. In the first step, ∑ARs were enriched by solid‐phase extraction from wheat grain and quinoa seed extracts. The subsequent application of silver ion chromatography (SIC), silica gel, coated with 20% AgNO3, then deactivated with 1% water) enabled an unprecedented full separation of saturated mARs from conventional ARs. Specifically, saturated mARs were eluted with n‐hexane/ethyl acetate (92:8, v/v), and conventional ARs with n‐hexane/ethyl acetate (80:20, v/v). The unpreceded separation indicated that the SIC method could be useful not only for separations according to the degree of unsaturation, but also in the case of steric hindrance by additional (alkyl) substituents. Continued fractionation enabled the collection of unsaturated ARs in wheat and quinoa extracts. In this way, 35 ∑ARs (including five mARs) were detected by gas chromatography/mass spectrometry analysis in wheat and 45 ∑ARs (including 21 mARs) in quinoa. These included several low abundant and partly unknown ∑ARs such as 1,3‐dihydroxy‐5‐tricosadienylbenzene.