This International Standard specifies a gas chromatographic method using capillary columns for the determination
of the content of trans fatty acid isomers of vegetable oils and fats.
The method is specially designed to evaluate, by a single capillary gas chromatographic (GC) procedure, the level
of trans isomers as formed during (high temperature) refining, or during hydrogenation of vegetable oils or fats.
The method may also be used to report all other fatty acids (e.g. to obtain the full fatty acid composition and total
amounts of saturated fatty acids, mono-unsaturated fatty acids and poly-unsaturated fatty acids) from the same
sample and same analysis.
NOTE 1 The trans-isomer content as obtained with this method may not agree with the trans-isomer content as obtained
using other methods.
NOTE 2 During (high temperature) refining (deacidification and deodorization), only geometrical isomers are formed of the
mono- and poly-unsaturated fatty acids; i.e. the double bond(s) remain(s) at the same natural position. During hydrogenation,
both positional and geometrical isomers are formed.
NOTE 3 For some specific cis- and trans-isomers formed during hydrogenation, co-elution is possible. This could influence
the accuracy of the result. The level of these isomers is usually negligible in normal partially hydrogenated oils and fats.
Diese ÖNORM legt ein kapillargaschromatographisches Verfahren zur Bestimmung des Gehaltes an Trans-Fettsäure-Isomeren in pflanzlichen Ölen und Fetten fest. Das Verfahren ist speziell dazu bestimmt, die Menge der bei (Hochtemperatur-)Raffination oder bei der Hydrierung pflanzlicher Öle und Fette gebildeten Trans-Isomere mit Kapillar-Gaschromatographie (Kapillar-GV) in einem Schritt zu bestimmen. Das Verfahren ist ebenfalls zur Analyse aller anderen Fettsäuren anwendbar (zB um die Gesamt-Fettsäurezusammensetzung und die Gesamtmenge gesättigter Fettsäuren, einfach-ungesättigter Fettsäuren und mehrfach-ungesättigter Fettsäuren) in derselben Probe in einem Analysengang zu bestimmen.