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Trans fatty acid isomers and the trans ‐9/ trans ‐11 index in fat containing foods
Author(s) -
Kuhnt Katrin,
Baehr Melanie,
Rohrer Carsten,
Jahreis Gerhard
Publication year - 2011
Publication title -
european journal of lipid science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.614
H-Index - 94
eISSN - 1438-9312
pISSN - 1438-7697
DOI - 10.1002/ejlt.201100037
Subject(s) - elaidic acid , food science , vaccenic acid , ruminant , chemistry , trans fat , fatty acid , animal fat , trifluoroacetic acid , saturated fat , biology , organic chemistry , linoleic acid , conjugated linoleic acid , biochemistry , cholesterol , ecology , crop
To determine trans fatty acid (TFA) distribution of contemporary foods, especially regarding individual trans octadecenoic acids ( trans C18:1), 339 German foods of six categories (semi‐solid fats, deep‐fried potato products, bakery products, confectioneries, instant products and butter) were analysed using two GC methods. Results showed a high variation of TFA content between and within the categories containing between 0 and 40.5% of FAME except in butter, which is a source of natural TFA. The mean TFA values were below 2.0% of FAME, however, bakery products contained 4.5% and butter fat 3.2%, respectively. In addition, the distribution of individual trans C18:1 differed. In samples containing ruminant fat (butter and various confectioneries), vaccenic acid ( t 11‐C18:1, t 11) predominated, while in foods containing industrially hydrogenated fats, elaidic acid ( trans‐ 9, t 9‐) and t 10‐C18:1 were the major trans isomers.. This was reflected by a low t 9/ t 11 index of 0.3 and 0.5 in butter and ruminant fat containing confectioneries, respectively, whilst the highest index was observed in shortenings and deep‐fried potato products at 5.2 and 6.8, respectively. In conclusion, the TFA content of foods available on the German market is generally declining, but substantial variations are present. The t 9/ t 11 index could be used as an indicator to determine ruminant fat. Practical applications: A number of studies provide evidence that a high TFA intake, particularly of industrial origin, adversely affects human health. The TFA content of foods could be reduced due to the introduction of several mandatory regulations and modifications regarding the hydrogenation process of oils. The most abundant dietary TFA are the isomers of trans C18:1. Unfortunately, the differentiation of these isomers is not yet very common, though the trans C18:1 profile differs depending on its origin (bacterial hydrogenation in the rumen or industrial hydrogenation). To date, data for TFA content including the trans C18:1 profile of different food categories are limited. The present study confirmed that the TFA contents in German foods are declining. However, TFA are still elevated, especially in bakery products and confectioneries, which are produced using mainly industrial but also ruminant fats. Therefore, the t 9/ t 11 index imparts important information on the source of TFA in processed foods.