At high temperature, the fatty acid's double bonds can alter geometry from cis to trans. This most often occurs by refining (deodorising) of oils for human consumption.
- Thermal isomerisation does not alter the double bond position and it is seldom that more than one trans-bond is formed in each fatty acid.
- Hydrogenation is used to increase the melting point and stability of oils and fat. With partial hydrogenation, a large amount of fatty acid isomers are forms that were not present in the original product.
- A third source of trans fatty acids is isomerisation in the digestion process of ruminating animals.
Nofima Ingrediens is studying the formation of trans fatty acids by thermal isomerisation in fish oils and omega-3 concentrates.
Analytical methodology is also being developed for all types of trans fatty acids in marine lipids.
We also offer guidance in the choice of raw materials and processing conditions to avoid trans fatty acids in products.
The nutritional effects of trans fatty acids from partially hydrogenated oil have been carried out at Nofima Ingrediens with pigs as the model animals.
This work is also of relevance for studying any eventual health/nutritional effects of trans fatty acids that can be found in today's diet containing a relatively low content of trans fatty acids.
Relevant issues:
- Optimisation of the refining/deodorising process of oils to avoid formation of trans fatty acids
- Develop an analytical method to identify which fatty acid has trans-bonds in marine oils for human consumption
- Chart the content of trans fatty acids in products produced from ruminating animals.
- The health effects of trans fatty acids that may be found in oils for human consumption
