01 March 2012
Scientists in Canada have shown that sausages can be made using vegetable oil and a gelling agent instead of animal fat, without altering the texture. With the continual push for healthy eating and eliminating saturated fat from our diets, this novel use of an ethylcellulose organogelator (oleogel) could be applied to substantially reduce the amount of saturated fat in foods.
According to the World Health Organisation, cardiovascular disease is the leading cause of death worldwide and there is evidence that links the disease with high saturated fat consumption. Scientists have been investigating alternatives to hard fats (such as saturated and trans fats) to reduce the risk of cardiovascular disease. But, it is very difficult to find replacements, says lead researcher Alejandro Marangoni from the University of Guelph. 'You are left with oil, which does not have any structuring ability,' he adds.
Marangoni's team made their oleogel using the gelling agent ethylcellulose, a known organogelator for vegetable oils. 'We had to heat ethylcellulose up quite a bit to go in to triglyceride oils but once that happened, upon cooling, we found that a network formed and we had something almost as hard as a rubber ball!' says Marangoni.
An oleogel (middle) was used to replace hard fat in a frankfurter. The image on the right is a scanning electron micrograph showing the texture of a soybean oil organogel
The researchers then used texture profile analysis and a mechanical method to test the gel's hardness to assess oleogels consisting of 4-10% ethylcellulose in canola, soyabean and flaxseed oils. They found that the oleogel strength increased with increasing polymer molecular weight, composition and fatty acid composition of the vegetable oil.
They also found that frankfurters cooked with the canola oil oleogel showed no notable differences in chewiness or hardness compared with conventional animal fat frankfurters. 'We made some really good breakfast sausages with oleogels!' says Marangoni. 'We can easily replace two-thirds of the saturated fat.'
'The work shows that ethylcelluloses can be used to create the desirable textural characteristics without using saturated or trans fats,' says David McClements, an expert in food science at the University of Massachusetts, US. 'This may be a novel approach towards improving the healthfulness of many food products.'
Marangoni's team is now creating a database of oleogel hardness for a variety of applications, which they hope will include food systems.
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A K Zetzl, A G Marangoni and S Barbut, Food Funct., 2012, DOI: 10.1039/c2fo10202a
This paper is part of a themed issue on the delivery of functionality in complex food systems. Guest editor: Alejandro Marangoni
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