Wageningen researchers have developed a new technique to solidify liquid fatty acids by using proteins. Using this method, it is possible to replace unhealthy fats in products such as cookies and sausages by healthier fats.
Solid fats, such as butter, contain many saturated fatty acids and trans fats. These fats increase the risk of cardiovascular diseases, but also ensure that cookies remain crunchy and chocolate does not melt at room temperature. Conversely, fats that are soft or liquid at room temperature, vegetable oils for example, contain many unsaturated fatty acids. Those are healthier, but you can’t use them to make cookies or chocolate. This is the reason why scientists are looking for ways to replace saturated fatty acids by unsaturated fatty acids without losing the structure and form of solid fat.
Researcher Auke de Vries succeeded in turning a liquid fat (oil) into a gel without using saturated fatty acids. He received his doctorate on 8 March for his research under professor Erik van der Linden at the Physics and Physical Chemistry of Foods group.
‘It is the first time we managed to produce these “oleogels” using proteins’, tells copromotor Elke Scholten of the Physics and Physical Chemistry of Foods group. ‘There are also other methods to produce oleogels, but those are relatively expensive or unsuitable for use in foods. Proteins are a good alternative: they are healthy, readily available and cheaper.’
‘Several challenges had to be overcome before it was achieved’, says Scholten. ‘Proteins easily form gels in water – like in yoghurt and cheese. But they do not mix well with oil. The same happens as when you add water to oil.’ The researchers modified the structure of the proteins, improving their solubility in oil. ‘If you put this protein powder directly into oil, it will still form lumps’, explains Scholten. By first solving the proteins in water and progressively replacing the water by oil, the proteins can slowly ‘get accustomed’ to the change. They then form a network in the liquid oil that creates a solid structure.
Cookies and sausages
The researchers have already tested the oleogels in cookies and sausages. A small group of people have tried these. ‘They equally liked the real sausages and the ones we made. The cookies were less crunchy, which was why not everyone liked them as much as the cookies made with butter.’ Scholten wants to offer the cookies and sausages to a larger test panel and if they are assessed positively, they could be launched on the market in the short term.
Left to right: cookie made with sunflower oil, oleogel, butter. Photo: Anne Wesseling
In the future, Scholten would like to find out which other types of proteins are suitable for this technique. ‘We used whey proteins for this research. Whey is a by-product of the cheese industry. However, it should also be possible to produce gels using other proteins. We are currently looking into vegetable proteins from potatoes, for example. That would make the product fit for vegans as well.’
Whether it will be possible to produce healthier chocolate is something Scholten doubts: ‘The structure of chocolate is very important for the taste, and it is highly complex to reproduce. Besides, chocolate still contains a lot of sugar, so I fear that healthy chocolate is something we should not count on anytime soon.’