Yummy…milk fat!

What should the dairy industry do with the huge amounts of milk fat surplus it is stuck with? TU Delft researcher, Dr Marta Lubary, says some of this fat can be turned into aromatic substances.

Thanks to the trend of people buying light, healthy products, the dairy industry is able to develop many new lucrative products. But this is also problematic, because what should the industry do with all that surplus fat? Making butter from it isn’t a solution, as the butter market is saturated, and that’s not likely to change.

“The decline in milk fat consumption experienced over the last decades has prompted lots of research into alternative uses for this natural fat”, says Dr Marta Lubary, who last month defended her thesis, titled ‘Added-value milk fat derivatives from integrated processes using supercritical technology’.
Lubary believes things will only get worse for the European dairy industry, because this industry is currently protected by a quota system that is set to disappear in 2015. “This system guarantees a minimum selling price. As the EU market price for dairy products is higher than the world price, exports are generally subsidized.

“Subsidized exports are one of the means to absorb excess butter.”
Getting rid of excess fat will become much more difficult when the EU dairy industry loses its protections and must operate in a free market. Luckily milk fat isn’t all that bad, Lubary says: “Triglycerides, the main components of fats, consist of one glycerol molecule and three fatty acid chains. In most milk fat molecules one of these fatty acids has a short chain. And that’s interesting. Short chains are relatively rare in natural fats. You can use them, for example, to make aromatic substances.”

The trick is to obtain pure fractions of the different chains. For this Lubary experimented with a solvent called supercritical carbon dioxide, a relatively high pressured and high temperature carbon dioxide, which, when in such states, has properties that are an intermediate between liquid and gas and are advantageous for processing compounds, such as oils and fats.
“By varying the temperature and pressure, you can vary which fractions of the milk fat the fatty acids dissolve in”, says Lubary, who first used enzymes called lipases, which are also present in our saliva, to break up the milk fat molecules.

But by adding ethanol to the mixture, she managed to form fatty acid ethyl esters, which are molecules with a fruity flavour. Lubary says that she believes she is the first researcher to use this technique for milk fat.
“There was a strong scent of pineapple and pear in the laboratory, and that was a much better smell than when I started my research,” Lubary says, laughing. “I had used fish oil to practice with the supercritical carbon dioxide fractionation technique, and that smelt terrible.”

Talk to me about the weather…. As an international student from Colombia one of the biggest changes in my lifestyle over the past two years stems for the shifting, seasonal weather conditions here. The first fact is that the Netherlands, lying in the temperate or tepid latitudes of the globe, between the tropics and the polar circles, has generally mild shifts between summer and winter and a moderate maritime climate, rather than extreme hot or cold, according to my Lonely Planet travel guide. When preparing your trip to Delft from a distant warm country, you’re ready to face the weather; in your luggage a big jacket is packed, because winter winds can be cold and the official Dutch website for tourists says you ‘should certainly wrap up well in January and February’. And they add: One of the nice things about Holland is that ‘the Dutch are relaxed about clothes’. And I must admit that, yes!, all this about geographical, social and cultural conditions is really true, but nobody tells you about the impact the weather can have on your feelings and emotions. Yet international students report the significant influence that Dutch weather conditions have on their perceptual and emotional estimations of the university, the city and the country, all of which radically changes their lifestyles. So with winter coming, it’s better if you’re ready to face it.

Editor Redactie

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