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Milk’s many miracles

New research results show that milk contains even more beneficial substances than known previously. The research indicates that breeding work could be able to bring forth different types of milk for different purposes.

The more that is known about milk content and its dynamics the better chances there are to use different types of milk for different purposes. Photo: Colourbox

Milk is healthy, as most people know. It contains almost all the important nutrients, including proteins, minerals and vitamins. But milk has so much more. With the aid of advanced technology – the so-called metabonomics – scientists from Aarhus University have found a range of interesting correlations between milk composition and other factors, such as cow breed, feeding, disease, and coagulation ability.

Lately, the scientists have found that milk contains certain sugars that are beneficial to the health – complex oligosaccharides – and that the content of choline in the milk can possibly be used as an indicator of how well the milk coagulates, that is, its ability to become a solid and cohesive mass. This is a necessary quality for cheese-making.

These two interesting discoveries have been done by studying milk metabolites using the so-called NMR-method and were carried out as part of the Milk Genomics project. The method can be used to create individual profiles of metabolites.

The good ”cheese milk”

Concurrently, researchers at Aarhus University working on the Milk Genomics project studied the cows’ individual ability to produce milk with good cheese-making traits. By comparing the individual cow’s metabolite profile with knowledge of the individual cow’s cheese-making quality, the scientists found that there is a correlation between the milk’s content of choline, which belongs to the vitamin B group, and the milk’s ability to coagulate.

- We found that there is a higher choline content in milk that coagulates well. This means that choline can be used as a possible indicator for whether milk has good coagulation properties, says postdoc Ulrik Sundekilde from Aarhus University, who made the discovery in the course of his PhD studies.

The latest advances in genetics have made it possible to breed cows that produce milk with good coagulation properties but breeding work is a lengthy process. Until a population of good “cheese cows” has been built up it is therefore very advantageous to be able to use other methods to ensure that the milk is good at coagulating.

- We are now also conducting studies in which we add choline to the milk to see if it promotes its ability to coagulate, says Ulrik Sundekilde.

The good ”baby milk”

Another discovery Ulrik Sundekilde made was that milk contains certain healthy carbohydrates that have not previously been known and that there is an individual variation between cows with regard to the content of these carbohydrates, which are complex oligosaccharides.

This discovery can have practical implications for the production of breast milk substitutes.

- Humans cannot metabolize complex oligosaccharides but our intestinal bacteria can. The complex oligosaccharides provide nutrition for particularly the beneficial bacteria in our gut, explains Ulrik Sundekilde.

Colostrum has a higher content of these oligosaccharides than regular milk. They are necessary to kick start the development of the child’s intestinal flora. Not all children get colostrum from their mother and are instead fed a breast milk substitute made on the basis of cow milk. It would be very beneficial if one could use milk exclusively from cows that have a high content of complex oligosaccharides for the production of breast milk substitutes.

- Our work with creating individual metabolite profiles of cows has opened a window of opportunity to breed cows that produce certain kinds of specialised milk. For example, a ”cheese cow” would produce milk with a high cholin content and an optimal protein composition while a cow specialised for production of breast milk substitute would have a high content of oligosaccharides and a low content of whey protein in her milk in order to avoid allergic reactions, says Ulrik Sundekilde.

Facts about metabonomics

Metabonomics is a technology that enables scientists to gain a whole snapshot of what milk contains. The technology creates a profile of the molecules’ metabolites. By applying it to milk it is possible to obtain a complete picture of the unique chemical fingerprint that is left by specific processes in the milk’s cells.

Read the article Milk is not just milk here.

For more information please contact: Postdoc Ulrik Kræmer Sundekilde, Department of Food Science, e-mail: ulrikk.sundekilde@agrsci.dk, telephone: +45 8715 4882