A Queen's University researcher is discovering how cows can producespecialised milk. Dr Marina Murphy reports
We've always known that Irish butter is best. Now it is even better. Irish scientists have discovered how to get cows to produce milk that lends itself to a softer, tastier butter that spreads even at fridge temperatures, with technology that may find its way into dairies all over the world.
Irish butter is softer because the cows are fed on grass in the summer, whereas UK animals are fed on silage. "This is a good starting point, but we have discovered how to make the butter even softer," says Dr Anna Fearon of the school of agriculture and food science, at Queen's University, Belfast.
"We have bypassed the factory altogether, getting the cows to produce a healthier, low-fat milk that produces a tastier butter that spreads straight from the fridge," she says. Butter produced with milk from grass-fed cows is not soft enough on its own to spread at such low temperatures.
The technology is already used by the Dromona factory in Cullybackey near Ballymena, Co Antrim, and Fearon has been in talks with dairies in Australia and with Minneaopolis-based Land O'Lakes, the biggest dairy company in the world, about adopting the Belfast researcher's technology.
Dr Fearon and her team have found they can manipulate the type and amount of fat in milk by changing the cow's diet. Adding rape seed to the diet results in milk with healthier fats. Because these fats are softer, the milk is more suitable for butter production.
"We have made a spreadable butter naturally, by going through the cow and not the factory," says Dr Fearon. "This represents an important change in the mindset. Instead of saying "milk is milk" and just accepting one milk for all, lets design it for the product we are going to put it in," she says.
The same technique could be used to tailor milk destined for cheese or ice-cream manufacture. Milk for cheese production would need to have higher levels of protein, but milk composition is usually manipulated by chemical means in a factory.
Dr Fearon says the new technology could have important implications for the competitiveness of the dairy industry. "We are using a natural process to produce a high quality healthy product. This means that if people want to take the healthy option, they can still have dairy \."
Cows fed on the rape seed produce milk with lower levels of saturated fatty acids, (the bad fats that are known to cause cholesterol build-up). The milk contains higher levels of mono-unsaturated fats (the good fats that reduce cholesterol). The respective levels of the fats can be altered by changing the amount of rape-seed in the cows' diet, Fearon explains.
Her study involved 64 Holstein-Fresian dairy cows given either 200, 400 or 600 g of rape-seed oil per day (provided as whole rape seeds) for 20 weeks. The concentration of the major good fat, oleic acid, the main component of olive oil, increased by a third at the highest dose of rape-seed oil. Levels of another good fat, conjugated linoleic acid, also increased. Animal studies suggest that this fat protects against heart disease and cancer. It also helps to regulate diabetes and weight.
The increased level of the good fats also means that the risk of oxidation is reduced. Oxidation refers to a chemical reaction that can occur with butter fats, making them more likely to cause cholesterol build-up.
Dr Fearon says Northern Ireland provided the perfect setting for the development of this technology. "We have the farmers, co-operative factory, scientists, animal-feed companies and retailers, all of whom were very eager to be involved in something that worked," she says. The scheme operates with milk producers from counties Antrim, Down and Derry.
Dr Fearon's research is reported this week in the Journal of the Science of Food and Agriculture.
• Dr Murphy is news editor of Chemistry & Industry, the journal of the UK Society of Chemical Industry