In the mix

For years dairy processors have striven to create the ultimate low fat, creamy, tasty, low salt, functional food product. And central to this has been the processes involved in manufacturing it, some of which include traditional practices mixed with modern technology, such as microencapsulation, cold extrusion, nanotechnology and high shear mixing.

Over the last few years, having received adverse publicity over the nutritional value of dairy products, manufacturers have responded by launching healthier products. In the cheese market, for example, "health concerns have led to a boost in demand for low- or reduced-fat cheese, whilst processed cheese sales have suffered," according to Chris Brockman, market research manager at Leatherhead Food Research (LFR). "This has also led to most players in this segment re-launching their products on a healthier platform."

At LFR, research carried out in the brined cheese market - on products such as feta and halloumi - has shown it is possible to increase the intestinal heath benefits and enhance immune response through microencapsulation of probiotic microorganisms. "Probiotic microorganism concentrations need to be about 100M colony forming units per gram in order to deliver human health benefits," says Rachel Wilson, senior technical advisor at LFR. "Their concentrations, however, decrease during storage but probiotic microorganisms can be encapsulated to enhance their stability and shelf-life in functional foods."

Through the microencapsulation of the probiotic strains Bifidobacterium bifidum BB-12 and Lactobacillus acidophilus LA-5, "it has been shown that products maintained therapeutic levels during storage of white brined cheese at 4°C for 90 days", Wilson says.

Another processing technology used in the dairy industry, which helps to preserve the health benefits of foods and ingredients, is high-pressure processing (HPP).

New Zealand based dairy and ingredient company, Fonterra, for example, has turned the high water pressures normally used as food preservation tool into a precision instrument for working with dairy products. The HPP technology means that health benefits of fresh and unprocessed foods can now be delivered in ready-to-drink and long-life dairy formats. Manufacturers can include heat-sensitive ingredients such as live probiotic bacteria or pieces of fruit in dairy products, as well as extend the shelf-life of cultured products.

The process was the result of four years of research and development by Fonterra's innovation team. "It is expected to lead to increased sales of speciality ingredients that can now be incorporated into functional foods, such as ready-to-drink beverages," says the company. "It means, for example, a manufacturer can add wellness-enhancing ingredients such as probiotics, immunoglobulins and lactoferrin to juices, milk drinks and yogurts without sacrificing their shelf-life."

One of the greatest struggles a processor faces in the dairy industry, is reducing fat without compromising on texture and taste, as consumers demand healthier products. The reduced fat cheddar market in the UK, for example, was worth £56M in 2008, up 36% on 2007, and is still growing strong, says LFR. Dairy Crest and Lactalis both introduced lighter cheddar versions, within their Cathedral City and Seriously ranges. Milk Link has also continued to invest in lower-fat cheeses at its Taw Valley plant.

In ice cream, for years Unilever has been developing new technologies and processes to improve the creaminess of its products, while reducing fat content. During the conventional process of making ice cream, air bubbles fuse, which is associated with a loss of creaminess, explains Unilever. By applying cold extrusion technology, first used by Unilever, in its Port Sunlight businesses for texturing soap, it found that it could retain small air bubbles and the fine microstructure of the product.

The extrusion process used for Unilever's highly vicious material makes use of a low energy pump. The team is currently looking at ways to apply the technology to its full range of ice cream products, including fruit-based ice creams.

Its research and development team is also undertaking trials with LFR to use an experimental ultra-high energy mixer at the University of Liverpool (UoL). The high-pressure, high shear mixer helps develop nano-emulsions, which can be used to reduce the fat content of dairy products, as well as improving textural and organoleptic qualities. Preliminary trials indicated that nano-sized droplets could be produced under specific conditions; however further studies need to be carried out to establish this observation, says LFR.

"Unfortunately this work has been delayed for some time, but we are hoping to continue the studies soon," says LFR. In addition to the work with UoL, studies on the use of microfluidisation, have shown a reduction in size of oil droplets - which could also be of use in dairy products to improve creaminess.

"There has been a significant interest in a number of novel, emerging or non-traditional methods for food processing over recent years," adds Wilson. "Technology advancements will ultimately improve the health benefits of dairy products." FM

Key contacts ​

Leatherhead Food Research (LFR) 01372 376761 ​

University of Liverpool 0151 794 2000 ​

Fonterra 00 649 374 9000 ​

Unilever 020 7822 5252​