Dairy products - without the waste
Dairy foods are a healthy part of many people's diets. Now milk powder and mozzarella-type cheese could become healthier for the environment as well. EU-funded researchers are applying new techniques to production lines to save energy and water, while finding uses for processing waste. Results to date include a new pasteurisation technique and microwave heating process.
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It takes a lot of energy and water to make milk powder and mozzarella. Cleaning, sterilisation and pasteurisation alone account for much of this as they take place at 80°C and use large volumes of water. Researchers in the ENREMILK project are investigating how non-traditional manufacturing techniques can use resources more wisely while maintaining product safety and quality.
Successes so far include a milk pasteurisation technique that uses pressure instead of heat, an energy-saving microwave process for pre-heating concentrates and high-viscous products prior to spray-drying them into powder, and a water-saving extrusion technique for making mozzarella-type cheese. They are now developing these and other techniques further. They also plan to develop new ways to recycle waste heat from current spray-drying techniques and water from traditional mozzarella texturising techniques, and to find profitable uses for side-products such as whey.
It’s not just the environment that gains from these new processes they save time and money for manufacturers. And some ENERMILK consortium members are branching out into new business areas thanks to their involvement with the project.
Project coordinator Ana Lucia Vásquez-Caicedo of the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB explains that dairy processing has the highest energy and water consumption of all food industries. Members of the ENREMILK consortium a group of research institutions, technology SMEs and food manufacturers were already studying various technologies that can cut resource use, but had not applied them to dairy manufacturing. “The project was an opportunity to test some very promising techniques,” says Vásquez-Caicedo.
Real-world trials on such a wide range of techniques would have been prohibitively expensive. The project consortium also had to be certain from an early stage that manufacturers would find it economically worthwhile to adopt these new techniques. They therefore developed an IT platform that helped them visualise data on resource inputs and outputs for mozzarella and powdered milk production lines. This showed them which processes to target for resource savings, and gave the theoretical impact of various alternative technologies.
The most promising techniques were then selected, based on their performance, cost and ability to improve production. For example, the team found that pasteurisation with high pressure maintains the sensory quality of skimmed milk better that traditional thermal pasteurisation. They also saw that microwave technology used for pre-heating reduced accumulation of deposits in pipes (fouling) for larger batches, and required less frequent equipment cleaning than traditional indirect heating techniques. Subsequently, spray drying milk or milk products like quark and yogurt into powder was more efficient, using less energy compared to the current spray-drying processing line. A third process produced mozzarella-type cheese using extrusion technology, which needs less water than the traditional process of stretching the cheese in large baths.
“Dairy manufacturers who were involved in these tests are very happy with the results,” says Vásquez-Caicedo Project partners are now refining technologies or looking for further applications. Meanwhile, microwave manufacturer DanTech has already developed new machines, in part because of the project, while extrusion machinery producer Helix previously operational only in plastics will now produce equipment for food industries, says Vásquez-Caicedo.
The project has also strengthened links between the participating universities, which have shared project results though publications and conferences in Europe and the US.
The remaining months of the project will focus on recycling waste energy, water and other products from manufacturing. At the University of Hohenheim, a pilot prototype is using superheated steam to dry milk. “It is efficient, quick and causes no product oxidation,” says Vásquez-Caicedo.
The project covered many different technologies, in a multinational, multi-disciplinary consortium. “Without the FP7 funding, a project of this size, scale and breadth of scope would have been difficult to set up,” the coordinator says.