21 February 2025
Interview: Not for lack of drying
A Senior Research Officer at Teagasc Moorepark’s Food Research Centre, Eoin Murphy is focused on improving drying processes and associated energy usage in the dairy industry. An upcoming symposium in Cork will be examining this sector’s challenges and opportunities.
Eoin Murphy’s research at Moorepark’s Food Research Centre seeks to future proof dairy powder production methods. Credit: Fergal O’Gorman
Eoin Murphy currently works as a Senior Research Officer in Teagasc’s Food Chemistry & Technology department, using his background in process engineering and food science to work on academic and industrial drying projects supporting the agri-food industry, especially dairy. His current research focuses on dairy powders: their manufacture, drying processes and end properties.
“Spray-drying is near-ubiquitous for powder production in the dairy industry,” he explains. “Recently, there’s been focus on reducing associated energy usage, given the large-scale pressure around energy costs.”
Eoin is also interested in other drying technologies applicable to dairy and food that can provide solutions to current challenges and anticipate future concerns. Besides drying, he’s interested in the design and engineering aspects of food processing operations. Drying generally sits at the end of complicated process flows; this allows collaboration with experts in other areas, which is one of his favourite parts of the job.
Can you put your research into context for us?
My research is engaged with dehydration processes and powder manufacture. Drying is inherently about preserving food for long shelf-life: reducing its weight and volume, turning a fresh product into something shelf-stable and transportable. A figure we see a lot: for every ten litres of milk produced in Ireland, nine of those are exported – either as cheese or butter or dairy powders. So even when making cheeses, you’re making whey, which is widely converted into powder. Hence the value of dried dairy is important to our national economy. In 2023, Bord Bia valued dairy exports at just over €3 billion. It’s an important sector in Ireland, built around farmer-owned cooperatives and ultimately supporting local business and providing employment in rural Ireland.
How has this field developed over time?
Drying itself is a prehistoric means of preservation. When talking about dried food in a contemporary sense, particularly dried dairy, the typical technology is spray-drying. In this process, milk is first pre-concentrated using an evaporator or filtration process. It’s then sprayed in droplets into an air-drier at temperatures of 180-200°C, quickly extracting water. This type of technology has been in place at large scale since the mid-20th century. It’s improving constantly in terms of hygienic quality, energy usage and design.
A study in France some years ago estimated that a quarter of its national dairy sector’s energy usage came from dehydration – those final steps of concentration and spray-drying. This gives you an idea of the importance of energy reduction – more so in recent years as energy costs are rising globally, alongside the environmental and sustainability concerns underpinning the focus on energy reduction.
This work is balanced against awareness that you’re producing commodity or consumer products. Quality aspects are vital, these products have to perform to expectations. This is part of the focus of our upcoming symposium, which our department is organising on behalf of the International Dairy Federation. The symposium will look at production and use of dairy powders, and striking the balance between producing materials that perform as expected, versus optimising the processes, technologies and efficiencies involved in that production. Spray-drying is the biggest process in this, but beyond improving the existing process we’re always interested in potential new processes.
“Energy use is a vital issue, unlikely to change; we need to continue to adapt to the industry’s energy needs.”
What are the challenges surrounding this topic?
You can make lots of different things from milk – regular, recombined or isolated products. The challenges will vary for each product. Drying typically sits at the end of a long production chain, so all those upstream processes influence it. You can’t necessarily optimise a single process in isolation, you have to consider it within that chain. Thus, our research is collaborative, with lots of work between colleagues across our department and with other universities and Research Performing Organisations (RPOs) in our pilot-scale facilities here. So, while it’s a challenging area, its enjoyable and rewarding because we get to work at pilot-scale and look ahead to industry-scale and think about real-world applications.
What research have you been doing in this field?
It’s broadly split into two different categories. First, supporting prevailing production set-ups: working to improve energy efficiency and product quality associated with spray-drying processes. Second, setting up our novel drying platform: looking at new drying methods and the effects on product quality and process efficiency. More recently we have also been working on drying other food types, for example, plant and cereal extracts.
In terms of supporting the prevailing infrastructure, Teagasc’s Food Chemistry & Technology Department is engaged in a number of research collaborations with industry. We are also part of the Dairy Processing Technology Centre (DPTC) consortium – working with industry partners and other RPOs to demonstrate at pilot and industrial scale how energy efficiency can be improved in powder manufacture.As part of that project, I’ve worked closely with my colleague Norah O’Shea to increase data capture in the drying process, upgrading facilities to better understand energy usage there. We examined this data with our colleagues John Tobin and Jonathan Magan at pilot scale; we then took this to industrial scale and demonstrated, at scale, an energy reduction of 5%.
For our novel drying platform, we’re working in-house on three different technologies. We recently concluded an innovation partnership with Enterprise Ireland and six dairy companies, looking at lower-energy alternatives to spray-drying for lower-value dairy products. We have a PhD student examining technology for higher-end products, looking at consumer benefits such as solubility, appearance and nutritional benefits. Lastly, we’re investigating technology for producing dried dairy snacks.
What has the industry response been?
We have lots of positive engagement. On campus we have Moorepark Technology, Ltd., which is a significant pilot plant used by the Irish and international dairy industry. One of the challenges is translating pilot scale to industry scale, so it’s good to get constructive feedback on how to adapt processes to different scales.
Where next for this research?
Our research requires us to be responsive to our industry and the geopolitical climate. We need to move in tandem with the Irish dairy industry to help it overcome its challenges. Energy use is a vital issue, unlikely to change; we need to continue to adapt to the industry’s energy needs. This includes ongoing examination of alternative technologies and improving production processes.
Up close and personal
What’s your favourite animal?
My five-year-old son’s a big fan of the “toughest animal in the world” – the honey badger – so I’d have to go with that.
If you hadn’t ended up in research, what other job would you have wanted to give a go?
The word “wanted” is doing a lot of heavy lifting there; I would’ve “wanted” to be a striker for Man Utd – if I could’ve is another question!
What are you most proud of professionally?
We’re at the interface between academia and industry, supervising lots of PhDs/MScs. It’s hugely rewarding to see former students come full circle and be your future collaborators in either space.
The IDF Joint Symposium on Dairy Drying Technology & Recombined Milk Products will be taking place in Cork across 13-15 May. For more details and to register, click here.