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Werner Hofacker - The right perspective is important

Instead of normal office-style table and chairs, the office of Werner Hofacker, Professor of Thermal Process Engineering at Constance University of Applied Sciences, is furnished with a table with a carved elephant and two dark, exotic wood chairs. “The chairs are made from a single piece of wood, waste wood actually,” explains the researcher. While the expensive tree trunks are exported, the regional artisans use the remaining stubs and turn them into artistic tools and furniture. The furniture comes from Togo, and Hofacker brought it with him to Germany when he came back from a four-year stay in Africa.

Prof. Werner Hofacker lived for four years in Africa and is involved in international projects dealing with environmental sciences and education planning. (Photo: Keller-Ullrich)
In Africa as well as at Constance University of Applied Sciences, Hofacher is looking into one of the most original questions to face humanity: How can food be preserved? Professor Hofacker is not interested in the development of modern freezers, smoke ovens or salting machines but rather in the oldest method of preservation: drying. Our ancestors used to dry meat, fruit, mushrooms, cereal and herbs in times of abundance in order to prepare for times of scarcity. Stock sourcing was, and still is, vital to human survival.

Determining quality and optimising processes

Drying is simple, at least in principle, and virtually works on its own. In practice, however, many things can go wrong. In the worst case, food is spoiled and rendered inedible.

Dried food must not be harmful to health, and must also appear appetising and be nutritious. That is why the researcher is interested in several criteria, including appearance, colour, taste and ingredients. While it is relatively easy to determine the content of vitamins and proteins, the colour can only be assessed with a specific analytical method. Pure visual inspection is not sufficient as a scientific criterion. That is why complicated optical methods had to be developed to enable the analysis of the food colour using photographs.

Packed in transparent glasses or bags, the results of a huge number of experiments are neatly stored away in the laboratory of Constance University of Applied Sciences. Students even labelled one of the apparatus “Hofacker’s vegetable analyser”. It is not only the colour of the dried food that is important, but also how the food looks when it is consumed. For example, leek in packet soups must be a savoury green colour when cooked.

Together with his colleagues, Professor Hofacker is developing and optimising methods for the preparation of food, for example a cutting device using a high-pressure water jet, which enables food to be prepared extremely hygienically. The machine’s integrated camera makes sure that all the slices are exactly the same. Hofacker is also focusing on continuously improving the actual drying process. The scientists are working on the development of methods that have least impact on the environment as well as methods that involve the use of renewable energies. The goal is to prepare food in an energy-efficient way and as much care as possible is taken either to prevent waste or to recycle.

Crossing disciplines

Hofacker’s students have named this food drying device “Hofacker’s vegetable analyser”
The work of the process engineers not only requires technical, but also biochemical knowledge. Their goal is to find out what kind of alterations food undergoes during the drying processes, for example through heat, and how these changes can be influenced.

The researchers are also interested in the ingredients. Equally, the consistence of food is also of great importance. Apples might be as crispy as potato crisps, or soft and rubber-like.
“Even though the food undergoes changes during the drying processes, it is still possible to influence the type of changes,” said Professor Hofacker. As he is not only interested in the technical optimisation of food, but also in education planning and organisation, Hofacker has initiated an environmental and process engineering master’s course together with colleagues from the Ravensburg-Weingarten University of Applied Sciences and the Zurich University in Winterthur (Switzerland), in which the three universities work in cooperation under the roof of the International Lake Constance University.

The students are able to cross the borders of technology, biotechnology, ecology or management. The work of the environmental and process engineers also needs to take into account cultural, religious and social features. “Our goal is to adapt the knowledge gained to the respective regional particularities,” said Professor Hofacker explaining that making compromises and convincing people are a necessary part of his work.

”In many cases, one needs to look at something from some distance,” said Professor Hofacker recalling his work in Africa. But also in Germany, he always makes sure to take a step back to obtain the overview he needs. For example, he lives and works at two different sides of Lake Constance and takes the ferry to work. In addition, Professor Hofacker is a sports pilot, which enables him to look down at his workplace, city and region from a completely different perspective. And in so doing, he is able to feed his interest in the constant changes that occur.


mek – 01.02.2008
© BIOPRO Baden-Württemberg GmbH

Further information:
Mechanical Engineering
Constance University of Applied Sciences
Brauneggerstraße 55
78462 Constance
Tel.: +49 (0)7531 206-593
Fax: +49 (0)7531 20687-593
E-mail: hofacker@fh-konstanz.de

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