Alternative products based on plant proteins are increasingly playing the leading role at the former Department of Meat Technology, which has been renamed the Department of Food Material Science at the University of Hohenheim. But why is it that certain vegan sausage varieties are closer to the animal-based original than others? 

At the University of Hohenheim in Stuttgart, Germany, young researchers and students of the Food Science and Biotechnology Bachelor's degree program are getting to the bottom of this question together and looking for innovative solutions. In a project seminar, they developed a solution for a problem that has so far posed a challenge to food manufacturers: A tasty vegan cooked ham with the right amount of bite resistance. 

Tiled rooms, silvery machines reminiscent of oversized food processors, smokehouses... at first glance, the Technical Center looks similar to a butcher shop. There are even butcher hooks. Pork halves can only rarely be found hanging here nowadays, though. Once a year, a master butcher demonstrates expert disjointing for students. However, the focus of the research undertaken in the Center has shifted.

Sebastian Mannweiler, Dominic Oppen, Maurice König and Theresa Scheuerer are four of a total of nine doctoral candidates at the department. Their research projects are primarily concerned with products based on plant proteins.

"To produce vegan sausage alternatives, you essentially need the same equipment as for the meat-based original," stated Mannweiler. "We have therefore been able to expand our research spectrum enormously in recent years without any major new investments. For the same reason, by the way, manufacturers of meat and sausage products have also managed to establish themselves very successfully in the new market segment. Rügenwalder Mühle, for example, even sold more vegetarian products than meat for the first time in 2022."

"Meaty" mouthfeel poses challenge

The young food scientists want to give further impetus to this development through their research at the University of Hohenheim.

"The increasing demand for meat substitutes is mainly due to a growing number of flexitarians," said König. "This target group does not reject meat because of its taste, but wants to be more conscious of their consumption, for example, for reasons of carbon footprint or animal welfare. Market research shows that these individuals are particularly persuaded by vegan products that emulate their animal-based role models as closely as possible in appearance, texture, and taste."

And this is exactly where the mission of the young researchers begins. While there are already a large number of convincing plant-based analog products on the market for some animal products such as minced meat or cooked sausages, harder sausage types such as cooked ham or salami still pose a major challenge. The reason for this is their complex texture with muscle fibers, which is characterized by a specific "meaty" mouthfeel when chewed.

Students conduct research

Students of the Bachelor's program Food Science and Biotechnology are also involved in the search for innovative solutions. An optimal framework for this is provided by "Humboldt reloaded", an award-winning initiative at the University of Hohenheim that enables students to participate in real research in small groups from the very beginning of their studies."In our project seminar 'Ham without Oink,' we worked together to develop a vegan cooked ham with a smoked crust that is firm, but at the same time elastic and juicy, reminiscent of the original when chewed," summarized Saskia, a student participant.

To this end, students have been able to use the Food Material Science Technical Center for several days over the past six months for their experiments. "Our first task was to find the right ingredients. To do this, we first researched existing recipes and then tried them out and varied them ourselves in the Technical Center," said fellow student Rebecca.

Searching for the optimal recipe

The first insight? Many vegan sausage alternatives use vegetable thickeners, such as guar gum, carrageenan, agar agar, or pectin. They ensure, for example, that a vegan Lyoner sausage is juicy and at the same time firm when it is cut. However, such hydrocolloids are less suitable for vegan ham because the end product lacks the necessary bite resistance and the desired texture.

Instead, the two students tried the wheat protein gluten as a water-binding alternative. One advantage: By stretching the base mass, the long-chain protein molecules can be brought into a uniform orientation. This creates a fibrous structure that resembles the feel of meat in the mouth.

The next step is fine tuning: To make the mass for the vegan ham even firmer, the students treated it with the enzyme transglutaminase, which causes better cross-linking of the proteins. In addition, it was necessary to bring the ingredients into the optimal ratio as well as find the right blend of spices and suitable natural colorings. Finally, the last process step was smoking for a tasty crust and longer shelf life.

In the end, of course, the different product variants also have to pass the taste test. The students have already selected their favorites with expert support from their supervisors and a real master butcher. Now they want to know whether these would also convince potential customers. To find out, Saskia and Rebecca want to serve samples to other students outside the Mensa with a short survey afterwards.

Vegan pizza salami, chew analysis, high protein cheese alternative

The young researchers at the Department of Food Material Science are particularly interested in getting new students enthusiastic for experimentation and showing them the diversity of current research topics. Dominic Oppen can still remember his first experiments during his studies. Among other things, he tinkered with a vegan pizza salami in his Master's thesis.

Today, as a doctoral candidate, he is developing a method in a current research project to analyze jaw movements and muscle activities of the chewing process with a special chewing camera. 

“What we refer to as ‘oral processing’ is based on methods of sports medicine and physiology and is used in dentistry, among other fields. I, on the other hand, am interested in comparing the chewing sensation of meat substitutes such as our vegan cooked ham as accurately as possible with the animal-based original," said Oppen.

But meat substitutes are not the only focus at the department. Doctoral candidate Theresa Scheuerer, for example, is researching a new generation of vegan cheese alternatives. 

"Substitute products on the market today, for the most part, have a very different nutritional profile than the original. That is to say they are mainly based on starch and fat. I am interested in novel products with high protein content that can be produced as sustainably as possible. In my experiments, I use microalgae or waste yeast, which is a residual material from beer production, as a protein source," said Scheuerer.