Crispy muesli for breakfast, a pizza from the freezer for lunch and a delicious fruit yoghurt in the evening - a large amount of sugar is hidden in many foods. In the long term, this promotes the development of numerous diseases, such as obesity and diabetes.

In the "ReformBIO " project, funded by the Federal Ministry of Food and Agriculture as part of the Federal Organic Farming Scheme (BÖL), scientists at Bremerhaven University of Applied Sciences are looking at how the sugar content in organic food can be significantly reduced. This can be a major challenge in some cases, because: Using less sugar is not a solution.

Every single ingredient in a food has an effect on its taste and consistency. It makes a difference whether wheat or rye flour is used for baked goods and whether a preparation of strawberries or blueberries is added to a fruit yoghurt. "Each raw material has different properties and reacts additionally in combination with the other components in a product. So it may be that we have to adjust the baking time for biscuits, for example, or add more or less liquid because we use other types of flour or syrup instead of sugar," explains project worker Lisa Nitze. Sugar not only provides sweetness in the products, but also the right texture. Biscuits become crispy and brown, yoghurt creamy. If it is reduced, the desired consistency has to be produced elsewhere. "In conventional production, we could resort to additives. That is only allowed to a limited extent in the organic sector. For example, we are not allowed to use additives that have been chemically or enzymatically altered."

Product development is science

30 percent less sugar in organic food with the same mouthfeel and taste - that is the goal of the project. Even if real products are to be created in the end, research and development does not work without theory. Therefore, the scientists first read up on the current state of research and looked at the composition of foods that are already available on the market: What is the average sugar content and which types of sugar were used? What effects do certain ingredients have on the product? 

For the first trials, the products from the supermarket were "recreated" in the laboratory. "At first, we only reduce the sugar content in five-percent steps and don't change anything else about the composition. Then we compare the results. The question is how and when the product changes sensory characteristics. Does it only become less sweet or does it also have a different consistency? Depending on what we find in the tests, we then have to adjust the raw materials and the technical parameters, such as the baking time," says Nitze. The search for the reasons for the sensory changes is particularly fun for project manager Kirsten Buchecker: "It's real detective work. We think together about what the cause could be and then test whether we were right with our guesses. Sometimes we come up with the solution very easily, but sometimes it's a bit trickier." In addition, new findings from other research projects are constantly coming in, which can also be important for "ReformBIO". Keeping this in mind is important for the success of the project.

The biggest challenge in product development so far has been the sugar-reduced fruit yoghurt. Unlike the other products, this one was made exclusively with a sugar reduction instead of resorting to other sweeteners. During the trials, a special feature became apparent: "A sugar reduction of up to 20 per cent is possible without major problems. But if we reduce the sugar content by 25 percent, the yoghurt becomes runny," Lisa Nitze knows. The reason: in combination with thickening agents, the sugar forms structures that provide the desired consistency. If the sugar content is too low, this no longer works. In the university's laboratory, the project team has been working to ensure that the yoghurt does not turn into drinking yoghurt. "There are natural thickeners that we are allowed to use. But these not only interact with each other, but also react with the pH of the product. Since all the fruits we used have a different sweetness-acid ratio and therefore a different pH, the quantity ratio is different for each type of yoghurt. In addition, thickeners either have a flavour of their own or make the fruit no longer taste good. Then you would have to work with flavourings, which is not desired in the organic sector," explains Buchecker.

Consumers' habits must be taken into account

It is precisely the flavourings found in conventional yoghurt that make it even more difficult for food technologists. Since they usually have little to do with the natural taste of fruit, they change consumers' expectations of what strawberry yoghurt, for example, should taste like. "The learned preferences of consumers are a big issue for us when we work with natural products. So we have to find a way to emphasise the natural taste of the fruit more," says Buchecker. For strawberry yoghurt, the scientists were able to observe that sugar reduction itself helps the natural flavour. "The problem with strawberry yoghurt is that the strawberry is normally hardly noticeable. That changes when the sugar is reduced by ten percent. That's when the fruit suddenly comes through," says Lisa Nitze. The researchers can use this for their developments and look for components that further enhance this.

One scientific approach they are pursuing is so-called food pairing. In this process, foods are combined that do not match at first glance, but have similar aromatic compounds. These are stored in a database that the project workers access. In this way, they also find combinations that surprise themselves. "The combination of mango and kohlrabi might be particularly unusual. If you leave the fruit mixture to soak for a day, the cabbage note of the kohlrabi disappears and the taste of the mango is enhanced," explains Kirsten Buchecker. The Georg-August University in Göttingen recently discovered that food pairing has great potential, especially in the organic sector. As a project partner, it conducted consumer:inside studies. The results show that almost half of consumers are open to food pairing and associate it with more taste. Organic consumers in particular are open to innovative flavour combinations.

Not everything always runs smoothly

When the numerous experiments in the laboratory finally produce the desired result, the scientists are particularly pleased. However, they also repeatedly encounter problems where neither the state of research nor their own investigations help them. "So far, for example, we have not found a solution with which we could maintain the firm consistency of the yoghurt with a sugar reduction of 25 per cent or more. We are working on it, but possibly the result in the end is that it simply doesn't work," says Nitze. And that, too, would then be an important finding for science and for the companies that are working on sugar reduction in their products. In general, it is often the things that do not immediately deliver the desired result that bring the greatest gain in knowledge. "If everything always worked without problems, then we would learn nothing. We learn through failure. Then we have to become active and think about what the problem is. That's why one of the most important qualities in research is curiosity," says Buchecker. 

Sometimes the scientists come to results that surprise them - despite all their experience. "With our crunchy muesli, we tried out different types of syrup and adjusted the water content accordingly. Nevertheless, we did not get any clustering, i.e. no crunchy pieces, with some varieties. We couldn't explain that at first," says Lisa Nitze. They then examined the individual ingredients more closely and finally discovered the decisive factor: "Sugar always consists of two molecules: fructose and glucose. We found that fructose does not crystallise and thus does not form clusters. So agave syrup, for example, does not work as an alternative sweetener. But maltose, which is in rice syrup, crystallises very well." They are happy to pass on this finding to companies working on sugar-reduced foods. The Bundesverband Naturwaren und Naturkost (BNN) (Federal Association for Natural Products and Natural Foods) also carries the results directly into the organic sector with a working group of researchers, manufacturers and traders.

When Kirsten Buchecker and Lisa Nitze are satisfied with their product, the sensory panel starts. Here, the food is presented to students of the bachelor's degree programme in life technology/food economics for sensory evaluation. They are specially trained and evaluate in objective categories instead of "tastes good" or "doesn't taste good". This filters out whether something needs to be changed in the recipe. In the best case, the scientists also get hints about what is not right. It can take several months until the panel is satisfied with the sensory properties of the product. Only then do consumer tests follow. "It is important that we come very close to the sensory characteristics of the original product. Nevertheless, there can be perceived losses. It is important to be very open about this and to explain why changes have been made," says Buchecker. The scientists are currently working on shortbread biscuits and cookies. They have developed several flavours, which they are currently tasting. "We are still struggling with the mouthfeel here. It's not yet the same as with conventional biscuits," Buchecker continues.

Students are involved in the research process

Students are also involved in the project outside of the panels. They support Kirsten Buchecker and Lisa Nitze through their research work in various areas. "Our students are involved from day 1 and work in our lab alongside their studies. In the process, they learn not only how to work independently and creatively, but also how to communicate with companies. Their research results flow into their Bachelor's theses," says Kirsten Buchecker. And what happens after graduation? "They don't have to worry about that. The companies are very interested in the students - especially if they have already worked with them. All the students we've worked with have been able to go straight into work."

When the work on the biscuits is finished, the scientists have one more challenge. The last product to be developed is sugar-reduced soft drinks. Until then, the project will be represented at various trade fairs and congresses - and will always have samples in its luggage.