Designing successful functional food and drink

What types of ‘added’ health benefits do consumers today want from food products?​

Karensa Broersen: On a general level, there is a lot of interest in products that support healthy aging. This can cover bone strength, muscle retention and more. But we also see a continued demand for products that specifically promote digestive and gut health.

Both of these trends can include products naturally high in, for example, protein and fibre, but also products enriched with ingredients that offer specific health benefits, such as prebiotic fibres, bio-active proteins and probiotics.

What do manufacturers need to consider when developing new products for the health-conscious market?​

KB: When you are designing a product that offers health benefits, you need to consider what the ingredients bring to the table, and how processing impacts them.

For both healthy aging and digestive health, digestible, high-quality protein and essential amino acids are key. But proteins are not created equal! For example, in dairy proteins, we see a difference in the performance of whey versus casein proteins, which can be further impacted by processing. In one study in healthy volunteers, we compared the digestive rates of pasteurised skimmed milk, UHT skimmed milk and low fat stirred yoghurt. Each was 80:20 casein:whey protein, but they were exposed to different heat treatments and pH conditions. The results showed higher postprandial blood essential amino acid levels from the yoghurt compared to both milks.

When we add plant alternatives into consideration, the situation becomes even more complex. The protein quality from milk in general is higher than from plant sources. Some plant proteins, from pea and soy for example, come quite close to dairy protein quality, but those from wheat, rice or almonds have much lower essential amino acids scores.

Why is it so important to take product design into account early, when, for example, adding a pre- or probiotic?​

KB:  Pre- and probiotics are an excellent example of why you have to consider product and process early and hand-in-hand during development. Both can offer specific health benefits in the gut, so it makes sense to combine them in one product. But achieving that is not so easy.

To give an example, there is a huge market trend for ‘frozen desserts’ containing probiotics. Mostly this has involved yoghurt-based treats, but what about a full-fat ice cream, with a neutral pH, containing both a probiotic and a prebiotic – specifically inulin? How would the processing conditions (which includes preparing the mix, pasteurisation and homogenisation, etc.) and temperature cycling impact the survival of the probiotic and prebiotic? And when is the right moment to add them in?

We found, firstly, that by adding the probiotic after cooling, we achieved a good survival rate. But the samples that contained inulin had an even higher probiotic survival rate than the samples without inulin. And, because the probiotic bacteria were kept at a cold temperature within the ice cream matrix, they didn’t consume the prebiotic. Finally, the inulin did not impact the microstructure of the ice cream.

But all the elements – processing, conditions, matrix, prebiotic and probiotic – had to come together in the product design to achieve this. By taking a holistic approach, we were able to use our product (ice cream) to create and deliver a ‘synbiotic’: a mix of pre- and probiotics that beneficially affects the host by improving the survival and activity of beneficial microorganisms in the gut.

What tools are available to streamline the design of products with health benefits?​

KB:  Various in vitro​ models can play an important role in product development. Using high throughput screening assays, for example, you can screen a large number of potential ingredients, probiotic bacteria, etc. for safety and specific characteristics, quickly and cost effectively. Combined with bioinformatics, this can also provide useful insights for later clinical trial design.

In vitro​ digestion models that simulate conditions in the gastric chamber and small intestine let you test functions such as the availability of essential amino acids for absorption into the bloodstream, again before clinical trials.

In vitro​ tests can also be very helpful after clinical trials, especially if you need to further explore an unexpected result. In the earlier example of differing amino acid uptake between yogurt and milk, we wanted a better understanding of why that was happening. In vitro models revealed a possible hypothesis related to the differences in structures formed by the two products under gastric conditions, as well as the fact that one of the proteins was more susceptible to digestion when it had been treated with higher heat.

Of course, in the end, your product has to taste good and ‘feel right’. Sensory investigations such as tribology provide quantitative insight into how your product will react in the mouth.

Can in vitro models be combined to provide more information?​

KB. Different types of in vitro modelling have usually been done as a standalone analysis. But we are indeed seeing a move towards combining models. This approach shows a lot of promise for lab-based learning!

You can, for example, subject your probiotic bacteria to a realistic ‘journey’ through the digestive system: exposing them to simulated gastric and pancreatic juices, as well as realistic pH conditions and digestion times.

Another interesting area for this combined approach is digestion and immunity. We start by subjecting the product, ingredient, or probiotic to the simulated gastric conditions using an in vitro​ model. Then, we take the resulting digestates and run them through cell culture models to screen for the potential efficacy to protect against infection.

What are the main drivers for successful product design and shorter time to market?​

KB: Designing a product has to be done in a holistic and comprehensive way. You need to begin analysing the different requirements and challenges from the very beginning. For example, when selecting an ingredient, don’t look only at the health benefit it offers, but also how it will react in the matrix, during processing, throughout the product’s shelf-life and during digestion by the consumer. By taking all of this into consideration from the start, you may avoid the risk of discovering an expensive or even unsurmountable problem half-way through development – which will cost money and delay your time to market.