In the previous blog, we looked at the range of alternative protein options available and how to choose the right one for your new product. Having chosen the right protein source (or sources), the challenge turns to ensuring you can maintain the desired functionality of that protein during processing and deliver the associated benefits to your customers.
In this blog, which was also shown recently in Food Navigator, the role of processing in protein functionality was put under the microscope by asking questions to Peter de Jong, Principal Scientist Processing at NIZO. In addition to his role at NIZO, Peter is professor of dairy process technology at Van Hall Larenstein University of Applied Sciences and director of New Technology Development for Food at the Institute for Sustainable Process Technology.

Why is protein functionality a key issue for process development?

The food industry is increasingly aware of the value of protein in food products. That goes a lot further than just the amount of protein, but also the functionality it brings. For example, as Fred van de Velde explained last month, protein functionality can influence the taste and texture of a food product, affecting how attractive the product is to consumers. It can also impact production efficiency. For example, processing can cause certain proteins to coagulate, leading to fouling and regular production shutdowns for cleaning. And of course, there is the nutritional impact of proteins, not just in terms of macronutrient properties but also more subtle effects such as binding vitamins and, particularly topical right now, their impact on immune response and anti-viral activity.
The interest in these effects is growing rapidly as the protein transition opens up new / alternative protein sources, many of which offer much greater protein functionality that meat does. For example, there is a lot of interest right now in raw milk because it seems effect our immune systems and possibly reduce allergies.

What is the impact of processing on protein functionality?

The goal of processing is to deliver a food product that is tasty, nutritious and safe. Traditionally, the food industry has taken the cautious approach – using heat treatments like pasteurisation and UHT that ensure all pathogens are killed or deactivated. However, temperatures above 80 C reduce or even destroy the functionality of many proteins. A good illustration is the Maillard reaction, where heat causes sugar molecules to bind with amino acids. You might want this when searing a steak or baking a biscuit, but when you are processing milk it reduces the bioavailability of vital amino acids like lysine which in turn can reduce benefits raw milk has for the immune system (Figure 1). Consequently, there is a big drive towards milder processing that still delivers maximum food safety while leaving more of the protein functionality intact.

So, can we just turn down the heat?

Unfortunately, it isn’t as simple as that. We at NIZO have analysed a lot of production processes and have found a great deal of variation in the protein functionality impact of seemingly similar process. Looking at the Maillard reaction I mentioned earlier, even processes as familiar as pasteurisation or UHT can vary in the amount of amino acid lost by a factor of two.
This shows two things. First, that there is plenty of room to optimize current processes. Second, food manufacturing processes are very complex, with multiple possible reactions between ingredients, each of which interacts differently with the process conditions. And that makes optimizing a process extremely challenging.

How do you start to optimize such a complex process?

One way is through data analytics: collecting as much data as you can from your factory and analysing it for any correlations. But this is a bit of a black box approach. It can help you identify which conditions or temperatures are linked to specific outcomes, but it doesn’t give you any insight into why or how to fix the issue. So, it isn’t really any help if you are trying to design a new process.
A better approach is through computer modelling of your factory set up. This does require deep understanding of the chemical reactions that can occur during food processing, but once you have built your model – or had it built for you – you can thoroughly explore the impact of variations in process conditions, either by manually tweaking process parameters in the model or by running simulations.
The results can be incredible. We have seen cases where manufacturers have been able to optimize process performance and improve bioavailability of nutrients by up to 30% without affecting the products physical properties or microbial quality specifications.

What other new technologies could help manufacturers retain protein functionality?

The industry is always innovating, finding new ways to make products better. One technology that I am excited by at the moment is called Innovative Steam Injection or ISI. This involves a very short blast of very high temperature – around 160 C for up to 1 second. This is enough to inactivate microorganisms in the food but, crucially, does not denature the proteins. Prototype ISI processes have been able to deliver “pasteurised” milk with shelf lives up to 60 days and just one-third the degradation of proteins such as β-lactoglobulin, immunoglobulin and lactoferrin (Figure 2). And even expert tasters couldn’t taste the difference.

And it is not just for dairy. ISI can be used with any pumpable fluid product. This could be very important for the protein transition as the microorganism contaminants in plant-based proteins are much more diverse and less well known. Currently, the plant-based food industry relies on extreme heat treatments which certainly kill off all pathogens but also destroy the desired functionality. As I said before, understanding how your protein interacts with your process allows you to find approaches that eliminate what needs to be eliminated (microorganisms, fouling, etc) but keeps what you want to keep in terms of nutrition, digestibility and flavour. The plant-based sector is starting to figure out what this means, but I think they could still learn a lot from the dairy sector.

Industry insights from NIZO 

One of the key challenges an issues facing the food industry today, is protein transition –  the growing move away from animal proteins to alternative sources. Fred van de Velde, head of NIZO’s Protein Functionality Expertise Group has more than 20 years’ professional experience in protein functionality, Fred oversees NIZO’s “source-to-society” activities in protein food technology covering the full range of protein sources. He is also professor of protein transition in food through his chair at the HAS University of Applied Sciences in the Netherlands. In this blog, which was also shown recently in Food Navigator, the protein transition was put under the microscope by asking questions to Fred.  

What protein options are there for plant-based foods? 

The protein transition is massively diversifying the range of proteins available to ingredient and food product manufacturers. Alongside the traditional animal-based sources – meat, eggs, milk – we now have many different plant-based alternatives including legumes like soybeans, peas and chickpeas, as well as maize, potatoes and oilseeds. More options are appearing all the time, from emerging sources including fava beans (also called faba or broad beans) and green leaves to future possibilities such as microalgae and proteins from single-celled organisms produced by fermentation.  

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That’s quite a bewildering array. How do I choose the best option for a new food product? 

Obviously, each protein source has its pros and cons and, when you are starting to develop a new plant-based product, understanding and evaluating them can seem an overwhelming task. But you can simplify the process by thinking about four basic considerations. 
There are the proteins that consumers already know and actively look for on the shelves. Think of milk substitutes like oats, almonds, coconut or soy. Then there are the proteins such as soy, pea and potato that product developers like to work with because they are easy to process and have the right functionality (gelling, foaming, emulsifying, etc.) to directly replace animal-based proteins.  
Next there are environmental factors such as land, water and energy usage and carbon dioxide emissions. Peas and fava beans have low emissions and water usage, as do sources that come from side streams of other products, for example rapeseed which would otherwise be waste from edible oil production. Finally, there are the nutritionists’ favourites that deliver as close as possible to a full complement of essential amino acids without causing allergy issues. For that, you could combine legume and cereal sources. 

Comparison of the water consumption for various protein sources 

So choosing a protein comes down finding the right balance of those considerations? 

Exactly. And that balance will depend on factors such as the type of product you are making and your brand image. For example, consumers are accustomed to choosing milk alternatives and drinks based on the protein types. But for semi-hard cheeses and meat substitutes, they are more likely to choose a product based on how closely it mimics the traditional, animal-based original. 
Similarly, some existing companies have built a strong brand based on soy, almond or oat milk substitutes and want to leverage that successful position as they move into new products. Meanwhile, new players in the market may want to carve out their own niche in this growing market by stressing their environmental credentials or nutritional benefits. 

And once you have decided your marketing position, your protein choice follows from there? 

Of course, you still need to consider the technical aspects of the proteins that fit your marketing decisions. Can they deliver the taste, texture and appearance you want for your product? It is worth remembering that there may be no perfect, off-the-shelf choice. 

How does that all work in practice? 

Let’s take a cream cheese substitute as an example. Consumer favourites like oats, coconut and rice are too low in protein and don’t have the technical functionality to resemble cream cheese.  
Product development favourites such as soy and potato can deliver nice textures, while peas and fava beans also bring environmental benefits. However, the sheer number of different suppliers and variants make screening the options costly and time consuming. Moreover, most legume-based proteins can bring an unwanted beany taste to the end product. Meanwhile, another environmental favourite, rapeseed has a dark colour that isn’t appropriate for a cream cheese. Finally, the nutritionists’ favourite of pulse plus cereal can lead to grittiness at high protein concentrations as well as beany and other off flavours. 

Does a plant-based cream cheese always have to be a compromise? 

Not at all. There are ways that you can improve the technical characteristics of your product. One is to combine different protein types in one product. For instance, we recently surveyed milk alternative for barista applications and found that many have a headline protein type for consumer recognition plus “hidden” secondary proteins to improve technical functionality. 
Another very promising option is fermentation, which can improve the flavour and texture of a product without adding extra “chemicals” to your ingredient list. 
Off flavours arise due to various components such as hexanal, pentanal and 2-pentylfuran. These components are common to many protein sources, but the ratios vary and define the flavour of the end product. The levels of these components in the end product can be reduced by fermentation with an appropriate culture – either in creating the protein ingredient or the final product. And we have carried out extensive taste testing to show that changing the ratios and overall levels of these components does indeed reduce the intensity of unwanted flavours. 

Comparison of various flavour components in pea proteins before fermentation (ref) and after fermentation with various cultures. 

Perceived “beany” taste of pea proteins before fermentation (ref) and after fermentation with various cultures. 

In fact, for products such as semi-hard cheeses, fermentation with different cultures could allow you to create multiple products with different flavour profiles – e.g. a gouda-like product and a cheddar-like product – from essentially the same ingredients. At the same time, fermentation can improve the firmness of your product and remove any grittiness. It can also be used to extend shelf lives without preservatives.  

Firmness of cream cheese alternatives made with pea proteins fermented with various cultures. 

There are a vast number of cultures suitable for fermentation in food production. NIZO alone has established a database of over 8000 cultures that can be screened and selected for the appropriate functionality. Many of these are lactic acid bacteria, developed for fermenting dairy products and may need to be modified for use with plant-based products. 

In short, protein choices are typically driven by marketing considerations around the type of product and your brand rather than purely technical characteristics. But if necessary, functionality, taste and texture can all be improved using carefully considered fermentation. 

Clinical trials can help companies meet growing consumer demand for ‘functional’ food and drinks. But while ‘health’ is the goal, these are not the same as pharmaceutical trials. What do you need to know to ensure a smooth, efficient and effective project that substantiates your product’s health benefits? 

We expect more and more from our food. In 2019, half of global consumers increased their consumption of ‘functional’ foods and drinks. There was a 34.5% increase in the number of sports nutrition products launched with an immunity benefit claim. And there were twice as many snacks launched with digestive/gut health claims than in the previous year. The foods we pick have become an important part of our life goals: to live longer, live healthier, live fitter… 

Standout from the crowd 

Which means functional health benefits continue to offer an attractive way for companies to add value to their food products – and to make them stand out on supermarket shelves stocked to the brim with a never-ending selection of food and beverages to tempt consumers. 

It’s a challenge, but more than that it’s an opportunity: to find or develop new ingredients, and then scientifically demonstrate their benefits to regulators and consumers alike. 

Essential validation 

Clinical trials form a key component in this approach. They allow manufacturers to identify new approaches to their products, and to answer questions such as: What new ingredients are available for human consumption? What nutritional qualities do they have? How do they affect health? What additional benefits do existing products have on health concerns such as resistance to infection? 

By testing the food or beverage ingredients on volunteers, we can assess the proof of concept, gain insight on the impact of an ingredient, collect evidence of a health benefit, characterise ingredients by their effects, and provide measurable outcomes to meet regulatory requirements. 

Food is not pharma 

With all of our years running clinical trials for food and beverage ingredients, we at NIZO have built up experience and understanding of some of the issues to keep in mind when you need to substantiate the health benefits of your product. 

Firstly, clinical trials for food and beverage ingredients and compounds are in many ways similar to pharmaceutical trials. For example, the study designs are similar, the quality assurance requirements are strict to protect study subjects and data integrity, study protocols are reviewed by medical-ethical committees, etc. 

However, testing foods raises some significant and unique challenges. In food trials, we are not looking to cure or treat a health condition. Instead, we are seeking to evaluate how the ingredient helps prevent or mitigate symptoms, or enhance performance, for example. That means, on the one hand, we need to carry out the trials on relatively healthy individuals. But on the other hand, to show a benefit, we may need to ‘create’ a stress factor for the volunteers. 

Unlike pharmaceutical compounds, foods generally have multifactorial effects, acting through several different mechanisms at the same time. The volunteers’ own diets can impact the study results, so that needs to be closely monitored. The results also should be analysed by scientists and professionals with an in-depth knowledge of ingredient properties and food matrices. 

On a very practical level, it can be more difficult to arrange a ‘blind’ test with a food product, than with an anonymous pill. And the food ingredient has to be provided in a form that the volunteers can ingest and which is palatable: so taste, texture, solubility, freshness, etc. need to be considered in a way that is mostly not an issue for pharma trials. 

Prepare for success 

With all of this to keep in mind, for a smooth, efficient and effective clinical trial, you want to work with a company that combines food, nutrition and health expertise. Make sure that the team responsible for your trial understands how food ingredients are digested and metabolised – and most importantly, what this means for the human body. But don’t forget the importance of food technology, processing and safety. And finally, work with a testing company that provides not just data, but interpretation, guidance and consultancy, so that you can make decisions informed by data, but driven by expertise. 

Beer, bread, yoghurt. Fermented products are familiar to everyone. But fermentation can be used for a much wider range of products than just these old favourites. Looking to replace animal-derived products with plant-based ones? Fermentation is a natural way to improve the proteins for application of plant-based alternative products. 

When you are making plant-based products, it isn’t quite as straightforward as replacing the proteins with ones derived from plants. Plant-based proteins often have an unpleasant taste, and their solubility can vary depending on the source. Fermentation offers a solution, allowing you to change the characteristics of proteins ingredients. There is a huge range of microorganisms that can be used for such purposes. But not all microorganisms are suited for this. So, the first step is to find the right one for your needs by screening for the specific characteristics that your product needs. 

Another application of fermentation that I use as Product Manager for Protein Technology at NIZO, is to remove the unpleasant taste of proteins derived from plant-based sources such as pea proteins. Pea proteins often have a beany taste due to amongst others hexanal. Certain microorganisms can break down hexanal, and therefore reduce or even remove the beany taste. The same process can be used to reduce other off-flavours. 

Besides removing unwanted flavours, fermentation can also be used to create the flavours you do want. Imagine, for example, recreating the taste of dairy products in plant-based alternatives.  

It can also improve the texture of products through exopolysaccharide (EPS) production or hydrolytic breakdown of proteins. This approach can, for example, be used to improve the texture and  mouthfeel of plant-based cream cheese. 

Finally, fermentation can be used to increase food safety by preventing the growth of unwanted bacteria. This happens through, among other things, the acidification of the product during fermentation. This is the fermentation that has been known and used since olden times. However, fermentation can also be used to produce antimicrobial components such as bacteriocins. In this way, outgrowth of unwanted (pathogenic) microorganisms can be inhibited. 

These application examples are just some of the ways that fermentation can be used to create and improve plant-based ingredients and products through natural means. If you would like to know more, you can watch my coming webcast on December 3, 3.00-3.30PM CET, where I dive deeper into topics such as unwanted tastes and  improving textures through fermentation. 

Alternative proteins offer a perfect solution to a more sustainable food production system. Customers are ready to embrace this trend, but will do so only if taste, texture and healthfulness remain uncompromised. 

The world population keeps increasing: In 2050, there will be nearly 10 billion mouths to feed. Our current animal food production system will not suffice.  Therefore, food producers, ingredient companies and researchers are on a quest to find sustainable alternatives. Enter plant proteins. Available in abundance, they are often a side or waste-stream of existing food production processes. Moreover, they can offer additional benefits such as muscle health support, improved digestion and weight control. But while consumers are actively trying to eat more plant-based or animal-and-plant-protein blended foods (and reduce their meat consumption), they are not willing to compromise on taste and texture. Indeed, customers’ expectations are skyrocketing: They want something special, and they want it now. And it should be as transparent and sustainable as possible.

Bridging the gap

If we are to meet their expectations, we will need to bridge the gap between our understanding of animal-derived proteins and alternative ones such as plants, algae and insects. Microalgae, for instance, are known to be highly functional as foaming agents or emulsifiers. But how do we apply them without creating fishy and musty off-flavors, or green or red off-colors? We could make use of insects. After all, they can quickly produce large amounts of protein-rich biomass and have the potential to convert low-value waste into higher-value insect proteins. But as long as the Western world struggles to accept their application in a visible form, we will need to grind them, leading to brown off-coloring and protein hydrolysis. A success story of alternative proteins is presented by the extraction of RuBisCo, the world’s most abundant protein. NIZO scientists have been able to prevent off-color and solubility issues while upscaling and testing the process at a semi-industrial level.

Selecting proteins

When it comes to meeting customer demands in support health aspects such as weight control, it pays off to look into the satiety potentials of various proteins. Whey protein, for instance, hardly increases in viscosity in the stomach. It is also easily degraded; thus, readily available for consumption, making it ideal for rapid muscle recovery. Casein, on the other hand, is broken down slowly and absorbed later, making it more ideal for long-term recovery. Pea protein takes a middle position, breaking down more quickly than casein, but slower than whey.

Solving taste and texture issues

Another issue we face is the deterioration of flavor and the decrease of solubility during extraction and processing. Increasing our understanding of their impact on the quality and functionality of proteins will enable us to adjust the production process and develop ingredients that deliver the optimal sensory perception. It is worth noting that we don’t need new and expensive drying techniques to keep plant protein in its native state. By adapting critical conventional steps during extraction and spray drying, it is possible to maintain functional properties and tailor ingredients for specific applications.

Blending proteins

If we are to live up to customer expectations concerning nutritional benefits, we will need to look into protein blends. After all, many plant proteins require blending to provide a complete nutritional profile. There are various tools on the market that support the search for the right proteins to be blended (see the figure). To tailor to customers who wish to experience new food sensations, we can use protein blends to develop food products with novel texture and sensory attributes.

Processing proteins

A final challenge to overcome has to do with the impact of product properties on processing conditions. For example, an important issue of spray drying is fouling of the dryer due to stickiness of the product. This is especially true for products with a high content of carbohydrates and proteins, such as infant formula. Fouling results in shorter run times between cleaning procedures and, at worst, causes blocking of the dryer by lumps of powder. Improved process control by humidity measurements can minimize fouling, extend the time between clean-in-place procedures and avoid blockages.

Can we meet customer demand?

Can we meet customer expectations regarding flavor, texture, health and sustainability of plant-based products? The answer is yes. But there are challenges to overcome. Most importantly, we will need to expand our understanding of plant, insect and microalgal proteins. In addition, we can develop products with new texture and sensory attributes, or ensure that replacement of animal protein does not compromise taste, texture and nutritional properties. Either way, we will need to focus on the creation of synergizing protein blends and the optimization of extraction and processing methods. Although we still have ground to cover, if we continue our quest, we will be able to feed those 10 billion people in 2050 with healthy, sustainable and tasty foods.

A healthy diet is essential for preventing infection and keeping the immune system working properly. But what is a healthy diet? Clearly, if we know which nutrients and food ingredients are healthy, we can ensure we consume enough of them. For some dietary interventions and single nutrients, solid evidence from clinical research has been used to inform the public and provide dietary advice. A well-known example is the use of folic acid before and during the first weeks of pregnancy to prevent neural tube defects in new-borns.

Indeed, all nutrition and health claims used in the marketing of food products must be backed up by scientific evidence. For example, if a food manufacturer has an ingredient that looks like it might boost immunity in cultured cells, they must also prove it does the same in humans. However, food clinical trials are costly and time-consuming, especially if you’re looking for robust results. Being able to test an ingredient’s effect on health in relatively small groups and over short time periods therefore saves manufacturers both time and money.

Human challenge models as an alternative to food clinical trials

To address this need, we have designed several proof-of-concept clinical trials. Traditionally, food clinical trials test the effects of a product on the long-term health status of a large group of healthy subjects. However, NIZO’s “human challenge models” rely on a more sensitive marker of health, namely stress resilience.

So how does it work? In these models, healthy volunteers are challenged by exposing them to a moderate external “stressor”. The stressors given to volunteers include mild gut or respiratory infections to test whether a certain ingredient enhances resistance to infection, for example. Starting a few weeks preceding the infection, half of them are given the product of interest while the other half receive placebo. Researchers compare their clinical and physiological responses to see how each group responds to the challenge. Such a model has been used to demonstrate in healthy adults that an ingredient added to infant formula can increase resistance to infection with bacteria that cause diarrhoea. The results of this study were published in The Journal of Nutrition in 2016.

Our clients are always pleasantly surprised to discover that a sufficient number of people are willing to volunteer for these challenge experiments. The controlled settings offer several key advantages, including fewer subjects and shorter timelines. Crucially, these studies also meet the regulatory requirements for substantiating health benefits for the gut and immune system.

Integrating multiple areas of expertise

However, our researchers don’t only look at clinical outcomes. We also collect biological samples from participants and analyse numerous biomarkers, including microbiome profiles. The wide range of systems and models available enables them to help clients study the mechanism of action of functional ingredients.

“NIZO’s strength when executing clinical and preclinical health studies lies in the smart combination and integration of various areas of expertise”

Expertise Group Leader Nutrition & Health, Alwine Kardinaal

Sweetness enhancement using naturally occurring aromas is a promising way of reducing the sugar content of flavoured beverages while maintaining taste. Research at NIZO suggests that the ability of consumers to differentiate between taste and aroma is limited, and that aromas can be used to produce long-lasting sweetness-enhancing effects.

Reducing sugar content

An interest in healthier foods is growing on the part of both consumers and the food industry. The demand for products containing less sugar poses a challenge for the producers of flavoured drinks, which by tradition have high sugar content. While many drinks producers have solved this by replacing some or all of the sugar content with artificial or processed sweeteners, consumer organisations are starting to resist the wide application of such sweeteners. The additional dilemma for producers is that while consumers prefer not to compromise on taste, they are also increasingly on the lookout for products that contain natural ingredients, free of E numbers and artificial additives.

Aromas instead of sweeteners

This has led to a search for alternative strategies to keep these label-conscious consumers happy while avoiding high sugar content. One such strategy currently being explored at NIZO is to make use of so-called cross-modal effects: by being exposed to many different foods, we learn to associate food aromas with the taste they usually accompany. Therefore adding an aroma to mimic the smell of sugar-rich versions of the food increases the perceived sweetness by mere suggestion. In other words, the brain tells us the sweetness is there, even when the sweet ingredient is not. However, until now it was unclear whether the sweetness-enhancing effect of an aroma is strong enough to enhance taste perception in the longer term.

Separate stimulation of nose and tongue

Using aroma-induced sweetness enhancement in real foods is also a relatively new concept, and studying how taste experience can be improved with aromas requires specialised equipment. NIZO has at its disposal both an olfactometer – that can deliver precise amounts of aromas into a subject’s nose while they are consuming food for example – and a gustometer, used to deliver precise amounts of taste stimuli onto a subject’s tongue.

Ethyl hexanoate: a naturally-occurring aroma from apples

Such devices have allowed us to demonstrate that a drink is perceived as much sweeter if a sweet-smelling aroma is delivered to the nose at the same time. One of the aromas being tested at NIZO is ethyl hexanoate (HEX), a natural aroma component that is synthesised in apples during ripening. Interestingly, we see the same effect if we add HEX in liquid form to apple juice. While it is fairly easy to persuade people that the apple juice they are tasting contains a higher amount of sugar than it actually does – just by adding HEX to the apple juice – this cross-modal effect is the strongest in untrained test subjects who are exposed to HEX for the first time. This suggests that giving it to the same subjects repeatedly might reduce the effect, and that people can learn to tell the difference between taste and aroma.

The test panel

To determine whether or not HEX’s sweetness-enhancing effect is stable enough to support long-term application in food products, researchers at NIZO conducted a series of tasting sessions using a panel of 21 test subjects. They monitored the effect of adding HEX to apple juice, whereby the test subjects underwent two types of tasting sessions that alternated in a fixed schedule over a 6-month period. In all tasting sessions, subjects were given apple juice with or without added sugar that varied in HEX content. In the ‘evaluation’ sessions, subjects were asked to taste an unlabelled sample and rate its sweetness. In the ‘feedback’ sessions, a computer screen simply told them whether or not the apple juice they were tasting contained added sugar. This allowed them to learn whether the sweetness they experienced was due to added sugar or added aroma.

Learning to tell the difference

As expected, the effect was strongest during the initial session, i.e. before subjects had been given the opportunity to learn the difference between taste and aroma. During this ‘untrained’ session, subjects gave unsweetened apple juice with a higher HEX content a consistently higher sweetness rating. While this effect disappeared just after the feedback sessions, it recovered significantly during the final evaluation at 6 months for all but the highest HEX concentration. This suggests that the subjects in this test panel did not learn to distinguish between sugar and aroma-induced sweetness.

Sweetness enhancement effects stand the test of time

The result is encouraging since the experimental setup was – intentionally – a worst-case scenario: during the feedback sessions subjects were explicitly told whether or not the samples contained added sugar, whereas in real-life situations people are not always fully informed of a product’s content. After all, it is up to consumers themselves to read the label. It is therefore likely that if explicit sugar content provided on a computer screen during tasting does not negatively impact aroma-induced sweetness enhancement in the long term, the effect will also stand the test of time in real life. While a conclusive answer will require a longitudinal consumer study, these results clearly indicate that aromas have potential for enhancing sweetness in flavoured beverages. NIZO is looking forward to helping the food industry make use of such developments to help reduce the levels of sugar in their products while maintaining taste.

The experiments and findings described above were published in a paper presented at the 15th Weurman Flavour Research Symposium in Austria in September 2017 (Brattinga et al, 2017).

How to tackle undesirable microbes in foods, in particular bacterial spores?

High rates of spoilage before the end of shelf life of foods? Consumer complaints? Or worse, cases of foodborne illness due to consumption of your products? This must be avoided and safeguarded in production. As all foods placed on the market must be safe and of high quality, clearly, control of microbes that may cause food spoilage or that lead to foodborne illness has high-level priority in the food industry.

To control contaminants in fresh ready-to-eat foods, the food industry uses different conditions to prevent outgrowth of undesirable microbes. For example, low storage temperatures and short distribution chains. In processed foods, undesirable microbes are often eliminated by applying heat or alternative treatments that kill them. However, bacterial spores, which are the hardiest forms of life on earth, may survive such treatments. Their ubiquitous presence in the environment means that their presence in food ingredients and in food processing facilities is inevitable. As a result, sporeformers may lead to a reduced shelf life of products due to spoilage and in the case of foodborne pathogenic sporeformers, consumption of products in which growth has occurred may even lead to illness or death. Clearly, contaminants originating from ingredients or the processing environment must be controlled during and following production to achieve the required shelf life and assure food safety. But how to do that?

1. Analyse the number of pathogenic spores which are present in ingredients and finished product

To prevent potential problems with spores in finished food products that undergo heat treatments, the ingredients generally have specifications for spores. Many different methods exist to detect spores of different types of sporeformers, as not all spores behave the same. Different growth media may be used and incubation may take place at specific temperatures (e.g. psychrotrophic, mesophilic or thermophilic species) or in the presence or absence of oxygen. In addition, a distinction can be made in the heat resistance of spores by applying different heat treatments (e.g. 10 min 80°C, 30 min 100°C, 30 min 106°C). When setting specifications for spore concentrations in ingredients, it is critical to apply meaningful methods with relevant detection limits. Ideally, the methods allow for a link between the sporeformers present in ingredients and the potential defect rates in finished products after production. Knowledge about spore detection, problem species, impact of processing on different spore types and growth potential in finished products is crucial for such assessments.

2. Identify the source of contamination

Sporeformers may enter the production chain via ingredients. Another contamination route is via processing equipment containing biofilms that shed spores into the product. This may happen in holding tanks, on transport belts, around seals and even in heating equipment, such as the regenerative section of pasteurizers or in evaporators (by thermophilic species). When spores cause problems in finished product, a ‘track-and-trace’ approach of the problem microbes can identify the source of the contamination. By assessing the genetic make-up of the problem organism and of isolates in ingredients and along the production lines, a source can be found.

3. Define acceptable levels of pathogenic spores in finished products

Even low levels of spores in finished product may lead to spoilage or foodborne illness if they survive and if outgrowth can occur: one per packaging unit may be enough! When spores are present in ingredients, reduction to acceptable levels can be achieved by inactivation (e.g. by heat treatments) or by removal (in liquid products e.g. by bactofugation or ultrafiltration). The efficacy of such treatments can be assessed experimentally. To do so, it is critical to use spores with representative properties. The efficacy can also be calculated using modelling approaches when relevant data are available. If adjustment of processing conditions does not suffice, reduction at source may be necessary.

4. Select conditions that prevent outgrowth

Spores can ‘wake up’ via the process of germination in nutritious environments. This may happen during food production or in finished products. When conditions in the product (e.g. water activity, pH) and during storage (e.g. temperature) are favourable for outgrowth, the sporeformers can multiply. Traditional preservatives that are effective in preventing germination and outgrowth of spores (for instance sorbate and benzoate) are used less nowadays. New formulations and novel processing methods are being developed, for instance based on clean label preservatives and combinatory treatments. The efficacy of such formulations must be evaluated in products using relevant strains of sporeformers and spores thereof. This requires knowledge of species to inoculate and often high-throughput testing of conditions, to ensure efficacy of treatments.

Global demographic shifts and a world population projected to reach 9.7 billion by 2050 lead to an increasing demand for high-quality nutritional products, especially for elderly people. This will put pressure on food production and protein supply. To meet this growing demand, producers are combining vegetable and animal proteins and finding innovative ways to use available proteins more efficiently. The biggest challenge is developing high-protein applications with the right properties (structure, texture, flavour, digestibility) without increasing the food product’s carbon footprint.

Everyone needs protein

Elderly people need to maintain their muscle mass, so their diet must contain enough highly digestible protein. Other consumers need foods that help control weight and reduce the risk of obesity. For them, too, high-protein products can play an important role because they create a relatively high sense of satiety.

While proteins have obvious benefits, products with a high protein content can be undesirable from a sensory perspective: too viscous and hard to swallow in liquids, or too chewy in a solid state. Texture problems can also occur in low-fat products where fat has been replaced with extra protein. These products are perceived as drier and less juicy. To improve consumer acceptance of high-protein products, it is crucial to control their viscosity and texture. This means decreasing liquid products’ viscosity and improving the overall mouthfeel of both liquid and solid products.

Optimal digestibility

To meet the growing demand for protein, food manufacturers are turning to high-quality proteins from alternative sources, such as plants, algae and insects. The industry is also increasingly interested in pea protein, which has a good amino acid composition. However, digestibility is also of importance. Using Nizo’s SIMPHYD platform for in vitro modeling of food’s behaviour in the stomach, the digestibility of pea protein was compared with that of whey and casein proteins. Whey protein hardly increases in viscosity in the stomach, is easily degraded and hence readily available for absorption, making it ideal for rapid muscle recovery (as a ‘fast’ dietary protein). Casein, on the other hand, becomes significantly more viscous and is broken down slowly and absorbed later, making it more suitable for long-term recovery (a ‘slow’ dietary protein). Compared to whey and casein, pea protein turned out to be exactly in the middle. It creates some viscosity and breaks down more quickly than casein, but slower than whey. In other words, it is a moderately fast protein. This knowledge is essential for developing products than promote rapid recovery after a workout or products that can help maintain long-term muscle function.

In vivo measurement

Laboratory animals are sometimes used to test digestibility in an in vivo situation. As digestion takes place in the small intestine, this is also the spot where we would prefer to measure digestibility of proteins in humans.

The small intestine is essential for our health as this is where about 90% of nutrients are absorbed and key signals are generated to control our metabolism and immune system. There is increasing scientific evidence that an imbalance in our intestinal microbiome can lead to a number of diseases, including metabolic and immunological disorders such as obesity, diabetes, and inflammatory diseases. However, most studies focus on the fecal microbiome in the large intestine and pay scant attention to the possible role of the small intestinal microbiome. However, taking samples from the small intestine is a highly invasive procedure, requiring insertion of a tube through the esophagus and stomach.

At Nizo we recently made significant progress in solving this problem by developing the IntelliCap, a minimally invasive technology for taking samples from the small intestine. This measurement device, which had already been CE-marked for drug delivery and real-time measurement of temperature and pH in the gastrointestinal tract, was also approved for the aspiration of fluids. Therefore, the IntelliCap CR system can now also sample the small intestinal microbiota. Philips spin-off Medimetrics Personalized Drug Delivery BV developed the sampling device, which measures only 11mm by 26mm. This capsule has proven its worth as a means of measuring the microbiome in the small intestine, and could possibly also measure in vivo digestion of protein in the small intestine. This enables a more accurately assessment of digestibility, and hence the quality of different types of protein.


Just as the source of protein affects its digestibility, the way of processing could also have an impact on digestibility and hence the quality of proteins. Go4Dairy, a recently launched research programme, focuses on the impact of glycation on protein’s nutritional value. In the literature, Maillard products are associated with negative health effects, including hypersensitivity of the immune system, reduced digestibility, reduced bioavailability of lysine in particular, changes in gut bacteria and even carcinogenic effects. Much remains unknown, however. Go4Dairy’s aim is to reduce and control the glycation of proteins so as to optimise their nutritional value.

Proteins for the future

High-quality proteins are essential in our diet and are crucial for healthy ageing. In view of the impending protein shortage, current technological developments in plant protein structure, texture, taste and digestibility are all important steps toward creating a sustainable protein supply for a growing world population.

Recently, an interesting article in the Economist about the high diversity of yeast in cacao and coffee bean fermentations caught my eye. As an Expertise Group Leader Fermentation at NIZO, I know that the final products of both coffee and cacao are the result of fermentation seems like basic information. However, most consumers are under the impression that both products are directly derived from the plant and are only industrially processed. They are not aware that the final product is a result of natural fermentation, which is essential to final flavour formation.

Both for cacao and coffee beans, fermentation is performed by a mixture of yeasts that produce a variety of flavours, whilst the most well-known product of yeast, alcohol, is either produced in low amounts or evaporates during the process. The interesting observation reported in the Economist article related to the high diversity of yeast identified in the cacao and coffee beans isolated from different locations. All these different yeast are expected to produce different flavour molecules. This allowed for the possibility to use cacao yeasts from Costa Rica in a cacao fermentation executed in the Dominican Republic, thereby adding specific flavours normally only present in Costa Rica cacao beans to cacao beans from the Dominican Republic.

Fermentation in the dairy industry

All very exciting, but the dairy industry together with NIZO has done the same things for over 65 years now. Cheese production is one of the best known examples of fermentation. Using mixtures of bacteria results in a seemingly limitless range of flavours and they are responsible for the characteristic of – for instance – gouda, cheddar and Swiss-type cheeses. The addition of fungi results in very different types again such as brie or blue cheese, all to be found in supermarkets all over Europe and the US. All these cheeses show a high diversity in flavour and textures that are the result of using different organisms for the fermentation.

Fermentation translated to other applications

New food-grade strains to create new flavours are continuously isolated from nature. Interestingly, these strains do not have to be dairy-based. We at NIZO have shown that a food-grade bacterium from a plant can be evolved to grow on milk within a period of months. This can lead to an even larger variety of flavours that are the result of fermentation.

It is exciting to see that the technology, long used in the dairy industry, is finally translated to the coffee and chocolate industry. What I see as the next step is to use yeast isolated from coffee beans for cacao fermentation and vice versa. Although this may seem challenging at first from a scientific point of view, this is a much smaller step than the previously successfully conducted conversion of a plant bacterium to a dairy bacterium. This can lead to an even greater diversity of potential new flavours in the coffee and chocolate industry.

High troughput platform for screening

The biggest challenge in this will be to find out what type of flavours are of interest to a consumer, which is what marketing departments are looking for. To study thousands of new fermented products at NIZO we have developed a high throughput platform that screens thousands of fermentations simultaneously at a 200mg scale. In addition to the miniaturised process being an almost perfect copy of the industrial scale process, using cheese as a model in this case, it also proven to be able to detect specific flavour molecules and link this to the desired flavours.

It is clear that the food industry is at the verge of a breakthrough in finally leveraging the large natural diversity of bacteria and yeasts in nature. This will results in new flavours and therefore completely new products with unexpected, original and unique characteristics. I myself cannot think of a more exciting and brighter future.