Yeast brings flavour to our fermented beverages. Using state-of-the-art technology to unlock the chemical composition of a certain beverage can help us predict how the product will taste and smell, how much it will be liked by consumers, and how changes in the concentration of specific compounds affect appreciation.
November 1, 2019
We talked to Professor Kevin Verstrepen, Director at the Center for Microbiology of Leuven Institute for Beer Research, about how his team uses their biomolecular expertise to generate new superior industrial yeasts without using genetic modification.
“My lab at the university of Leuven and VIB in Belgium studies the basic physiology and genetics of yeast cells. While much of our work revolves around understanding how genes work and evolve, we also apply our expertise to generate superior industrial yeasts. This includes yeasts that produce specific aromas for food and beverage fermentations. Many of our projects are in close collaboration with industrial partners, and while I cannot disclose the specific targets of most of these projects, I can say that we have generated special starter cultures for cocoa fermentation that produce more flavourful chocolate. Many projects are aimed at producing yeasts that yield beers with special aromas, as well as yeasts that are more suited to produce low and non-alcoholic beverages.
More recently, we realised that the arsenal of equipment and expertise that we have in our lab to measure the concentrations of hundreds of aroma compounds in foods and beverages, combined with our knowledge of mathematical modelling and bio-informatics also puts us in a unique position to leverage the power of machine learning to find and understand the connection between the chemical composition of foods and beverages and the perceived aroma and consumer appreciation. Using this technology, we are now making models that use the chemical composition of a certain beverage to predict how the product will taste and smell, how much it will be liked by consumers, and how changes in the concentration of specific compounds would change the appreciation. We believe that these models are useful tools for the tuning of existing products, as well as for the development of novel products.”
“Simply put yeast cells eat sugars and convert them into carbon dioxide gas and alcohol. However, apart from these primary metabolites, the cells also produce many different secondary metabolites, including many different aroma compounds like glycerol, fusel alcohols, aldehydes, esters and acids. These are often by-products of the cells’ metabolism and only made in tiny quantities. However, many have extremely low flavour thresholds and these metabolites are therefore vital for the aroma of fermented foods and beverages.”
“We do not really have a product range, in the sense that we do not really sell anything and only offer our expertise in research. We always work together with companies to help tackle specific questions and problems, through the development of knowledge and models, as well as through the production of novel yeast variants that can achieve results that existing natural yeasts cannot. Importantly, we often use non-GMO technologies, so that these new yeasts can be readily employed, and several companies are already using the yeasts that we developed in their production. Examples include yeasts that can grow in extreme conditions and produce more or less aroma compounds. Specifically, we are getting a lot of requests to produce yeast cells that are better suited for making low-alcohol beers and wines, not only because they produce (slightly) less alcohol, but also because they produce more aromas, so that sufficient aroma compounds are left after the alcohol has been stripped from the product.”
“We use a combination of just about all the state-of-the-art technology in biomolecular research, going from robots that allow us to analyse thousands of yeasts in a short timeframe, to automated chromatography to analyse the chemical composition of many samples. On the molecular side, we often use natural breeding (sexual crossing) of yeasts so that the new yeasts are completely natural and not genetically modified. But here too, we use the latest technologies, including whole-genome sequencing and QTL mapping to discover molecular markers that can guide the breeding schemes. And of course, we are also capable of using tools like Crispr/Cas and even synthetic biology, where we make complete synthetic chromosomes to have yeast cells produce exogeneous compounds of interest.”
“It is very difficult to say how an industry is evolving. Clearly, trends towards healthier and more personalized foods are emerging; so perhaps we are going to see more personalized products in the food market. Luxurious niche products that are marketed as part of a unique experience are also on the rise. Such trends always come with a countermovement, and the back-to-basics trend, where consumers like products of local low-tech producers that fit in this picture. But, those are trends that are easy to spot. Under the surface, I see a lot of renewed interest in probiotics, so that may be an important emerging market. The really big question is to what extent synthetic biology will really break through, especially in Europe. The possibilities are limitless, but it is always difficult to predict the consumer perception. I somehow do have a feeling that people are more open towards GM technologies these days, and I am very afraid that the EU policymakers have made a few very poor decisions in that respect. I hope that the rulings on Crispr/Cas gene editing are revised so that the EU industry can start using these tools and keep playing a forefront role in the global market.”
