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Contrary to the definition, “Dietary fiber contains lignin, which is not metabolized by mammalian animals”, we have our doubts according to our recent results.

The possible metabolic reactions of the aromatic biopolymer lignin were investigated as a part of the GOOD-project: Improved gut health by wood-derived gums (Jane and Aatos Erkko Foundation). In the experimental setup of the project, rats consumed hemicelluloses (mainly xylan) derived from birch wood in their diet. In the first part of the project, it was found that xylan has potential as a prebiotic dietary fiber promoting gut health.

Reference to the first part of the study on xylan promoting gut health:

Kynkäänniemi, E., Lahtinen, M. H., Jian, C., Salonen, A., Hatanpää, T., Mikkonen, K. S., & Pajari, A. M. (2022). Gut microbiota can utilize prebiotic birch glucuronoxylan in production of short-chain fatty acids in rats. Food & Function, 13(6), 3746-3759. https://doi.org/10.1039/D1FO03922A

In the experimental setup the xylan groups were further divided into two different groups: one group obtained purified xylan, whereas the other group also obtained lignin, which is present in the unpurified xylan. By using many modern analytical tools in chemistry and gut microbiome research, we gained multiple pieces of evidence showing that lignin is metabolized by the action of certain gut microbes from the Eggerthella genus in the large intestine to smaller molecules, such as sinapic and ferulic acids, and their derivatives. The collaboration in our multidisciplinary research team was integral and many of the tools used came from the field wood chemistry. In addition, knowledge in food and nutrition, and gut microbiome research were essential in order to gather, interpret, and make conclusions of all the findings.

Reference to the second part of the study on lignin metabolism:

Lahtinen, M. H., Kynkäänniemi, E., Jian, C., Salonen, A., Pajari, A.-M., Mikkonen, K. S., Metabolic fate of lignin in birch glucuronoxylan extracts as dietary fiber studied in a rat model. Mol. Nutr. Food Res. 2023, 2300201. https://doi.org/10.1002/mnfr.202300201

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Exploring Helsinki: Our Thrilling City Adventure

The Food Materials Science Research Group embarked on a refreshing summer recreational event. Turning the bustling streets of Helsinki into our playground, we delved into an exciting Foxtrail city adventure.

Under the sunny sky, we collected at Rautatientori on May 29, 2023, at 2 pm, brimming with enthusiasm for our urban quest. We split into four teams. Two teams took on the challenge of Route Sampo, where modernity meets history, while the other two teams chose Route Louhi, where the bustling city meets tranquility. Equipped with the instructions, we were prepared for the adventure ahead.

As we followed the trail, we discovered a different side of Helsinki. From modern and historical buildings to green parks and beautiful shores, each clue led us deeper into the heart of the city. We were amazed by the vibrant tulips blooming at the entrance of an ancient castle and a magnificent sailing ship gracing the port. The excitement grew with each puzzle we solved, and the satisfaction of unraveling each clue motivated us to keep going.

Of course, the trail had its challenges. Some clues puzzled us, while others took us on unexpected detours. With some luck, the fastest team reached the destination in just two hours, stumbling upon the correct path without finding all the clues. However, not all teams were as fortunate. One team struggled briefly with a clue and almost boarded a ship bound for Suomenlinna, a distant island location. But we persisted and overcame each obstacle.

Afterwards, we enjoyed a reinvigorating and delightful meal. The thrill of reaching milestones, combined with the breathtaking views, made the journey truly worthwhile.

Our city adventure in Helsinki was an unforgettable experience. It revealed the city’s hidden treasures and left us with lasting memories. Additionally, it brought us closer as a group. In moments of puzzlement, we gathered together, shared ideas, and contemplated the intricate clues. Some riddles tested our patience and challenged our collective intelligence, but we approached the journey as a team, celebrating each breakthrough. This collaborative spirit mirrored our approach to research problems, strengthening our bonds and creating unforgettable memories.

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FinPowder: Wood hemicelluloses are effective wall materials for spray dried microencapsulation of bioactive compounds from bilberry with improved functional properties of produced microcapsules

Two years have passed since Abedalghani Halahlah (Abed) who is working as a doctoral researcher commenced in the FinPowder project (here) at the University of Helsinki (Abed, Figures a and b).  We are now back to deliver more interesting findings/outcomes to add to the previously revealed results (here) that have already been published as two impactful articles.

First article: Abedalghani Halahlah, Vieno Piironen, Kirsi S. Mikkonen, and Thao M. Ho. “Wood Hemicelluloses as Innovative Wall Materials for Spray-Dried Microencapsulation of Berry Juice: Part 1—Effect of Homogenization Techniques on their Feed Solution Properties.” Food and Bioprocess Technology 16, no. 4 (2023): 909-929.

Second article: Abedalghani Halahlah, Heikki Räikkönen, Vieno Piironen, Fabio Valoppi, Kirsi S. Mikkonen, and Thao M. Ho. “Wood hemicelluloses as sustainable wall materials to protect bioactive compounds during spray drying of bilberries.” Powder Technology 415 (2023): 118148.

In the first article we revealed that, magnetic stirring is the best choice for preparing wood hemicellulose (glucuronoxylans and galactoglucomannans) feed solutions for the spray-dried microencapsulation of bilberry juice. This is because microfluidization caused a loss of total anthocyanin content of the feed solutions. Furthermore, galactoglucomannans feed solutions formed a gel-like structure within a short time after ultrasonication and microfluidization, making these solutions unsuitable for spray-drying. Here also, we reported, for the first time, the formation of gel-like structures from a pressurized hot water extraction galactoglucomannans solution which was further investigated in a separate study (here). While in the second article, we demonstrated that wood-based hemicelluloses are efficient wall materials for the spray-dried microencapsulation of bilberry juice. The encapsulation efficiency values of wood-based hemicelluloses were relatively high and close to that of gum arabic (∼ 73%). Due to the natural presence of lignin-derived phenolic compounds in the structure of wood-based hemicelluloses, their microencapsulate powders had significantly higher phenolic content and antioxidant activities than gum arabic powders.

The findings of these two studies provide another value-added application of wood hemicelluloses obtained from waste and by products of the forest industry. Wood hemicelluloses can replace the currently used wall materials in the production of high-quality bilberry powders via a more cost-effective method (i.e., spray drying) than those currently used (freeze drying and freezing), thus offering an economic opportunity to bring bilberry products to global consumers. Alongside these financial gains, wood hemicelluloses also bring health benefits by adding dietary fibres and antioxidant functionality to the final products.

The experimental work was continued by further advancing the functional properties of produced microcapsules, for example by optimizing the ability of wood hemicelluloses to retain and protect bioactive compounds during spraying. In this regard, we carefully planned two models/approaches of experiments to obtain the best bioactive compounds retention and functional properties of the produced microcapsules. The first approach involved the use of carboxymethyl cellulose as a co-wall material combined with wood hemicelluloses to produce the microcapsules at fixed spray drying conditions. During this stage, we also used an advanced analytical technique (computed X-ray microtomography) in collaboration with Department of Chemistry at University of Helsinki to reveal interesting information regarding the internal and external structure and thickness of coating layer of the microcapsules (Figure-c) In the second approach we used wood hemicelluloses alone as wall materials but aimed to find the best processing conditions including inlet and outlet temperatures and the ratio between wood hemicellulose and bioactive compounds (Figure-d). The optimal microcapsules were further analyzed for their phenolic compounds profile including anthocyanins by Ultra-High-Performance Liquid Chromatography (Figure-e).

Luckily, we were able to improve the retention of the bioactive compounds in both approaches with very interesting observations and results that are currently under preparation for publication. The results provide valuable steps towards production of food powders and functional ingredients with high added nutritional values and functional properties with minimal cost.

The FinPowder project has received a third year of funding from the Finnish Natural Resources Research Foundation to conduct further investigations on microcapsule stability and digestibility. In the near future, the optimal microcapsules of wood hemicellulose will be studied for their storage stability over 6 months and in vitro digestion. More to come!

Figure: (a) Abed next to the Liquid Chromatography instrument and (b) conducting spray drying experiments (c) X-ray microtomography images exhibiting the internal and external structure, wall thickness and diameter, (d) The effect of spray drying conditions on the encapsulation efficiency, illustrated as three-dimensional plots and (e) Chromatogram shows 9 peaks of different anthocyanins compounds were found in the microcapsules.

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iOLEO state of play: a synchrotron study of lipid carriers

Last December, four FoMSci group members travelled to Italy to work in the Elettra Sincrotrone Trieste facilities. This experiment is a part of the iOLEO project (three-year research grant), which aims to develop novel oleogels with tailorable digestibility, unlocking the potential of oleogels as a tool for fat replacement and bodyweight management.

MSc Tiago C. Pinto, who is working as a doctoral researcher for the iOLEO project, under the supervision of Docent Fabio Valoppi, carefully oversaw the planning of this intensive study. After months of painstakingly planning the work, the 48-hour experiment took place at the XRD1 beamline, with the intent of shedding light on the evolution of lipid crystals contained in engineered oleogel-based emulsions during simulated gastrointestinal digestion. This very ambitious experiment encompassed the in-situ analysis of 16 emulsion formulations with different lipid core materials and emulsifiers, each of them requiring at least 4 hours of simulated digestion. Time constraints were evident, and the complexity of the experiment required Tiago and Fabio to be joined by MSc Afsane Kazerani Garcia and BSc Christos Papadogiannakis. As they are both working on oleogel-related projects, their proficiency in the lab and familiarity with the topic was very valuable in making this experiment a fruitful one. Cooperation and teamwork were the factors that made this a successful venture, but the ability to keep calm even when things weren’t working in the researchers’ favour was key.

“Keeping the morale up while working two consecutive 20-hour shifts, with a small break of about 4 hours between them is not easy, especially when everything seemed to be stacked against us. After all the months of preparation and planning, having only 48 hours to accomplish everything that I intended brought a lot of pressure. Luckily, we were able to make it through and come out on the other side with very interesting observations. The dataset is still under processing, but we are confident that these are results that can provide a very valuable step towards revolutionising the field.”, Tiago said.

The results are being analysed with the collaboration of beamline scientist Dr. Luisa Barba, whose expertise and availability were essential during the planning and execution of the experiment. After the beam time, the team took a much-deserved day of rest with some exploring of the city of Trieste, as well as a short visit across the border to the historic port town of Koper, in Slovenia.

One of the most prevalent targets in the study of oleogels is their use as a replacement of fats from food chains, with one of the biggest hurdles being the achievement of similar macroscopic properties to replicate them. The characterisation of matter via X-rays can reveal structural differences at the molecular level that justify macroscopic properties and their variations. X-rays are an invaluable probe of the structure of matter, and the range of problems where X-rays have proved to be decisive in unravelling a material structure is very wide. In this case, understanding the evolution of lipid crystals (lipid crystal size, shape, and polymorphic form) will allow a better design of emulsions, leading to a tailored lipid digestion and release. This knowledge is of paramount importance when designing and developing engineered emulsions with tailorable digestibility. The synchrotron analysis offers the possibility to structurally characterise matter at many different levels, in a way that wouldn’t be possible using benchtop X-ray diffraction equipment. The level of detail that these results provide will play a pivotal role in understanding the structural response of simple differences in the composition of engineered emulsions.

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Writing retreat in Tvärminne 19.-21.10.2022

The writing retreat has been an annual event, organized by the Food Materials Science Research Group since 2018, with the intent of setting aside the experimental work and shifting the focus to scientific writing activities. This year, we embarked on a journey to a different location and experienced three fruitful days at the Tvärminne zoological station of the University of Helsinki.

During our retreat in Tvärminne, a beautiful rural area in southern Finland, the members of our group, along with our group leader, Kirsi Mikkonen, got the chance to get together and be productive in a breathtaking place by the sea. We spent most of our time in the classroom, reserved for quiet working, which helped us productively engage in writing, some of us commencing new applications, others finishing old, nearly forgotten publications. Group meetings and fertile scientific discussions were held outside of the classroom. In addition to the hard-working time, everyone enjoyed the delicious meals and desserts during lunch and dinner. The group members sat together chatting, while admiring the amazing sea views. This gave us the opportunity to talk about each other’s work, and get to know new and old lab members better.

Following lunch, some chose to take a walk, enjoy the serene environment and admire wild berries and mushrooms. To reward ourselves after a long day of work, we indulged in going to the sauna and swimming in the cold waters, amongst some friendly jellyfish. After the sauna, we all got together to eat, play games and sing karaoke.

Overall, it was a unique experience, as we had the ability to work productively and share thoughts and ideas with our colleagues.

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A year into making mushroom mycelia a mainstream food – Update on MyShroom

‘MyShroom’, funded by Business Finland’s Research to Business Programme, started in August 2021 with the aim to bring tasty, ecological, protein-rich fungal food to the growing vegan and meat alternatives market.

With an increasing global need for sustainable food, fungi are becoming an attractive option for consumers seeking nutritious, affordable, ecological, ethical, safe, easy-to-use, protein- and fiber-rich food. In our current practice, only about 5% of edible fungal material is consumed as mushrooms, while the rest remains unused in the form of mycelia, waiting for its potential to be unlocked as a sustainable food source. Through ‘MyShroom’, using liquid fermentation from food industry side-streams to feed and grow edible mushroom mycelia, we are not only creating attractive foods but also returning food waste back to humans to consume in a safe, ecological, and circular way.

We initially conducted the screening of 19 different varieties of edible mushrooms using 4 different food industry side-streams. In parallel, clearance from the University of Helsinki Ethical Review Board was obtained to conduct preliminary sensory evaluations which complemented the screening studies, leading us to choose a suitable mushroom variety and culture media. During the last year, we have optimised production, increasing mycelia yield and reducing growth time. We have been able to grow mycelia with additional fermentation products to obtain exceptional nutritional value with a sensory profile rich in mushroom, umami flavour and texture resembling egg white and meat. We have also developed a mycelia-based cheese analogue and validated the product type with a consumer pool, which developed our understanding about what customers are expecting from alternative food products. We have also managed to engage a great number of potential stakeholders from multiple countries within various branches of food industry such as plant-based food, ready-made food, dairy, bakery, pet food, and fine dining restaurants.

In the upcoming year, we will develop strategies to utilise our existing vertical farming facilities to scale our production from laboratory to pilot and then industrial scale. By having our stakeholders participate in our early phase piloting and product validation testing, we are expecting to establish partnerships with manufacturers and potential customers. With many industry partners showing keen interest towards our products, their feedback based on customer needs will help us to finalise our product/s. We will also conduct product texture development, sensory evaluation, and consumer perception studies. In the alternative food market, mushroom mycelia bring added value to customers in a tastier, healthier manner with clean label benefits.

Ultimately, we want to produce food that is healthy for you as well as the environment and edible mushroom mycelia, which are full of potential, will help us get there.

 

MyShroom Team: Shuddhodana, Jutta Varis, Minna Isotupa, Marko Saapunki, Pauliina Lankinen, Pekka Varmanen, Mari Sandell, Laila Seppä and Kirsi Mikkonen.

The team is supported by Elena Inguglia and Kajsa Kajander from Helsinki Innovation Services.

Picture from left to right: mycelia, sensory attributes, mycelia cornucopia (drawn by Julia Varis).

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A new Academy of Finland (AoF) postdoc research project explores an innovative way to utilise wood hemicelluloses

Wood hemicelluloses are currently treated as low-value by-products of the pulp and paper industry and remain outside of the biorefinery process. The development of value-added applications of hemicelluloses for producing new advanced products will boost forestry operations, promote economic growth, and secure employment in rural areas. To support this goal, Thao Minh Ho in the FoMSci group received funding for a 3-year AoF postdoc research project to develop an innovative approach to employ wood hemicelluloses as capsule wall materials to formulate new synbiotic powders. The project entitled “SynCap: Design of spray-dried synbiotic microcapsules for healthy, functional, and sustainable powders” aims to establish wood hemicelluloses as superior wall materials in the production of microcapsules of probiotics, and potentially many other bioactive compounds.

This project will bring the interdisciplinary expertise and knowledge in food materials sciences, food chemistry, food digestion and microbiology from different research groups within the Faculty of Agriculture and Forestry. The project also establishes a new collaboration with the Biomass Science and Technology research group at the University of Copenhagen (Denmark).

Every year, the AoF funds high-quality scientific research in various fields with the aim of contributing to the renewal, diversification and internalisation of Finnish research. The SynCap project is one of 32 successful applications (out of 217, 15%) in biosciences, health and the environment research fields granted in 2022.

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New project: VegeSense aims to secure the supply of high-quality vegetable products

Left: M.Sc. Maria Waldén. Right: Dr. Mourad Kharbach.The food chain is in a shift towards more ecological practices. To feed the growing world population in a sustainable manner, it’s crucial to find solutions to reduce food waste and shift our eating habits to remain within the boundaries of environmental resources. To succeed, the movement towards a planetary diet must be appealing, affordable and uncomplicated for consumers. With ready-cut fresh vegetables consumers can conveniently increase their consumption of fresh vegetables, however the shelf-life of this product category is very limited due to rapid quality loss, often because of over-ripening, browning and tissue degradation, which leads to significant amounts of food waste.

Currently, the underlying deterioration mechanisms after processing and packaging are not sufficiently understood. To tackle this waste, our new project VegeSense, led by Assoc. Prof. Kirsi S. Mikkonen and funded by Novo Nordisk Foundation, aims to provide complementary understanding of these deterioration processes by researching the key metabolites and their role in the quality loss of ready-cut fresh vegetables.

M.Sc. Maria Waldén started in the project as a doctoral researcher in January. Her work is co-supervised by Prof. Mari Sandell and Assoc. Prof. Saijaliisa Kangasjärvi and it will focus on how packaging effects the sensorial quality of ready-cut vegetables and what volatile compounds originate from their metabolic reactions, thus defining their shelf-life. Maria feels very excited about the topic and finds it immensely meaningful, as there is a high possibility of finding solutions that could be applied to practice at an industrial scale rather quickly to reduce environmental pressure. The project is highly multidisciplinary combining food technology, analytical chemistry, plant science and data science. This diversity will allow these complex mechanisms to be deciphered through research from a combination of perspectives and scientific backgrounds.

Dr. Mourad Kharbach started in March as a postdoctoral researcher. He will collaborate with Assoc. Prof. Arto Klami from the Department of Computer Science. Mourad has experience working with large data sets collected by advanced real-time (spectral or chromatography) instruments from different matrices and extracting the hidden information by means of statistical, machine & deep learning, or chemometric tools and linking these with the desired outputs. Particularly, he will develop statistical approaches to analyze untargeted and targeted fingerprinting (e.g., hyperspectral imaging, spectroscopic, and chromatographic) profiles moving beyond traditional lab-based experiments. Mourad will lead the development of non-destructive, fast, reliable, and sensitive methods for sustainable solutions of food materials in terms of quality and safety with the goal to optimally join human forces and machines.

Through this project we aim to provide solutions for reducing food waste and limiting climate change via the improved shelf-life of fresh-cut vegetables and their increased consumption. The resulting improvements in packaging technology would be highly applicable to the food industry and could therefore help the food industry to keep costs – both environmental and economical – in control, which we hope would eventually lead to a decrease in prices and increase in vegetable consumption. By making it financially possible for consumers to conveniently increase their use of fresh vegetables in their diets, healthy eating habits and sustainability can be enhanced.

We are eagerly waiting for another two researchers from the areas of plant science and analytical chemistry to join us in June, complementing our team with their expertise. We will hear more about their work soon, stay tuned!

Picture from left to right: M.Sc. Maria Waldén, spectral imaging test setup, Dr. Mourad Kharbach.

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Wood hemicelluloses have great potential as wall materials for spray-dried microencapsulation of bilberry juice

The FinPowder research project funded by Finnish Natural Resources Research Foundation aims to develop a new strategy to offer sustainable and healthy food choices to global consumers while also valorizing Finnish wood-based hemicelluloses and wild berries. Further information about the project can be found here.

Since FinPowder commenced in April 2021, we have evaluated the suitability of different types of hemicelluloses and celluloses for spray-dried microencapsulation of bilberry juice. We have also optimized the methods for the preparation of feed solutions including bilberry juice, and selected hemicelluloses and celluloses. Thanks to a parallel research project driven by Doc. Fabio Valoppi, a new laboratory spray-drier (B-290, Buchi Labortechnik GmbHDE, Essen, Germany) has been installed in our laboratory (Figure), which has provided a research instrument upgrade that also supports the FinPowder project. Initial results of spray-dried microencapsulation of bilberry juice indicated that hemicellulose had a high retention capacity for bioactive compounds during spray drying with an encapsulation efficiency of 70–80%, similar to that of conventional wall materials (gum arabic and maltodextrin). We used a scanning electron microscope (SEM) to determine the morphology and physical appearance of microcapsule powders coated by sGGM are shown in the figure.

Along with the spray-drier installation, we have worked with a technical engineer from Buchi to successfully design a customized drying chamber which allows the collection of powders at different distances in the drying chamber while they are being dried. We have also installed and carried out testing with a high speed camera system that allows us to investigate the particle powder formation, live. These analyses enable us the first time in this project to characterize microcapsule wall formation happening during the spray-dried microencapsulation process. The FinPowder project has received a second year of funding from the Finnish Natural Resources Research Foundation to conduct further investigation on microcapsule powder characteristics, optimization of the spray-dried microencapsulation process, and investigation on the formation mechanism of microcapsule wall. More to come!

Figure: A Buchi spray-drier, physical appearance and morphology (SEM image, on the right) of bilberry microcapsule powders prepared from hemicelluloses.

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The in vivo study on modified fat systems has started!

Research on oleogels and their functionality in mice has started at the University of Helsinki Biomedicum animal facilities, designed by docent Fabio Valoppi’s research group in collaboration with docent Teemu Aitta-Aho.

This novel investigation will look for physiological differences between mice fed diets high in oleogels and other fats including their body composition, food-related behaviour, and weight fluctuations, along with other characteristics during a three-month period. These mice will become integral research participants in this study as we depend on information from them to ensure that the developed oleogels are safe to eat, bringing them closer to their possible commercialization.

Although it is vital to understand the impact of the consumption for any given food or ingredient in humans, forecasting their behaviour during digestion is complicated. A meal’s effects on i.e. hormone production, absorption of nutrients and impact on gut microbiota is not easy to predict, and science can only go so far with laboratory models.  In vitro digestions models analyse pH constants, as the gut’s equivalent enzymes and acids are delivered by a set of spatulas and beakers, attempting to mimic the human digestive process. As you can imagine, this process falls short when determining several aspects of the digestion of oleogel-containing food, such as: How much is safe to eat? What kind of hormonal response do they activate? Or how does it affect cholesterol (both good and bad ones) in blood? Certainly, we need to answer these and many other questions before proceeding.

Hopefully this study will run smoothly, allowing us to fill in knowledge gaps about oleogels and supports the data obtained by us and many other food scientists around the world that are looking for healthier substitutes of saturated fats.

Pictures from left to right: mice diet comparison and visual inspection, research assistant M. Sc. Afsane Kazerani collaborating with one study subject.