Author: Ida E Nikkilä

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ROCK – building new knowledge to valorize forest resources

ROCK: ROle of lignin Carbohydrate complexes as Key to stable emulsions project has been completed. The project was designed to valorize forest resources, especially those from Nordic forests. Hemicelluloses-rich extracts, obtained by an environmentally-friendly water-extraction method was previously identified as a functional substance for stabilizing emulsions. Although rich in hemicelluloses, they also contain a certain amount of other polysaccharides and lignin co- extracted. When we commenced this project, the reason for the excellent stability performance of hemicellulose extracts as emulsifiers was still unclear and our hypothesis was that at least some of the residual lignins could be covalently linked to the polysaccharides forming so-called lignin-carbohydrates complexes (LCC). Such hybrid composites have two distinct regions, one more hydrophilic (hemicellulose part) and other more hydrophobic (lignin part). As a result, each region can interact with the different phases of the emulsion, possibly explaining the emulsion stability achieved using hemicellulose-based emulsifier. Our main aim was to investigate the presence of LCC in hemicelluloses extract and identify the role of such structures in emulsion stabilization. To do this we investigated the structures and functionalities of hemicelluloses extracts. In the initial part of this study, we characterized various types of hemicelluloses extracts obtained from birch and spruce wood. Using a combination of fractionation and advanced identification techniques, we demonstrated that some of the lignin residues in the extracts were involved in the formation of LCC linkages of various types (i.e., phenylglycoside, benzylether, and gamma-ester). A previous posted blog with these findings can be found here.

Next, we investigated how the different polymer populations in the hemicelluloses extract, including the LCC structures, are distributed between the emulsion phases (i.e., droplet interface and continuous phase) and what aspects drive such distribution. Beyond differences in the appearance (see figure), we discovered that the hemicelluloses populations in the various emulsion phases also differed in terms of their chemical and structural aspects. The residual lignin is a component of fundamental importance for the hemicelluloses orientation during emulsification and for the stability of the emulsions. Moreover, the various LCC structures identified in the hemicelluloses extracts were fractionated between emulsion phases depending of their type. In summary, ROCK provided the cornerstone to better understand the composition of hemicelluloses extracts and their functionality in emulsion, pushing the wood-hemicelluloses a step closer to added-value applications.

The ROCK project was funded by Tandem Forest Value and led by Assoc. Prof. Kirsi Mikkonen (University of Helsinki, Finland) and Prof. Martin Lawoko (Royal Institute of Technology, Sweden).

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Unravelling the assembly mechanisms of emulsions: a new collaboration between FoMSci (University of Helsinki), BiCMat-Aalto and BiCMat-UBC groups (Aalto University and University of British Columbia)

We are pleased to announce the launching of a research collaboration between FoMSci (University of Helsinki) and Biobased Colloids and Materials operating both in Aalto University (BiCMat-Aalto) and University of British Columbia, Canada (BiCMat-UBC), led by Prof. Orlando Rojas. This collaboration is boosted by the joining of two postdoctoral researchers, Drs. Mamata Bhattarai and Emilie Ressouche working under the joint supervision of Profs. Rojas and Mikkonen. Mamata finished her PhD from FoMSci in November 2020, and Emilie comes from the Department of Applied Physics, in the Molecular Materials group, led by Prof. Olli Ikkala.

The research topics and the know-how available in both groups are complementary: FoMSci brings expertise in emulsions, hemicelluloses, and food applications.; BiCMat also works with multiphase systems based on lignocellulosic bio-colloids. Together, the groups will investigate the mechanisms responsible for the formation of emulsions stabilized by bio-based compounds such as lignin/hemicellulose complexes, and plant- as well as marine-derived bioresources.

This research project aligns with the goals of the BioElCell Research project, funded by Advanced ERC (2018-2023) in BiCMat, and will also bring an expansion to our Academy of Finland funded ENVISION project, leading to a wider comprehension of emulsions stabilized by wood hemicelluloses.

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We nailed it again: four new funded projects to FoMSci

Between November and December 2020 our FoMSci group has received four new grants: three to Fabio Valoppi (iOLEO, ENGEL, and iFOOD), and one to Thao Minh Ho (FinPowder).

Fabio’s projects: The iOLEO and ENGEL projects, funded by the University of Helsinki three-year research grant scheme (7% success rate – only 9 projects were funded among 128 submitted) and the Jane and Aatos Erkko Foundation, respectively. These projects aim to develop new oleogels with body weight managing abilities unlocking the potential of oleogels as multi-functional fat substitutes. Mr. Tiago Pinto has been selected and hired as a new PhD student in the iOLEO project and will begin his work in April 2021. For the other project, ENGEL, we are currently in the process of hiring a postdoctoral researcher. The iFOOD project, funded by HELSUS, aims to develop a new digital tool to simulate mechanical properties of food products using finite element method simulation. This project is based on the existing and fruitful collaboration between FoMSci and the Electronics Research Laboratories (ETLA) also from the University of Helsinki.

Thao’s project: The FinPowder project, funded by the Finnish Natural Resources Research Foundation, aims to design powder particles to protect functional compounds of wild berry during spray drying. These coating materials originate from sustainable and natural sources that are extremely low in calories and cost, namely wood-based celluloses and hemicelluloses. Mr. Abedalghani Halahlah has been selected and hired as our new PhD student to work in the FinPowder project and will join the FoMSci group within a couple of months. Abedalghani will be co-supervised by Associate Professor Kirsi Mikkonen and Dr. Thao Minh Ho, in collaboration with Professor Vieno Piironen.

The cherry on the cake is that thanks to these new projects, our group will now be able to purchase a brand-new lab scale spray dryer!

Even though 2020 has been a tough year, we ended it in the best way possible with new funding, new people joining FoMSci, and new equipment. Writing proposals can be very energy demanding, but the doors that these new projects will open make it worth all the effort we put in during the writing process.

2021 has already started, and new and exciting times are waiting for us ahead!

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Integrating Freshpack technology into existing production lines

The Freshpack project aims to establish an active packaging technology that prevents premature spoilage of fresh produce. The technology provides a longer shelf-life by slowing down natural ripening and inhibiting microbial spoilage of fruits, berries, and vegetables. This research-based project is driving the preparation of our novel technology for commercialization. We have worked closely with operators throughout the food distribution chain to explore the best way to integrate the technology into existing production lines. In addition to Finnish operators, we have had global interest from countries including Italy, Japan, and Nigeria. With regard to food packaging legislation and the interpretation of its scope, we have had interesting discussions with the Finnish Food Authority and other food and contact material legislation experts. More comprehensive investigation will begin next year.

Based on discussions with stakeholders, the first fresh produce target category will most likely be berries, because of their valuable price and relatively short shelf-life. So far, we have managed to increase the shelf-life of blueberries and raspberries by several days in a wide range of temperatures. This enables the technology to be transferred to real-life distribution chain settings. After preliminary tests, we will continue with large-scale storage testing including microbial safety evaluation.

Over the past year, we have worked intensively on overcoming technical issues to ensure that our first minimum viable product (MVP) is easily adoptable at a low cost. The MVP will be a Freshpack pad that simultaneously provides moisture absorption and cushioning properties. Pads are already widely used in the berry packaging industry allowing for effortless implementation into existing production lines. While concentrating on a pad solution, we are also looking for future funding options to gain full benefit from this technology. Future applications will contain more scalable options, for example, coating for cardboard and layers for plastic films.

Despite the current constraints caused by Covid19, we have managed to take the project forward as planned. This is partly due to our expanded team, which grew by two at the beginning of the year. Dr. Mari Lehtonen, who is one of the researchers behind this technology, returned to work on technical development and MSc Kimmo Peltola joined to assist in the laboratory.

Stay tuned for the next updates!

A previously published blog post of the Freshpack project can be found here.

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Just PhDone

On November 25th, FoMSci group member Mamata Bhattarai defended her doctoral dissertation entitled “Associative behavior of spruce galactoglucomannans in aqueous solutions and emulsions” in the Faculty of Agriculture and Forestry, University of Helsinki. Wood galactoglucomannans or spruce gum are hemicelluloses that are available as side-streams of forest industries. Mamata studied their solubility in water and their performance as emulsion stabilisers, to potentially be used in industries including food, pharmaceutical, and cosmetics. Her work provides essential information to improve sustainability within the forestry industry by adding value to treasured wood resources that are otherwise wasted.

We enjoyed a lively discussion between Mamata and her opponent Professor Francisco M. Goycoolea from School of Food Science and Nutrition, University of Leeds. After the defense, we celebrated Mamata’s excellent work with a toast and lighting up our Spruce of the Future.

The whole FoMSci group congratulates Mamata for her great work and excellent defense! You can find her research work here. Her work was also featured by Helsinki University press, link here.

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Enzyme industry side stream as a novel source for hydrocolloids

One of the key research topics of our Food Materials Science research group is side stream characterization where we aim to make efficient use of wasted natural resources. In our resent study, we focused on side stream biomass obtained from enzyme industry. This type of biomass is obtained during down-stream processing where the enzymes are separated and collected from the leftover biomass, including for example microorganism cells, and the growth medium. Currently, this biomass is treated as waste. However, the biomass is a source for potentially valuable compounds, for example, cell wall heteropolysaccharides.

Our recently published open access article “Fungal Cell Biomass from Enzyme Industry as a Sustainable Source of Hydrocolloids” by Ida Nikkilä et al. reveals the basic composition of this biomass and the fractions obtained from it via alkaline and water extraction. Further, the functional properties of the extracts as hydrocolloids were studied in water suspensions and emulsions prepared from biomass extracts. The study showed that this type of biomass can be fractioned via water and alkaline extraction, and the extracts have potential as hydrocolloids. More specifically, the alkaline extract was found to form a relatively stable emulsion. This was the first time that fungal biomass was studied as a source for hydrocolloids.

This study was part of the Academy of Finland funded “Reassembly of fungal polysaccharides for biocompatible interfaces” (REPLY) -project. A previously posted blog from this project can be found here.

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New AoF postdoc grant addresses pharmaceutical pollution in water

Do you know that you might be taking in medicines every day without you knowing it? It is possible when the water you drink is contaminated with pharmaceutical pollutants. These are residual drug molecules, which stay in water because conventional wastewater treatment methods cannot completely remove them. Pharmaceutical pollutants affect water resources, including drinking water in various parts of the world, and may pose health hazards to humans. The good news, though, is that the recently awarded postdoc grant to Melissa Agustin by the Academy of Finland (AoF) offers a potential solution to this global problem on pharmaceutical pollution. The project entitled: “Pickering emulsion-based synthesis of lignocellulose aerogels as adsorbents for pharmaceutical pollutants (PickPollutants)” will develop bio-based materials capable of removing residual drug molecules from water. This multidisciplinary project will employ the expertise in emulsion and aerogel research of the FoMSci group, with support from local and international collaborators: Aalto University, University of Eastern Finland, Finnish Environmental Institute, and Hamburg Institute of Technology.

The PickPollutants project is among the 15% successful applications in natural sciences and engineering to be granted a three-year funding by the AoF in 2020. Yearly, the AoF grants funding to high-quality scientific research in various fields with the aim of contributing to the renewal, diversification and increase internalization of Finnish research.

Kudos to Melissa´s new project! This shows that here in FoMSci, we care not only about the foods you eat, but also about the water you drink!

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Links between lignin and hemicelluloses in spruce extract

The Food Materials Science research group continues to innovate in the use of Nordic forest resources in advanced applications for food and other novel materials. For this, a deep understanding on the chemical and structural aspects of wood components is crucial. Assessment of cellulose, hemicelluloses, and lignin alone is needed, but also the identification and elucidation of linkages between those structures: the so-called lignin-carbohydrate complexes (LCCs). Despite of paramount importance for applications, the identification of LCC bonds is challenging because of their relatively low frequency in wood extracts.

A recent research article by Danila Carvalho et al. tackled this challenge and improved the identification of LCC bonds in spruce hot water extract using an elegant combination of fractionation techniques, including chemical, enzymatic, and physical methods. Such techniques resulted in the fractionation of LCC bonds and enabled the identification of three types of LCCs, namely: phenylglycoside (PG), benzylether (BE) and gamma-ester (GE). This research developed an efficient analytical methodology for LCC identification, which may facilitate the study of LCC functionalities and, consequently, open novel opportunities of applications for wood-based derivatives.

This research was a result of the collaborative project: “Role of lignin carbohydrate complexes as key to stable emulsions” (ROCK), funded by Tandem Forest Values programme by Kungliga Skogs- och Lantbruksakademien (KSLA), Sweden, and led by Assist. Prof. Kirsi Mikkonen (University of Helsinki, Finland) and Assoc. Prof. Martin Lawoko (Royal Institute of Technology, Sweden).

The open access article is available here.

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PARTIFACE: Green route to wood-derived Janus particles for stabilized interfaces

We are extremely thrilled to start our new research project “PARTIFACE” since the beginning of June 2020, supported by the European Research Council and led by Assist. Prof. Kirsi S. Mikkonen. This project aims to develop a green conversion route using enzymatic crosslinking to build a novel concept, in which tailored bi-facial “Janus” particles will be prepared from two of the most abundant, but underexploited wood-based biopolymers: lignin and hemicelluloses.

Using environmentally friendly technology, this project will design sophisticated and sustainable hierarchical architectures from the abovementioned biopolymers. Due to their two ‘faces’ with opposite properties, these tailored wood-based particles are expected to have a superior capacity to stabilize emulsion interfaces.

Therefore, we envision a breakthrough in interface and colloid science, contributing to more sustainable use of the Earth’s resources.

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New work reveals detailed features of spruce gum (galactoglucomannan) in water

The Food Materials Science group studies the applicability of spruce gum in dispersion-based systems, such as food, beverages, cosmetics, and chemicals. To formulate applications of spruce gum to produce high quality products, knowledge on its solution properties is very essential.

A recently published article by Mamata Bhattarai et al. reveals that spruce gum forms higher-order structures in water, such as aggregates and colloidal particles. We demonstrated this, for the first time, by fractionating and studying all the fractions of spruce gum using asymmetric field-flow fractionation and a combination of light scattering and electron microscopy.

Spruce gum is mainly composed of galactoglucomannan polysaccharides, but also other structures are co-extracted from spruce wood with the polysaccharides. Unpurified spruce gum containing high levels of lignin occurred in water in the form of polysaccharide-aggregate-particle mixture. Spruce gum after purification by ethanol precipitation did not show particles, but the aggregates still existed. Characterization of this unique mixture of spruce gum was challenging; thus, several parameters during the analytical fractionation had to be optimized. The article discusses several aspects about challenges to fractionate complex polysaccharide mixtures and possible approaches to address them.

The work was a result of excellent collaboration between the FoMSci group (Department of Food and Nutrition, University of Helsinki), Department of Physics (University of Helsinki), and the University of Natural Resources and Life Sciences (BOKU), Austria.

The article is available as open access here.