 I would like to thank the organizers for giving me the opportunity to present today is a pity I cannot be in London in the south of Sweden in the tropical south of Sweden. But anyway, we're having a very nice day here in Stockholm as well. So the title of my talk is hemicellulosis molecular structure assembly in plant cell walls and food applications. And I also wanted to highlight the contribution of of Cetil and you must see the beauty student who has basically introduced our group into the wonders of x-ray and neutron scattering so she's a very, very big contributor of this of this presentation. So the starting point of the research that we do in my group is actually understanding the molecular structure and super molecular assembly of plant cell walls. And from a biological point of view, plant cell walls is the tissue that is the tissue that surrounds plant cells and provides them with different functions such as structural support and other regulatory functions. And also a plant cell walls are the main renewable resource from plant biomass that we can use for bioenergy and also for material applications. But also in this context, in the context of the Nordic light cell food, a plant cell walls are very important components in many plant based foods, for example, in cereals and fruits and vegetables, etc. So basically understanding them, the structure is very important, not only to utilize the different components that are present in this in this plant based foods, but also to understand the viability and all the other other properties. So from a molecular perspective, plant cell walls are very complex and hierarchical structures composed mainly by polysaccharides and here you can see a sketch of the composition and assembly of cereal plant cell walls. Where we have cellulose microfibries embedded in a matrix of different matrix polysaccharides, for example, Arabinox islands and beta-glucans. We have also pectins, proteins, phenolics, lignin, etc. So you can see this is a very complex and rich composition of different molecules. All of them have different molecular structure depending on the tissue, depending on the variety, depending on the developmental stage. And also what is important to understand is that what contributes to plant cell wall function and recalcitrance is what are the different interactions between the different components. We have covalent cross-linking, we have hydrogen bonding non-polar interactions. So basically understanding the complexity of this system is what we want to achieve. We are mainly interested in hemicelluloses in my group, which is, as I said, an important component in plant cell walls. In some tissues, for example, in cereal brands is actually up to 50% of the total composition. And these hemicelluloses are, as I said, matrix polysaccharides that interlock cellulose microfibries. And they have a wide diversity of structures. They have a similar backbone as cellulose, meaning that they have a backbone of beta-1-4 linkages. But differently from cellulose, we can find different sugars in the backbone, glucose, mannose, and xylose. We can find different decorations by both neutral sugars, for example galactose or arabinox, but also acidic sugars like glucuronic acid. And also we find acetylation, different chemical modifications. So all of these basically complex structures have a role, and that's what we are actually very interested in deciphering. So for a long time, people thought that this pattern of sugars was random, so there was no specific ordering in the way that the different backbone sugars, the sugar modifications and the acetylations were placed in the polymer. But actually from very recent years, there has been a lot of progress by us and other researchers in the field using glycomics or mass-petrometric based glycomics to try to decipher if there is actually a sequence in the order of the sugars in hemicellulose. And we have actually found that there are actually regular structures, and now we can start thinking what is actually the implications of these sugars, of these sequences. So we know now that the different sequences, they are able to modulate macromolecular conformation and chain flexibility. They also fine-tune the hydration or aggregation possibilities of these hemicelluloses. They tailor interactions with the other wood component, with the other components in plant cell walls, with the cellulose and with the lignin. And also from an application point of view, they also prevent enzymatic deconstruction and influence different macroscopic functional properties, like for example, rheological properties when we are making different applications from these hemicelluloses. And I just wanted to highlight just two important contributions that we did recently about, you know, how these sequences might influence plant cell wall assembly. So this is a sketch, a molecular model that we made for the assembly of plant cell walls, where we actually could find that manans, for example, with high acetylation are much more flexible. But the presence of a specific regular features in Xiland actually tailors the interaction with cellulose. So you can actually find, as you can see here, Xiland, which is an important hemicellulose, co-crystallizing on the surface of cellulose. On the other hand, you can find also other motives with a high clustering of glucuronic acid, which actually interact with the phenolic component. So it has a big implication on the assembly of plant cell walls. But also when we're trying to make different cell wall components, we have also found that this molecular structure influence the way these hemicelluloses assemble. So we can find a rigid layers of hemicelluloses closely absorbed onto Xiland, onto cellulose surfaces, and also flexible Xiland components. And this we discovered like that is very important to change the properties of these cellulose fibular networks. So having Xiland drastically increases the ductility of these fibular networks and having manan drastically increase the compressibility of this cellular network. So what we found is that last year in collaboration with the University of Queensland in Australia, and it has also implications for food applications because we can actually now combining hemicelluloses and cellulose, we could maybe find you in different gels materials that can be used in dietary fibre applications. So now jumping onto the main topic of the talk today, I wanted to show you a project that we've been driving for for some years now, trying to valorize by products from serial production, and how X-ray scattering techniques have really helped us to understand the properties of the different food products that we are creating from this, from this serial by products. So at the starting point of this project, we were collaborating together with landmen and novizimes was to valorize the outer layer of the serial grain, the bran which constitutes approximately 20% of the overall serial kernel. And I put here the same picture again we were very interested in valorizing particularly the Arabian Xiland, the hemicelluloses in serial bran, because they constitute approximately again 50% of the total composition. In order to do that, we designed a process using just water in high pressure and temperature what we call subcritical water extraction. And this allowed us to isolate and fractionate these feruloy-related Arabian Xiland, these wonderful orange strings here with high molecular weight at around 100,000 Dalton, and most importantly keeping these phenolic acids covalently bound to the hemicellulose structure. And you will see now why this is so important to us. On one side keeping this phenolic acid actually keeps and gives this hemicellulose some antioxidant properties that are quite important in different applications. So, and this is actually part of the PST work. What we wanted to see if we could use this feruloy-related Arabian Xiland making films that could be used as barriers combining not only the oxygen properties of the of the of the films but also the antioxidant properties of this ferulic acid covalently bound. We did prove that so we could see that we could make self-tanding films that were favored by the molecular composition of these Arabian Xiland. And we found that ferulic acid in covalent form provided higher antioxidant activity to these films rather than have, you know, free ferulic acid added to the film. So in some part of the project we wanted to make gels of this feruloy-related Arabian Xiland. And in order to do that we basically mimicked what CDL cells do when they're creating their cell walls. So what we did was using the presence of this ferulic acid we use lacquist oxidation to create radicals and be able to recreate these covalent bonds in these in these gels. Remember that when we do this enzymatic reaction we decrease the amount of ferulic acid and we increase the amount of these the ferulic bridges that we can find. Also by size exclusion chromatography we confirmed that these covalent bound structures on one half have higher molecular weight than the free feruloy-related Arabian Xiland but also smaller sizes. So basically we're creating a more compact polymeric topology but with higher molecular weight. Then we teamed up with Patricia Lopez-Sante at Chalmers and she helped us doing a rheological analysis and we prepared different gels. First of all, you can see here the appearance of the gels by enzymatic crosslinking and here after we did some regeneration of these gels by freeze drying and resuspending at different pHs. And you can see here how the viscosity drastically increases when we have the crosslink but also even more when we regenerated the films in after freeze drying. And here you can see in cryo-SEM the porous structure of these films. But at this stage we had no idea about how the ultra-structure of these gels looked like. And this is when I have to again give the credit to Cicilli, she was really pushy, I really want to understand, I really want to get to know better synchrotron and scattering techniques. So it was her idea to apply to this Vinova project to increase the knowledge base of in scattering techniques. And we were very happy also to couple with Thomas Privilege at Maxfort Laboratory. We've been trying to collaborate for some years and Vinova gave us the opportunity to do that. So we're very thankful to do that and it has actually highlighted so much the importance to go beyond molecular level and understand supramolecular organization. So first of all, we did some wide angle x-ray scattering from both the polymeric and the crosslink films. And we could see basically that the local crystallinity increased both upon enzymatic crosslinking, but it was not so much influenced by regeneration. You can see here that it almost the crystallinity degree doubles when we are crosslinking enzymatically. Then we moved forward and we did some preliminary lab scale x small angle x-ray scattering from both the crosslink and the regenerated films. Here you can see the preliminary results that we obtained also in the lab source at Chalmers. So now we decided to feed the results from x from sax to the correlation length equation with these two terms, the N exponent, the power law for larger aggregates, and then the Lorent exponent and the correlation length for the polymeric range. This has really helped us to really understand what happens to our gels, and we're now in the discussion on trying to propose a model of how does this supramolecular organization of our films, of our gels look like. So we've seen that a regeneration causes a larger power law exponent so we're thinking that this creates the higher density of the clusters. We're also finding a larger correlation length upon regeneration, and then we can see that basically we have a junctions of the polymeric chains where we have higher order, but we also have a more density and larger clusters at larger orders of size. And we can see that these films combine both chemical crosslinking and physical effects that contribute to both hydrogen bonding, sorry, I contribute both to network formation and to the rheological properties. And now we're very excited because next week, we will be running the first analysis at the Cossack beam line in Lund, and hopefully we'll be able to go in September to Lund to basically further down the study of this complex of these complex gels. So I just wanted to finish. I mean, I think I'm preaching for the converted here but it's very important for all of us in the in the food science area to understand structure because it correlates basically to the raw materials processing products and health. And also, from my standpoint what I have learned a lot in this in basically this last year is the need to integrate the biochemical analysis that we're mainly experts in my lab at KTH but also with advanced bio physical characterization and that's what exactly a neutral and x-ray scattering can provide is a further understanding of other orders of magnitude. So in this presentation I just wanted to highlight that as an example, the complex composition of molecular structure and architecture of plant-based materials and how hemicellulosis basically contribute to disassembly at a molecular level and how we can use these hemicellulosis as valuable matrices. These are packaging applications, as I can show you with antioxidant properties, but also as food gels that can also contribute to texture but also hopefully adding some nutritional benefits in terms of prebiotic activity and also antioxidant properties. So I wanted to again thank my group, especially to Sechil, who will present her thesis on the 4th of November. So if you're interested in basically a bit more of the detail that I have provided today, please contact me and I will provide you the link for her presentation. And finally, of course, I wanted to thank the support in this particular case from Formas to the overall project and specifically to Vinova for actually giving us the possibility not only to Sechil but also for PIs that are completely unaware of x-ray scattering techniques of the potential of this platform. So thank you very much. Thank you very much for a very interesting, very fast presentation.