Neutrons and Food 8 at MLZ

Extrusion-based 3D food printing enables highly accurate spatial control, but its wider deployment remains constrained by the absence of robust and transferable material parameters for printability. Consequently, commercial systems often rely on proprietary inks, while academic studies frequently report formulation-specific processing windows, thereby counteracting personalization. In plant-based edible inks, inadequate correlation between protein attributes and techno-functionality, together with an incomplete understanding of process-structure interactions, further compounds this challenge.

X-ray scattering (XRS) provides a non-destructive route to characterize hierarchical and multiscale structure in complex food systems, enabling probing for features potentially relevant to printing performance. Herewith, four soy-based formulations prepared from two techno-functionally distinct soy protein isolates (SPI) under distinct pre-processing routes (direct kneading or high-shear-homogenization), were investigated using benchtop XRS with wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS), including measurements of individual dry ingredients, hydrated components and thermal treatment.

Scattering patterns differed between shortly hydrated and overnight-hydrated inks, highlighting the utility of benchtop access for tracking structural evolution due to processing steps dependence. WAXS distinguished differences in secondary protein fractions of differing purity. SAXS revealed the emergence of a distinct low-q feature (q = 0.01–0.08 Å⁻¹) upon heating of pure SPI. Similar signatures have been linked to protein nano-aggregate formation in structured plant-protein matrices and in the present study, a related low-q shoulder was also observed in the pre-processed formulated inks but not in the individual ingredients. These structural observations were distinct across the four formulations yet showed consistent trends alongside microstructural features visualized by confocal laser scanning microscopy and mechanically characterized by rheology-derived gel strength, suggesting that ingredient selection, including SPI type and pre-processing route, influences protein aggregate formation and ultimately printability.

Overall, benchtop XRS demonstrated its capability as an effective screening tool for multiscale structural characterization of multi-component edible inks, providing a structure-informed basis for future work on how protein aggregation characteristics may govern processing performance in plant-based 3D food printing.

Small-angle scattering (SAS) is an ideal tool for non-destructive nanostructure analysis. However, due to the overlapping structural information from many different phases, we often prefer to measure model case suppressing the number of constituent phases. In the case of dairy food products, they include fat globule, casein micelles and colloidal calcium phosphate (CCP). And for simplifying system, skimmed milk without fat is often used for SAS studies. However, for studying cheese, all of those constituent phases are important to form cheese shape. Another important factor is the producing process which must affect to the nanostructure. Therefore, well controlling process is required for taking out the key structure from real cheese. Based on these conditions, we make a team with scattering and dairy science and study “Real” Gouda cheese by using laboratory scale small-angle X-ray scattering (SAXS) which can trace long term change by both in-situ and ex-situ way. The results show the aggregation of CCP during the first week after production. Aggregation of casein micelles were also studied by laboratory USAXS together with texture. Based on the obtained structure-texture relationship, we are proceeding to control texture of cheese which will be presented also in this talk.

High pressure food processing (HPP) is widely applied in sterilization, homogenization, chemical synthesis, and the modulation of organoleptic properties. Owing to the complexity of food matrices, HPP requires the coordinated optimization of temperature, pressure, pH, ionic strength, and other interdependent variables, to achieve targeted structural or functional outcomes. HPP hold time—ranging from millisecond pressure pulses to hour long treatments—is a critical parameter, often determined using ex situ measurements and empirical approaches.
Short hold times are accessible to in situ techniques that simultaneously probe form and structure factors with a relatively high throughput, such as small angle X ray scattering (SAXS). However, longer pressure exposures remain difficult to study using methods susceptible to radiation damage, or that require the use of non-native probes. Small angle neutron scattering (SANS), a non-destructive technique with broad spatial and temporal resolution, is uniquely suited for in situ investigations of pressure hold time effects, including hysteresis and reversibility. This presentation will highlight applications of high pressure SANS (HP SANS) to systems such as blended plant–dairy proteins, hen egg white protein solutions, and gelatin, emphasizing the complementarity of SAXS, SANS, and diffusing wave spectroscopy (DWS) to support HPP process engineering.

Hypothesis: The structural details of foams made with pea albumins are affected by the pH of the initial solution and followed heat treatment.
Experiments: An in situ, time-resolved investigation of foams prepared with pea albumins was conducted using small-angle neutron scattering (SANS) in combination with imaging and conductance measurements. Solutions were tested at pH three pH values (3, 4.5, and 8) before and after heating (90 ◦C for 1 and 5 min).
Findings: The characteristic structures present in the foam from the nano to the meso-scale differed during drainage depending on solution pH. Foams obtained at pH 3, had the largest bubble radius and thinnest plateau border, as well as the highest extent of liquid drainage. At pH 4.5, close to the isoelectric point of the proteins, foams displayed similar bubbles’ behavior to those at pH 8, but with the largest film thickness. In this case, the proteins were extensively aggregated. Heating of the solutions prior to foaming did not significantly affect the foam aging regardless of pH. The quantification of specific surface areas and film thickness over time without sample disruption shows to be a powerful approach to designing foam structures.

Oil/water interfaces are found in cosmetics, drug delivery, and food systems. These emulsion systems are often stabilized by proteins and/or low molecular weight emulsifiers such as phospholipids. Research questions about the interfacial structure of mixed interfaces, such as their composition and arrangement, as well as their interfacial rheology and dynamics, remain unanswered.
This study investigated the impact of the fatty acid chain length, the charge,and the nature of phospholipid head groups on the interfacial structure, rheology and interfacial dynamics of protein-stabilized emulsions. A combination of conventional methods – such as drop tensiometry and interfacial rheology – and advanced methods – such as small angle neutron scattering and neutron spin echo spectroscopy – helps us to answer research questions about complex interfacial systems.
The head group of phospholipids strongly affects the interfacial structure and rheology of a β-lactoglobulin-stabilized emulsion. The interfacial structure was resolved using small-angle neutron scattering with partial structure factor analysis and coarse-grained modeling. The interfacial dynamics are characterized by 2D diffusion within the interfacial layer of the oil droplet and height fluctuations normal to the interfacial layer. The interfacial dynamics of the protein are inert for changes in interfacial structure, composition, and rheology, although structure and rheology have a strong influence on each other. These results provide guidance for the emulsion characteristics of food, cosmetics, and drug delivery systems.

In recent decades, the utilization of sustainable protein sources has become a major focus of food research. Within the field of plant-based proteins, green biomass proteins are attracting increasing interest. Alfalfa (Medicago sativa L.) represents a promising regional biomass source, yielding large amounts of protein-rich material [1].

However, the isolation of pure and functional protein fractions from green biomass remains challenging due to rigid cell walls and secondary metabolites [2]. To access the white protein fraction, rich in ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCo), different isolation protocols were evaluated [3,4]. Two promising approaches, developed at Aarhus University were selected. One protocol is based on acid precipitation followed by washing and microfiltration, whereas the second protocol relies on ultrafiltration.

The resulting protein concentrates were analyzed with respect to their techno-functional properties using neutron-based techniques. Small angle neutron scattering (SANS) revealed pronounced differences in structural properties between the two concentrates. The ultrafiltrated protein concentrate showed higher solubility and higher RuBisCo purity than the acid-precipitated and microfiltered concentrate.
These structural differences directly influenced techno-functional characteristics, particularly protein behavior at oil/water interface.
Protein samples were kindly provided by Trine Dalsgaard and colleagues (Aarhus University).

The diverse properties of plant-based proteins give a wide range of possible food applications, e.g. as emulsifiers in alternative foods or functional drinks [1]. Their isolation is laborious due to accompanying components. Therefore, understanding protein behavior within complex food matrices is essential for both food science and process optimization.
Especially RuBisCo gained interest in the last years as it proved to have favorable techno-functional properties [2]. Its isolation process from alfalfa green biomass (Medicago sativa L.) is impaired by various (secondary) metabolites. Alfalfa is rich in polyphenols, which can bind to proteins and subsequently reduce the protein yield [3, 4]. In turn they are oxidized by polyphenol oxidase, causing enzymatic browning, which can negatively influence the consumers acceptance [5]. These interactions highlight that proteins cannot be considered independently during the isolation process but are part of an interconnected plant system.
Using specific spectrophotometric methods to quantify the total phenolic and protein content as well as the enzyme activity of the PPO in combination with SAXS-measurement the system is viewed as an integrated whole. Continuous measurements along the isolation protocol identify structural changes and optimal process parameters. This gain of knowledge improves the isolation of RuBisCo from alfalfa and delivers valuable insights for the purification of proteins from green biomasses.

Plant-based meat analogues have been widely promoted as an alternative protein source to reduce consumption of meat for potential environmental and health benefits. However, despite rapid product development, many plant-based products still lack the structural and textural complexity of conventional meat.
In this study, different soy protein sources (isolate vs concentrate), with and without additional soy fibre, was used for high moisture extrusion cooking. Small- and ultra-small-angle neutron scattering techniques were used for probing the structural features, between 1 nm to 20 µm, of protein “dough” (before extrusion) and protein analogues (after extrusion). Complementary texture analysis and microscopy were used to relate neutron-derived length scales to fibrous alignment.
Distinct differences in hierarchical organisation were observed between soy protein systems of differing purity, reflected in changes in the network compactness. Fibre addition disrupted the structural continuity of a pure protein system (>90% protein dry weight). These neutron-resolved structural changes correlated with differences in fibrous texture and alignment. This work demonstrates the value of neutron scattering for linking structure across length scales in complex food systems and is intended to provide the structural basis for future in situ studies of the high moisture extrusion processing of plant proteins, linking dynamic structure evolution to processing and functional properties.

Espresso is prepared by extraction from finely ground coffee under high pressure, yielding a concentrated coffee rich in emulsified lipids, polysaccharides, and solids that contribute to its unique aroma and mouthfeel. While the aroma and flavor compounds in coffee have been meticulously studied for decades, relatively few studies have addressed these colloidal structures. In this presentation, I will present our insights on the colloidal structures present in our daily coffee. We combined imaging, scattering, and rheological techniques to unravel the size, structure, and interactions of espresso colloids. We find extracted oil droplets, mostly in the submicron range, stabilized by protein-polysaccharide complexes at their interface, and relatively long fiber-like polymer structures. The size of extracted oil droplets gradually decreases as a function of extraction time, and the first fraction shows clear evidence for unfolded polymers in its scattering profile. The rheological characterization of espresso revealed that the first milliliters of espresso exhibit a considerable shear viscosity and even viscoelasticity, while later fractions have negligible viscosity. Combined, our results show that the size and structure of extracted lipids and polymers strongly depend on the extraction time. Mostly the first fraction contributes to the ‘body’ of espresso due to its high concentration of dispersed colloids and the early extraction of unfolded polymers.

Caseinates are functional protein ingredients derived from milk, which form small, nanometer-sized aggregates in solution. They form stable gel networks upon acidification, which can be strengthened by cross-linking using enzymes such as transglutaminase.

While the acid-induced gel formation of cross-linked caseinates has been studied in detail in the past, the conformational changes of the caseinate nanoparticles induced by cross-linking remain largely unexplored. Light scattering indicated some changes in size, density and shape (doi:10.1016/j.foodhyd.2019.01.043), but these might be artefacts from dilution. SAXS, however, allows to study the conformation of caseinates in undiluted systems.

In this study, caseinate (27g/L) with varying degrees of enzymatic cross-linking was investigated using SAXS before and after dilution. SAXS of the undiluted solutions revealed minimal conformational changes. However, upon dilution to 10 g/L protein and, especially, upon addition of urea, the differences became more apparent, indicating dissociation of un- and less cross-linked casein.

In the presentation, the conformation of caseinates cross-linked using transglutaminase will be discussed and related to their acid gelation properties. With the rise of new technologies such as precision fermentation, new protein ingredients such as microbial caseins will enter the market soon, and understanding of their structure-function interrelations is needed to exploit their potential in food.

Small angle neutron scattering (SANS) provides unique sensitivity to hierarchical organization in complex soft-matter systems and is particularly well suited for probing the internal structure of the casein micelle in milk. In this contribution, we present newly obtained SANS data on reconstituted milk samples, focusing on how the internal organization of the casein micelle evolves as a function of reconstitution time and concentration.
First, we investigated the structural development of the casein micelle following reconstitution from milk powder. The SANS data reveal clear and systematic changes in the internal micellar structure over time, with measurable differences persisting for up to 24 hours after reconstitution. These results indicate that the casein micelle does not instantaneously recover its equilibrium internal organization upon rehydration, but instead undergoes a gradual structural reorganization.
Second, we examine the effect of concentration, and concomitantly mineral concentration, on the micellar structure. Variations in concentration lead to pronounced changes in the scattering profiles, highlighting the strong coupling between casein organization and mineral-mediated interactions within the micelle.
Initial modelling of the SANS data is presented, capturing the main structural features and trends observed experimentally. Ongoing work aims to apply our comprehensive structural model, previously developed for small angle X-ray scattering (SAXS) data on casein micelles (J. S. Pedersen et al 2022 and 2026), to the SANS measurements. This modelling approach is expected to provide a holistic and quantitative description of the internal organization of the casein micelle, bridging neutron and X-ray scattering insights and advancing our understanding of milk as a dynamic, multiscale colloidal system.

SAXS remains challenging for complex systems such as EYG and casein fusion proteins. It provides quantitative insights into intermediate structures and internal organization and allows a statistical description of the dynamic fine structure of macroscopic complexes, especially relevant for our artificial casein microparticles and fibres used for enzyme immobilization.
We investigated native and lyophilized egg yolk granules (EYG) as well as recombinant casein fusion proteins using SAXS. In EYG, lyophilization led to a loss of LDL and expansion of HDL structures, as indicated by Porod exponents and peaks at q ~0.019–0.037 Å- 1. Functional tests confirmed stable oil-in-water emulsions after rehydration. Higher EYG concentrations resulted in smaller droplets and improved stability.
In the SAXS curves of casein fusion proteins, the intrinsically disordered casein moieties curves could be described by modified Lorentz functions, while compact fusion proteins were modelled with spherical shape factors, considering known radii of gyration. Further analyses showed that these fusion proteins can be successfully incorporated into microparticles and fibres. We report on the influence of the nano- and aggregate structure on porosity and distribution within the functional materials.
Elucidation of the average nano- and aggregate structure enables the targeted production of sustainable, functional foods and recombinant casein biopolymer constructs for biocatalysis and enzyme immobilization.

Seaweeds are increasingly recognised as sustainable, nutrient-dense candidates for future food systems, yet the mechanisms governing their gastrointestinal digestion remain unclear. Here, we show how the multiscale architecture of the red seaweed Porphyra umbilicalis (nori) governs protein bioaccessibility during digestion. Combining in vitro digestion with a multi-technique approach (microscopy, SAXS, SANS, X-ray holotomography), we tracked digestion-driven transformations from the nanoscale to the microscale. We found that Nori cell walls remain largely intact after gastric digestion, with a porphyran-rich dense matrix restricting pepsin access towards intracellular proteins. In contrast, intestinal conditions triggered pronounced cell wall disruption, enabling protein release and subsequent hydrolysis into peptides. Importantly, the released peptides and polysaccharides further interacted with bile salts, reshaping micellar assembly and suggesting an additional route by which seaweed components may modulate lipid digestion. Overall, our results demonstrate that protein–polysaccharide interactions in seaweeds not only control digestibility but also direct the self-assembly of digestion products. This structural–functional study provides a mechanistic basis for designing seaweed-based foods with improved nutritional performance and motivates future neutron-enabled studies linking the nanostructure of digestion to physiological outcomes, such as nutrient absorption and satiety

Plant cell wall polysaccharides play a key role in determining the structure, mechanical properties and digestibility of plant-based and alternative foods. However, their hierarchical organization in complex hydrated matrices remains challenging to resolve using conventional techniques. Small angle neutron scattering (SANS), especially when combined with X-ray scattering and complementary tools such as microscopy and rheology, provides unique insights into the nanoscale organization of polysaccharides.

Here, we present a series of studies using SANS to unravel the multi-scale structure of cell wall polysaccharides in both model and complex food matrices. In composite cellulose hydrogels containing major plant cell wall polysaccharides, SANS revealed distinct interaction mechanisms, including their co-crystallization with cellulose microfibrils and surface adsorption. In agar-based hydrogels, combined SAXS/SANS enabled the identification of double-helix aggregation and bundle formation as the structural basis of gelation, linking molecular organization to macroscopic rheological properties. This structural framework was then applied to a complex system: the edible seaweed Porphyra and its structural evolution during in vitro gastrointestinal digestion. The results revealed the presence of gel-like polysaccharide networks protecting seaweed cells, which limited enzyme accessibility and protein release during the gastric phase, but were disrupted after the intestinal phase, resulting in a relatively high protein digestibility.

These studies highlight the potential of neutron scattering to support the rational design of sustainable food materials with tailored functionality and digestibility.

Microemulsions are mixtures of water, oil, surfactant, and co-surfactant that spontaneously self-assemble into diverse nanostructures governed by composition and environmental conditions. Although their phase behavior has been studied for decades, designing food-grade, pH-responsive microemulsions remains a challenge. Their rational design depends on a molecular-level understanding of structural response mechanisms. Beyond molecular composition, surface interactions, spatial confinement, and hierarchical structuring play a decisive role in directing the functional behavior of these materials.

This presentation demonstrates pH- and composition-responsive microemulsions engineered for applications such as nutrient extraction and drug delivery. It provides a fundamental analysis of the pH-triggered co-assembly of lecithin and oleic acid with selected bioactives. Using in situ SAXS and (GI)SANS combined with selective deuteration and solvent contrast variation, we analyse structure formation in both, the bulk phases and at the liquid-liquid interface across diverse length and time scales. We track the evolution of spatial confinement and hierarchical structuring as pH and ionic strength are varied. Supported by numerical data modelling, we map the distribution of molecules within these systems. These studies are complemented by tensiometry and release experiments for a direct connection between material properties and function.

The structural transformations are interpreted within theoretical frameworks such as the critical packing parameter model. They are correlated macroscopic changes of material parameters, such as drug uptake and release, and rheological properties. Building on these findings, we propose advanced design principles for creating adaptive, functional microemulsions that bridge formulation science and state-of-the-art nanostructural characterization.

(1) Gradzielski, M. and al. Using Microemulsions: Formulation Based on Knowledge of Their Mesostructure. Chem. Rev. 2021.
(2) Salentinig, S.; Phan, S.; Darwish, T. A.; Kirby, N.; Boyd, B. J.; Gilbert, E. P. pH-Responsive Micelles Based on Caprylic Acid. Langmuir 2014.
(3) Balogh, J. and al. A SANS Contrast Variation Study of Microemulsion Droplet Growth. J. Phys. Chem. B 2007.

Pulses and beans are important protein sources in the current protein transition, but much of the behavior of pulse proteins in food systems is still unknown. In particular in interface-dominated materials (emulsions, foams, etc), the nanoscopic behaviour of a protein – how they fold, stretch, and lock into place – governs whether a two-dimensional protein assembly ends up as a soft gel, a rigid glass, or something in between.

In our lab we have used high resolution AFM to reveal the superstructures of pulse proteins on the air-water interface. While this is very insightful, such films are lifted from the interface and are dry. Scattering techniques are ideal for an in-situ analysis of pulse protein interfacial superstructures. In our recent work, we have performed different scattering experiments to glean in situ information on several hierarchical levels. Transmission small-angle neutron scattering with contrast variation shows how the individual protein shape is affected by adsorption to the interface, whereas in situ grazing incidence (GI)SAXS gives us a unique insight in how protein superstructures are formed during the adsorption and aging process. Together, these insights build a multi-scale picture of how conformation translates into function.

Simple intestinal in vitro digestion studies combined with synchrotron SAXS have suggested a rich lipid nanostructural polymorphism in bovine milk. Here we present similar studies on a range of commercial plant emulsion milk substitution products and show significant differences despite comparable compositions of fat, protein and minerals. We expand the digestion studies to include a gastric phase as well as test different gastric lipase options and the inclusion of bile salts and phospholipids - all yielding dramatic differences of the final nanostructural outcomes.

Acid- and rennet-induced gelation are key processing steps for dairy products such as cheese and yoghurt. Milk gelation is often affected by heat treatment, which is critical for ensuring microbial safety. Understanding how heat treatment modifies gelation behavior, is essential for optimizing dairy product processing. However, the structural changes induced by heat treatment during gelation was not completely understood, and milk from different animal origins may respond differently to heat treatment. Therefore, the aim of this study is to investigate the impact of heat treatment on acid- and rennet-induced gel in goat and cow milk. SESANS was used to probe heat-induced structural changes. A fractal model was used to identify differences in structural parameters, including fractal dimension and correlation length. These parameters correlate with the packing compactness and average aggregate size of casein micelles in gels. Heat treatment exhibited opposite effects on the fractal dimension of acid and rennet gels, with an increase observed in acid gels and a decrease in rennet gels. Compared to cow casein micelles, goat casein micelles exhibited a different sensitivity to heat treatment. In particular, rennet gels from goat milk showed fewer structural changes than those from cow milk. Overall, the results demonstrate the capability of SESANS to study structure in complex dairy systems and contribute to characterization of dairy products from different animal species.

Dairy gels are networks formed by the aggregation of colloidal scale particles, casein micelles, in milk. This class of materials represent a well developed technology for the modulation of sensory properties, storage and transport of milk products, and such technologies may be developed for other food gels. Previously we have examined the equilibrium structure of dairy gels formed by acid and enzymic gelation using ultra-small angle neutron scattering (USANS) and neutron imaging. A comparison of the data with a calculation based on the fractal dimension and single correlation length of the gel network (Teixeira/Chen model) and material composition yields a perspective on the spatial heterogeneity in a representative volume of the gel. An analysis of the gel’s mechanical properties through the interpretation of oscillatory rheology has provided an equivalent fractal dimension. Here we our describe experimental efforts in following the evolution of this fractal dimension and the kinetics of casein micelle aggregation. Two types of small angle neutron scattering have examined use the point by point measurement of Bonse-Hart USANS on the KOOKABURRA instrument (ANSTO, Lucas Heights, Australia) and very small angle neutron scattering VSANS at the Chinese Spallation Neutron Source (Dongguan, China) on an area detector to understand the time course evolution of the network. USANS measurements provide an unequivocal, but with temporally limited temporal resolution, probe of VSANS measurements provide insights into the early aggregation process with superior time resolution. To bridge the spatial resolution between conventional neutron radiography and small angle scattering we have examined gel formation dark field imaging on the BOA and FOCUS beamlines at the Paul Scherrer Institute (Villigen, Switzerland).

Increasing the temperature of protein dispersions initiates the denaturation via breaking of hydrogen and disulfide bonds. These denatured proteins undergo hydrophobic attraction due to exposure of the hydrophobic sites of the protein, resulting in the formation of smaller protein aggregates, which finally leads to protein gelation by forming an intermolecular network structure at the gelation temperature (TG). Protein gels can also be obtained at lower relative temperatures, a process called cold-set gelation. This method holds significant potential in various applications, including medicine and the food industry, due to its mild processing conditions. In this work [1], we examine the ethanol-driven cold-set gelation of BSA protein, where gelation could be achieved at temperatures as low as room temperature. The gel formation has been established by both macroscopically, using visual inspection and tube inversion tests and microscopically, using rheology measurements. We further probed the modification in inter-protein interactions during such gelation and resultant structures using SANS and DLS techniques. Interestingly, alcohol-induced cold gelation of protein could be completely suppressed on the addition of the ionic surfactant, SDS. The underlying mechanism has been explained based on competing interactions in the presence of alcohol and SDS.
[1] D. Saha et al., Food Hydrocolloids 172, 111991 (2026).

Neutron scattering experiments, particularly on soft matter, often require precise labelling in order to target selected parts of the material to be studied. Due to the large quantity of hydrogen atoms in soft matter and the marked contrast between hydrogen and its isotope, deuterium, selectively replacing hydrogen atoms with deuterium is a versatile strategy to influence the contrast within a material.

We run a deuteration service at the Jülich Center for Neutron Science (JCNS) to assist users of the MLZ neutron instruments and other neutron facilities in their experiments. In this talk we want to present which kind of deuterated materials we have already synthesized for applications in food science. This includes deuterated trigylceride oils for the investigation of emulsions as well as deuterated food surfactants from the Tween and Span families.

Finally, we wish to inform the food science community how they can access our service in order to obtain deuterated materials for their neutron experiments and give a general overview on the possibilities and limitations of synthetic deuteration.

Neutron imaging has rapidly become a powerful technique across many scientific fields, offering unique contrast for light elements and hydrogenous materials through methods such as conventional radiography and tomography, grating interferometry, and wavelength-resolved imaging. While neutron scattering is widely established in food science, the community has only begun to exploit the diverse opportunities and contrast modalities that neutron imaging can provide.

This contribution reviews notable examples where neutron imaging delivered non-destructive insight into complex food systems. Applications include water migration during drying, moisture redistribution in meat during cooking, microstructure of extruded Spirulina–starch foams, water distribution in bread related to shelf life, and freeze-drying dynamics. These studies demonstrate the method’s ability to probe hydrogen-rich phases under realistic thermal and humidity conditions.

Opportunities emerging from new contrast modalities will be discussed, including dark-field imaging, wavelength-resolved imaging enabling thermography, selected deuteration, and multimodal neutron–X-ray tomography, which all remain underexplored in food research. Advanced analysis using Digital Volume Correlation offers new ways to quantify internal movements and material transport in food systems and processing.

Selected References: Defraeye (2013, 2015); Scussat (2016); Mannes (2016); Martínez-Sanz (2020); Vorhauer-Huget (2020); Hilmer (2024).

The gentle yet cost-efficient drying of sensitive products in the food and pharmaceutical industries is becoming increasingly important. However, the freeze-drying process is very time-consuming and costly, which is due to poor mass and heat transfer. Therefore, a microwave freeze-drying process was developed, in which the bulk material is continuously mixed in a rotating drum.
To determine the influence of the drum's rotational speed and the particle size on the drying process without interference, the drying process characteristics and spatial homogeneity were studied using in-operando imaging at the Centre for Energy Research in Budapest. Using this technique allows monitoring non-invasively not only the drying characteristics but also the changes in particle bulk during drying. For this purpose, a dryer suitable for the requirements of microwave freeze-drying and neutron imaging was developed first, and then the drying process was imaged in-operando for two drum rotational speeds and two different particle sizes for maltodextrin model particles. This approach enabled real-time quantification of local water content through step-wedge calibration and determination of initial outer porosity. High-resolution imaging provided accurate moisture mapping and showed that rotational speed primarily affects drying homogeneity, while particle size had a smaller influence on drying kinetics under the tested conditions. Furthermore, changes in porosity during drying and decrease in total bulk volume during the drying process were also observed and analyzed.

Pea proteins have gained interest due to their potential to become a sustainable alternative to animal derived food proteins. Today most development work is focused on the protein fraction but requires further studies on the interaction between different components. Of particular interest are the interactions with lipids, as there is lack of fundamental knowledge despite their key role in the plant seed architecture and their importance in obtaining palatable products. In earlier work, we have shown by using neutron reflectometry that these proteins interact with model lipid membranes produced with synthetic phospholipids (1). Recently we have been able to show that the native polar lipid fraction from pea self-assemble into well-defined lipid bilayers on a silicon block. We here used for the first time, magnetic reference layers and polarized neutrons (2) to study native pea lipids bilayers. This allowed us not only to characterise the bilayer structure but how purified pea proteins, i.e. legumin and vicilin, interact with this natural lipid extract. We noted that vicilin show stronger interaction, i.e., denser protein layer, with the lipid bilayer than legumin. We discuss how such an interaction might be facilitated by the compact structure of pea proteins, which is dominated by hydrogen (beta-sheet stacks) bridges and hydrophobic interactions.
1. G. U. Atül, M. R. Machingauta, A. Luchini, A. Vorobiev, M. Corredig, T. Nylander. Food Hydrocolloids, 2026, 172, 111842.
2. O. Dikaia, A. Luchini, T. Nylander, A. Grunin, A. Vorobiev, A.Goikhman. J. Appl. Cryst. 2024, 57, 1145–1153.

Soft matter systems, such as colloids and emulsions, are central to food architecture. Their structural response to mechanical forces - like those during mixing or pumping - dictates final texture and stability. In this study, we investigate the interplay between shear flow and microstructure in a stable, surfactant-free glycerol-in-silicone oil emulsion.To overcome the limitations of light-based techniques in opaque fluids, we pioneer the use of $in$ $situ$ neutron dark-field imaging (DFI) using a novel single hexagonal grating. This technique captures spatially resolved maps of anisotropic small-angle neutron scattering (SANS) signals over large sample areas in a single shot, avoiding the need for time-consuming scanning.Our results reveal significant droplet elongation and the formation of reversible bands with alternating droplet density within a Couette cell. By combining this high-resolution structural mapping with simultaneous macroscopic rheology, we demonstrate a powerful multimodal probe for concentrated, opaque systems. This methodology allows for the characterization of complex ingredients from the nanometer to the micron range, leveraging neutron contrast matching to isolate specific components under realistic processing conditions.