The principle behind these systems is deceptively simple. Instead of chemically altering oil molecules the way hydrogenation does, oleogelation physically entraps edible oils within three-dimensional networks built by tiny amounts of gelators—waxes, fatty acids, monoglycerides, or phytosterols. The unsaturated fatty acid profile of olive, flaxseed, or sunflower oil remains intact, yet the liquid gains solid-like characteristics. Hydrogels work the same trick with water, using hydrophilic polymer chains from alginate, pectin, carrageenan, gelatin, or whey protein to hold large quantities of aqueous phase without dissolving. The result is a semi-solid matrix whose architecture, not its chemistry, determines how it feels in the mouth and how it breaks down in the gut.

The review draws a sharp technical distinction between two classes of structuring agents. Low molecular weight gelators, typically under 2000 daltons, self-assemble through weak non-covalent forces—hydrogen bonds, van der Waals interactions, π–π stacking, and hydrophobic effects—into fibrils, ribbons, helices, or crystalline platelets that entangle into a network. Waxes form dense crystalline platelets, while mixtures of β-sitosterol and γ-oryzanol assemble into tubular fibrillar structures stabilized by hydrogen bonding. Polymeric gelators, by contrast, immobilize liquids through chain entanglement, electrostatic association, and physical or chemical cross-linking, producing continuous matrices with interconnected pores. Each approach has trade-offs: crystalline networks deliver efficient oil structuring at low concentrations but can suffer from polymorphism, temperature sensitivity, and oil leakage, while polymer networks offer superior mechanical strength and thermal stability at higher production cost and lower reversibility.

Crystallization-driven gelation is the most prevalent oleogel mechanism. The gelator dissolves in oil at elevated temperature, then cooling triggers nucleation: small crystalline domains grow as chain segments align, entangle through intervening segments, and cluster into a three-dimensional meshwork that immobilizes oil in its voids by capillary action. The final gel properties depend heavily on crystal morphology, polymorphism, cooling rate, and gelator concentration—small changes in any of these can swing the mechanical properties, oil content, and release behavior dramatically. For high molecular weight polymers that cannot dissolve in oil, indirect methods come into play: a hydrogel or emulsion template is first built and cross-linked chemically, enzymatically with transglutaminase, or by radiation, then the aqueous phase is removed or replaced so the polymer framework stays undisturbed while oil is physically entrapped.

Hydrogel formation follows its own cross-linking logic. Physical hydrogels rely on reversible non-covalent interactions—hydrogen bonding in carboxymethyl cellulose and polyvinyl alcohol, ionic bonding in the famous calcium alginate egg-box structure, and hydrophobic clustering in amphiphilic polymers. These gels are biocompatible and stimuli-responsive but mechanically weak, prone to swelling, syneresis, and premature degradation under manufacturing stress. Chemical hydrogels, built from permanent covalent cross-links formed by grafting agents, polymerization with bifunctional monomers, gamma or electron-beam radiation, or enzymatic catalysis, are far more durable and structurally stable, though residual cross-linkers raise toxicity and biocompatibility questions that regulators scrutinize closely.

Where the review turns genuinely viral is in its treatment of digestion. Structured gels do not just change texture; they change metabolism. In conventional emulsions, lipid droplets are rapidly exposed to pancreatic lipase, producing sudden peaks in blood triglycerides. Oleogels create what researchers call the cage effect: a densely packed crystalline lattice forms a steric barrier that restricts lipase access to the oil–water interface, while the viscous internal environment slows the diffusion of free fatty acids out of the matrix. The consequence is delayed lipolysis, blunted postprandial lipemia, prolonged satiety, and a steadier release of mixed micelles—the bile-salt assemblies that lipophilic nutrients like curcumin, vitamin D, and lycopene need to cross the intestinal mucus barrier. Slower, coordinated lipid digestion can roughly double the absorption of these fat-soluble compounds.

Hydrogels add a second layer of precision: stimuli-responsive delivery. Alginate and pectin networks stay contracted at gastric pH around 2, protecting probiotics, antioxidants, and enzymes from denaturation, then swell or dissolve as pH rises to 6.5–7.0 in the small intestine, releasing their cargo exactly where absorption occurs. Some polysaccharide hydrogels resist human digestive enzymes entirely and break down only through microbial fermentation in the colon, enabling prebiotic effects and targeted colon health. The experimental evidence is striking: alginate–chitosan hydrogels preserved probiotic viability above 70 percent through gastric conditions, while free probiotics fell below 20 percent. κ-Carrageenan hydrogel beads achieved 74.61 percent encapsulation efficiency with sustained, pH-responsive release of curcumin, and curcumin-loaded bigels maintained 97.55 percent curcumin stability with improved digestion performance.

Bigels—hybrid structures containing both an aqueous gel phase and an oil gel phase—represent the review’s vision of all-in-one precision delivery. Because the two phases can be engineered to release their contents on different kinetic schedules, a single bigel can deliver an initial burst of flavor or energy from its hydrogel component in the mouth or upper gut, followed hours later by prolonged release of functional lipids from its oleogel component in the ileum. Incompatible nutrients such as hydrophilic vitamin C and lipophilic vitamin D3 can be co-encapsulated in one matrix, with a prebiotic released in the upper gastrointestinal tract while an antioxidant deploys in the lower regions. Emulsion gels extend this logic further, supporting co-delivery of multiple solutes within soft colloidal structures built from natural polymer self-assembly, cross-linking, crystallization, and molecular template assembly.

The food applications read like a menu from the near future. Ethylcellulose and wax oleogels can replace butter or lard in cookies and cakes, cutting saturated fat content by up to 80 percent while preserving crispness, and stabilize liquid cocoa butter to prevent fat bloom and keep chocolate glossier and heat-resistant. In plant-based meats, carefully tuned ratios of oleogels for fat content and hydrogels for moisture produce white fat particles that do not instantly melt, recreating the succulence of beef and pork; oleogels can also replace pork back fat in sausages with unsaturated olive or flaxseed oil. Bigels from sunflower and canola oil yield margarines that spread straight from the fridge with minimal trans fats, while hydrogel–oleogel substitutes for casein improve melting in vegan cheeses. These gels are also ideal inks for 3D food printing: their shear-thinning rheology lets them flow under pressure but hold shape at rest, allowing printers to deposit precise nutrient doses into customized snacks, and hydrogel coatings sprayed on strawberries or avocados measurably extend shelf life.

Commercialization remains the hard part. Scaling up requires precise thermal control and consistent gelator sourcing, and natural gelators vary batch to batch in rheology, strength, and encapsulation efficiency. Consumer acceptance hinges on mouthfeel, taste, and flavor release, while novel formulations must pass GRAS evaluation in the United States and EFSA safety assessment in the European Union, covering toxicity, digestibility, allergens, and migration. The clean-label trend may restrict synthetically produced systems, and few studies have yet combined performance data with techno-economic assessment or converted in vitro digestion results into validated in vivo human outcomes. Still, the trajectory is clear: personalized nutrition, AI-based formulation, sustainable gels from agricultural waste, and hybrid bigel systems are converging on a future where food structure is designed molecule by molecule. Oleogels and hydrogels are no longer laboratory curiosities—they are the emerging soft matter platforms for the next generation of nutritional foods, where what holds your food together may also decide how well it feeds you.

Subject of Research: Soft matter food structuring and targeted nutrient delivery

Article Title: Advanced oleogel and hydrogel systems: emerging platforms for food structuring and targeted nutrient delivery

Article References: Pandey, R., & Mathur, G. (2026). Advanced oleogel and hydrogel systems: emerging platforms for food structuring and targeted nutrient delivery. Frontiers in Soft Matter, 6, Article 1867312. https://doi.org/10.3389/frsfm.2026.1867312

Image Credits: AI Generated

DOI: 10.3389/frsfm.2026.1867312

Keywords: oleogels, hydrogels, bigels, food science, nutrient delivery, soft matter, digestion modulation, 3D food printing, Advanced, oleogel, hydrogel, systems

The research team prepared pork leg meat by removing connective tissue and grinding lean and fat portions together at a ratio of 8.5 to 1.5. Into this base emulsion they mixed a seasoned formulation containing sugar, fish sauce, glycerol, spices, salt, and water, then varied the gelatin concentration from 0 to 2.5 percent by weight. Each formulation was printed into a rectangular slab mimicking pork jerky using a food-grade extrusion printer operating at 25 degrees Celsius with a 1.55-millimeter nozzle, 100 percent infill, and a printing speed of 30 millimeters per second. The printed products were then hot-air dried, baked, and analyzed for everything from gel strength to moisture distribution.

Rheological measurements revealed why gelatin matters so much. In dynamic frequency sweeps, the storage modulus G-prime exceeded the loss modulus G-double-prime in every formulation, meaning the material behaved predominantly as a solid-like viscoelastic gel. That solid-like character is exactly what a printed layer needs: it allows the extruded strand to support the weight of subsequent layers without collapsing. Gel strength rose significantly with gelatin content, climbing from 119.62 grams in the untreated paste to 154.48 grams at the highest dosage, a change the authors attribute to hydrogen bonds forming between gelatin molecules and the myofibrillar proteins that make up 50 to 55 percent of pork’s total protein.

But more gelatin is not always better. When the concentration reached 2 percent, the researchers observed clogging and adhesion at the nozzle, likely because undissolved gelatin particles or overly viscous aggregates disrupted the uniformity of the paste and jammed the extrusion process. The sweet spot turned out to be 1 percent gelatin, which produced the best layer adhesion, the highest printing fidelity, and no structural collapse. Confocal laser scanning microscopy confirmed the story visually: without gelatin the protein network was loose and porous with large voids, while moderate gelatin addition produced a densely cross-linked, compact matrix. At 2.5 percent, however, the network showed signs of stacking and compression, as excess macromolecular gelatin crowded the native pork proteins.

Water is the hidden variable in printed meat. Using low-field nuclear magnetic resonance, the team identified three water populations in the gels — bound water, immobilized water, and free water — corresponding to relaxation peaks at roughly 0.01 to 10, 10 to 100, and 100 to 1000 milliseconds. At the optimal 1 percent gelatin level, all three relaxation times reached their shortest values, indicating the tightest integration of water into the protein network, while the free-water fraction peaked at 1.09 percent, providing just enough lubrication for smooth extrusion. Water-holding capacity climbed in a dose-dependent manner, reaching 80 percent at 1 percent gelatin, and the baking loss rate fell to its minimum of 48.63 percent at the same concentration — a meaningful economic gain, since every percentage point of moisture lost during cooking is weight and value lost from the product.

Fourier-transform infrared spectroscopy added a conformational dimension to the findings. The alpha-helix content of the proteins, which was only 17 percent in the unmodified paste, rose to 23 percent as gelatin increased to 1.5 percent, while the proportion of disordered random coils initially declined. Because alpha-helical content reflects hydrophobic groups and sulfhydryl groups being folded back into the protein interior, this shift signals a more ordered, elastic gel. The authors note that gel performance peaks at a certain degree of helical unfolding or re-formation, and their data pinpoint 1 percent gelatin as the concentration that achieves that balance.

The most novel part of the study, however, descends to the molecular scale. Because myofibrillar proteins contain fluorescent tryptophan and tyrosine residues, the team could use fluorescence spectroscopy as a molecular spy. When oleic acid or palmitic acid — the two predominant fatty acids in pork — were added to purified myofibrillar protein, the intrinsic fluorescence dimmed progressively, with quenching efficiencies of 51.70 percent for oleic acid and 50.74 percent for palmitic acid in the binary systems. Stern-Volmer analysis showed that the quenching constants decreased as temperature rose from 328.15 to 338.15 kelvin, the signature of static quenching: the fatty acids form stable, non-fluorescent ground-state complexes with the protein rather than merely colliding with it.

Gelatin rewired these interactions in revealing ways. In the ternary systems containing gelatin, quenching efficiencies dropped to 33.81 percent for the oleic acid combination and 41.5 percent for palmitic acid, showing that gelatin partially shields the protein’s fluorescent residues from fatty acid binding. Binding constants and the number of binding sites both increased in the presence of gelatin, with the effect stronger for palmitic acid than for oleic acid. Thermodynamic analysis of enthalpy and entropy changes showed that oleic acid alone binds myofibrillar protein through hydrophobic interactions, an endothermic process that strengthens with heat. Add gelatin, however, and the dominant forces shift to van der Waals interactions and hydrogen bonds — the same forces that govern palmitic acid binding with or without gelatin. Synchronous fluorescence spectra reinforced the picture, showing blue shifts of up to 4 nanometers that indicate the amino acid microenvironments became less polar and more hydrophobic, with gelatin exerting a stronger influence on tyrosine than on tryptophan.

What makes this study compelling is the way it connects the molecular ledger to the printed object on the plate. Gelatin’s thermally reversible triple-helix gelation and strong shear-thinning behavior give the paste the flow profile needed for smooth extrusion and the rapid re-gelling needed for self-supporting layers, while its protein nature lets it weave directly into the myofibrillar network in a way that polysaccharide hydrocolloids such as carrageenan and gellan gum cannot. By modulating how fatty acids bind to the protein matrix — softening quenching, increasing binding capacity, and steering oleic acid toward hydrogen-bonded association — gelatin stabilizes the entire lipid-protein-water architecture that determines whether a printed pork product holds its shape, retains its moisture, and survives the oven. For a field racing toward personalized nutrition, cultured-meat scaffolds, and printed meals for dysphagia patients, the message is that printability is not just a rheology problem; it is a molecular recognition problem, and the right hydrocolloid can solve both at once.

Subject of Research: Gelatin modulation of 3D printing properties and fatty acid–myofibrillar protein interactions in pork mince

Article Title: Study on the modulation of the properties of 3D printing pork mince and interaction mechanisms with myofibrillar proteins and fatty acids by gelatin

Article References: Wu, L., Wang, A., & Cui, Q. (2026). Study on the modulation of the properties of 3D printing pork mince and interaction mechanisms with myofibrillar proteins and fatty acids by gelatin. Food Chemistry: X, 39, Article 104543. https://doi.org/10.1016/j.fochx.2026.104543

Image Credits: AI Generated

DOI: 10.1016/j.fochx.2026.104543

Keywords: 3D food printing, gelatin, pork mince, myofibrillar proteins, oleic acid, palmitic acid, fluorescence spectroscopy, rheology, water-holding capacity, protein conformation, food hydrocolloids, static quenching

The research, led by Yongquan Wang of Anhui Agricultural University together with colleagues including Haichuan Shi and Wenjia Yan, set out to answer a deceptively simple question: does the industrial method used to pull protein out of broken rice change the protein’s structure enough to alter its behavior as an emulsion stabilizer? The answer turned out to be a resounding yes, and the consequences ripple through every downstream property of the final food product, from droplet size and elasticity to vitamin retention and suitability for people with dysphagia, the swallowing disorder that affects millions of elderly and hospitalized patients worldwide.

The team compared two extraction routes. The first was enzymatic extraction, in which thermostable alpha-amylase digests the starch surrounding the protein, releasing it in stages. By repeating the enzymatic treatment, the researchers produced three protein samples with escalating purity: 29.47 percent protein after one round, 55.04 percent after two, and 67.95 percent after three. The second route was the classic alkali solubilization and acid precipitation method, the workhorse of industrial protein production because of its high yield and low cost. Here, rice flour was stirred in dilute sodium hydroxide to loosen the tight starch matrix, and the dissolved protein was then precipitated at pH 4.8, yielding a fourth sample that was 91.75 percent protein.

Structural analysis revealed that the two methods sculpted the protein in fundamentally different ways. Fourier transform infrared spectroscopy, focused on the amide I region of the spectra, showed that repeated enzymatic hydrolysis reduced beta-sheet content by roughly 8 percent and increased alpha-helix content by about 13 percent, consistent with proteins being progressively liberated from the starch matrix. Alkaline extraction, by contrast, disrupted the hydrogen bonds that hold alpha-helices together, producing a protein with less helical structure and more beta-turns, a signature of a more folded conformation. The alkaline sample also showed a weakened hydrogen-bonding network overall, with its NH and OH stretching bands shifted in a way that suggested freer, less constrained molecular groups.

Those molecular differences translated directly into particle-level behavior. The once-enzymatically extracted protein formed particles roughly 450 nanometers larger than its twice- and thrice-extracted counterparts, while the alkaline-extracted protein produced the smallest particles of all, at just 201 nanometers. More striking was the wettability. Measured through the three-phase contact angle at an oil-water interface, the enzymatic samples ranged from 66.8 to 77.8 degrees, indicating hydrophilic particles that favor oil-in-water emulsions. The alkaline sample registered 127.0 degrees, a dramatic swing toward hydrophobicity, apparently because alkali disruption of hydrogen bonds exposed hydrophobic groups on the molecular surface. Since contact angles near 90 degrees maximize the energy barrier against particle desorption, this shift matters enormously for interfacial anchoring.

All four proteins then faced the same test: stabilizing a high-internal-phase emulsion, or HIPE, in which the oil phase occupies 83 percent of the volume, far above the 74 percent threshold at which droplets are forced into densely packed, gel-like arrangements. Every sample succeeded in producing a self-supporting emulsion that did not flow when its container was inverted, with no visible creaming. But the details differed. Emulsions stabilized by the once-extracted enzymatic protein had droplets averaging 55 micrometers, while those made with the more refined enzymatic proteins produced droplets of 31 to 32 micrometers. Confocal laser scanning microscopy, with the oil stained red and the protein stained green, confirmed a classic oil-in-water architecture of tightly packed droplets in every case.

Stress testing separated the winners from the also-rans. After 30 days of storage, the emulsion made with the crudest protein showed slight oil separation and droplet growth to 132 micrometers, evidence of flocculation and coalescence. The emulsions stabilized by the thrice-enzymatically extracted and alkaline-extracted proteins, however, remained homogeneous through centrifugation at 9000 times gravity, a month of storage, heating at 90 degrees Celsius for 30 minutes, and salt concentrations up to 300 millimolar sodium chloride. Rheological measurements reinforced the picture: the alkaline and thrice-extracted samples showed the highest consistency coefficients and the strongest storage moduli, confirming that their emulsions were predominantly elastic, gel-like materials rather than simple viscous liquids.

That gel-like elasticity is precisely what 3D food printing demands. Loaded into a FOODBOT D1 printer and extruded through a 0.84-millimeter nozzle, the emulsions made from the two most refined proteins retained crisp pentagonal shapes, while those from the crudest proteins slumped and lost their structure. The researchers then ran the standardized tests of the International Dysphagia Diet Standardisation Initiative, the framework that classifies texture-modified foods on an eight-level scale. The fork drip, spoon tilt, and fork pressure tests showed that the printed products from the thrice-enzymatic and alkaline samples met the criteria for Level 4, the pureed and extremely thick consistency prescribed for people with swallowing difficulties, deforming easily under a fork without leaving residue or whitening a thumbnail pressed against them.

The delivery payload was alpha-tocopherol, the most biologically active form of vitamin E, a compound with antioxidant, immunoregulatory, anti-inflammatory, and neuroprotective functions that is nonetheless crippled by poor water solubility, instability, and low bioavailability. Dissolved in the corn oil phase at 1 percent, the vitamin was encapsulated with efficiency exceeding 97 percent and loading capacity above 23 percent. When the emulsions were bombarded with ultraviolet light for 48 hours, more than 78 percent of the encapsulated alpha-tocopherol survived, a 41 percent improvement over the free compound, an effect the authors attribute to the protein layer at the oil-water interface acting as a physical sunshade. During simulated digestion, gastric release was held to between 19.1 and 22.0 percent, protecting the vitamin through the stomach, while the intestinal phase delivered a bioaccessibility of 66.3 to 70.0 percent.

The study sketches a clear causal chain with implications well beyond rice. The extraction method dictates protein structure; structure governs particle size, wettability, and interfacial behavior; and those interfacial properties determine whether the final emulsion can survive storage, heat, and salt, hold a printed shape, and shield a delicate nutrient on its journey through the digestive tract. For a protein stream that has historically been waste, the work suggests a route into premium functional foods, particularly for aging populations. The authors caution that considerable work remains before industrial scale-up: future studies must test the system in varied food matrices, verify bioavailability in animal models, conduct sensory characterization and clinical swallowing trials, and complete life-cycle and techno-economic analyses. But the core demonstration stands: a byproduct once fit only for feed can be transformed, with the right chemistry, into a printable, swallow-safe carrier for essential nutrients.

Subject of Research: Rice protein extraction methods and their influence on high-internal-phase emulsions for 3D-printed dysphagia-friendly food delivery of alpha-tocopherol

Article Title: Rice protein stabilized high-internal-phase emulsions for delivery of α-tocopherol in 3D-printed dysphagia-friendly foods: Influence of extraction methods

Article References: Shi, H., Yan, W., Zhang, M., Qin, M., Wang, J., Liu, X., & Wang, Y. (2026). Rice protein stabilized high-internal-phase emulsions for delivery of α-tocopherol in 3D-printed dysphagia-friendly foods: Influence of extraction methods. Food Chemistry: X, 39, Article 104509. https://doi.org/10.1016/j.fochx.2026.104509

Image Credits: AI Generated

DOI: 10.1016/j.fochx.2026.104509

Keywords: rice protein, high-internal-phase emulsion, Pickering emulsion, 3D food printing, dysphagia, alpha-tocopherol, protein extraction, encapsulation, IDDSI, rheology, bioaccessibility, food chemistry

The motivation is pressing. A rapidly aging global population, together with growing numbers of people living with dysphagia — difficulty swallowing — has created urgent demand for foods that are simultaneously safe, nutritious, and appealing. Such foods must meet strict texture standards to reduce the risk of aspiration, yet they also need to carry meaningful nutrition, particularly lipophilic bioactive compounds, to counter the malnutrition that often accompanies chewing and swallowing disorders. Traditional thickening systems built on starches or hydrocolloids fall short: they struggle to deliver high nutrient density, they cannot structure healthy lipids efficiently, and they tend to break down or separate during long storage.

The team’s starting point was a protein-based Pickering emulsion, a class of systems in which solid particles — rather than synthetic surfactants — adsorb at the oil–water interface and form a protective shell around droplets. The researchers built their interface from ovalbumin, the main protein of egg white, working together with tea polyphenols and hyaluronic acid. Ovalbumin’s amphiphilic character lets it anchor at the interface and form a film, tea polyphenols reinforce the particles through hydrogen bonding and hydrophobic interactions while adding antioxidant capacity, and hyaluronic acid thickens the interfacial layer. When the oil fraction is pushed above 74 percent, the result is a high internal phase emulsion, or HIPE: a material so packed with droplets that it behaves like a soft solid, self-supporting and stable, ideal for loading fat-soluble nutrients.

But stability alone was not enough. A HIPE’s solid-like rheology, the very property that makes it stable, also makes it difficult to process by conventional filling and molding, and even harder to shape with the precision that modern personalized nutrition demands. Enter 3D printing. Extrusion-based food printing promises digital control over both geometry and internal microstructure, which in turn governs how a food breaks apart in the mouth and how nutrients are released. The catch is that a good printing ink must be a rheological paradox: thin and flowing under the high shear of the nozzle, yet instantly stiff and self-supporting the moment extrusion stops.

To resolve that paradox, the researchers turned to the mud–sand analogy. Undissolved gellan gum particles, added at 0.3 percent, played the role of sand: rigid fillers that embed in the droplet network, anchor it physically, and boost mechanical strength. Xanthan gum, tested at 0.2, 0.6, and 1 percent, played the role of mud: its long molecular chains weave a continuous viscoelastic network through the aqueous phase, thickening the system, imparting the shear-thinning behavior needed for smooth extrusion, and reconnecting the gellan particles into a coherent whole. The base formulation — 25 percent composite aqueous phase and 75 percent soybean oil — was homogenized at 12,000 rpm to produce emulsions containing 75 percent oil, well into high internal phase territory.

Spectroscopic and scattering analyses confirmed that the additions were gentle on the protein. Fourier-transform infrared spectra showed that the amide bands of ovalbumin, near 1635 and 1534 per centimeter, remained essentially unchanged across all formulations, meaning the protein’s conformation was barely disturbed. X-ray diffraction revealed a broadly amorphous structure, with xanthan gum actually suppressing the local crystallization of tea polyphenols at higher concentrations, yielding a more uniform composite. Zeta potential measurements told a subtler story: adding gellan gum diluted the system’s net negative charge from about −32 to −26 millivolts, yet the steric hindrance and physical network of the undissolved particles more than compensated, and xanthan gum restored the potential to roughly −35 millivolts at the optimal dose.

Microscopy and stability testing made the synergy vivid. Confocal laser scanning images of the control emulsion showed heterogeneous, flocculated droplets with clear signs of coalescence — the thin interfacial film simply could not withstand the capillary pressures inside a HIPE. Gellan gum alone produced a bipolar droplet distribution, but the combination of gellan and xanthan gum produced small, evenly dispersed droplets locked inside a dense gel matrix. Under centrifugation, the control lost nearly 13 percent of its oil; the best dual-polysaccharide formulation lost none. After 30 days of refrigerated storage, every emulsion remained free of visible phase separation, and heat treatment at 85 degrees Celsius actually strengthened most of the modified systems, as denatured protein formed tougher interfacial films and hydrated gellan molecules tightened the gel network.

The rheological measurements revealed exactly why the material prints so well. All samples showed pronounced shear-thinning, and the storage modulus exceeded the loss modulus throughout, confirming solid-like behavior. As xanthan gum concentration rose, the storage modulus climbed from about 1049 pascals in the control to more than 2500 pascals, while the loss tangent fell — hallmarks of a stronger, more elastic gel. Critically, three-interval thixotropy tests showed that the xanthan-rich formulations recovered roughly 85 percent of their structure after 300 seconds of high shear, thanks to flexible xanthan chains that rapidly re-entangle and bridge the disrupted gellan particles. Yield points shifted to strains above 50 percent, meaning the ink resists deformation during handling yet flows cleanly through the nozzle.

Printing trials put those numbers to the test. The control emulsion exceeded its target dimensions by up to 110 percent, with broken filaments, blurred contours, and collapsed cylinders. Adding gellan gum helped, but deviations still reached 45 percent. The dual-polysaccharide inks, by contrast, achieved near-zero deviation — within a ±3 percent tolerance — producing cylinders and cuboids with crisp edges, uniform layers, and robust interlayer adhesion. The optimal formulation, 0.3 percent gellan gum with 0.6 percent xanthan gum, also proved the most resilient: it survived freeze–thaw cycling better than the 1 percent xanthan version, whose overly rigid network was punctured by growing ice crystals, and it showed the mildest oxidation during a week of storage at −4 degrees Celsius.

Perhaps most importantly for its intended users, the printed foods passed the international standard for dysphagia diets. In fork pressure and spoon tilt tests aligned with the IDDSI framework, the samples deformed under roughly 17 kilopascals — comparable to the force of the tongue during swallowing — broke into small, safe pieces with no large lumps, and held their shape on a tilted spoon, placing them at Levels 6 to 7, soft and bite-sized to easy-to-chew. After steam treatment, the printed constructs retained their form, held water well, and showed a tender texture with reduced adhesiveness, lowering choking risk. The mud–sand design, the authors conclude, offers a generalizable strategy for turning protein-based HIPEs into precision food inks — a step toward printed meals that are simultaneously beautiful, stable, nutrient-dense, and safe for those who need them most.

Subject of Research: Polysaccharide-reinforced protein-based high internal phase emulsions for 3D-printed dysphagia foods

Article Title: “Mud-Sand Structure”-Inspired Synergistic Reinforcement of Gellan Gum and Xanthan Gum on the 3D Printing Properties of Protein-Based High Internal Phase Emulsions

Article References: Xie, Y., He, C., Yu, X., Ma, J., Zhao, E., Liu, M., Zhang, H., Yuan, J., Zhou, Y., Zhu, Q., Cheng, Y., & Liu, Y. (2026). “Mud-Sand Structure”-Inspired Synergistic Reinforcement of Gellan Gum and Xanthan Gum on the 3D Printing Properties of Protein-Based High Internal Phase Emulsions. Current Research in Food Science, Article 101579. https://doi.org/10.1016/j.crfs.2026.101579

Image Credits: AI Generated

DOI: 10.1016/j.crfs.2026.101579

Keywords: 3D food printing, high internal phase emulsion, Pickering emulsion, gellan gum, xanthan gum, ovalbumin, dysphagia, rheology, food ink, IDDSI, tea polyphenols, hyaluronic acid

The central insight running through the collection is that foods rarely sit comfortably on either side of the fluid-solid divide. Instead, they travel continuously through liquid-like, viscoelastic, plastic and solid-like regimes as their internal microstructure evolves. In some materials, a network is born through gelation or crystallization; in others, molecular mobility is frozen out by cooling or a glass transition. In yield-stress materials such as pastes, flow destroys a pre-existing structure that then rebuilds. During drying, cooking and frying, changes in moisture content can simultaneously alter mechanical properties and generate internal stresses and deformation. This continuous, mechanism-dependent journey between states is precisely why food structuring has historically been treated empirically, with process-property relationships assembled through trial and error rather than derived from first principles.

A major theme of the Special Issue is the tight coupling between transport processes, changing material properties and mechanical deformation, particularly during drying. Hu and colleagues present a multiphase, multiscale mechanistic model for hot-air drying of shiitake mushroom, capturing how water removal reshapes the material while it shrinks and stresses. Veser and co-workers predict cabbage-seed drying at laboratory and industrial scales using a non-equilibrium sorption-isotherm approach, while Rizki and colleagues track material-property changes during electrohydrodynamic drying with a close look at the falling-rate period, the stage where moisture loss slows and the material stiffens most dramatically. Shah and Takhar push the coupling even further in microwave frying, combining unsaturated transport based on hybrid mixture theory with electromagnetic equations. Together, these studies make a forceful case that heat and mass transfer cannot be modeled independently of the evolving physical state of the food.

Deformation itself can become a tool rather than a nuisance, and several contributions exploit this deliberately. van der Sman, Curatolo and Teresi investigated buckling during the drying of edible soft matter with a cylindrical core-shell geometry, showing how drying-induced mechanical instabilities generate intricate, predictable deformation patterns. In a companion study, the same team demonstrated programmable shape morphing during drying through symmetry breaking, effectively using moisture gradients to sculpt foods into designed shapes rather than accepting warping as a processing defect. Grasa, Teresi and van der Sman extended the coupled transport-mechanics framework to large-strain anisotropic behavior of meat during cooking using finite-element modeling. These works signal a shift in the field: instead of treating shrinkage, curling and buckling as quality problems to suppress, researchers are beginning to engineer them for structure design.

Underlying this shift is a broader theoretical realignment. Food rheology has traditionally concentrated on materials in their flowing state, while the mechanics of foods undergoing large deformations in a more solid-like condition received comparatively little attention. Meanwhile, advances in soft-matter mechanics and poromechanics now allow deformation, viscoelasticity and moisture transport to be described within thermodynamically consistent frameworks. A particularly striking conceptual bridge is the mathematical correspondence between the configuration tensor used in advanced rheological models and the Cauchy-Green tensor used in large-deformation mechanics. This equivalence offers a common language for materials that alternate between flowing and solid-like states, and its implications for elasto-viscoplastic food materials and stress-driven moisture migration are explored in a recent review by van der Sman in Current Opinion in Food Science. The practical consequence could be a new generation of models that predict, rather than merely reproduce, how foods behave through their whole processing journey.

At the opposite end of the fluid-solid transition lie processes in which a material must first flow in a controlled manner and then preserve its generated shape, and nowhere is this clearer than in three-dimensional food printing. Kim and colleagues examined the printability and structural properties of plant-based scallop adductor-muscle analogues, relating performance to amylose content and the pasting behavior of different rice cultivars. Liu and co-workers studied edible three-dimensionally printed emulsion gels, showing how inulin incorporation modifies both mechanical and sensory properties. Both studies converge on a key conclusion: printability is not simply a question of viscosity. A printable food must respond appropriately during extrusion, then recover or develop enough structural integrity after deposition to hold its printed geometry, a dual requirement that demands careful control across the entire fluid-solid spectrum.

The mechanisms by which foods acquire that structural integrity vary enormously across systems, and the Special Issue maps this diversity down to the molecular scale. Renzetti and colleagues investigated cereal and tuber starches, identifying hydrogen-bond density and glass-transition temperature as governing factors in gelatinization and gel rheology, thereby linking molecular interactions and thermal transitions directly to macroscopic mechanical behavior. On a different front, Holian, Bolton and Wilson explored how structure can be generated in soft solids to produce heat-stable milk chocolate, a formulation challenge that hinges on managing the solid-fat network so the product survives warming without collapsing. Both studies underscore that transitions between fluid-like and solid-like response ultimately originate at smaller length scales, from molecular mobility and intermolecular interactions up to the formation of mesoscopic networks that carry load.

Structured lipid systems offer further illustration of the same soft-matter principle. Shuai and colleagues investigated rice-bran-wax-structured macadamia oleogels and temperature-responsive water-in-oil emulsions, showing how organization of the lipid phase provides a route to tuning mechanical and functional properties, including delivery of bioactive compounds such as astaxanthin. Rasouli Pirouzian and co-workers, in their study of sucrose-free probiotic dark chocolate, addressed formulation optimization in relation to rheological characteristics and the viability of Saccharomyces boulardii. Although oleogels and functional chocolates sit far from drying mushrooms or printed gels on the supermarket shelf, they obey the same underlying rule: macroscopic material behavior emerges from an evolving internal structure whose formation is dictated by composition and processing conditions. This unity of principle is what makes the cross-disciplinary framing of edible soft matter so productive.

Taken together, the contributions point to a future in which food structuring moves from empirical process-property relations toward a genuinely mechanistic and predictive science. Achieving that will require closer integration of experimental characterization and modeling across length and time scales, with rheological and mechanical measurements increasingly combined with techniques that track microstructure, moisture distribution and deformation in real time during processing. Constitutive models, in turn, must evolve beyond reproducing behavior under narrow conditions toward formulations that capture the evolution of internal structure and its coupling to deformation, temperature and moisture transport. The Wageningen symposium and the resulting collection demonstrate the value of bringing food scientists, rheologists, physicists and solid-matter mechanicians to the same table. If that cross-fertilization continues, the next generation of foods may be designed, on paper, from the flow and setting behavior of their molecular ingredients upward.

Subject of Research: The fluid-to-solid state transitions of edible soft matter during food processing

Article Title: Edible soft matter in between fluid and solid states

Article References: van der Sman, R. G. M., Anderson, P. D., & Teresi, L. (2026). Edible soft matter in between fluid and solid states. Current Research in Food Science, 13, Article 101561. https://doi.org/10.1016/j.crfs.2026.101561

Image Credits: AI Generated

DOI: 10.1016/j.crfs.2026.101561

Keywords: edible soft matter, food rheology, food drying, 3D food printing, gelatinization, glass transition, oleogels, moisture transport, large-deformation mechanics, food structure, buckling, chocolate structuring