Development of soy protein isolate emulsion gels as extrusion-based 3D food printing inks: Effect of polysaccharides incorporation

Digestibility modulating and 3D printing of gliadin/resveratrol nanoparticle-filled starch gels

This study assessed the impact of resveratrol-loaded gliadin nanoparticles on starch digestibility and explored their potential for 3D printing. The starch hydrolysis was significantly decreased to 57.7 %, 62.8 % and 41.0 % after filling with resveratrol (Res), gliadin (Gli) nanoparticles, and Res-loaded Gli (Gli/Res) nanoparticles, respectively. Correspondingly, the α-amylase activity was reduced to 51.5 %, 68.4 % and 32.9 %. Fluorescence red-shift and molecular docking revealed the formation of a non-covalent complex between α-amylase and Res. The molecular interaction between α-amylase and Res was visualized by confocal microscopy. The complex was stabilized by 7 hydrogen bonds and 49 hydrophobic interactions. Wheat starch containing Gli/Res nanoparticles exhibited suitable rheological properties for high-accuracy 3D printing. Gli/Res nanoparticles reduced the predicted glycemic index of 3D printed starch gels to approximately 45. These findings revealed the synergistic effect of Res controlled release and Gli binding to α-amylase on starch hydrolysis, demonstrating potential for developing low-glycemic index 3D printed foods.

Thiol-modified hyaluronic acid and hydroxyl radical-induced oxidation synergistically enhance the gelling capacity of ginkgo seed proteins

The objective of this work was to investigate the effect of synthetic thiol-modified hyaluronic acid (HASH) on the gelation properties of ginkgo seed protein isolate (GSPI) under non-oxidizing (NOX) or oxidizing (OX) conditions. Under NOX conditions, HASH mediated the disruption of disulfide bonds, leading to a dose-dependent dissociation of GSPI. Conversely, in OX conditions, hydroxyl radical-induced oxidation facilitated the formation of interprotein disulfide bonds. Incremental increases in HASH concentration were found to significantly enhance the textural characteristics of the GSPI gel, achieving optimal elasticity. Moreover, HASH incorporation conferred increased rigidity and porosity to the gel matrix, markedly improving the water holding capacity and reducing the protein leachability. Additionally, OX conditions amplified the beneficial effect of HASH on gel strength and hydration properties. This study elucidates a novel approach for enhancing the gel properties of GSPI and modulating protein-polysaccharide interaction through the chemical modification of natural polysaccharides.

Oleogel-based Pickering emulsions stabilized by pea protein isolate aggregates with different morphologies: Curcumin protection and microencapsulation

In this study, the effect of pea protein isolate aggregate morphologies on the basic properties and potential applications of oleogel-based Pickering emulsions was investigated. The results showed that pea protein fibrils exhibited a three-phase contact angle of 81.3° and a more effective reduction of oil-water interfacial tension, which suggested better emulsification properties. Meanwhile, microscopic analysis revealed that pea protein fibrils were effectively adsorbed on the oil-water interface, forming a spatial hindrance that prevented droplet coalescence. The oleogel-based Pickering emulsion stabilized by pea protein fibril exhibited higher stability, stronger gel strength, and improved the bioavailability of curcumin. Additionally, the microcapsules generated from oleogel-based Pickering emulsions stabilized by pea protein fibrils maintained better physical integrity during the spray drying process. This work could provide valuable insights into the effects of pea protein aggregate morphologies on the stabilization of oleogel-based Pickering emulsions and their potential applications in the food industry.

Micronutrient supplemented dysphagia food: Rheology and β-carotene delivery of 3D printing egg yolk-carboxymethyl cellulose emulsion gels

The development of dysphagia foods has focused on macronutrient supplementation, with a lack of micronutrient-supplemented dysphagia foods reported. This study developed a low-fat emulsion gel for micronutrient supplementation in dysphagia patients. The results showed that carboxymethyl cellulose (CMC) improved the pseudoplasticity and viscosity (from 906.1 to 1253 Pa·s at 0.1 s-1) of egg yolk and CMC emulsion gels (ECEG), allowing easy tongue push and low-speed flow. The excellent shear recovery ability (66.91 %) of the ECEG ensures that its structure is effectively restored after chewing, allowing for efficient delivery of micronutrients. CMC can affect the viscoelastic properties (K7 = 2263.88, K8 = 384.28) and yield stress (189.4 Pa) of ECEGs. ECEG has a favorable 3D printed appearance, flavor, swallowing safety (IDDSI: level 5), β-carotene bioaccessibility (22.01 %) and suitable water distribution (T22 > 95 %). These properties ensure safe and enjoyable consumption for dysphagia patients. At CMC contents of 0.5-0.75 wt%, the ECEG formed emulsion-filled emulsion gels mainly by depletion attraction. Then, the gel network formed by egg yolk and CMC (EYCMC) dominated, and the ECEG transformed into a granular gel. The soft-solid nature of emulsion-filled gels provides better structural recovery and is suitable for encapsulated nutrients and efficient transportation. Our study proposes new solutions for micronutrient supplementation in special populations.

Impact of konjac glucomannan on hot extrusion 3D printability of cake gel

Several foods, including cake gel (CG), have a wide range of applications, but are natively non-printable, restricting their usage in 3D printed products. In this work, for the first time, hot extrusion 3D printing of CG with excellent print quality was achieved. Levels of konjac glucomannan (KG) addition, printing temperature, and other process parameters were optimized. A detailed investigation of rheological properties was performed to understand the underlying mechanisms, assessing small and large amplitude oscillatory shear effects, temperature sweeps, and thixotropy behavior; the loss factor value was found to be less than 1 for all gel formulations. Also, texture, crystallinity and functional group studies were conducted, and results were correlated with improvements in printability; particularly, texture values showed a 2-fold increase with the addition of 8 % KG. Similarly, it was observed that the increased levels of storage modulus (~9000 Pa) and apparent viscosity (91,543 mPas) in the 8 % KG formulation at a CG:KG ratio of 1:1.5 contributed to printability and post-printing stability. With a reduction in KG content, the melting temperature gradient was found to decrease, but crystallinity increased. The highest melting temperature of the gel formulation was for 8 % KG at ~140 °C, based on the thermal analysis results. The findings of this research provide insights into the development of ready-to-eat foods layer-by-layer fabricated using hot extrusion 3D food printing. Specifically, using a similar approach CGs can be conveniently used in 3D-printed bakeries, confectionary other formulations for customized/personalized finishes.

Development and characterization of quinoa protein-fucoidan emulsion gels with excellent rheological properties for 3D printing and curcumin encapsulation stability

Using of low-fat emulsion gels stabilized by quinoa protein (QP) for 3D food printing was limited by their defective rheological properties. The study was to explore the feasibility of using fucoidan (FU) to improve the printability and curcumin encapsulation stability of QP emulsion gel. The gels with 0.5-0.75 % FU incorporated were proved to be the most promising ink. Rheological analysis confirmed their great printing potential from the three-stages simulated 3D printing process. The incorporation of FU into emulsions induced more QP molecules adsorbed at the oil-water interface and smaller droplets size. When gel was induced by gluconate δ-lactone, these electrostatic interactions transformed into electrostatic attraction, resulting in a denser gel network. Adding FU to the gel improved its textural properties. Moreover, the gels with FU incorporated exerted better curcumin storage stability. This study provides a simple way to develop and improve the edible 3D printing inks for future food manufacturing.

Recent Advances in Plant-Based Edible Emulsion Gels for 3D-Printed Foods

3D printing has emerged as a suitable technology for creating foodstuff with functional, sensorial, and nutritional attributes. There is growing interest in creating plant-based foods as alternatives to address current demands, especially to tailor consumer preferences. Consequently, plant-derived edible inks for additive manufacturing have emerged as suitable options, including emulsion gels (or emulgels). These gels can be formulated entirely from plant-derived lipids, proteins, polysaccharides, and/or other ingredients to form complex fluids that belong to the category of soft matter. This review summarizes the most recent advances in the areas of formation, structuring, properties, and applications of plant-based emulsion gels for 3D-printed food. These semisolid materials can be extruded to the set or solidified into structures with predesigned shapes, fidelity, and sensory attributes across the senses (taste, smell, sight, and touch) along with nutrition values. Emulsion gels can be formed by either solely gelling the continuous phase or combining this process with the formation of a particle network through aggregation and close packing. The current challenges facing the development of edible inks using plant-based materials are critically discussed to stimulate further advances in the rapidly growing field of personalized 3D-printed foods.

Enhancing 3D food printing precision: Development and interaction behavior of soy protein isolate-konjac glucomannan-xanthan gum composite ink based on hot-melt extrusion

In the field of 3D printing, the physicochemical properties of composite inks are pivotal for constructing accurate printing networks. However, the precise fabrication of molded simulants using food 3D printing technology remains a challenging endeavor. The molecular structure and rheological properties of soybean protein isolate (SPI) make it prone to fracture under high shear stress, compromising printing accuracy and stability. This study aimed to address the deficiencies in precision and stability of existing soy protein-based inks for plant-based meats by developing a food composite ink system that incorporated SPI, konjac glucomannan (KGM), and xanthan gum (XG). The new ink system was designed to capitalize on the interactions between proteins and polysaccharides, as well as the synergistic effects of polysaccharides, to achieve high printing precision and the potential for simulant preparation. The addition of KGM and XG to the ink formulation enhanced the shear-thinning behavior, which was more amenable to the printing process, compared to the control group consisting of SPI alone. The SK1X1 composite ink demonstrated a significant improvement in printing precision by 40 % and in printing stability by 59 %, with final values reaching 99.11 % and 98.51 %, respectively. Additionally, hydrogen bonding was identified as a predominant factor in the gel network structure of SPI-KGM-XG composite inks. The self-assembling behavior of KGM-XG with SPI resulted in a robust spatial network structure, which in turn enhanced the thermal stability of the ink. In conclusion, the SPI-KGM-XG blends were determined to be suitable for use as thermo-extruded edible inks, and the synergistic effect of KGM-XG bolstered the gel properties of the hybrid inks, positioning them as ideal candidates for application in the 3D printing of meat simulants.

pH-regulated preparation and structural characterization of non-covalent complexes of soybean isolate proteins with different charged polysaccharides

Soybean protein isolate (SPI) exhibits limited functional properties in processing applications due to environmental stressors such as pH, salt ion, and temperature. The present study was devoted to exploring the non-covalent assembly of SPI with chitosan (CS), glucan (GL) and sodium alginate (SA) under different pH conditions. At a fixed mixing ratio (1:1), the phase behavior, protein solubility, and surface hydrophobicity (H0) of the resulting protein-polysaccharide complexes (PPCs) exhibited great differences due to the diversity of polysaccharide charge density and structure. Specifically, CS and SA primarily incorporated with SPI through electrostatic interactions, resulting in a pronounced enhancement of SPI solubility near the isoelectric point, with increases of 37.1 % and 51.6 %, respectively. In contrast, the combination of GL with SPI dominated by hydrophobic interactions and hydrogen bonds, yielding a similar protein solubility and H0 to SPI itself under different pH. Further analysis in charge density indicates that heat treatment promotes the electrostatic complexation of proteins with polysaccharides, whereas an increase in ionic strength inhibits the non-covalent assembly, and this effect was pronounced in the anionic polysaccharide system. In addition, the formation of electrostatic complexes exerted a positive effect on the stability of the emulsions, while the co-soluble systems tended to produce emulsion particles with smaller particle sizes. In summary, the charged polysaccharides showed great potential to modulate protein structure and enhance the stability of protein emulsions compared with the nonionic polysaccharides.

Formation, structural characterization and hypoglycemic activity in vitro of yeast polysaccharide hydrogels

Yeast polysaccharide has antioxidant, anti-tumor, antiviral, immune-enhancing, and adsorption properties; however, their utilization rate remains limited due to poor solubility. This study employed crude yeast polysaccharide (C-YP) as a raw material and utilized a 14 wt% NaOH aqueous solution as an environmentally friendly solvent to develop innovative yeast polysaccharide hydrogels (H-YPs). The prepared H-YPs exhibited a porous network structure with high water content. An elevation in yeast polysaccharide concentration corresponded with increased hardness and gel strength, reaching values of 665.0 gf and 155.0 g*cm, respectively. Furthermore, the H-YPs demonstrated non-cytotoxic characteristics, sustaining cell viability above 80 %. In vitro hypoglycemic assays indicated that H-YPs exhibited substantial inhibitory activity against the enzymes α-glucosidase and α-amylase, indicating their potential applicability in the development of healthy food gels.

Casein-grape seed proanthocyanidins complexes stabilized Pickering emulsion gels based on Lycium Barbarum seed oil with excellent mechanical properties and oxidation resistance

Pickering emulsion gels received extensive attention in encapsulating fat-soluble substances such as Lycium barbarum seed oil (LBSO). However, the gels presented poor mechanical properties, otherwise, their physical encapsulation cannot inhibit lipid peroxidation. Herein, grape seed proanthocyanidins (OPCs) and casein (CAS) complexes interacted through hydrogen and covalent bonds were proposed to build Pickering emulsion gels and encapsulate LBSO, which changed the secondary structures of CAS and further enhanced emulsifying ability, oxidation resistance, and gelling performance. The CAS-OPCs gels had better microstructures and mechanical properties due to the enhancement of hydrogen and covalent interactions. Furthermore, gels with OPC contents of 8.00 mg/mL had performance in 3D printing. And gels reduced the peroxide value of LBSO (9.33±0.20 to 1.39±0.22 mmol/kg) after heating. This study helps reveal the possible mechanisms of OPCs on gels and provides a reference for the application and research of OPCs and CAS composites in Pickering emulsion gels.

Study on the enhanced 3D printing performance of high internal phase emulsions using protein fibrosis strategy

Soy glycinin amyloid fibrils (11Fs) with different lengths were prepare, and their influence on 3D printing performance of high internal phase emulsions (HIPEs) were investigated. The longest fibril with an average length of 1594.40 ± 135.56 nm and a maximum surface charge of 27.62 ± 0.57 mV was obtained after 9 h heating treatment. The intermolecular force analysis revealed that the formation of amyloid fibrils was mainly mediated by hydrophobic interaction. The interfacial rheology showed the fibrils had faster diffusion and rearrangement rate at the oil-water interface compared with 11S, leading to a quicker reduction in the interfacial tension. Notably, the interfacial film formed by 11F9 maintained the highest dilatational modulus, which might be attributed to the entanglement of long fibrils to form a more elastic and tough network structure, thereby enhancing the storage and thermal stability of HIPEs. With increasing fibril length, the viscosity, G' and G'' of HIPEs slightly increased, and the linear viscoelastic region (LVR) gradually widened. 3D printing test revealed that HIPEs formed of 11F9 had good extrudability, high printability and shape fidelity. This study could provide a promising guide for enhancing the 3D printing performance of protein-based HIPEs.

Structural modification of whey protein isolate via electrostatic complexation with Tremella polysaccharides and its effect on emulsion stability at pH 4.5

Emulsions play an important role in food systems by encapsulating and delivering active compounds, but maintaining their stability under various conditions can be challenging. This study explored how the concentrations of Tremella polysaccharides (TPs) (0-0.75 %) affects the structural of whey protein isolate (WPI) and the stability of their emulsions at pH 4.5. At this pH, electrostatic interactions between WPI and TPs exposed hydrophobic groups within the protein, increased β-sheet contents, and improved the hydrophilic-hydrophobic balance, which enhanced emulsifying performance. WPI-TPs complexes (WTS) showed a high emulsifying activity index (57.85 m2/g) and emulsion stability index (82.03 %). Compared to WPI-only emulsions, WTS emulsions had smaller particle sizes, lower Turbiscan Stability Index (TSI) values, and higher viscoelasticity, thermal stability, freeze-thaw stability, and re-emulsification capacity. Importantly, when the TPs concentration in WTS emulsions exceeded 0.375 %, the TSI value dropped below 1, showing no particle migration or peak thickness, indicating full emulsion stability. These findings suggest that TPs help stabilize WPI emulsions near their isoelectric point (pH 4.5) and offer a promising approach to improving WPI functionality in acidic environments. The WTS system provides a reliable way to stabilize emulsions under acidic conditions, supporting the development of natural, stable emulsifiers for food applications.

Structural and rheological properties of bigels formed with xanthan gum hydrogel and lecithin/glycerol monostearate oleogel

This study aimed to investigate the structural and rheological properties of bigels formed with xanthan gum hydrogel and lecithin/glycerol monostearate oleogel. Different ratios (7:3, 6:4, 5:5, 4:6, and 3:7, respectively) of xanthan gum hydrogel and lecithin/glycerol monostearate oleogel were used for producing bigels (BG-7:3, BG-6:4, BG-5:5, BG-4:6, and BG-3:7). Through visual appearance, inversion test, and storage stability test, all bigels showed a white creamy appearance with self-standing properties and storage stability for three weeks. According to CLSM analysis, BG-7:3, BG-6:4, and BG-5:5 formed an oleogel-in-hydrogel system, whereas BG-4:6 and BG-3:7 showed a bicontinuous system. Solvent holding capacity was >95 % for all bigels. Steady shear rheological analysis and three interval thixotropic test revealed that all bigels exhibited shear-thinning behavior and thixotropic recovery. Frequency sweep test revealed that storage modulus (G'), loss modulus (G″), and complex viscosity (η*) of bigels were remarkably increased as the ratio of oleogel fraction increased in bigels. These results suggest that bigels formed with xanthan gum hydrogel and lecithin/glycerol monostearate oleogel can be unique candidates for replacing fat in the food industry.

Influence of variation in phase ratio and protein content on physicochemical properties and structure of soy protein isolate-konjac glucomannan double emulsion gels applicable as solid cubic fat substitutes

The effects of variations in the ratios of the inner water phase (W1), palm oil phase (O), and outer water phase (W2) in double emulsions (W/O/W), as well as the soy protein concentrations in W2, on the physicochemical properties and structure of double emulsion gels (DEG) used as solid cubic fat substitutes were investigated. Results showed that an increase in the proportion of O led to a 144 % increase in the size of the double emulsion particles, and a 15.38 % decrease in the cohesiveness of the DEG. The large aggregated oil droplets enlarged the network's porosity. High protein content contributed to the formation of a denser DEG network, resulting in a 32.64 % increase in the gel's hardness. Additionally, variations in the W1:O ratio had a highly significant effect on the properties of the DEG. These results conclusively proved the feasibility of improving DEG properties by adjusting the basic emulsion ratios.

The potential of protein-polysaccharide-based O/W and W/O emulsion gels strengthened by solid fat crystallization as realistic fat analogs

Herein, we develop novel O/W and W/O emulsion gels based on soybean protein isolate nanoparticles, xanthan gum, and crystalline fat to enhance 3D printability and achieve an effective alternative to butter. Palm mid fraction can self-assemble to form a fat crystal network, thus improving the structural strength of emulsion gels. Different emulsion gels are obtained by adjusting the sequence of crystallization and emulsification. The increased viscoelastic modulus of O/W emulsion gel is attributed to the tighter network structure between emulsion droplets. W/O emulsion gels exhibit better freeze-thaw stability due to the presence of fat crystal networks at the oil-water interface and the continuous phase. W/O emulsion gels with 60 wt% oil phase fractions had minimal print deformation rate. Both W/O and O/W emulsion gels significantly improve the hardness, gumminess, and chewiness of baked cakes. These findings provide new strategies for designing emulsion gels utilized in 3D printing and fat replacement.

Synergistic modification of ovalbumin by pH-driven and metal-phenolic networks: Development of dysphagia friendly high internal phase Pickering emulsions

Dysphagia is a common functional disorder that limits the variety of available foods. This study explored the coordination assembly of tannic acid (TA) with Fe3+ to form a metal-phenolic network (MPN) and developed ovalbumin (OVA)/MPN via a pH-driven method as a novel emulsifier to stabilize high internal phase Pickering emulsions (HIPPEs). Results indicated that, following pH-driven treatment, the OVA/MPN composite particles exhibited smaller sizes, enhanced electrostatic repulsion, and improved stability. UV-visible spectroscopy confirmed the successful assembly of MPN with OVA, while pH-driven processes facilitated MPN formation. Multi-spectral technology showed that MPN altered the intermolecular interactions and structural properties of OVA. The cooperatively modified OVA demonstrated superior interfacial wettability and emulsifying properties. Rheological studies revealed that all HIPPEs exhibited gel-like behavior and shear-thinning characteristics. HIPPEs stabilized by OVA, modified synergistically through pH-driven and MPN introduction, showed a dense network structure with higher viscosity, modulus, yield stress, and elasticity. IDDSI testing showed that HIPPEs with TA below 8 mg/mL had low-risk swallowing characteristics, while those with 12 mg/mL exhibited reduced rheological performance and failed the Level 4 dysphagia test. These findings provide crucial insights for the future development of HIPPEs suitable for individuals with dysphagia.

Plant protein edible inks: Upgrading from 3D to 4D food printing

The utilization of plant proteins to formulate edible inks for 3D/4D food printing applications may help address challenges linked to food sustainability, personalized nutrition, and security. We investigate the suitability of various plant proteins for this purpose, including their molecular, functional, and nutritional attributes. Furthermore, we examine the potential of plant protein-based edible inks in 4D printing applications, where the shape or other properties of a material change over time, enabling controlled release profiles and texture modulations. We also discuss the environmental implications, regulatory considerations, and consumer acceptance of plant-based 3D/4D printed foods. Pea and soy proteins are widely used as inks for 3D/4D food printing applications due to their excellent structure-forming abilities, as well as their functional and nutritional properties. However, solely plant protein-based inks often lack essential characteristics required for optimal performance. Their properties can be enhanced by incorporating other food ingredients, such as polysaccharides and polyphenols. As this emerging field holds promise for addressing multiple global food-related challenges, it necessitates interdisciplinary collaboration and ongoing research to unlock its full potential.

Insights into the material and 3D printing behaviour of fiber-enriched protein gels

One of the widely used materials in food printing is soy protein isolate (SPI) due to its functional and nutritional properties. However, a major printing drawback of SPI gels is network brittleness due to extensive aggregation leading to rheological properties that are unsuitable for printing. In this study, 0.4 %, 0.8 %, 1.2 %, 1.6 % and 2.0 % w/w milled psyllium husk and apple fibers were integrated into 20 % w/w SPI inks to improve the network properties and printability. Microstructural, textural, rheological properties and printability were investigated by microscopy, texture profile analysis, rheometry and image analysis. Incorporating psyllium husk fibers resulted in an interpenetrating protein-fiber network. This led to an increase in the network strength from 2155.8 Pa to 4228.15 Pa, relative to soy protein inks only, making them less susceptible to deformation during extrusion. Additionally, the geometrical deviation of the printed cubes decreased from 37.00 ± 4.55 % (length) and 24.00 ± 4.45 % (height) in the control inks to 13.86 ± 1.61 % and 24.86 ± 3.17 % respectively at psyllium husk concentration of 2.0 w/w %. The results showed that psyllium husk improved ink flexibility due to the high water-holding capacity of the fibers while maintaining structural integrity. This study revealed that the interpenetrating network effect of soluble dietary fibers in SPI inks improved printability while apple fibers with a high fraction of insoluble fibers embedded in a soy protein ink network caused printing defects. The findings highlight the potential to understand the influence of dietary fiber with varying physicochemical properties on 3D food printing of protein inks.

Hyaluronic acid promotes heat-induced gelation of ginkgo seed proteins

This study aimed to investigate how varying concentrations (0.01-0.5 %, w/v) and molecular weights (50, 500, 1500 kDa) of hyaluronic acid (HA) affect the physicochemical properties of heat-induced ginkgo seed protein isolate (GSPI)-HA composite gel. Incorporating HA increased viscosity (up to 14 times) and charge (up to 23 %) of GSPI-HA aggregates, while reducing particle size (up to 31 %) and improving gel texture, particularly with high molecular weight HA. However, high concentrations (0.5 %, w/v) of HA weakened gel texture. Non-covalent bonds primarily drive the formation of a continuous gel network between HA and GSPI, resulting in small pores and enhanced hydration properties. With increasing HA molecular weight, non-covalent interactions between GSPI and HA increased, leading to improved gel thermal stability. Overall, the study suggests that manipulating the molecular weight and concentration of HA can enhance the gelling properties of GSPI, leading to the development of a diverse array of GSPI-HA composite gels with varied properties.

Strategy to kill two birds with one stone: High internal phase Pickering emulsions to modulate 3D printed pork texture as a dysphagia diet

This study proposes a kill two birds with one stone strategy to improve the health and safety of pork with high internal phase Pickering emulsions (HIPPEs). HIPPEs improved the pseudoplasticity and viscosity (from 619.3 to 1712 Pa·s at 0.1 s-1) of the pork, favoring smooth extrusion and adhesion of the ink. Shear recovery of pork gel increased from 39.20 % to 77.78 % by addition of HIPPEs. HIPPEs enhanced the pork gel viscoelastic properties (K4 = 341.29, K5 = 453.11) and yield stress (268.55 Pa). HIPPEs-adjusted pork gel (HPG) has favorable 3D printing, pork aroma, safe swallowing (level 5 food), and high digestibility (80.40 %), demonstrating its potential as a dysphagia diet. HPG reduced the cooking loss of pork (from 30.8 % to 1.9 %), which is suitable for dysphagic patients with reduced salivation. HIPPEs adjusts the properties of pork gel by filling and winding gel networks. These results provide new ideas for the development of special formula foods.

Recent advances in the plant protein-polyphenol interactions for the stabilization of emulsions

Proteins from plant sources including legumes, cereals and oilseeds are gaining attention due to their suitability for sustainable production, functionality, and positive consumer perception. On the other hand, polyphenols (PPs) are receiving considerable attention as natural ingredients in the human diet due to their potent antioxidant and anti-inflammatory properties. Recent studies indicate that the emulsifying properties of plant proteins (PLPs) can be improved after modification through covalent and/or non-covalent interactions with PPs due to the changes in the conformation and/or the surface chemistry of the proteins. Complexes formed between PLPs-PPs can serve as innovative ingredients for developing novel food products with modified textural properties. Also, Pickering emulsions, multiple emulsions, multilayer emulsions, nanoemulsions, and high internal phase emulsions can be stabilized by such systems to deliver bioactive compounds. This paper reviews the most recent research on the PLP-PP interactions and their role in the stabilization of various emulsion-based systems. A special emphasis is given to modifying the structure and functionality of PLPs and PPs. The challenges and opportunities of applying PLP-PP interactions in emulsion-based systems are also highlighted.

Glycan degradation in Polygonati Rhizoma: Effects of traditional 'nine steaming and nine basking' on low molecular weight Fructans and polysaccharides

The traditional "nine steaming and nine basking" method for processing Polygonati Rhizoma has been practiced in China for over two millennia. However, research on its impact on glycans, particularly low molecular weight fructans, is limited. Therefore, dynamic changes in glycans were analyzed based on the two common species, Polygonatum filipes and Polygonatum cyrtonema. Results revealed the significant degradation of low molecular weight fructans within the first three processing cycles, with complete degradation by the seventh cycle, suggesting that the traditional technique may be excessive. Molecular weight analysis indicated the aggregation, degradation, and reaggregation of polysaccharides, with a notable decrease in fructose and an increase in galactose. This suggested that fructans were the primary constituents before processing, while galactans prevailed afterward. No significant differences in carbohydrate changes were found between the two species. This study enhances our understanding of the traditional processing mechanisms and promotes the efficient utilization of Polygonati Rhizoma.

Impact of high-intensity ultrasound on interfacial protein adsorption of non-dairy whipping cream: Whipping properties and foam stabilization model

In this paper, the competitive adsorption and practical application characteristics of ultrasound treatment on the oil-water interface in non-dairy whipping cream were explored. The results showed that ultrasound treatment promoted the competitive adsorption of casein, resulting in an increase of interfacial protein loading in the system by 4.82 mg/m2 and a decrease in oil droplet size by 0.20 μm. In addition, due to the increase of interfacial protein in the system, the partial coalescence of the fat globule of systems decreased, which led to a rapid collapse of the foam after 2 days of storage. Ultrasound weakened the strength of the gel network inside emulsions, which weakened the anti-deformation ability of emulsions. Although the LVR of the ultrasonically treated samples narrowed after churning, the G' value increased. In addition, the stress yield point of the foams shifted to higher strains as the ultrasonic power increased, implying better resistance to deformation.

Enhancement of soy protein functionality by conjugation or complexation with polysaccharides or polyphenols: A review

Soy proteins have good nutritional quality and exhibit a range of useful functional attributes, making them a viable option for replacing animal proteins in the development of more sustainable and eco-friendly plant-based food products. Nevertheless, soy proteins are prone to denaturation and/or aggregation under conditions they encounter in some food and beverage products (including certain pH, ionic, and thermal conditions), which adversely impact their functional performance. This problem can often be overcome by covalently (conjugation) or noncovalently (complexation) linking the soy proteins to polysaccharides or polyphenols, thereby expanding their application scope. Compared to soy proteins alone, these conjugates or complexes exhibit enhanced technofunctional performance, including improved solubility, emulsification, foaming, gelling, antimicrobial properties, and antioxidant capacities. Conjugates are typically more stable than complexes, which may be an advantage for some food applications. However, complexes do not require additional regulatory approval, which makes them more suitable for most food applications. This review aims to comprehensively examine the enhancement of soy protein functionality through conjugation or complexation with polysaccharides or polyphenols. The research focuses on how these modifications enhance solubility, emulsification potential, foaming, gelling, and antioxidant properties, reduce the allergenicity of soy proteins, and enable their potential applications in plant-based food development, 3D food printing, fat substitutes, functional food carriers, and hypoallergenic foods.

Improving the rheological and tribological properties of emulsion-filled gel by ultrasound-assisted cross-linked myofibrillar protein emulsion: Insight into the simulation of oral processing

This study aimed to investigate the effect of ultrasound-assisted cross-linking of myofibrillar protein (MP) emulsions on the enhancement of rheological and tribological properties of emulsion-filled gel. The micro-morphology, texture, water hold capacity (WHC), chemical forces, linear shear rheological behavior, large amplitude oscillatory shear (LAOS), oil-released content, and simulated oral friction of the water-filled gel (WP-G), the original MP fabricated emulsion-filled gel (NP-G), the crosslinked MP fabricated emulsion-filled gel (NPG-G), and the ultrasound treated crosslinked MP fabricated emulsion-filled gel (NPGU-G) were determined. Results indicated that emulsion as filler phase significantly improved the rheological and tribological properties of the gel, especially for the ultrasound-assisted MP emulsion-filled gel (NPGU-G) group, the smaller droplet size of emulsion contributed to the density and structural uniformity of the gel. Based on the excellent hydrophobic interaction between emulsion droplets and protein matrix, the NPGU-G group presented enhanced hardness, gumminess, chewiness, hydrophobic interaction, creep-recovery behavior, and the retarded transition of nonlinear response. Furthermore, the lower oil-released content and reduced friction coefficient in the NPGU-G group also indicated that the smaller emulsion droplets contributed to the gel quality and mouth lubrication. Consequently, this study demonstrated that ultrasound-assisted cross-linked MP emulsion with smaller droplets can be successfully filled into gel structures, form a denser network structure, and improve the quality of the emulsion-filled gel.

Octenyl succinic anhydride starch enhanced 3D printability of corn starch-based emulsion-filled gels incorporating egg yolk

This work investigated the effect of octenyl succinic anhydride starch (OSAS) on the 3D printing performance of corn starch-based emulsion-filled gels containing egg yolk. The influence of OSA-S concentration on emulsion droplet size, ζ-potential and stability, as well as the printing performance, rheological properties and microstructure of gel were discussed. The results indicated that the addition of OSA-S significantly improved the accuracy of the printed objects, with the best accuracy of the models printed using OSA-1.6 and OSA-2.0 inks. Emulsion tests showed that increasing the OSA-S content reduced the droplet size, increased its ζ-potential, and enhanced the stability of the emulsion. Rheological analyses showed that the energy storage modulus, loss modulus, and apparent viscosity of the gels were slightly enhanced with increasing OSA-S content. Microstructural analysis showed that OSA-S increased the density of the gel microstructural network. In addition, the addition of OSA-S enhanced the thermal stability of the gels and facilitated the transition of water molecule states from free water to bound water. The melting temperature of the gel gradually increased from 135.72 °C to 147.52 °C with the increase of OSA content. This study aims to develop promising 3D printing ink to facilitate its industrial applications.

Effect of polysaccharide on structures and gel properties of microgel particle reconstructed soybean protein isolate/polysaccharide complex emulsion gels as solid fat mimetic

In this work, a soybean protein isolate (SPI)/polysaccharide microgel particle reconstructed emulsion gels (MPEG) were fabricated through heat-induced gel (HG)-microgel particle-transglutaminase (TG) induced gel process in the presence of four polysaccharides (κ-carrageenan, κC; konjac glucomannan, KGM; high-acyl gellan, HA and xanthan gum, XG). HG exhibited a higher springiness than that of pig back fat (PBF) regardless of polysaccharide type and concentration. After forming MPEG, the springiness was significantly lowered at ≥0.6 % κC, which made MPEG exhibit similar springiness of PBF; while SPI/KGM, SPI/XG and SPI/HA systems failed to regulate the springiness property. Rheological behavior revealed the loss in elasticity, the increase in the plastic deformation of SPI/κC MPEG, while KGM, XG and HA systems still exhibited elasticity dominated rheological properties. Compared with KGM, XG, the presence of excess κC and HA disturbed the continuous protein network structure, resulting to the aggregation of microgel particles and oil droplets. Disulfide bonds and hydrophobic interactions mainly contributed to the formation of MPEG, while the addition of κC weakened the contribution of them, which was not conducive to the formation of gel network. This study provides a guidance on the development of solid fat mimetic based on the microgel particle emulsion gels.

Enhanced 3D printing performance of soybean protein isolate nanoparticle-based O/W Pickering emulsion gels by incorporating different polysaccharides

This work investigated the feasibility of employing soybean protein isolate nanoparticles (SPINPs) as emulsifiers and polysaccharides with different charge properties as thickeners to develop oil-in-water (O/W) Pickering emulsion gels 3D printing inks. The impact of non-covalent interactions between SPINPs and various polysaccharides on the microstructure, rheological properties, and 3D printability of emulsion gels was investigated at pH 3 and pH 7, respectively. Results showed that Locust bean gum (LBG) and Konjac gum (KG) stabilized emulsion gels mainly by increasing the viscosity of the aqueous phase. Chitosan (CS) and xanthan gum (XG) improved the system's viscosity while combining with SPINPs via electrostatic interactions. Small amplitude oscillatory shear and large amplitude oscillatory shear test results showed the highest recovery rate (97.45 %) and gel strength of 7-XG, exhibiting good potential for 3D printing. The Lissajous curves revealed the weakest gel structure and larger dimensional printing deviation (27.57 %) of 3-XG. The 3D-printed products of LBG and KG emulsion gels demonstrated smooth and slightly flawed surface texture. The print deformation rate of CS emulsion gels was <5.5 %, which was most suitable for developing 3D printing inks. This study offers valuable insights for creating and designing protein-polysaccharide-based 3D printing inks.

Optimization of ultrasonication assisted extraction of Aegle marmelos fruit shell nano polysaccharide and evaluation of photocatalytic dye reduction and edible coating for fresh-cut fruits

Aegle marmelos (AM) fruit shell, considered waste, is an excellent source of bioactive compounds, including polysaccharides. Therefore, this study focuses on the extraction of AM polysaccharides using an ultrasonication-assisted approach. Different parameters, including ultrasonic power (200-600 W), time (5-15 min), and solid-to-solvent ratio (10-20 mg/mL), were employed, and significantly (p < 0.05) higher yield (16.93 %) was achieved at 400 W for 10 min. Monosaccharides composition revealed galactose (30.56 ± 0.76 %), galacturonic acid (24.72 ± 0.12 %), arabinose (17.26 ± 0.35 %), xylose (11.48 ± 0.21 %), glucose (10.52 ± 0.26 %), and rhamnose (5.39 ± 0.67 %), which were then confirmed by 13C spectrum. AM polysaccharides revealed nanoscale size with excellent structural crystallinity and thermal stability. Edible coatings of varying concentrations (0.5-2 %) were formulated and optimized 1 % coating, demonstrating efficacy in mitigating weight loss, microbial proliferation, and browning in cut apples. As well, AM polysaccharides prominently degraded 82.79 ± 0.39 % of methyl green. Overall, bael shells as a valuable source of polysaccharides, offering the potential for both photocatalytic dye degradation and food preservation.

The Influence of Protein Components on Quinoa Protein-Xanthan Gum Complex Gels at Different pH Levels

The study aimed to prepare complex gels of sonicated quinoa protein (QP) and polysaccharides, comparing the effects of different protein components and pH on gel properties. FTIR analysis demonstrated that the β-structure in protein at pH 7.0 was enhanced by ultrasonic treatment, which could promote the formation of a gel network. Moreover, XG-AG (gel prepared by xanthan gum and albumin) and XG-GG (gel prepared by xanthan gum and globulin) exhibited higher levels of disulfide bonds and free sulfhydryl groups in the gel, requiring more energy to break the intermolecular sulfide bonds during heating. Under the same heating conditions, the rheological properties and gel strength of XG-UQPG (gel prepared by xanthan gum and ultrasonically treated QP) were superior to those of XG-UGG (gel prepared by xanthan gum and ultrasonically treated globulin) and XG-UAG (gel prepared by xanthan gum and ultrasonically treated albumin). Additionally, XG-UGG (pH 7.0) demonstrated the highest water holding capacity (WHC) and oil holding capacity (OHC). This was attributed to the disulfide bonds created in the proteins by the ultrasound treatment, encouraging them to interact to form more uniform holes in gel that can hold more water/oil molecules. Conversely, at pH 4.5, the WHCs of the gels were reduced due to the presence of rougher protein structures. These findings shed light on the impact of protein composition on gel properties and offer insights into enhancing the quality of quinoa protein gel.

Soy protein isolate-xanthan gum complexes to stabilize Pickering emulsions for quercetin delivery

This study aimed to prepare soy protein isolate-xanthan gum complexes (SPI-XG) at pH 7.0 and as emulsifiers to prepare Pickering emulsions for delivering quercetin (Que). The results showed that SPI-XG exhibited a gel network structure in which protein particles were embedded. Fourier transform infrared spectroscopy (FTIR) and molecular docking elucidated that SPI-XG formed through hydrogen bonding, hydrophobic, and electrostatic interactions. Three-phase contact angle (θo/w) of SPI-XG approached 90° with biphasic wettability. SPI-XG adsorbed at the oil-water interface to form an interfacial layer with a gel network structure, which prevented droplet aggregation. Following in vitro simulated digestion, Que displayed higher bioaccessibility in SPI-XG stabilized Pickering emulsions (SPI-XG PEs) than SPI stabilized Pickering emulsions. In conclusion, SPI-XG PEs were a promising system for Que delivery.

Exploring gelation properties and structural features on 3D printability of compound proteins emulsion gels: Emphasizing pH-regulated non-covalent interactions with xanthan gum

Rational regulation of pH and xanthan gum (XG) concentration has the potential to modulate interactions among macromolecules and enhance 3D printability. This study investigated non-covalent interactions between XG and other components within compound proteins emulsion gel systems across varying pH values (4.0-8.0) and XG concentrations (0-1 wt%) and systematically explored impacts of gelation properties and structural features on 3D printability. The results of rheological and structural features indicated that pH-regulated non-covalent interactions were crucial for maintaining structural stability of emulsion gels with the addition of XG. The 3D printability of emulsion gels would be significantly improved through moderate depletion flocculation produced when XG concentration was 0.75 wt% at the pH 6.0. Mechanical properties like viscosity exhibited a strongly negative correlation with 3D printability, whereas structural stability showed a significantly positive correlation. Overall, this study provided theoretical insights for the development of emulsion gels for 3D printing by regulating non-covalent interactions.

Preparation and Characterization of Ultrasonically Modified Peanut Protein-Guar Gum Composite Emulsion Gels for 3D Printing

This study aimed to prepare ultrasonically modified peanut protein-guar gum composite emulsion gels for 3D printing. The composition of the composite emulsion gels was determined in single-factor and orthogonal experiments. The results revealed that the optimal composite emulsion gels consisted of 6% peanut protein, 50% oil and 0.2% guar gum. After crushing pretreatment for 45 s, the printing deviation of the composite emulsion gels was reduced to 8.58 ± 0.20%. Moreover, after ultrasonic treatment (200 W for 20 min) of peanut proteins, the obtained composite emulsion gels presented the highest yield stress, hardness and G' values, as well as a denser and more homogeneous microstructure. After protein ultrasonic modification (200 W or 600 W for 20 min), the printing accuracy and self-supporting properties of the composite emulsion gels for printing complex shapes significantly improved, which was attributed to their stronger textural and rheological properties; however, ultrasonically modified peanut protein-guar gum composite emulsion gels were not suitable for printing products with smooth surfaces.

Ultrasonic treatment of emulsion gels with different soy protein-hemp protein composite ratios: Changes in structural and physicochemical properties

To improve the emulsion gel system of single soybean isolate protein (SPI) and to broaden the application field of hemp protein isolate (HPI), ultrasonic treatment and HPI were introduced to improve the properties of SPI emulsion gel and to explore the mechanism. The results showed that the gel strength (218.6 g) and water-holding capacity (86.24 %) of the emulsion gels were improved under ultrasonic treatments when the ratio of SPI:HPI was >6:4, and the reticulation structure of the gels was enhanced. When the ratio of SPI:HPI was <6:4, the gel structure was loose and formless. Ultrasonic treatment has a significant effect on the emulsion gel with the ratio of SPI:HPI was >6:4. Appropriate ultrasonic treatment (400 W) changed the protein structure, improved the rheological properties of emulsion gels to form the protein-oil-coated network structure. However, excessive ultrasonic treatment (600 W) will destroy the conformation of the protein, reducing the stability of the structure. The effect of ultrasonic treatment on emulsion gels with the ratio of SPI:HPI was <6:4 is low, but improved the gel protein digestibility. This study provides a theoretical basis for the application of ultrasonic in composite protein emulsion gels systems and the development and application of HPI.

Protein-based Emulsion Hydrogels and Their Application in the Development of Sustainable Food Products

Consumers have become more conscious of their diet, resulting in an increased demand for low-calorie and nutrient-rich food. Therefore, finding alternative ways to develop food products with improved nutritional values has become necessary without compromising the textural and sensorial properties. In the last few years, emulsion gels have gained much popularity for oil structuring, delivery of bioactive compounds, and development of nutritious food products. Protein-stabilized emulsion hydrogels have the most significant potential to be utilized in the food industry as they contain natural ingredients that help with clean label tags. Different gelation methods can be used to fabricate emulsion gels depending on the requirements of end products. Emulsion hydrogels' rheological, textural, mechanical, and structural properties can be modified by altering their composition, oil concentration, gelation method, and gelling environment, such as pH, temperature, etc. This review addresses using protein-based emulsion gels to develop novel food products with reduced-calorie and nutrition-rich content.

Investigating viscoelastic properties and structural stability mechanisms of oil bodies emulsion gels: Role of non-intrinsic protein

This research aims to investigate the mechanism of the effect of intrinsic and non-intrinsic protein content on the stability of oil bodies (OBs) emulsion gels. We employed small amplitude oscillation shear (SAOS) and large amplitude oscillation shear (LAOS) to measure the linear and nonlinear rheological properties of the OBs emulsion gels. The SAOS test indicated that an increase in non-intrinsic protein content weakened the interaction between OBs, decreasing their storage modulus (G'). The LAOS test demonstrated that the increase in non-intrinsic protein content affected the structural recombination and destruction behavior of OBs emulsion gels under large strains. Overall, the content of non-intrinsic protein during the extraction process is a crucial factor affecting the stability of OBs emulsion gels. These findings provide insights into the potential strategies for improving oil extraction efficiency and offer a foundation for further investigation into the functional properties of OBs.

Fabrication of high internal phase emulsions (HIPEs) using pea protein isolate-hyaluronic acid-tannic acid complexes: Application of curcumin-loaded HIPEs as edible inks for 3D food printing

Pea protein isolate (PPI)-hyaluronic acid (HA)-tannic acid (TA) ternary complexes were assembled using non-covalent interactions, their potential application in 3D printing and delivery of curcumin were investigated. As the HA-to-TA ratio in the complexes changed from 1:0 to 0:1, the oil-water interfacial tension first decreased and then increased, and the secondary structure of the proteins changed. The composition of the complexes (HA-to-TA ratio) was optimized to produce high internal phase emulsions (HIPEs) containing small uniform oil droplets with good storage and thermal stability. When the HA to TA ratio is 7:1 (P-H7-T1), HIPEs exhibited better viscosity, viscoelasticity, and thixotropy, which contributed to its preferable 3D printing. Moreover, curcumin-loaded HIPEs stabilized by P-H7-T1 showed a high lipid digestibility (≈101%) and curcumin bioaccessibility (≈79%). In summary, the PPI-HA-TA-stabilized HIPEs have good potential to be 3D-printable materials that could be loaded with bioactive components.

Citrus peel powder alters the rheological properties and 3D printing performance of potato starch gel

Owing to the growing interest in sustainable resource utilization, the current study explores the potential replacement of pectin with citrus peel powder (CP) in starch-based 3D food printing ink formulations. The effect of different concentrations of pectin (1 %, 2 %, 3 %) and CP (1 %, 2 %, 3 %) on the printing fidelity, microstructure, rheological and textural properties of potato starch gel were investigated. The results showed that the 3D printing performance of CP-added inks was higher than that of pectin-added inks at all tested concentrations. The storage modulus of CP-added ink was higher than that of pectin-added ink proving higher printing fidelity of CP-added inks. Additionally, hardness, gumminess, springiness and chewiness of food ink increased with an increase in the concentration of CP while decreased with an increase in concentration of pectin. Interestingly, pectin and CP-added inks displayed similar in vitro digestibility, suggesting an insignificant effect of replacing pectin with CP on in vitro glucose release. Moreover, the antioxidant activity of CP-added ink was higher than pectin-added ink demonstrating the potential applications of CP-added ink in functional ink development. Therefore, this study claims for effective replacement of pectin with CP in starch-based 3D food printing ink formulations as a promising sustainable additive.

Effectiveness of gellan gum scaffolds loaded with Boswellia serrata extract for in-situ modulation of pro-inflammatory pathways affecting cartilage healing

In this study, we developed a composite hydrogel based on Gellan gum containing Boswellia serrata extract (BSE). BSE was either incorporated directly or loaded into an MgAl-layered double hydroxide (LDH) clay to create a multifunctional cartilage substitute. This composite was designed to provide anti-inflammatory properties while enhancing chondrogenesis. Additionally, LDH was exploited to facilitate the loading of hydrophobic BSE components and to improve the hydrogel's mechanical properties. A calcination process was also adopted on LDH to increase BSE loading. Physicochemical and mechanical characterizations were performed by spectroscopic (XPS and FTIR), thermogravimetric, rheological, compression test, weight loss and morphological (SEM) investigations. RPLC-ESI-FTMS was employed to investigate the boswellic acids release in simulated synovial fluid. The composites were cytocompatible and capable of supporting the mesenchymal stem cells (hMSC) growth in a 3D-conformation. Loading BSE resulted in the modulation of the pro-inflammatory cascade by down-regulating COX2, PGE2 and IL1β. Chondrogenesis studies demonstrated an enhanced differentiation, leading to the up-regulation of COL 2 and ACAN. This effect was attributed to the efficacy of BSE in reducing the inflammation through PGE2 down-regulation and IL10 up-regulation. Proteomics studies confirmed gene expression findings by revealing an anti-inflammatory protein signature during chondrogenesis of the cells cultivated onto loaded specimens. Concluding, BSE-loaded composites hold promise as a tool for the in-situ modulation of the inflammatory cascade while preserving cartilage healing.

The relationship between nonlinear viscoelasticity and baking performance in low-saturated puff pastry margarine

The oil phase obtained by blending and oleogel methods has potential for the production of non‑hydrogenated and low-saturated puff pastry margarine, thereby reducing intakes of both types of dietary fat. The crystal form, microstructure, rheology, and baking applications of puff pastry margarines prepared with anhydrous milk fat (AMF)/palm stearin (POs), POs/palm oil (PO), beef tallow (BT)/PO, or AMF/POs/diacetyl tartaric acid ester of mono(di)glycerides (DATEM) oleogels were investigated using X-ray scattering, polarized light microscope, and rheometer, respectively. All margarines exhibited β'-form crystal and strongly viscoelastic at low strain. With the addition of DATEM oleogel, their crystal microstructure became more uniform and finer, and the croissants were less hard (1690) and chewiness (160). The chewiness of croissants produced using the margarines was significantly improved with POs content. The theoretical basis for preparation and application in non‑hydrogenated and low-saturated puff pastry margarine was provided in the present study.

Development, characterization and underling mechanism of 3D printable quinoa protein emulsion gels by incorporating of different polysaccharides for curcumin delivery

Emulsion gels stabilized by food-grade polymers such as proteins and polysaccharides are edible 3D food printing inks with various applications in food industry. In this study, 3D printable quinoa protein emulsion gels with four polysaccharides incorporated were fabricated to delivery curcumin. The effect of inulin (INU), fucoidan (FU), dextran sulfate (DS), and sodium alginate (SA) on the microstructure, rheological properties, and 3D printing performance of quinoa protein emulsion gels were all investigated. The results showed that the incorporation of four polysaccharides promoted formation of tightly packed oil droplets within gel networks, along with enhanced hardness, water holding capacity, freeze-thaw stability and decreased swelling ratio of the QP emulsion gel. All samples exhibited shear thinning behavior and polysaccharides increased viscoelasticity of QP emulsion gel. The hydrophobic interactions and disulfide bond are the main chemical molecular force of emulsion gels, INU significantly increased the hydrogen bonds interactions, and anionic polysaccharide (FU, DS, and SA) significantly increased the electrostatic interactions. QP-INU exerted best printing performance as identified by preferable self-supporting capability and high line printing accuracy. The addition of polysaccharides improved the encapsulation efficiency of curcumin in QP emulsion gel. In vitro release property showed that FU increased the bioavailability of curcumin, DS and SA decreased bioavailability of curcumin with delayed digestion rate. This study demonstrated the potential of utilizing polysaccharides to improve the flexibility of QP emulsion gel for 3D printing functional food.

Xanthan gum ink based on Lycium ruthenicum anthocyanin as an indicator of color change for monitoring freshness of cold fresh meat

The continuous development of intelligent food packaging has led to an increased focus on using freshness-indicating inks, which could provide a high level of quality control and consumer experience. This study aimed to further promote the application of xanthan gum ink in food freshness indication by optimizing its performance in screen printing. A novel freshness-indicating ink was prepared using Lycium ruthenicum anthocyanin (LRA) as the core indicator, glucose as the pigment carrier, soybean oil as the linker, and xanthan gum (XG) as the thickener. Scanning electron microscopy (SEM) demonstrated that the ink was uniformly distributed on paper using screen printing. Rheological and particle size analyses revealed that the incorporation of XG significantly enhanced the interaction force between droplets in the ink system. Further tests on viscosity, fineness, and initial dryness indicated that XG, a natural microbial polysaccharide with excellent stability, could effectively improve the flowability of the ink. Specifically, at a 0.3 % XG content, the ink exhibited a unimodal particle size distribution with an average particle size of 851.02 nm and a zeta potential of -27 mV. This indicated the ink system was stable and uniform, with optimal rheological properties and printing suitability. Furthermore, the printed freshness indication labels exhibited a significant change in color as the freshness of the refrigerated meat changed. This study develops a natural and safe method for monitoring the freshness of refrigerated meat and provides an optimized idea for applying indicator inks.

Advances of protein-based emulsion gels as fat analogues: Systematic classification, formation mechanism, and food application

Fat plays a pivotal role in the appearance, flavor, texture, and palatability of food. However, excessive fat consumption poses a significant risk for chronic ailments such as obesity, hypercholesterolemia, and cardiovascular disease. Therefore, the development of green, healthy, and stable protein-based emulsion gel as an alternative to traditional fats represents a novel approach to designing low-fat food. This paper reviews the emulsification behavior of proteins from different sources to gain a comprehensive understanding of their potential in the development of emulsion gels with fat-analog properties. It further investigates the emulsifying potential of protein combined with diverse substances. Then, the mechanisms of protein-stabilized emulsion gels with fat-analog properties are discussed, mainly involving single proteins, proteins-polysaccharides, as well as proteins-polyphenols. Moreover, the potential applications of protein emulsion gels as fat analogues in the food industry are also encompassed. By combining natural proteins with other components such as polysaccharides, polyphenols, or biopolymers, it is possible to enhance the stability of the emulsion gels and improve its fat-analog texture properties. In addition to their advantages in protecting oil oxidation, limiting hydrogenated oil intake, and delivering bioactive substances, protein-based emulsion gels have potential in food 3D printing and the development of specialty fats for plant-based meat.

Emulsion gels prepared from Longzhua mushroom polysaccharides with self-gelling properties as β-carotene carriers: Stability and in vitro digestibility of β-carotene

β-Carotene is widely used in food systems because of its biological activity; however, β-carotene has poor chemical stability and low bioavailability. Thus, researchers use encapsulated delivery systems to overcome these disadvantages. In this study, we prepared emulsion gels to encapsulate β-carotene, using Longzhua mushroom polysaccharide (LMP), which can autonomously form weak gels. The LMP emulsion gel (LEG) exhibited a high water-holding capacity of up to 95.06 %. All samples showed adequate storage stability for 28 days. Increasing the polysaccharide content in the emulsion gel enhanced the encapsulation efficiency of β-carotene (96.76 %-98.27 %), the release of free fatty acids (68.21 %-81.44 %), and the photostability (80.65 %-91.27 %), thermal stability (73.84 %-97.08 %), and bioaccessibility (18.28 %-30.26 %) of β-carotene. In conclusion, LEG is a promising fat-soluble material that can be used for food-grade encapsulated delivery systems.

A Comprehensive Review on Harnessing Soy Proteins in the Manufacture of Healthy Foods through Extrusion

The global development of livestock production systems, accelerated by the growing demand for animal products, has greatly contributed to land-use change, greenhouse gas emissions, and pollution of the local environment. Further, excessive consumption of animal products has been linked with cardiovascular diseases, digestive system diseases, diabetes, and cancer. On the other hand, snacks, pasta, and bread available on the market are made from wheat, fat, salt, and sugar, which contribute to the risk of cardiovascular diseases. To counter these issues, a range of plant protein-based food products have been developed using different processing techniques, such as extrusion. Given the easy scalability, low cost of extrusion technology, and health benefits of soy proteins, this review focuses on the extrusion of soy protein and the potential application of soy protein-based extrudates in the manufacture of healthy, nutritious, and sustainable meat analogs, snacks, pasta products, and breakfast cereals. This review discusses the addition of soy protein to reformulate hypercaloric foods through extrusion technology. It also explores physical and chemical changes of soy proteins/soy protein blends during low and high moisture extrusion. Hydrogen bonds, disulfide bonds, and hydrophobic interactions influence the properties of the extrudates. Adding soy protein to snacks, pasta, breakfast cereals, and meat analogs affects their nutritional value, physicochemical properties, and sensory characteristics. The use of soy proteins in the production of low-calorie food could be an excellent opportunity for the future development of the soybean processing industry.

Applications of physical and chemical treatments in plant-based gels for food 3D printing

Extrusion-based three-dimensional (3D) printing has been extensively studied in the food manufacturing industry. This technology places particular emphasis on the rheological properties of the printing ink. Gel system is the most suitable ink system and benefits from the composition of plant raw materials and gel properties of multiple components; green, healthy aspects of the advantages of the development of plant-based gel system has achieved a great deal of attention. However, the relevant treatment technologies are still only at the laboratory stage. With a view toward encouraging further optimization of ink printing performance and advances in this field, in this review, we present a comprehensive overview of the application of diverse plant-based gel systems in 3D food printing and emphasize the utilization of different treatment methods to enhance the printability of these gel systems. The treatment technologies described in this review are categorized into three distinct groups, physical, chemical, and physicochemical synergistic treatments. We comprehensively assess the specific application of these technologies in various plant-based gel 3D printing systems and present valuable insights regarding the challenges and opportunities for further advances in this field.

Development of soy protein isolate gels added with Tremella polysaccharides and psyllium husk powder as 3D printing inks for people with dysphagia

The aim of this study was to investigate the feasibility of soy protein isolate (SPI) gels added with Tremella polysaccharides (TPs) and psyllium husk powder (PHP) as 3D printing inks for developing dysphagia-friendly food and elucidate the potential mechanism of TPs and PHP in enhancing the printing and swallowing performance of SPI gels. The results indicated that the SPI gels with a TP : PHP ratio of 3 : 7 could be effectively used as printing inks to manufacture dysphagia-friendly food. The addition of TPs increased the free water content, resulting in a decrease in the viscosity of the SPI gels, which, in turn, reduced the line width of the 3D-printed product and structural strength of the gel system. The addition of PHP increased disulfide bond interactions and excluded volume interactions, which determined the mechanical strength of SPI gels and increased the line width of the printed product. The synergistic effects between TPs and PHP improved the printing precision and structural stability. This study presents meaningful insights for the utilization of 3D printing in the creation of dysphagia-friendly food using protein-polysaccharide complexes.

Tailoring 3D-printed high internal phase emulsion-rice starch gels: Role of amylose in rheology and bioactive stability

This study investigated the properties of 3D-printed high internal phase emulsion (HIPE)-rice starch gels, specially tailored for personalized nutrition by co-encapsulating resveratrol and β-carotene. We examined the influence of amylose content on various parameters, including functional groups, linear and nonlinear rheology, printed precision and microstructural stability. Additionally, we assessed the protective efficacy and release in vitro digestion of these gels on the encapsulated bioactive components. Compared to HIPE, HIPE-starch gels differently impacted by amylose content in starches. Low-level amylose weakened the network structure, attributed to amylose mainly responsible for gel formation and weak hydrogen bond interaction between the surface-active molecules and amylose due to gelatinized starch granules rupturing the protein network. Oppositely, high-level amylose led to denser, more gel-like structures with enhanced mechanical strength and reversible deformation resistance, making them suitable for 3D printing. Furthermore, 3D-printed gels with high-level amylose demonstrated well-defined structures, smooth surfaces, stable printing and less dimension deviation. They were also regarded as effective entrapping and delivery systems for resveratrol and β-carotene, protecting them against degradation from environment and damage under the erosion of digestive fluid. Overall, this research offers a straightforward strategy for creating reduced-fat HIPE gels that serve as the carrier for personalized nutraceutical foods.

Impact of Oil Bodies on Structure, Rheology and Function of Acid-Mediated Soy Protein Isolate Gels

Oil bodies (OBs) are naturally occurring pre-emulsified oil droplets that have broad application prospects in emulsions and gels. The main purpose of this research was to examine the impact of the OB content on the structure and functional aspects of acid-mediated soy protein isolate (SPI) gel filled with OBs. The results indicated that the peanut oil body (POBs) content significantly affected the water holding capacity of the gel. The rheological and textural analyses showed that POBs reduced the gel strength and hardness. The scanning electron and confocal laser scanning microscopy analyses revealed that POBs aggregated during gel formation and reduced the gel network density. The Fourier transform infrared spectrum (FTIR) analysis demonstrated that POBs participated in protein gels through hydrogen bonds, steric hindrance and hydrophobic interactions. Therefore, OBs served as inactive filler in the acid-mediated protein gel, replaced traditional oils and provided alternative ingredients for the development of new emulsion-filled gels.