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Summary: In this work, soy protein isolates (SPIs) were subjected to microparticulation, turning soy protein ingredients into microparticles with improved thermal stability which could be used in high‐protein foods. The pH is a critical determinant in microparticulation. Our work is mainly to investigate the effect of pH on the formation and properties of protein microparticles. To clarify the effects of pH conditions on the properties of the resulting particles, microparticulation was performed at different pH conditions (7.0, 6.0 and 5.0). Aggregation behaviours described by the parameters calculated from the protein dispersion viscosity combined with the observation of the morphology change were used to analyse the particle formation process. For the microparticles prepared at pH 5.0, soy proteins were more inclined to aggregate into clusters on a micro‐scale which had a flexible conformation. After spray drying, This powder could be easily dispersed in water, creating a dispersion with a protein concentration of 10 wt%. At this concentration, the thermal gelation capacity of the proteins was observed to decrease. Conversely, the tendency of protein aggregation was largely restricted when soy protein microparticulation was carried out at pH 7.0. As these soy protein particles in nano‐scale were dispersed in water, a decrease rather than an increase was recorded in the viscosity of this dispersion after it was heated, suggesting that these particles had improved thermal stability. This work has demonstrated that implementing appropriate pH conditions during microparticulation can prepare soy protein particles with different sizes and rheological properties, which might meet the demands of various food processing. [ABSTRACT FROM AUTHOR]

Abstract The aim of this study was to assess the effect of oil type and solvent quality on the structure formation and rheological properties of zein-stabilized oil-in-glycerol emulsion gels. To change the interactions within the system, four types of oil (medium chain triglyceride (MCT) oil, sunflower oil, extra virgin olive (EVO) oil, and castor oil) with different polarity were used, and the solvent quality was modified by temperature and water addition. In all cases, emulsion gels were obtained with G' > G''. At each protein concentration and oil content, the gel strength and crossover strain γ co increased with an increase in oil polarity, indicating the formation of a stronger gel structure and higher stability against structure breakdown. These results are related to the fact that a higher oil polarity decreases the oil-protein hydrophobic interactions and thereby increasing the interactions between the proteins to form a strong network in the continuous phase. In addition, water addition to the continuous phase enhanced the gel strength and the resistance against structure breakdown for more apolar MCT oil, while the opposite results were observed for the more polar castor oil. The zein-based emulsion gels showed a thermo-responsive behavior, and different responses in structure collapse and rearrangements during heating and cooling were found for different oils. These simple approaches form an interesting route to tune the rheological properties of zein-based emulsion gels. Graphical abstract The structure formation and rheological behavior of the zein stabilized oil-in-glycerol emulsion gels can be tuned by changing the interplay between the different interactions within the system. Image 101 Highlights • Zein self assembles to form oil-in-glycerol emulsions gels. • Gel strength and crossover strain increase with an increase in oil polarity. • Water addition enhances the gel strength and crossover strain for more apolar oil. • Water addition decreases the gel strength and crossover strain for more polar oil. • The thermo-responsive behavior can be tuned by the oil type. [ABSTRACT FROM AUTHOR]

In the present work, the influence of hydrophobicity of zein/tannic acid complex particles (ZTPs) on the rheological behavior of ZTP-stabilized emulsion gels is described. The hydrophobicity of the particles was controlled by the incorporation of different amounts of hydrophilic tannic acid, while retaining a similar particle size. The resulting ZTPs with varying hydrophobicity were successfully used to form emulsion gels with similar oil droplet size. With a decrease in the hydrophobicity of ZTPs, the storage modulus (G′) of emulsion gels increased, while tan δ and the frequency dependence decreased, indicating the formation of a stronger gel network. The crossover strain, γ co , increased with a decrease in the hydrophobicity of ZTPs, indicating the gel network becomes more resistance against breakdown. In all cases, G′ increased in a power-law manner with an increase in protein concentration (G' ∼  c p n ) and oil content (G' ∼  φ m ). The exponent n and m decreased with decreasing particle hydrophobicity, indicating that hydrophobic interactions between particles within the particle network in the continuous phase and the oil droplets provide a relatively larger contribution to the gel strength for emulsion gels stabilized by ZTPs with higher hydrophobicity. Increasing the oil polarity provided a lower gel strength for emulsions stabilized by particles with high hydrophobicity, while it increased the gel strength for particles with low hydrophobicity. The results show that the rheological behavior of ZTP-stabilized emulsion gels can be tuned by changing the particle hydrophobicity and oil polarity, which provide interesting features for various applications in the food industry. [ABSTRACT FROM AUTHOR]

Starch granule oleogels were prepared and their rheological properties were precisely tuned using the capillary bridging phenomenon. The addition of a small amount of water to an oily suspension of starch granules can lead to starch granule bridging and network formation, transitioning it from a fluid-like to a gel-like state. Small-granule starches with high specific surface area and interfacial area exhibited a greater number of liquid bridges and stronger starch granules interactions, making them more prone to forming structurally stable oleogel systems. By increasing the content of water and starch granule, the starch oleogels exhibited three distinct structural states: pendular state (water ≤ 3.28 %, starch ≤ 17.85 %), pendular bridging network (water: 4.92 %, starch: 24.59 %), and capillary aggregates (water ≥ 6.56 %, starch > 24.59 %). Furthermore, the influence of starch granule surface lipids on the lubrication performance of the oleogel system was investigated. Surface roughness increased after extraction of surface lipids, and the friction coefficient also showed a significant increase. Overall, capillary suspension system can potentially be used to design novel fat food products, and our findings have established the correlation between starch granule surface properties and sensory perception in food, providing valuable insights for adjusting the oral processing characteristics of food. [Display omitted] [ABSTRACT FROM AUTHOR]

3D printing has extremely high requirements for the design of food matrices with suitable rheological properties. Starch exhibits considerable potential as a material for 3D printing. However, there is limited research available on the direct fabrication of oleogels using starch granules as building blocks. In this study, we developed a simple approach to fabricate plant-based oleogels as edible 3D printable materials by exploiting capillary forces between starch granules. When a small amount of water (less than 5 wt%) was added to starch granules dispersed in an oil phase, a pendular bridging network was formed between the starch granules. The rheological properties of the starch-oil suspension were significantly changed, transitioning it from a fluid-like to a gel-like state. The rheological properties of the oleogel could be altered by varying the starch granule volume fraction, the amount of water added, the structure of starch granules, and the oil-water interfacial tension. Confocal laser microscopy imaging demonstrated that starch granule oleogels exhibit three distinct structural states: pendular state, pendular bridge network, and capillary aggregation. Furthermore, the presence of water was identified as a liquid bridge between starch granules. Additionally, starch granule oleogels exhibited excellent thermal stability and freeze-thaw stability. Overall, this approach enhances the feasibility of preparing starch oleogels and provides valuable insights for the personalized 3D printing of oleogels. [Display omitted] • Starch granule based oleogels were successfully prepared through capillary attraction. • Untreated native starch granules were firstly used in the preparation of oleogels. • The oleogel network was formed by granules connected through meniscus bridges. • Modulating rheological properties of the oleogel via added water or starch content. [ABSTRACT FROM AUTHOR]

3D printing has been applied to create nutritious foods with tailored textures for the elderly. However, the edible materials that possess the elastoplastic properties and shear-thinning behavior required for direct-write 3D printing are limited. In this study, we developed a simple approach to fabricate Spirulina emulsion gels as edible 3D printable material by exploiting depletion attraction between emulsion droplets. By controlling the volume ratio of continuous and oil phases, mixing highly viscous Spirulina slurry and vegetable oil could form self-standing oil-in-water emulsion gels with elastoplastic rheological properties. Also, adding food polysaccharides into the continuous phase could act as depletants to drive the formation of emulsion gels. Auto-fluorescence spectroscopy and microscopy were employed to characterize the interfacial protein compositions of the emulsion, showing that phycobilisome (PBS) particles might play a dominant role in the formation of Spirulina emulsions. The depletion attraction could drive the adsorption of PBS particles onto the droplet interface, and the particle-armored droplets in the dispersed phase connected into a percolating droplet cluster, resulting in arrested dynamics and gelation. Overall, this novel approach can be applied by exploiting depletion attraction and opens up possibilities for using high-solids viscous food slurries to produce personalized 3D-printed foods. [Display omitted] • Self-standing emulsion gel is formed by mixing Spirulina slurry with vegetable oil. • PBS particles may play a dominant role in the formation of Spirulina emulsion. • Depletion attraction drives the adsorption of PBS particles onto droplet interface. • Particle-armored droplets are connected into a percolating cluster for gelation. • Polysaccharides as depletants modify the rheological properties of Spirulina emulsion. [ABSTRACT FROM AUTHOR]

Interparticle forces that govern the assembly of particles adsorbed at fluid interfaces determine the rheology and microstructure of particle laden interface. In this study, natural small molecule, tannic acid (TA), was used to modify particle-particle interactions and assembly behaviors of food grade hydrophobic protein particle (zein nanoparticle) at air-water interface. For bare zein particle (ZP), the rapid adsorption and high interparticle forces led to the low coverage and formation of large ZP aggregates at the interface. The hydrogen-bonding of TA weakened the particle hydrophobicity and thus interparticle forces at fluid interfaces. Therefore, the adsorption process and assembly rate of ZTP at the interface obviously reduced, which also provided enough time for ZTP to rearrange into orderly interfacial networks. Furthermore, the Lissajous plots of surface pressure versus deformation are used to understand the surface rheological response to large mechanical deformation in terms of interfacial microstructure. The rheological response of interface stabilized by ZTP showed strain hardening during extension and strain softening during compression. These findings indicate that the interfacial rheology and microstructure of zein particle-laden interface can be tuned by changing the TA content. [ABSTRACT FROM AUTHOR]

[Display omitted] • GA nanofibrils are effective and robust stabilizer to make soft-solid emulsion foams. • Stability and structural properties of emulsion foams were controlled by oil phase polarity. • Emulsion foam with polar castor oil had denser network microstructure, higher mechanical strength, and lower friction coefficients. • Volatile limonene oil weakened structural stability and lubrication ability of emulsion foams. Novel supramolecular nanofibrils assembled from food-grade saponin glycyrrhizic acid (GA) are effective building blocks to make complex multiphase systems, e.g., emulsion foams. In this work, the effects of different oil phases (castor oil, sunflower oil, dodecane, and limonene) on the formation, stability and structural properties of long-lived emulsion foams prepared by GA nanofibrils (GNs) were investigated. The obtained results showed that soft-solid emulsion foams (4 wt% GNs) can be fabricated, independently of oil phase, and their structural properties, viscoelasticity, and tribological properties can be well tuned by oil phase polarity. Compared to the GNs aqueous foams, the presence of jammed emulsion droplets in the liquid channels and at the surfaces of bubbles can provide a higher bubble stability for emulsion foams. For more polar oil phase (castor oil), GNs showed a higher affinity to the oil–water interface with a lower interfacial tension, thus forming smaller oil droplets and bubbles, which leads to the higher mechanical strength, denser network microstructures, and lower friction coefficients of emulsion foams. However, the limonene foam exhibited weak storage stability and rheological properties, as well as the relatively low lubrication, which may be related to the formation of oil droplet aggregates and clusters induced by the volatility of limonene. GN-based emulsion foams are thermoresponsive, independently of oils, and the temperature-switchable process for the destabilization and regeneration of foams can be controlled and repeated. These emulsion foams based on natural saponin nanofibrils with tunable properties have potential sustainable applications in foods, pharmaceuticals, and personal care products. [ABSTRACT FROM AUTHOR]