Small Amplitude Oscillatory Shear Research Articles

Effect of the Ratio of Protein to Water on the Weak Gel Nonlinear Viscoelastic Behavior of Fish Myofibrillar Protein Paste from Alaska Pollock

The linear and nonlinear rheological behaviors of fish myofibrillar protein (FMP) paste with 75%, 82%, and 90% moisture content were evaluated using small-amplitude oscillatory shear (SAOS) and large-amplitude oscillatory shear (LAOS) tests. SAOS revealed pastes with 75% and 82% moisture exhibited solid-like behavior, characterized by higher storage modulus (G′) than loss modulus (G″), indicative of weak gel properties with a strong protein interaction. In contrast, the 90% moisture content showed more viscous behavior due to weakened protein–protein entanglements. The frequency exponent (n′ and n″) from the power law equation varied slightly (0.24 to 0.36), indicating limited sensitivity to changes in deformation rate during SAOS. LAOS tests revealed significant structural changes, with Lissajous–Bowditch curves revealing early nonlinearities at 10% strain for 90% moisture content. Decomposed Chebyshev coefficients (e3/e1, v3/v1, S, and T) indicated strain stiffening at lower strains for the 75% and 82% moisture pastes (i.e., < 50% strain for 75% and < 10% strain for 82%), transitioning to strain thinning at higher strains. Additionally, numerical model confirmed the predictability of the 3D printing process from the nonlinear rheological data, confirmed the suitability of the 75% and 82% moisture pastes for applications requiring structural integrity. These insights are essential for optimizing processing conditions in industrial applications. The findings suggest that the 75% and 82% moisture pastes are suitable for applications requiring structural integrity, while the 90% moisture paste is ideal for flow-based processes. These insights are essential for optimizing processing conditions in industrial applications.

Effect of agitation during the early-age hydration on thixotropy and morphology of cement paste

AbstractThe effect of agitation during the early-age hydration on thixotropy and morphology of cement paste prepared with and without superplasticizers (SP) is investigated by applying penetration test, small amplitude oscillatory shear sweep test (SAOS), isothermal calorimetric test, scanning electron microscopy (SEM) and energy dispersive X-ray analyses (EDX). The results show that the agitation of cement paste during the induction period increases the heat flow rate and destroys existing structures of samples without changing the mineral composition of samples. Yet, if the agitation is applied during the acceleration period, the heat flow rate is significantly lowered and the morphology and mineral composition of samples undergo irreversible change, freshly formed syngenite is destroyed and no longer restored. The penetration force and the static yield stress grow linearly during the induction period and exponentially during the acceleration period. Agitation during the induction period destroys the structure, which causes the static yield stress and the penetration force values becoming nearly equal to zero. However, during the acceleration period, even after agitation the static yield stress and the penetration force exhibit high residual values, which indicates the impact of hydration to the structural build-up.

Effect of chitosan molecular weight and protein to polysaccharide ratio on the rheological and physicochemical properties of milk proteins–chitosan complex coacervate

The small amplitude oscillatory shear (SAOS) rheological properties of complex coacervate of milk proteins with high (HMC), medium (MMC), and low (LMC) molecular weight chitosan in the optimal ratios of milk proteins to chitosan (15:1, 10:1, and 5:1, respectively) were measured. In addition, the morphological (SEM), structural (XRD), and thermal (DSC) properties of the complex coacervates were investigated in comparison with the milk protein concentrate. Complex coacervates showed the shear-thinning behavior due to a linear decrease of complex viscosity with increasing frequency. Furthermore, the highest complex modulus and the more compact structure under optimal conditions, in terms of the ratio of protein to chitosan and pH, revealed strong electrostatic bonding between proteins and chitosan. All coacervates showed a G′ > G″ (Tanδ<1), indicating the formation of an interconnected gel-like structure that was described by the power law model. The maximum fracture stress was obtained at optimum conditions (R = 15:1, pH =6.7 for HMC; R = 10:1, pH =5.5 for MMC and R = 5:1, pH =4.6 for LMC), indicating the highest intermolecular interaction between milk proteins and chitosan. The coacervates had a completely amorphous structure similar to MPC, and according to DSC results, the ionic bonds between milk proteins and chitosan were not destroyed up to 300 °C. Coacervation leads to purified milk proteins at a low cost. In addition, the coacervates can be used for the encapsulation of heat-sensitive compounds, and also as a stabilizer to improve the texture of food.

Cellulose nanocrystal dispersion-ability in polylactides with various molecular weights prepared in dichloromethane/dimethyl sulfoxide solvents for electrospinning applications

In this study, effects of polylactide molecular weight, i.e., high (HPLA), medium (MPLA), low (LPLA), and dichloromethane (DCM)/dimethyl sulfoxide (DMSO) blend ratio on cellulose nanocrystal (CNC) dispersion quality in solution casted PLA/CNC nanocomposites were investigated via small amplitude oscillatory shear rheological analysis, while crystallization behavior, thermal degradation, morphological structure of the nanocomposites were also reported. Due to its low dielectric constant, none of the nanocomposites with 100DCM indicated a change in their complex viscosity as a result of poor CNC dispersion. This is while the increase in DMSO content (50%vv−1) improved CNC dispersion. The superior CNC dispersion-ability in PLAs with lower molecular weight was confirmed. The poorer CNC dispersion in HPLA attributes to hindering effect of higher molecular weight on solvent and nanoparticle diffusion. The better dispersed CNCs influenced crystal nucleation behavior of PLAs and increased crystallinity degree. In addition, the impact of well-dispersed CNCs on fiber formation quality of nanocomposites was reported. Introducing finely dispersed CNCs (1 wt%) in LPLA refined fiber diameters around 1200 nm with more homogenous structure. Besides, the use of 100DCM and the use of DMSO at high contents (50%vv−1) deteriorated fiber formation, respectively, due to low conductivity of DCM and high boiling temperature of DMSO.

Toughening Immiscible Polymer Blends: The Role of Interface-Crystallization-Induced Compatibilization Explored Through Nanoscale Visualization.

This study explores the novel approach of interface-crystallization-induced compatibilization (ICIC) via stereocomplexation as a promising method to improve the interfacial strength in thermodynamically immiscible polymers. Herein, two distinct reactive interfacial compatibilizers, poly(styrene-co-glycidyl methacrylate)-graft-poly(l-lactic acid) (SAL) and poly(styrene-co-glycidyl methacrylate)-graft-poly(d-lactic acid) (SAD) are synthesized via reactive melt blending in an integrated grafting and blending process. This approach is demonstrated to enhance the interfacial strength of immiscible polyvinylidene fluoride/poly l-lactic acid (PVDF/PLLA) 50/50 blends via ICIC. IR nanoimaging indicates a cocontinuous morphology in the blends. The blend compatibilized with SAD exhibits a higher storage modulus, as unveiled by small amplitude oscillatory shear (SAOS) in the melt state at a temperature below the melting temperature of the stereocomplex (SC) crystals and by DMTA measurements in the solid state. This increase is attributed to the formation of a 200-300 nm thick rigid interfacial SC crystalline layer that is directly visible using AFM imaging and chemically characterized via IR nanospectroscopy. This ICIC also results in a significant toughening of the blend, with the elongation at break increasing more than 20-fold. Moreover, the fracture toughness factor obtained from single edge-notch bending (SENB) tests is doubled with ICIC as compared to the uncompatibilized blend, indicating the strong crack-resistance capability as a result of ICIC. This improvement is also evident in SEM images, where thinner and longer fibrillation is observed on the fractured surface in the presence of ICIC.

Effects of Mixing and Large-Amplitude Oscillatory Shear Deformations on Microstructural Properties of Gliadin and Glutenin as Captured by Stop-Flow Frequency Sweeps in Small-Amplitude Oscillatory Shear.

Gliadin and glutenin extracted from vital wheat gluten were studied using Large Amplitude Oscillatory Shear (LAOS) followed by stop-flow frequency sweep tests after being subjected to short (4 min) and prolonged (60 min) mixing times. The LAOS tests were conducted at up to two different strain amplitudes (γ: 0.1%, 200%; ω: 10 rad/s) to apply small and large deformations to the gliadin and glutenin after mixing for different time periods. Frequency sweep tests (ω: 0.01-100 rad/s, γ: 0.06%) revealed an increase in the elasticity of gliadin with respect to an increasing mixing time, as evidenced by a robust increase in G'(ω), coupled with a less robust increase in G″(ω). Consistent with the increase in elasticity, a progressively lower tanδ(ω) and G'(ω) slope were observed for the gliadin that underwent 60 min of mixing followed by large LAOS deformations. However, G'(ω), G″(ω), and η*(ω) remained constant for glutenin as the mixing time increased. Elastic decay with an increase in tanδ(ω) was found for glutenin when subjected to prolonged mixing followed by large LAOS deformations, which became apparent at high frequencies. The stop-flow LAOS (non-linear region)-frequency sweep (linear region) tests provided an understanding of how exposure to different mixing times and LAOS deformations of different magnitudes influence the mechanical/rheological properties of the main gluten proteins.

Modulating the behavior of ethyl cellulose-based oleogels: The impact food-grade amphiphilic small molecules on structural, mechanical, and rheological properties

This work evaluates the ability of various lipid-based amphiphilic small molecules (ASMs) to modulate the mechanical and rheological properties of oleogels principally structured by ethyl cellulose (EC). Six ASMs varying in the chemical structure of their polar headgroups were used to produce EC-ASM oleogels. Stearic acid (StAc), monoacylglycerol (MAG), sodium stearoyl lactylate (SSL), and citric acid esters of monoglycerides (CITREM) all provided a dramatic enhancement in gel strength, while lactic acid (LACTEM) and acetic acid (ACETEM) esters produced only a marginal increase. Those additives which crystallized above 20 °C displayed pronounced changes in their network organization and crystal morphology in the presence of EC. Differences in the solid/liquid phase change behavior were also observed in select samples using differential scanning calorimetry. Both the small and large amplitude oscillatory shear responses were dependent on the ASM which was dependent on the chemistry of the headgroup, crystal network organization, and ability to plasticize the polymer network. The extent of thixotropic recovery was largely dependent on the polarity of functional groups in the ASMs, but was also influenced by the formation of a secondary crystal network. In general, ASMs which formed larger, system-spanning crystal networks (MAG, StAc) produced more brittle gels, while the highly hydrophilic, charged headgroup of SSL promoted a homogeneous distribution of small crystals, resulting in a tougher material. In the absence of a crystal network, stronger polar species in the ASM headgroup produced higher gel strength and increased elasticity. Thus, both ASM chemical structure and crystallization properties strongly contribute to the functionality of the resulting combined oleogelator systems.

Rheology of flexible fiber-reinforced cement pastes: Maximum packing fraction determination and structural build-up analysis

The maximum packing fraction (φfm) of flexible fibers is an essential parameter for understanding the rheological behavior of flexible fiber-reinforced cement paste (FFRCP). However, direct measurement of φfm of flexible fibers is still lacking. In this study, a shear rheology-based method for direct measurement of φfm was proposed and the assumption of fiber conformation under shear was verified by micro-CT. Based on this, a yield stress model for FFRCP was constructed to explain the entanglement and friction effects in the fiber network. Finally, static yield stress tests and small amplitude oscillatory shear (SAOS) tests were carried out to explore the structural build-up of FFRCP. It was found that the proposed method enables direct determination of φfm through only a few viscosity-fiber content data for a given FFRCP. Furthermore, the proposed model can describe the static yield stress of FFRCP well. Finally, the relative structural build-up rate of FFRCP follows a similar trend as the relative yield stress, with a critical relative fiber volume fraction (0.299) as the boundary. Subsequently, the relative structural build-up gradually deviates from the relative yield stress due to the limiting effect of the fibers.

Superposition of steady shear flow upon orthogonal small-amplitude oscillation from a rotarance theory

The novelty of this work is in its prediction of the non-Newtonian behavior of polymeric liquids in the orthogonal superposition of small-amplitude oscillatory shear flow upon steady shear flow. We do so using rotarance theory, namely, by considering only the orientability of the macromolecules in suspension. We arrive at explicit analytical solutions for the complex viscosity as a function of the steady shear rate and of the frequency of the superposed oscillation. Our results explain the canonical laboratory observations of orthogonal superposition: (α) the real part of the complex viscosity as a function of frequency decreases with increasing steady shear rate, (β) the curves of minus the imaginary part as a function of frequency go through a maximum, and (γ) the independence of the steady mean shear stress from the superposed oscillation. We compare our predictions with those of parallel superposition and discover that the further the macromolecular structure from axisymmetric, I3/I1=1, the greater the difference between parallel and superposition. In other words, studying both directions of superposition of either part of the complex viscosity uncovers the most important feature of macromolecular structure, the moment ratio, I3/I1, and thus, the macromolecular orientability.

Utilizing synergy of MLG and MWCNT with optimized mixing protocol to improve the high temperature stability of SBS modified bitumen

High temperature instability is the biggest problem which limits the application of Styrene-Butadiene-Styrene (SBS) modified bitumen in flexible pavements. Addition of multi-layer graphene (MLG) nanomaterial improves the performance of SBS modified bitumen, but deteriorates its thermal stability. The binary additive comprising of MLG and multi-walled carbon nanotubes (MWCNT) can be a way to improve the thermal stability through their synergistic effects, however, mixing protocol needs to be optimized simultaneously. In this present study, MLG, MWCNT and their combination have been dispersed by two different organic solvent dissolution protocols, i.e., wet and dry to prepare the SBS-nano modified binders. Thermal stability analysis and rheological characterization (small & large amplitude oscillatory shear) have been used to optimize the method and to compare the effect of sole and binary additive. Advanced tools such as Raman spectroscopy and Field emission scanning electron microscopy have been used to understand the underlying science at micro-molecular level. The synergistic effects of combined additives are prominently visible only in dry organic dissolution method and with this method, the combination of MLG-MWCNT (0.1phr-1phr) significantly eliminates the thermal instability of SBS modified binder by upto 96 %. This SBS-nano modified bitumen may serve as futuristic binder for the black top pavements.

Mechanism of sodium alginate synergistically improving foaming properties of pea protein isolate: Air/water interface microstructure and rheological properties

The synergistic effect of polysaccharides plays a crucial role in regulating the foaming properties of protein based aerated foods. In this study, the synergistic improvement mechanism of pea protein isolate (PPI)-sodium alginate (SA) composite on the foaming performance was determined through multi-component interaction, air/water interface adsorption behavior and foam properties. The results of interactions between PPI and SA indicated that SA and PPI could form smaller and more stable soluble composite through hydrogen bonding, hydrophobic interactions, and electrostatic interactions. The α-helix content of PPI significantly decreased, and PPI exhibited a more flexible secondary structure. In depth research on the air/water interfacial behavior and interfacial microstructure through adsorption kinetics, surface dilatational rheology and Lissajous plots indicated that the PPI-SA composite could accelerate the adsorption process, constructing a highly viscoelastic interface mainly based on elasticity. The results of foam properties showed soluble PPI-SA composite could prepare smaller and more dense foam with thicker and smoother interface film, which was beneficial to the foam stability. The results of small amplitude oscillatory shear and large amplitude oscillatory shear suggested that foam prepared by soluble PPI-SA composite showed stronger ability to resist deformation whether in linear or nonlinear viscoelastic region, revealing the good mechanical properties of these foam under extreme processing conditions and feasibility to improve the quality of aerated food. When the mass ratio of PPI/SA was 1:0.3, the foam properties was strongest. When the mass ratio of PPI/SA exceeded 1:0.3, insoluble substances appeared in the composite system, which was disadvantageous to foam properties and deformation resistance. Therefore, the complexation of PPI and SA was an effective way to improve the air/water interface and foaming properties of PPI, providing theoretical guidance for targeted regulation of the foaming properties of protein based aerated foods.

Early-age structural build-up and rheological assessment of alkali-activated slag-red clay brick waste pastes: Influence of silica modulus and precursors proportions

Sustainability plays a crucial role in the current context of the cement industry, and alkali-activated materials (AAMs) are emerging as eco-efficient alternative binders. On the other hand, the massive generation of red brick waste worldwide and its lack of a defined destination emphasizes this material as an alternative precursor that has been insufficiently explored in the literature. Based on this context, the present study aims to investigate the structural build-up, reaction kinetics, and rheological properties of alkali-activated pastes based on blast furnace slag (BFS) and red clay brick waste (RBCW). Fresh properties such as structural build-up, rheology, and reaction kinetics are lacking in the literature on RCBW-based AAMs, highlighting these properties as a research gap to be filled and discussed in depth in this paper. The flow sweep test was performed, linked to yield stress and viscosity properties. The structural build-up was evaluated by strain sweep and small amplitude oscillatory shear (SAOS) tests based on viscoelastic parameters: storage modulus, loss modulus, and phase angle. Isothermal calorimetry and in-situ FTIR were also conducted to complement the analysis and provide insight into the reaction kinetics, chemical structure, and product formation. Higher silica modulus (Ms) resulted in a lower structural build-up rate and a delayed reaction. Higher content of RCBW resulted in a delayed structuration process, which was linked to a delay in the precipitation of aluminosilicate gels. Early increase in the structural build-up in 25 % and 50 % RCBW blends (Ms = 1.0) is associated with the early formation of a well-percolated network.

Modulation of acid-induced pea protein gels by gellan gum and glucono-δ-lactone: Rheological and microstructural insights

This study investigated the effect of gellan gum (GG) and glucono-δ-lactone (GDL) on the acid-induced gel properties of pea protein isolate (PPI) pretreated with media milling. The inclusion of GG substantially enhanced the gel hardness of PPI gel from 18.69 g to 792.47 g though slightly reduced its water holding capacity (WHC). Rheological analysis showed that GG increased storage modulus (G’) and decreased damping factor of gels in the small amplitude oscillatory shear region and transformed its strain thinning behavior into weak strain overshoot behavior in the large amplitude oscillatory shear region. SEM revealed that GG transformed the microstructure of gel from a uniform particle aggregate structure to a chain-like architecture composed of filaments with small protein particles attached. Turbidity and zeta potential analysis showed that GG promoted the transformation of PPI from a soluble polymer system to an insoluble coagulant during acidification. When GG content was relatively high (0.2 %-0.3 %), high GDL content increased the electrostatic interaction between PPI and GG molecules, causing their rapid aggregation into a dense irregular aggregate structure, further enhancing gel strength and WHC. Overall, GG and GDL can offer the opportunity to modulate the microstructure and gel properties of acid-induced PPI gels, presenting potential for diversifying food gel design strategies through PPI-GG hybrid systems.

High internal phase Pickering emulsion solely stabilized by low-content chitosan: Insight into relations between network microstructures and rheological properties

Nano-sized and well-dispersed chitosan particles (CSPs) are prepared by adjusting pH towards pKa of chitosan (CS) aqueous solutions. The prepared CSPs are able to stabilize high internal phase Pickering emulsions (HIPPEs) with low CSP contents, at minimum of 0.2 wt% CSP stabilizing a maximum of 85 % oil phase fraction in a near-neutral environment. It is clarified by microscopy, small amplitude oscillatory shear (SAOS) and large amplitude oscillatory shear (LAOS) measurements that CSPs act as Pickering particle emulsifiers to form a network immobilizing oil droplets in HIPPEs. Using power-law analysis on SAOS results, the solid-like but frequency-dependent rheological response is attributed to the physical connection among CSPs, while the overshoot of the loss modulus in LAOS test is assigned to the featured resistance of networks to the applied large deformation. The oil phase fraction, CSP concentration, temperature and ionic strength are found to be key factors for the rheological behavior and emulsion stability. This work is expected to guide the design and processing of HIPPE stabilized solely by polysaccharides.

Morphological Influence on a Nonionic Bilayer Bending Rigidity and Compression Modulus.

The mechanical properties of multilamellar vesicles and their relevance to soft matter physics and material science are of significant interest. The bending rigidity, κ, and compression modulus, B, of three-dimensional (3D) finite nonspontaneous multilamellar vesicles, formed by a nonionic surfactant, are linked to nanoscale bilayer thickness, δ, estimated via small-angle X-ray scattering, and macroscopic elastic modulus measured through small-amplitude oscillatory shear experiments. κ and B significantly differ from the same system in the two-dimensional (2D) infinite nanostructured planar lamellar phase. Particularly, κ3D was found to be much smaller than κ2D, while an opposite behavior was seen for B. The 2D-to-3D morphology transition occurs under a transient mechanical field, resulting in rheopectic behavior. κ scales quadratically with δ, consistent with bilayer membrane theories, and linearly with vesicle radius in the densely packed state. These findings have implications for understanding and designing soft interfaces due to the influence of bending rigidity on transport properties.

Physicochemical Attributes and Dynamic-Mechanical Properties of a Traditional Himalayan Cheese – Kalari

ABSTRACT Kalari is a traditionally made Himalayan cheese. It is popular in the hilly belts of Jammu and Kashmir, India, and is also known as the “Mozzarella of Kashmir.” It is prepared from raw milk by natural acidification followed by heat coagulation. The present work aims to evaluate the physicochemical and rheological characteristics of Kalari and to gain insight into its composition and functional properties. Rheological characterization based on small amplitude oscillatory shear (SAOS) measurements reveals the cheese to be a viscoelastic material, with the elastic nature dominating viscous behavior at all test conditions. Temperature sweep and Arrhenius plot also enabled to identify rheological response of Kalari at elevated temperatures, which can further elucidate its functionality. Lower values of activation energy (39.57 KJ mol−1) and phase angle (28°) reiterate that the cheese does not flow extensively but undergoes softening and slight melting on exposure to high temperatures. Physicochemical characterization revealed the cheese to possess more protein (33.8% − 42.6%) and moisture (42.9% − 48.1%) than fat (7.5% − 11.9%).

Replacing solid fat in croissant dough using xanthan gum-based oleogels. Impact on rheological properties and final product quality

Healthier croissants prepared with xanthan gum-based oleogels have been evaluated by mechanical and sensory properties. Blends containing oleogel and conventional fat (shortening, SH) (50/50) were used as fat source in the croissant doughs. The shortening/oleogel (SH/OG) blends and doughs were rheologically characterized by Small and Large Amplitude Oscillatory Shear (SAOS-LAOS) tests, whereas both doughs and baked croissants were characterized by penetration and Texture Profile Analysis (TPA) tests. Acceptability and purchase intention tests of the selected croissants was also carried out, as well as discriminatory tests to confirm whether there were differences between the samples. Different oleogels were tried, combining four food structuring agents (whey protein (WP), polysorbate Tween (TW), soy lecithin (SL) and locust bean gum (LBG)) with xanthan gum (XG) in order to structure sunflower oil.Viscoelastic moduli presented differences depending on the structuring agent used in the oleogels. SH control was firmer than all blends. However, this pattern was not reproduced in the croissant doughs. The control dough, formulated only with the shortening had an intermediated behaviour in oscillatory shear. Indeed, in texture it presented the lowest values, with a hardness similar to that of the lecithin blend. However, doughs formulated with LBG or WP blends showed the highest values for both hardness and viscoelasticity. Baked croissants formulated with SL blend presented a crumb appearance and an airy structure similar to the control. Croissants formulated with the other blends were more compact and had higher hardness values. Therefore, formulation containing SL blend was selected for further analysis. Control and SL-based doughs followed the same pattern when large deformations were applied: shear stiffening and shear thinning behaviour. Regarding sensory analysis in final croissants, no differences in appearance, texture, flavour and overall liking were obtained. There was also no difference in purchase intention, so that the formulation with SL oleogels was optimal for the healthier croissants proposed.

Temperature- and Rate-Dependent Fracture in Disulfide Vitrimers.

The fracture behaviors of disulfide vitrimers are highly rate-dependent. Our investigation revealed that the temperature-dependent fracture behaviors of disulfide vitrimers cannot be entirely explained by a simple time-temperature superposition model. This Letter explores the impact of the dynamic nature of molecular defects on the temperature- and rate-dependent fracture behaviors of disulfide vitrimers. Considering that the high cross-linking density remains constant during the associated bond exchange reaction, we identify loop defects in the network as the primary dynamic defects. By employing small amplitude oscillatory shear, we measured the loop defect fraction in EPS25 disulfide vitrimers at varied temperatures, revealing an increased presence of loop defects at elevated temperatures. Furthermore, our findings indicate that the temperature-dependent fracture behaviors are attributed to the temperature-dependent number of loop defects in disulfide vitrimers.

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.

Development of corn starch-sodium alginate emulsion gels as animal fat substitute: Effect of oil concentration

Emulsion gels were prepared utilizing corn starch (CS), sodium alginate (SA), and corn oil through calcium ion induction for animal-fat analogs. The influence of oil concentration on the rheological properties, microstructure and lipid oxidation of the emulsion gel was analyzed. Results revealed that the emulsion gel containing 30% (v/v) oil exhibited no surplus oil leakage and demonstrated the highest gel strength. The results of the small amplitude oscillatory shear (SAOS) and large amplitude oscillatory shear (LAOS) test proved that the emulsion gel exhibited the greatest elasticity and deformation resistance when the oil content was 30% (v/v), imparting suitable mouth feel and transport stability as an animal fat substitute. Microstructure analysis indicated that SA crosslinked with Ca2+ to generate a network structure accompanied by the reinforcing effect of starch granules, enabling the dense network to capture an optimal quantity of oil to form a uniform gel network structure. Furthermore, the emulsion gel exhibited markedly lower lipid oxidation compared to bulk oil after 14 days of storage. As a new fat analog system, the CS-SA emulsion gel holds promising potential for applications in the food industry.