Soy Protein Research Articles

Soybean biorefinery and technological forecasts based on a bibliometric analysis and network mapping

Global warming and increasing pollution have become critical global issues, and, coupled depletion of traditional energy sources, have accelerated the adoption of more sustainable production systems, such as biorefineries. Biorefineries possess the capacity to integrate technologies and processes within a single facility, thereby generating biofuels, high-value-added chemical products, and energy. The current study aims to evaluate various scenarios of soybean biorefineries by employing a bibliometric analysis and network mapping to facilitate and implement technological forecasting. To achieve this objective, eight methodological steps were undertaken. The majority of studies reviewed were primarily concerned with the utilization of soybean straw and hulls, motivated by the need to address environmental challenges related to the disposal of substantial volumes of these residues. Research on the application of soy whey also emerged as significant, mainly due to its connection with soy protein isolates. The seven most promising technological avenues identified were nanocomposites, peroxidases, ethanol, green composites, biochar, films, and biodiesel. Consequently, the findings provide a bibliographic foundation for future research on the integration of soybean-derived residues, processes, and products, which could foster innovation within the biorefinery framework and lead to crucial advancements in the processes.

Fabrication of ultrafine Himalayan walnut oil Pickering emulsions by ultrasonic emulsification: Techno-functional properties of emulsions and microcapsules

In present scenario, much of the attention has been put on the production and utilization of Pickering emulsions deciphering enhanced stability and applicability over wide environmental conditions. In this context the present study was carried out to elaborate effect of different wall materials and pH systems on the physicochemical, structural and morphological properties of Himalayan walnut oil Pickering emulsions by ultrasonic emulsification. In this study, concentrated Pickering emulsion of Himalayan walnut oil (HWO) was prepared utilizing soy protein isolate (SPI), maltodextrin (MD) stabilized by pectin at varying concentrations and pH systems (4.0, 7.0). With increase in pectin and SPI concentration and lowering MD, stable emulsions were obtained as deciphered by an Emulsion stability index (ESI) of 100 for 7 days at ambient storage. HWO Pickering emulsions were analysed for particle size measurements (2.13–13.64 µm) and depicted negative zeta potential values (−3.70 to −18.58). Lyophilized HWO microcapsules depicted moderate encapsulation efficiency (44.69–57.63 %) whereas the hygroscopicity values of the microcapsule ranged from (0.21–12.10 %). Thermogravimetric analysis (TGA) of the samples depicted the temperature of maximum degradation rate up to 550 °C whereas XRD spectra depicted amorphous nature of oil microcapsules. FTIR spectra revealed a close association between the SPI-MD-Pectin matrix. SEM analysis revealed stable oil globules entrapped in protein-polysaccharide matrix with no visible cracks and fissures.

Emulsions co-stabilized by Polygonatum sibiricum saponin and soy protein isolate: Physical stability, interaction mechanism, interface behavior

This study investigates the interaction mechanism between Polygonatum sibiricum saponin (PSS) and soy protein isolate (SPI) to enhance the stability of oil-in-water emulsions, laying the foundation for an efficient PSS delivery system. Initially, we evaluated the stability of oil-in-water emulsions with various PSS concentrations (0.1%, 0.2%, 0.3%, 0.5%, and 1% w/w). Results indicated that PSS enhances emulsion stability by increasing absolute zeta potential, reducing average particle size, and improving resistance to external factors. Notably, concentrations of 0.3%, 0.5%, and 1% (w/w) PSS show significant improvements in emulsion stability (p < 0.05). Subsequently, we elucidated the mechanism by which PSS enhances stability. Our findings reveal that PSS interacts with SPI, inducing structural modifications in SPI and expanding its hydrophobic regions. Additionally, PSS forms SPI-PSS complexes through hydrogen bonding with aromatic amino acid residues in SPI, thereby reducing interfacial tension and maintaining stable viscoelasticity. Comparative analysis of Lissajous plots identifies the optimal PSS to SPI ratio as 0.3% (w/w) each, resulting in a resilient interface film formed by numerous SPI-PSS complexes capable of withstanding compression or extension. Overall, our study underscores the efficacy of PSS in navigating the emulsion system and collaborating with SPI to stabilize emulsions.

Controlled hydrolysis with preheating treatment and glutathione addition for enhanced foaming properties of soy protein isolate

This study investigates the effects of thermal treatment and glutathione addition on soy protein isolate (SPI) before pepsin-driven hydrolysis to obtain desirable hydrolysis with a high yield of soluble protein and good foaming properties. Various properties of SPI hydrolysates were measured to understand the change of SPI molecular composition related to foaming properties. The results revealed that the combination of glutathione and 55 °C thermal treatment yielded the most favorable SPI hydrolysate, characterized by excellent foaming capability (191.3%) and stability (93.1%), attributed to the highest relative composition (50.2%) of 7S. With the treatment temperature increasing from 55 °C to 75 °C, the reduction of 7S and generation of small molecular weight peptides negatively affected the foaming properties of SPI hydrolysates. The application of glutathione as a modulator, alongside mild thermal treatment, optimizes SPI hydrolysates for applications needing improved foaming and interfacial properties to achieve desirable foaming capability and stability. The study's findings offer promising potential for improving food products and formulations requiring enhanced foaming properties, with applications in industries like bakery and confectionery, leading to better texture, stability, and overall product quality.

Effect of pH-shifting and ultrasound on soy/potato protein structure and gelation

The substitution of meat proteins with plant-based proteins from various sources is often motivated by nutritional considerations. However, the inherent limited solubility of plant proteins, which results in suboptimal techno-functional properties, remains a persistent challenge in food formulation. The purpose of this study was to investigate the impact of pH-shifting (P), high-intensity ultrasound (U), and ultrasound-assisted pH-shifting on the structure and solubility of soy protein isolate (SPI), potato protein isolate (PPI), and the soy/potato protein complex (SPI/PPI complex). Additionally, a detailed examination of the gel properties of SPI, PPI, and the SPI/PPI complex was conducted to assess the changes that occurred before and after modification. The results of particle size, zeta potential, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), free sulfhydryl (R-SH), surface hydrophobicity (H0), Fourier transform infrared spectrum (FTIR) and fluorescence intensity showed that P and U treatment promoted the unfolding of proteins structures and decreased particle size, and augmented protein-water interactions, leading to enhanced solubility. The pH-shift and ultrasound (PU) treatment further amplified these structural alterations in proteins. Consequently, the gelling characteristics of the modified proteins were substantially improved, with notable increases in hardness, elasticity, and water-holding capacity (WHC). The findings facilitate developing more targeted plant protein-based gel products that specific techno-functional attributes, concurrently allowing for modifications to their nutritional profiles.

Biological Activities of Soy Protein Hydrolysate Conjugated with Mannose and Allulose.

The non-enzymatic conjugation of peptides through the Maillard reaction has gained attention as an effective method to enhance biological functions. This study focuses on two conjugate mixtures: crude soy protein hydrolysate (SPH) conjugated with mannose (SPHM) and crude soy protein hydrolysate conjugated with allulose (SPHA). These two mixtures were products of the Maillard reaction, also known as non-enzymatic glycation. In vitro experiments were conducted to evaluate the antioxidant, anti-pancreatic lipase, inhibition of Bovine Serum Albumin (BSA) denaturation, and anti-angiotensin converting enzyme (ACE) activities of these conjugated mixtures. The results indicate that conjugated mixtures significantly enhance the antioxidant potential demonstrated via the DPPH and FRAP assays. SPHA exhibits superior DPPH scavenging activity (280.87 ± 16.39 µg Trolox/mL) and FRAP value (38.91 ± 0.02 mg Trolox/mL). Additionally, both conjugate mixtures, at a concentration of 10 mg/mL, enhance the BSA denaturation properties, with SPHM showing slightly higher effectiveness compared to SPHA (19.78 ± 2.26% and 5.95 ± 3.89%, respectively). SPHA also shows an improvement in pancreatic lipase inhibition (29.43 ± 1.94%) when compared to the SPHM (23.34 ± 3.75%). Furthermore, both the conjugated mixtures and rare sugars exhibit ACE inhibitory properties on their own, effectively reducing ACE activity. Notably, the ACE inhibitory effects of the individual compounds and their conjugate mixtures (SPHM and SPHA) are comparable to those of positive control (Enalapril). In conclusion, SPHM and SPHA demonstrate a variety of bioactive properties, suggesting their potential use in functional foods or as ingredients in supplementary products.

High moisture extrusion of pulse proteins: Texture, structure, and in vitro digestion characteristics of extrudates

Pulse proteins are promising components for plant-based food development, yet their diverse subunit compositions, influenced by source origin, result in variable extrusion properties. This study utilized high moisture extrusion (60% moisture content) to prepare extrudates from four pulse proteins: soy, pea, chickpea and mung bean protein isolates (SPI, PPI, CPI, and MPI, respectively). The texture, structure, and in vitro digestion characteristics of extrudates were examined. The results showed that SPI and PPI were mainly composed of 7S and 11S globulins, while CPI and MPI were mainly composed of 7S globulins, and 11S globulins, respectively. SPI extrudates exhibited significantly lower hardness, chewiness, and transverse and longitudinal fracture stresses, while CPI extrudates exhibited a higher anisotropy index. SPI extrudates with a higher β-sheet content (39.08%) exhibited denser structures. The gastrointestinal digestibility (86.65%) of CPI extrudates was higher than other groups. Correlation analysis showed that 7S/11S ratio was positively correlated with the melt viscosity, while negatively correlated with the anisotropy index and in vitro digestibility. This study highlights the distinct extrusion properties of pulse proteins based on their unique subunit composition. The results provide insights for selecting appropriate protein sources and developing plant-based protein products with tailored textural attributes and desirable digestibility.

Soy protein isolate–based gel polymer electrolyte for flexible solid-state supercapacitor

At present, the polymer matrices of most polymer electrolytes are derived from petroleum-based synthetic polymers. Herein, sustainable and renewable soy protein isolate (SPI) was grafted with methacrylic acid (MAA) and then cross-linked by ring-opening reaction with polyethylene glycol diglycidyl ether as cross-linking agent to obtain a biomass-based polymer electrolyte. Results show that when the added amount of MAA is twice the quality of SPI, gel polymer electrolyte displays the best comprehensive properties and presents the highest ionic conductivity of 5.24 × 10−3 S/cm. The flexible supercapacitor was fabricated by using SPI-based gel polymer electrolyte with activated carbon electrodes, which exhibited excellent specific capacitance (128.63 F/g) and energy density (9.52 Wh/kg) at 0.5 A/g with a decent capacitance retention of 93% after 5000 charge–discharge cycles. It can be ascribed that grafting modification of SPI improves the interface performance of electrode–polymer electrolyte. Furthermore, potassium iodide is introduced to form a redox polymer electrolyte to achieve a high-energy-density supercapacitor, which provides outstanding energy density of 24.40 Wh/kg at 1.0 A/g. This work demonstrates that sustainable and renewable biomass can be converted into matrix of polymer electrolyte for high performance supercapacitor based on aqueous polymer electrolyte.

Effects of NaCl/KCl ratios on structural and properties changes in soy‐potato protein mixed gel

SummaryTo reduce the sodium salt content in protein gel‐based foods, this study investigated the effects of different Na‐K ratios on the gelation properties and structural changes of soy protein isolate (SPI) and potato protein isolate (PPI) composite gels. The results showed that the composite gel properties were further enhanced with increasing Na‐K ratio in the SPI/PPI gel system. Specifically, when the Na‐K ratio was 1:1, the SPI/PPI composite gel exhibited the highest gel strength, gel elasticity, WHC, storage modulus (G′), and β‐sheet content, whereas the α‐helix content and β‐turn content were the lowest. Scanning electron microscopy images revealed a dense and uniform network structure of the composite gel. The addition of low concentrations of Na+ and K+ improved the network structure and water‐holding capacity of the SPI/PPI gel during the heat‐induced gelation process. However, excessively high Na‐K ratios weakened the gel properties.

Mechanism of sucrose improving the mechanical characteristics of foams stabilized by soy protein isolate/gellan gum/guar gum ternary complex

Sucrose shows the potential of stabilizing foam system. This study systematically evaluated the mechanism by which sucrose improved foaming properties and mechanical characteristics of foams stabilized by soy protein isolate/gellan gum/guar gum ternary complex. Results showed that sucrose could bond to the surface of ternary complex or self-aggregate within the continuous phase, resulting in the neutralization of charges (nearly zero) and an increase in particle size (up to 62.54 μm). The addition of 30 % sucrose reinforced foam system with an increased foamability (305.99 %) but a longer foaming time (10 min) during foaming process. Moreover, the mechanical characteristics, including hardness, elastic strength (Power-law constant) and solid characteristic (frequency exponent), were also significantly enhanced to 1.26 N, 354.7956 and 2.5873, respectively, which were 1.65, 1.94 and 1.11 times than those of foams without sucrose. The microscopic mechanism lied in the reduced water freedom degree caused by sucrose, which generated a compact structural network around bubbles for providing a stable and stiff structure to foams. These findings will provide clear theoretical guidance for regulating mechanical characteristics of aerated foods by using sucrose as structural building blocks.

Nanoparticle and dialdehyde polysaccharide synergistically improving the physicochemical properties of soy protein isolate films enriched with lingonberry extract

The combination of proteins and anthocyanins showed great potential in constructing smart films, but their weak interactions led to poor mechanical properties in the resulted films. This study enhanced the physicochemical properties of lingonberry extract (LE)-enriched soy protein isolate (SPI) smart active films by incorporating dialdehyde konjac glucomannan (DKGM) as a cross-linker and quercetin-loaded shellac nanoparticles (SNPs-Qu) as fillers. The films’ chemical structure, thermal properties, surface and cross-sectional morphology were analyzed using FT-IR, DSC, and SEM, respectively. Additionally, the light-shielding properties, mechanical properties, water vapor permeability, and antioxidant properties of the films were systematically studied. The results indicated considerable interactions among film components. The combination of DKGM with SNPs-Qu significantly enhanced UV absorption while reducing moisture content from 35.07% to 24.84% and water vapor transmission from 0.63 to 0.41 (mm•g•m−2•h−1•KPa−1) of the films. Importantly, DKGM positively affected thermal stability and mechanical properties whereas SNPs-Qu improved internal structure and the antioxidant properties of the films significantly. Notably, film color shifted from red to yellow-green with rising pH levels effectively tracking pork filling freshness status. Overall, the smart active film constructed from SPI, LE, DKGM, and SNPs-Qu exhibited excellent physicochemical properties alongside pH-sensitive qualities—promising applications in smart food packaging.

Fabrication and characterization of bioactive curdlan and sodium alginate films for enhancing the shelf life of Volvariella volvacea

This study aimed to develop bioactive films based on curdlan (CD) and sodium alginate (SA) to enhance the shelf life of the Volvariella volvacea mushroom. A stable nanoemulsion of droplet size of 150.1 ± 5 nm was first formulated using 5% soy protein (Sp) and 10% lavender essential oil (LEO), achieved by ultrasound treatment for 10 min, resulting in small droplet sizes. In parallel, a CD-SA film was prepared by mixing them in a 1:1 ratio. The SpLEO nanoemulsion was then ex situ added to the CD-SA film at varying concentrations (4%, 6%, 8%, and 10%). The resulting bioactive film exhibited desirable properties, including water vapor permeability (1.15 ± 0.05 × 10−10 g m−1 Pa−1 s−1), swelling rate (547%), and tensile strength (10.1 ± 1.3 MPa). Docking and structural analyses suggested that ultrasound treatment enhanced the intermolecular hydrogen bonding, creating a uniform and regular surface and reduced crystallinity. The CD-SA film with ultrasound-treated 8% SpLEO nanoemulsion [i.e., (CD-SA/SpLEO-8)US] showed antibacterial activity against Escherichia coli and Staphylococcus aureus and extended the freshness of straw mushrooms prevention of spoilage during storage. Additionally, the film reduced respiration rate (975 mg CO₂/kg/h at 96 h) and ethylene production (160 ng/kg/s by 96 h) while effectively inhibiting straw mushroom autolysis. This led to a reduction in browning (2.91), total soluble solids (7.5%), weight loss (13.9%), and polyphenol oxidase activity (0.08 ΔOD420/min⋅g), thereby extending the shelf life of the mushrooms to 96 h. These findings highlight the potential of incorporating different molecules using ultrasound treatment to develop innovative edible films for food preservation.

A life cycle assessment of protein production from wheatgrass: Optimization potential of a novel vertical farming system

The global protein demand is expected to keep increasing due to a growing global population, combined with changing social demography and other factors. OrbiPlant®, a novel vertical farming technology developed in Germany, is used to cultivate wheatgrass (Triticum aestivum) as one possible solution for realizing a sustainable protein supply to meet this challenge. The objective of this study was to investigate the environmental impacts of wheatgrass protein concentrate powder produced in the novel vertical farming system and compare it with traditional protein sources (cheese and soy protein). To achieve this, a ‘cradle-to-gate’ life cycle assessment (LCA) was performed using OpenLCA software and Environment Footprint 3.1 method. The results show that wheatgrass protein from vertical farming has lower environmental impacts than cheese protein in terms of terrestrial eutrophication, and land use, similar impacts on freshwater ecotoxicity and particulate matter, but higher impacts in other categories. Due to the high environmental impact of the current Germany electricity mix, the overall environmental performance of wheatgrass protein remains non-competitive to traditional protein sources. By optimizing production, the environmental impact can be reduced to just 57.8 % of the cheese protein. This finding highlights the potential of the investigated wheatgrass protein from vertical farming system to reduce environmental impacts when substituting animal-based protein. Furthermore, it emphasizes the importance of utilizing renewable energy sources.

Comparative efficacy of amino acid availability and peptidomic analysis of alternative proteins from different sources under dynamic in vitro protein digestion

The increasing global demand for animal protein highlights the critical necessity of exploring alternative protein sources. Accessing the nutritional characteristics of emerging alternative proteins is vital for food processing and consumer acceptance. This study investigated the amino acid availability and peptidomics profiles of plant- (soy), fungal- (filamentous fungus Fusarium venenatum), microalgae- (Nannochloropsis oculata), and insect-based (black soldier fly) proteins using an advanced dynamic in vitro digestion system, with whey protein as a reference. After gastric digestion, soy and mycelial proteins, despite displaying distinct microstructures, exhibited slightly higher protein digestibility levels of 28.79% and 26.36%, respectively, compared to whey protein (22.39%). However, following small intestinal digestion, whey protein (61.31%) significantly outperformed alternative proteins. Mycelial protein (43.71%) exhibited digestibility similar to soy protein (46.12%), markedly surpassing both microalgae protein (33.35%) and insect protein (26.58%). Notably, insect protein achieved an amino acid availability nearly approaching that of whey protein, underscoring its substantial proteolysis capability. Furthermore, microalgae protein produced the highest percentage and number of bioactive peptides under simulated digestion, suggesting potential health benefits such as angiotensin I-converting enzyme (ACE) and dipeptidyl peptidase-IV (DPP-IV) inhibitor activities, which could mitigate the risk of hypertension and Type 2 diabetes. Alternative proteins from different sources demonstrate diverse digestive mechanisms and proteolysis profiles, thereby bolstering their potential applications as nutritious food ingredients in the future.

Noncovalent interaction between proanthocyanidins and soy protein isolate fibers: Structure, functionality and interaction mechanism

This study focused on the addition of different concentrations of proanthocyanidins (OPC) to form noncovalent complexes with soy protein isolate fibers (SPIF). To investigate the effects of polyphenols on the structural and functional properties of protein fibers and to elucidate the mechanism of their interaction. The addition of OPC unfolded the internal structure of the proteins, exposing the hydrophobic groups and reducing the β-sheet structure of SPIF, forming the SPIF-OPC complexes. And the binding of the two would be close to saturation, at the final concentration of added OPC was 0.5 or 1 mg/mL. Multiple spectroscopy and isothermal titration calorimetry analyses indicated that static quenching was the mechanism of fluorescence quenching of SPIF by OPC. The two spontaneously combined through hydrogen bonding and hydrophobic interactions. Transmission electron microscopy observations of the microscopic morphology also indicated that the addition of OPC altered the original long, semi-flexible fibers structure of SPIF. The fibers gradually showed a large number of branches and became short and curved. When the final concentration of added OPC was 4 mg/mL, the emulsifying activity index of SPIF increased by 78.40% and the foaming capacity of SPIF increased by 37.10%. The interaction mechanism of different concentrations of OPC with SPIF will be comprehensively understood from this study, thus expanding its application in food, medicine, cosmetics, and other fields.

Soy protein processing impacts the ice recrystallization inhibition activity of protein hydrolysates

Soy protein processing impacts the ice recrystallization inhibition activity of protein hydrolysates

Full-fat black soldier fly larvae meal and yellow mealworm meal: Impact on feed protein quality, growth and nutrient utilization of Atlantic salmon (Salmo salar) post smolts

The shift towards insect-based alternatives in aquafeeds stems from the need to reduce the carbon footprint associated with the ingredients used in salmon feeds. In the present study, we describe the effects of full-fat insect meal incorporation on amino acid derivatives in feeds and the growth performance and nutrient utilization of Atlantic salmon post-smolts fed insect meals. A 74-day growth trial was conducted employing 520 fish (143 ± 12.8 g); these fish were fed either a control diet (CO) that contained 20 % fishmeal, 20 % soy protein concentrate (SPC), 14 % wheat gluten, 19 % plant raw materials, 13 % fish oil and 6 % rapeseed oil, or one of four insect meal diets, prepared with either 5 % and 10 % black soldier fly larvae meal (BS5, BS10) or 15 % and 30 % mealworm meal (MW15, MW30), by substituting mainly SPC, wheat gluten and rapeseed oil. The inclusion levels of BS and MW were determined based on their distinct chemical compositions, specifically their lipid content. As regards the results, HPLC-based high-throughput data on amino acid derivatives revealed the following: carboxymethyllysine was significantly higher in the MW30 feed than in BS5, BS10 and MW15 feeds; carboxyethyllysine was higher in the MW15 and MW30 feeds compared to the others; furosine was lower in the MW15 feed compared to the CO, BS5 and MW30 feeds. Regarding the effect of the insect meals on Atlantic salmon post-smolts, their inclusion had no significant effect on feed conversion ratio, health indicators and the retention efficiency of macronutrients. Apparent digestibility coefficients (ADC) of dry matter, lipid, ash and energy were not significantly different. However, protein digestibility in the 30 % MW group (80.4 %) was significantly lower (P ≤ 0.05) compared to the control and BS5 group (84.5 %). Furthermore, the ADC of protein was found to decrease linearly with increasing levels of insect meals, with MW showing a significant relationship (adjusted r2 = 0.77, p = 0.014). Overall, our study highlights the efficacy of 5 and 10 % BS and 15 % MW as ingredients in the feeds of Atlantic salmon. Other focal points included the undesirable amino acid derivatives and a reduction in protein digestibility associated with 30 % of MW in the diet of Atlantic salmon. Hence, future investigations should focus on the effects of feed processing conditions on the protein quality of mealworm before suggesting higher inclusion levels to the feed industry.

Formation of thermal-induced microgels from soy protein hydrolysates: Effects of selective proteolysis on glycinin/β-conglycinin

This study explored the impact of selective proteolysis on the formation of thermally induced soy protein microgels. Glycinin hydrolysate (GH) and β-conglycinin hydrolysate (CH) were obtained by subjecting soy protein isolate to selective proteolysis for different hydrolysis time (10–90 min), as confirmed by SDS-PAGE. In the early stages of hydrolysis, free sulfhydryl, surface hydrophobicity, storage modulus (G′) and loss modulus (G″) of GH and CH increased, which enhanced their gelling potential. However, as hydrolysis time increased, the gel properties of the hydrolysates progressively weakened. Structural characterization of microgels revealed that GH yielded microgels with smaller particle sizes and coarser and relatively dispersed granular structures, while CH resulted in microgels with lower potential values, smoother surfaces, and lumps resembling strand-like formations. Analysis of the structure and intermolecular force of microgels showed that the microgel formed by the GH gradually tended to be disordered, whereas the secondary structure of microgels formed by CH showed lower random coil content, resulting in a dense gel network aggregated through disulfide bonding, hydrophobic interactions and hydrogen bonding as demonstrated by frequency-dependent storage moduli measurements. Overall, this study presents a thorough characterization of microgels and shows that they can be tailored by selective proteolysis, which enables controlling the β-conglycinin/glycinin ratio of soy protein.

Analysis of the effect of lactobacillus exopolysaccharide on the rheological properties of fermented soybean protein gel: Using acid-induced soybean protein as the model

In order to accurately describe the contribution of extracellular polysaccharide (EPS) to the rheological properties of the gel in the complex system induced by lactic acid bacteria fermentation, acid-induced soy protein isolate (SPI) was used as the model. The effect of exopolysaccharide produced by Lactobacillus casei (CEPS) on the macro rheological properties and microstructural changes of acid-induced SPI gel were analyzed by scaling model and image analyses. The estimated value of storage modulus (G′) at time infinity, gel point, G′ at 37 °C, enhancement effect of G′ during cooling (ΔG'), recovery rate, critical strain (γc) and fractal dimension (Df) exhibited strong CEPS concentration dependence. The addition of CEPS led to the formation of uniform and compact three-dimensional network, which was mainly represented by small voids and apertures. Therefore, by reducing the complexity of the fermentation gel system, this study explored the effect of CEPS on the rheological properties of fermented soy protein gels and the fermented soybean protein gel with good rheological properties can be selected by quantitative image analysis.

The effect of whey/soy protein fibril systems on the properties of fish gelatin stabilized emulsion gels

In this study, we investigated the effects of whey protein isolate fibril systems (WPF) and soy protein isolate fibril systems (SPF) combined with fish gelatin (FG) on the formation of emulsion gels. The aim was to evaluate how the origin and concentration of these fibril systems influence the structural, interfacial, and rheological properties of FG-stabilized emulsion gels, as well as their impact on creaming stability. FG was mixed with varying concentrations (0–2%) of WPF and SPF at pH 7, forming electrostatic complexes due to the opposite charge interactions between FG and the protein fibril dispersions. The results revealed that adding WPF and SPF increased surface hydrophobicity and enhanced interfacial activity. Increasing WPF concentrations led to a gradual decrease in emulsion droplet size owing to the increased absorbed protein content at the interface. Additionally, there was a significant improvement in the storage modulus of the emulsion gels. Conversely, introducing a small amount (0.1%) of SPF to FG increased the particle size, suggesting potential coalescence, but further increases in SPF concentration considerably reduced the particle size. Furthermore, SPF enhanced the viscoelasticity at lower concentrations, possibly due to a more uniform distribution within the continuous phase. However, excess SPF reduced the storage modulus of the emulsion gels. Our study provides valuable theoretical insights for the application of protein fibril systems in emulsion gel systems.