Emulsion Stability Research Articles

Pickering Emulsion of Curcumin Stabilized by Cellulose Nanocrystals/Chitosan Oligosaccharide: Effect in Promoting Wound Healing

Background: The stabilization of droplets in Pickering emulsions using solid particles has garnered significant attention through various methods. Cellulose and chitin derivatives in nature offer a sustainable source of Pickering emulsion stabilizers. Methods: In this study, medium-chain triglycerides were used as the oil phase for the preparation of emulsion. This study explores the potential of cellulose nanocrystals (CNC) and shell oligosaccharides (COS) as effective stabilizers for achieving stable Pickering emulsions. Optical microscopy, CLSM, and Cyro-SEM were employed to analyze CNC/COS–Cur, revealing the formation of bright and uniform yellow spherical emulsions. Results: CLSM and SEM results confirmed that CNC/COS formed a continuous and compact shell at the oil–water interface layer, enabling a stable 2~3 microns Pickering emulsion with CNS/COS–Cur as an oil-in-water emulsion stabilizer. Based on FTIR, XRD, and SEM analyses of CNC/COS, along with zeta potential measurements of the emulsion, we found that CNC and COS complexed via electrostatic adsorption, forming irregular rods measuring approximately 200–300 nm in length. An evaluation of the DPPH radical-scavenging ability demonstrated that the CNC/ COS–Cur Pickering emulsion performed well in vitro. In vivo experiments involving full-thickness skin excision surgery in rats revealed that CNC/COS–Cur facilitated wound repair processes. Measurements of the MDA and SOD content in healing tissues indicated that the CNC/COS–Cur Pickering emulsion increased SOD levels and reduced MDA content, effectively countering oxidative stress-induced damage. An assessment based on wound-healing rates and histopathological examination showed that CNC/COS-Cur promoted granulation tissue formation, fibroblast proliferation, angiogenesis, and an accelerated re-epithelialization process within the wound tissue, leading to enhanced collagen deposition and facilitating rapid wound-healing capabilities. An antibacterial efficacy assessment conducted in vitro demonstrated antibacterial activity.

Insights into the Pickering emulsions stabilized by yeast dietary fiber: Interfacial adsorption kinetics, rheological characteristics, and stabilization mechanisms

This study developed Pickering emulsions based on yeast dietary fiber (YDF) and investigated the interfacial adsorption kinetics of YDF, rheological properties and stabilization mechanisms of emulsions. Results indicated that increasing YDF concentration enhanced its diffusion and rearrangement at the oil-water interface. At a concentration of 8 %, YDF exhibited the highest diffusion rate (0.1406 mN·m−1·s-0.5) and rearrangement rate (18.8 s−1). The emulsion stabilized at this concentration had the smallest droplet size (1.55 μm) and the slowest droplet migration rate (0.34 mm/h), effectively suppressing droplet aggregation due to collisions and thereby improving the overall emulsion stability. Confocal laser scanning microscopy results confirmed that emulsion stability relied on the co-adsorption of proteins and polysaccharides from YDF at the interface, with proteins primarily adsorbed at the oil-water interface and polysaccharides responsible for the continuous phase network formation. This study demonstrates YDF's potential as an emulsion stabilizer and elucidates the stabilization mechanism of YDF-induced emulsion.

Investigation on the interfacial and emulsion stabilized behavior of dextran/ferritin/resveratrol composite nanoparticles

Glycation of ferritin provides a viable approach to enhance its physicochemical and functional properties. However, there is limited research on the interfacial adsorption properties of glycated ferritin-based colloidal particles. Therefore, this study selected recombinant human H-chain ferritin (rHuHF), rHuHF encapsulated with resveratrol (rHuHF–Res), and rHuHF–dextran glycoconjugates loaded with resveratrol (Dex–rHuHF–Res) as emulsifiers to investigate their interfacial adsorption properties. The results revealed that Dex–rHuHF–Res exhibited superior emulsifying properties and rheological behavior. It also increased the hydrophobicity of the microenvironment around Tyr and Trp residues, while hydrogen bonds, hydrophobic force, and salt bridge were identified as the most important intermolecular interactions. Dex–rHuHF–Res exhibited the biggest contact angle and lowest interface tension, which further reduced the diffusion (Kdiff) from the aqueous phase to the interface but promoted the penetration (Kp) and rearrangement (Kr) rates at the interface. Meanwhile, the emulsion stabilized by Dex–rHuHF–Res displayed excellent freeze-thaw stability, and Dex–rHuHF–Res can be more densely accumulated at the O/W interface to form an interface layer. These findings highlight the promising application of glycated ferritin in stabilizing Pickering emulsions, and deepen our understanding of the interplay among particle interaction, interface adsorption properties, and emulsion stability.

Myosin supramolecular self-assembly: The crucial precursor that manipulates the covalent aggregation, emulsification and rheological properties of myosin

The transformation of molecular conformation and self-assembly properties of myosin during the heating process at different ionic strengths (0.2 M, 0.4 M and 0.6 M NaCl) and its effect on rheological behavior and emulsification properties were investigated. Under incubation temperatures between 40 °C and 50 °C, myosin underwent a supramolecular self-assembly stage dominated by noncovalent forces (hydrogen bonding, ionic bonding and hydrophobic interactions). Higher ionic strength facilitated molecular rearrangement through enhanced swelling of myosin heads and head-to-head assemblies, which contributed to enhanced ordering and homogeneity of myosin covalent aggregates (above 60 °C) and manifested itself macroscopically as enhanced gel viscoelasticity and emulsion stability. In contrast, at lower ionic strength, the tail-to-tail assemblies of myosin led to the preferential formation of covalent cross-links in the tails, which resulted in the inability of molecular rearrangement and the formation of disordered aggregates and finally led to the deterioration of the gel and the destabilization of the emulsion. In conclusion, the supramolecular self-assembly behavior of myosin, as an intermediate process in myosin’s sol–gel transition, is crucial for the orderliness of myosin assemblies, gel network strengthening, and emulsion stability. The obtained insight provides a reference for the precise implementation of quality improvement strategies for meat products.

Investigation of the synergistic effects of SiO2 and Al2O3 nanoparticles with SDS and CTAB surfactants on the stability and improving phase behavior of water-oil emulsions

The stability of emulsions is a significant challenge across various industries, including food, pharmaceutical, and petroleum. Surface-active agents utilized for enhanced oil recovery often exhibit inadequate performance under high salinity reservoir conditions, presenting a critical barrier to effective emulsion stabilization. Furthermore, due to the extreme hydrophilic or hydrophobic nature of nanoparticles (NPs), they are not effective in stabilizing emulsions on their own. To address this limitation, a minimal quantity of surfactant was introduced into the NPs to improve their wettability and achieve dual wettability. This research has examined the synergistic effects of SiO₂ and Al₂O₃ NPs combined with sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) surfactants on water-oil emulsion stability. This approach enhanced emulsion stability by combining the stabilizing effects of both the NPs and the surfactants, an aspect that has not been previously addressed in phase behavior studies through the examination of the interactions and surface behavior of surfactant-nanoparticle complexes at the oil-water interface. Several experiments, including phase behavior, FT-IR, zeta potential, contact angle, and interfacial tension (IFT) tests, were performed to evaluate the interaction of surfactants with NPs. The results demonstrate that combining NPs with surfactants, especially those with opposite charges, significantly reduces IFT to the order of 10−6 mN/m, which can overcome capillary pressure, and enhances optimal salinity levels even up to 75000 ppm. Interactions between CTAB-SiO₂ and SDS-Al₂O₃ notably improve the hydrophobicity of NPs, resulting in IFT reductions of 11.4 and 7 mN/m, respectively, compared to NPs alone.

Synergistic effect and mechanism of stabilization of Pickering emulsion by carboxymethyl starch and xanthan gum

Pickering emulsions were prepared using different proportions of carboxymethyl starch (CMS) and xanthan gum (XG) combined systems as emulsifying stabilizers (The mass ratios of CMS and XG were 10:0, 9:1, 7:1, 5:1, 3:1 and 1:1, respectively). The synergistic mechanism between CMS and XG was also explored. The results demonstrated that CMS particles were uniformly and densely embedded in the gel-like structure formed by XG, and the electrostatic repulsion between CMS and XG led to a reduction in droplet size (from 3370 nm to 482 nm), resulting in a more compact and orderly droplet distribution. Combined systems of CMS and XG at different proportions enhanced the hardness (3.05–8.36 g), adhesiveness (3.26–8.41 g), and chewiness (4.05–8.20 g) of the emulsion. AFM observed that the emulsion particles were finer and more evenly dispersed. After heat treatment at 25 °C, 60 °C and 80 °C, the emulsion showed no significant stratification phenomenon, and CMS/XG enhanced the heat stability of the emulsion. LF-NMR confirmed that the oil and water could be evenly distributed and the emulsification of the system was complete. Especially when the ratio of CMS and XG was 3:1 and 1:1, the emulsion with a stable and long storage period could be obtained.

Exploring the biodiversity of plant proteins for sustainable foods: Composition and emulsifying properties of the proteins recovered by aqueous extraction from camelina (Camelina sativa L.) seeds

The food transition towards an increased consumption of plant proteins aimed at limiting environmental impacts requires a diversification of plant protein sources. In this study, we explored the potentialities of the sustainable oilseed crop camelina to provide dietary proteins and to prepare oil-in-water emulsions. An innovative green refinery process, including the removal by ultrasound of the mucilage attached at the surface of the seeds and extraction by grinding in water at pH 8, was used to recover aqueous extracts containing camelina seed proteins. These proteins, mainly composed of the 11S globulin cruciferins and the 2S albumin napins, contained the nine essential amino acids of nutritional interest. Camelina seed proteins exhibited low solubility in the range of pH H 5.5-2, attributed to the cruciferins. Oil-in-water emulsions stabilized by camelina seed proteins revealed the preferential adsorption of napin at the oil/water interface and exhibited physical instability below pH 7. Homogenization of the whole aqueous extracts containing oil bodies (OBs) induced the adsorption of cruciferins and napins together with oleosins at the surface of homogenized OBs, and their sedimentation below pH 6.5. Camelina seed proteins adsorbed at the oil/water interface governed the surface properties of the oil droplets and homogenized OBs and the physical stability of the emulsions as a function of pH. This work brings new insights into the potentialities of camelina seed proteins recovered by aqueous extraction that may serve as natural plant-based functional ingredients in the food industry and that will contribute to the development of innovative and sustainable plant-based food emulsions.

Enhancing soy protein isolate flexibility through non-covalent ferulic acid modification: implications for interfacial characteristics and protein-based emulsion performance

This study aims to enhance the flexibility of soy protein isolate (SPI) to improve its functional properties, focusing on the investigated the effects of ferulic acid (FA) on the structure, interfacial behaviour and emulsification performance of SPI. Our study showed that FA induces SPI structures to depolymerization and unfolding primarily through hydrogen bonding and hydrophobic interactions, thereby increasing the flexible structures (random coils and β-turns) of protein. These changes enhanced the interfacial functional properties of SPI, with 150 μmol/g of FA-modified SPI exhibiting the best molecular flexibility, and its emulsification and emulsification stability were improved by 21.26% and 39.86%, respectively, compared to unmodified SPI. In addition, non-covalently modified FA significantly improved emulsions stability. Emulsions stabilized by SPI-FA150 complexes exhibited better storage, heat, and freeze-thaw stability than SPI, with a significant reduction in oxidation products. This relationship between flexibility and function reveals the importance of structural modification in enhancing protein functionality. These discoveries shed new light on flexible protein processing technologies and the application of FA in protein functional modification.

Interfacial structure modification and enhanced emulsification stability of microalgae protein through interaction with anionic polysaccharides

Microalgae protein (MP) have emerged as a focal point of research within food processing due to its nutritional value and foaming properties. However, its isoelectric point around pH 4 leads to it susceptible to collision, binding, and precipitation. Additionally, MP has poor emulsification properties and only shows stability under strongly alkaline conditions. This study investigated the effects of food-grade anionic polysaccharides (guar gum (GG), gum arabic (GA), low acyl gellan gum (LG), and pectin (PT)) on the molecular structure and emulsification properties of MP. Results indicated that these anionic polysaccharides enhanced the UV absorption of MP near 620 nm, especially at 14 % content, while fluorescence intensity decreased due to amino acid residues masking without structural changes. The addition of polysaccharides resulted in bimodal or multimodal particle size distributions, with LG and PT showing larger particle sizes. At pH 4, negatively charged polysaccharides formed stable complexes with near-neutral MP, improving solution stability via electrostatic repulsion and diminishing turbidity. The droplet distribution analysis indicated that higher anionic polysaccharide ratios (1:4, 1:2, and 1:1) correlated with smaller droplet sizes and increased emulsion stability. Zeta-potential measurements revealed negative charges for emulsions, with LG-MP and PT-MP complexes displaying higher absolute values (15.0 to 20.7 mV) compared to GG-MP and GA-MP complexes, indicating superior stability. Storage stability analysis showed that LG-MP and PT-MP complexes stabilized emulsions had minimal delamination over two weeks. Rheological assessments showed that increasing GG and GA contents from 14 % to 50 % had negligible effects on apparent viscosity, while LG-MP (1:1) complexes stabilized emulsion displayed higher viscosity compared to PT-MP emulsions. Frequency sweep results showed that GG-MP, GA-MP, and LG-MP emulsions had greater elastic moduli (G') than viscous moduli (G"), indicating elastic behavior, whereas PT-MP emulsions transitioned from liquid-like to solid-like behavior as frequency increased. This study illustrates the advantages of high LG and PT content in preventing particle aggregation and enhancing emulsion stability, providing a theoretical and practical foundation for MP applications in food processing.

Functional, structural, and rheological properties of the complexes containing sunflower petal extract with dairy and plant-based proteins

This study aims to investigate the impact of sunflower petal extract (SFE) on the functional and structural properties of sodium caseinate and chickpea proteins. For this purpose, 3.5 % of sodium caseinate solution and 3.5 % of protein extracted from chickpea powder were prepared in phosphate buffer (pH = 7). SFE was used at different concentrations, from 1 to 3 % in different protein solutions and functional, structural and rheological properties were measured. The results revealed that complexation of SFE with different proteins can enhance the antioxidant, foaming properties, solubility, emulsion activity, emulsion stability, viscoelastic behavior, and can decrease surface hydrophobicity. FTIR and docking results showed that the most bonding type was non-covalent bonds. Major phenolic compounds containing heliannone A, B, and kaempferol had strong affinity with sodium caseinate, and then chickpea protein. Therefore, the results demonstrated that SFE and its complexes had appropriate emulsifying properties that reduces interfacial tension in the water/oil interface.

Rice husk derived lignin/silica hybrid nanoparticles stabilized pickering emulsion for phytosterol ester biosynthesis

This study investigates the production of lignin/silica hybrid nanoparticles (LSNPs) from rice husks, an abundant agricultural waste, and their capacity to stabilize Pickering emulsions for biocatalysis. Lignin extracted from rice husks under alkaline conditions was co-precipitated with silica to produce LSNPs in the presence or absence of ethanol as a co-solvent. Characterization of LSNPs revealed that ethanol played a key role in forming uniform, spherical nanoparticles and minimizing aggregation. Lignin imparted amphiphilicity to the LSNPs, which significantly improved their capacity to form stable Pickering emulsions. LSNPs were able to form stable oil-in-water Pickering emulsions while droplet size and emulsion stability were influenced by LSNPs concentration, oil/water ratio, temperature and pH. LSNPs-stabilized Pickering emulsions were evaluated for lipase-mediated biosynthesis of phytosterol esters, which are plant bioactive compounds that can reduce dietary cholesterol uptake. LSNPs-stabilized emulsions provided 1.915 × 106 times larger interfacial areas compared to conventional biphasic systems which facilitated improved mass transfer and lipase activity. Under optimal conditions, LSNPs-stabilized Pickering emulsion systems delivered 90.6 % phytosterol ester conversion in 4 h, compared to 10 h in biphasic systems. This research highlights the potential of sustainable, biomass-derived nanoparticles in Pickering emulsion applications and offers an environmentally friendly approach to produce bioactive compounds.

Bambara groundnut starch-soluble dietary fibre nanocomposite stabilised emulsions: Optimisation of emulsion stability and studies on time-dependent rheological properties

Due to their inherent thermodynamic instability, emulsions require stabilisers to maintain their integrity and prevent destabilisation. The effect of emulsion components (Bambara groundnut starch-soluble dietary fibre nanocomposite (STASOL), orange oil and water) on the rheological and stability properties of STASOL-stabilised emulsions was optimised. A randomised D-optimal exchange mixture design was used to determine the ratio of STASOL, orange oil and water required for a stable emulsion. The stability of these emulsions was evaluated using the initial mean backscattering index (BSAVO), Turbiscan stability index (TSI) and hysteresis loop area (HLA). The BSAVO (%), TSI and HLA of the emulsions ranged from 50.73% (14:30:56 STASOL:oil:water) to 70.47% (20:30:50 STASOL:oil:water), 0.0005 (20:30:50 STASOL:oil:water) to 0.1000 (8:42:50 STASOL:oil:water) and 0.37 Pas-1 (10:32:58 STASOL:oil:water) to 5.69 Pas-1 (20:30:50 STASOL:oil:water), respectively. Emulsions exhibited a direct relationship between STASOL concentration and stability metrics, with the highest stability achieved at 20% STASOL concentration, 30% orange oil and 50% water. An increase in STASOL concentration coupled with a decrease in oil concentration results in a stable emulsion. Numerical optimisation and experimental validation confirmed the effectiveness of the selected formulation, demonstrating STASOL's potential as a natural stabiliser in beverage emulsions and its ability to enhance stability compared to synthetic alternatives.

Impact of Storage Temperature on Physical Stability and Protein-Lipid Co-oxidation in Whey Protein functional Emulsions.

The aim of this study was to investigate the effect of different storage temperatures (4°C, 25°C and 45°C, denoted as T-4, T-25 and T-45, respectively) on the physical stability and protein-lipid co-oxidation of whey protein functional emulsions during the storage period at storage times of 1, 2, 3 and 6 months. At the 6th month of storage, samples stored at 45°C were less physically stable than samples stored at 4°C, as evidenced by an increase in particle size (5.50%), a decrease in zeta potential (7.93%), and a decrease in adsorbed protein concentration (36.8%). The most severe protein-lipid co-oxidation was induced in whey protein functional emulsions under 45°C temperature conditions with increasing storage time. Protein oxidation products (carbonyls, N′-formyl-L-kynurenine, and sulfhydryl groups) and lipid oxidation products (lipid hydroperoxides, thiobarbituric acid reactive substances) were at their highest levels, and significant molecular changes were observed in the molecules of adsorbed protein or unadsorbed proteins. As the storage temperature rises it exposes the active sites such as internal sulfhydryl and hydrophobic groups in the protein, promoting cross-linking and aggregation. Cluster and correlation analyses showed that protein-lipid co-oxidation of emulsions inevitably occurs during storage, but low-temperature storage can delay this process. This study is of guiding significance for the quality maintenance of functional nutritional emulsions and the selection of storage conditions. In addition, this study may provide clearer solutions to the problems of whey protein denaturation and formation of lipid oxides caused by protein-lipid co-oxidation in the food industry, as well as to the problem of increasing the shelf life of products by choosing the appropriate storage, packaging, and transportation temperatures.

Study on the stability, functional activity and preservation effect of oregano essential oil Pickering emulsion with different proportions of chicken bone gelatin/bacterial cellulose during storage

In this study, chicken bone gelatin (CBG) was extracted as a new substitute for traditional pig bone gelatin, and bacterial cellulose (BC) was used as the compound to prepare Oregano essential oil (OEO) Pickering emulsion. To explore a protein/polysaccharide emulsion system that can effectively prolong the functional activity of OEO during storage. The results indicated that the variation in CBG and BC content significantly influenced the physicochemical properties of the emulsions. The optimal formulation of OEO Pickering emulsion, prepared with a CBG-BC ratio of 6:2 (v/v), exhibited superior characteristics including appearance, encapsulation efficiency, and stability during preservation. After 7 d of storage at 4 °C, the rheological properties remained stable, with no significant differences observed in antioxidant and antibacterial activities. It was verified in the beef fresh-keeping experiment that the shelf life of beef samples in the 6-2-2 treatment group was 6 d longer than that in the control group and 3 d longer than that in the pure OEO group. This experiment enhanced the utilization of poultry by-products and provided a valuable reference for exploring suitable protein-polysaccharide systems embedding active substances for food preservation.

Improving emulsion stability: The role of flaxseed gum in stabilizing bovine bone protein hydrolysates emulsions.

The use of natural proteins as emulsifiers in stable emulsion systems has gained attention due to the increasing demand for healthy food products. However, the limited thermal stability and ionic tolerance of BBPH restrict its application in emulsions. This study explores the effects of FG on enhancing the stability of BBPH-based emulsions. FTIR and SEM confirmed that BBPH and FG form complexes through hydrophobic and electrostatic interactions, with increasing FG concentrations leading to higher turbidity and particle size. At 0.4 % FG, emulsions showed the smallest particle size (9.12 μm) and the highest zeta potential (-28.73 mV), indicating optimal interaction. Raman spectroscopy further supported these findings, showing enhanced oil-complex interactions and favorable rheological properties. The emulsions exhibited excellent stability during storage, with a creaming index of 1.786 % after 7 days. Oxidation tests showed low POV (0.596 mg/L) and TBARS (6.24 mg/L) after 15 days. FG also improved resistance to environmental stress, providing theoretical support for the broader use of BBPH in the food industry and highlighting FG's potential in stabilizing protein-based emulsions.

Pickering emulsions stabilized by cellulose nanofibers with tunable surface properties for thermal energy storage

Cellulose nanofibers (CNFs) have been widely used as a renewable emulsifier to stabilize two immiscible liquids due to their intrinsic amphiphilicity and excellent emulsifying ability. However, it remains challenging to fully understand the effects of carboxylate group content and surface charge density on the emulsifying ability of CNFs and the stability of Pickering emulsion. Herein, carboxymethylated CNFs were extracted from bleached kraft pulp using etherification reaction and high-pressure homogenization, allowing for easy surface charge density and size adjustment by changing sodium chloroacetate content and homogenization cycles. The optimizing CNFs possessed a high Zeta potential (−71.2 mV) and a suitable carboxylate group content (1.81 mmol/g), which enabled CNFs to irreversibly adsorb at the hydrophobic paraffin wax (PW) droplet surface and form interfacial steric barriers, providing large electrostatic repulsion between the PW droplets against coalescence. Thus, the CNF-stabilized PW emulsions could be stored for more than 6 months. Moreover, the phase change enthalpy of the freeze-dried emulsion is as high as 193.7 J/g, which provides the emulsion to reversibly store and release heat. This work provides a comprehensive insight into the interfacial stability mechanism of CNFs as stabilizers and facilitates the potential application in thermal energy storage.

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

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

Regulation of Microlocalization of Antioxidants by Surfactant Micelles in Oil-in-Water Emulsions.

The mass transport effect of aqueous micelles on antioxidants and oxidation products in emulsions may alter the rate, degree, and pathway of lipid oxidation. In this study, the dynamic mass transport of oxidation products and endogenous tocopherol during storage at different micelle concentrations was monitored by UV-vis spectrophotometry and high-performance liquid chromatography. Furthermore, the microlocalization of tocopherol in micelles was investigated using 1H nuclear magnetic resonance and nuclear Overhauser effect spectroscopy, fluorescence measurements, and molecular dynamics simulation. It was demonstrated that high-concentration micelles enhanced the emulsion stability by promoting the mass transport of hydroperoxides and endogenous antioxidants. The enhancement of micelles was a superposition effect of concentration, interaction sites, and binding force between tocopherols and Tween 20 molecules. Tween 20 concentration-induced favorable changes of microlocalization of tocopherol and dynamic mass transport demonstrated a new integrated perspective to control lipid oxidation.

High-intensity ultrasound-assisted alkaline extraction of soy protein: Optimization, modeling, physicochemical and functional properties

This study examined the effect of high-intensity ultrasound-assisted alkaline extraction (HUAE) on the extraction yield and the physicochemical and functional properties of soy protein (SP) using the two-pot multivariate method for the first time. Plackett-Burman Design (PBD) coupled with Response Surface Methodology (RSM) was systematically utilized to select and subsequently optimize the HUAE parameters. Based on PBD results, the significant extraction factors were liquid to solid ratio (LSR), temperature, ultrasonic amplitude, and extraction time. The optimum conditions for the maximal extraction yield and minimal energy consumption were 50:1 mL/g LSR, 50 °C, 48 % ultrasonic amplitude, and 10 min extraction time. At optimum conditions, the extraction yield (35.28 %) was significantly improved compared to traditional extraction (26.39 %). Besides, HUAE resulted in modification of the protein secondary and tertiary structures due to the unfolding of protein molecules and the exposure of hydrophobic groups or regions as shown by FTIR spectroscopy, free sulfhydryl analysis, and scanning electron microscopy. These structural changes led to decreased solubility and emulsifying activity but improved emulsion stabilization and antioxidant properties. With future development, HUAE could potentially produce soy protein for targeted applications, broadening its utilization and meeting the need for more sustainable alternative processing.

New food ingredient via acid-tolerant Rhizopus oligorporus growth

As the global population grows, the consumption of unsustainably produced proteins increases. Researching sustainable food sources with a positive environmental impact is essential. This research provides valuable insights into the production and application of nutrient rich food sources. The potential of the biomass generated through fermentation with R. oligosporus was evaluated as a new protein source with low environmental impact. A fermentation method has been optimized to maximize the biomass production of R. oligosporus mycelium in solid-state and submerged-state fermentation, yielding 5.9 g dry weight/L and 5 g dry weight/L, respectively. The growth medium for these fungi was adapted to acid-tolerant (pH 4-3) conditions to create a food development environment that is more difficult for pathogens to thrive in, both in solid state and submerged state fermentation. The highest protein content obtained was 38.4 % wet weight by solid state fermentation. Fungal biomass exhibited techno-functional properties relevant to food product development tested both on pH 4 and pH 3, showing high water absorption and emulsifying activity, particularly in submerged fermentation at pH 3. In contrast, solid-state fermentation at pH 4 resulted in higher emulsion stability. This research demonstrates the potential of Rhizopus oligosporus as an acid-tolerant, high-quality protein ingredient with valuable functional properties. Its efficient production using minimal resources makes it a valuable asset for the food industry.