Strategies to control and inhibit the flocculation of protein-stabilized oil-in-water emulsions

Raman spectroscopy and molecular dynamics simulations of protein microgels at the oil-water interface

The real-time structural changes of the molecular space conformation of myofibrillar protein microgels (MPM) after heat treatment (90 °C, 30 min) were analyzed by molecular dynamics simulation, and the structural properties and changes of MPM at the oil-water interface were analyzed by the combination of Raman spectroscopy and molecular dynamics simulation. The shift in the oil ratio had a major impact on the transformation of disulfide bonds within the protein molecule. Simultaneously, it caused tryptophan and tyrosine residues (I850 cm-1/ I850 cm-1 > 1) to become exposed, increasing the locations of amino acid residues in the protein that interact with the oil phase. HIPE with different oil phases influenced the change in spatial structural conformation of MPM, and there was a flexible structural change in the molecular space. The HIPE system, which was stabilized by 3.0 wt% MPM and 0.75 oil phase, exhibited a thixotropic recovery of >70 % and the highest elastic modulus G' (822.14 Pa) based on the rheological behavior. It is expected to provide a theoretical basis for the development and utilization of high internal phase emulsion stabilized by microgel protein in food industry.

Synergistic effects of xanthan gum and β-cyclodextrin on properties and stability of vegetable oil-based whipped cream

The synergistic effects between xanthan gum (XG) and β-cyclodextrin (β-CD) on the properties and stability of vegetable oil-based whipped cream stabilized by kidney bean protein aggregates was investigated. The visual appearance, SEM, TEM, CLSM, FT-IR and LF-NMR results showed that when the ratio of XG to β-CD in the XG-β-CD complex was appropriate, the hydrogen bonding effect between β-CD and XG was significant enhanced, the three-dimensional network structure has the highest density, the emulsion droplets were the smallest and evenly distributed. The unique tapered microstructure of β-CD acted as a bridge between the hydrophilic and hydrophobic components, effectively preventing the aggregation of oil droplets and establishing a flexible support system between oil droplets; while the flexible molecular structure of XG could support Pickering emulsion system. The XG-β-CD complex had a synergistic effect with protein aggregates, making it ideal for use in whipped cream products. This study explored the stability mechanism of β-CD in the Pickering emulsion-based whipped cream system, providing valuable insights into producing whole plant-based whipped cream by texturizing highly unsaturated oils. This effectively solves the problem of inadequate intake of unsaturated oil for individuals who consume excessive amounts of animal-derived fats.

Versatile cell cultivation on injectable poly(butylene adipate-co-terephthalate) microcarriers: Impact of surface properties across different cell types

Injectable cell therapies offer several advantages compared with traditional open surgery, including less trauma to the patient, shorter recovery time, and lower risk of infection. However, a significant problem is the difficulty in developing effective cell delivery carriers that are cyto-compatible and maintain cell viability both during and after injection. In the presented study, it was aimed to develop poly(butylene adipate-co-terephthalate) (PBAT) microcarriers using the emulsion preparation-solvent evaporation technique. The optimized diameter of the PBAT microcarriers was determined as 104 ± 15 μm at 700 rpm and there would be no blockage after injection due to the nonswelling feature of microcarriers. Furthermore, the cellular activities of PBAT microcarriers were evaluated in static culture for 7 days using L929 mouse fibroblasts, MC3T3-E1 mouse pre-osteoblasts, and rat adipose-derived mesenchymal cells (AdMSCs). 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide results and Sscanning electron microscope images showed that PBAT microcarriers increased the adhesion and proliferation properties of pre-osteoblasts and stem cells, while L929 fibroblasts formed aggregates by adhering to certain regions of the microcarrier surface and did not spread on the surface. These results emphasize that PBAT microcarriers can be used as injectable carriers, especially in stem cell therapies, but their surface properties need to be modified for some cells.

Encapsulation of Lactiplantibacillus plantarum with casein-gellan gum emulsions to enhance its storage, pasteurization, and gastrointestinal survival

Probiotics serve a very important role in human health. However, probiotics have poor stability during processing, storage, and gastrointestinal digestion. The gellan gum (GG) is less susceptible to enzymatic degradation and resistant to thermal and acidic environments. This study investigated the effect of casein (CS)-GG emulsions to encapsulate Lactiplantibacillus plantarum CICC 6002 (L. plantarum CICC 6002) on its storage stability, thermal stability, and gastrointestinal digestion. L. plantarum CICC 6002 was suspended in palm oil and emulsions were prepared using CS or CS-GG complexes. We found the CS-GG emulsions improved the viability of L. plantarum CICC 6002 after storage, pasteurization, and digestion compared to the CS emulsions. In addition, we investigated the influence of the gellan gum concentration on emulsion stability, and the optimal stability was observed in the emulsion prepared by CS-0.8% GG complex. This study provided a new strategy for the protection of probiotics based on CS-GG delivery system.

Process-Induced Molecular-Level Protein-Carbohydrate-Polyphenol Interactions in Milk-Tea Blends: A Review

The rapid increase in the production of powdered milk-tea blends is driven by a growing awareness of the presence of highly nutritious bioactive compounds and consumer demand for convenient beverages. However, the lack of literature on the impact of heat-induced component interactions during processing hinders the production of high-quality milk-tea powders. The production process of milk-tea powder blends includes the key steps of pasteurization, evaporation, and spray drying. Controlling heat-induced interactions, such as protein-protein, protein-carbohydrate, protein-polyphenol, carbohydrate-polyphenol, and carbohydrate-polyphenol, during pasteurization, concentration, and evaporation is essential for producing a high-quality milk-tea powder with favorable physical, structural, rheological, sensory, and nutritional qualities. Adjusting production parameters, such as the type and the composition of ingredients, processing methods, and processing conditions, is a great way to modify these interactions between components in the formulation, and thereby, provide improved properties and storage stability for the final product. Therefore, this review comprehensively discusses how molecular-level interactions among proteins, carbohydrates, and polyphenols are affected by various unit operations during the production of milk-tea powders.

Goose liver protein emulsion with enhanced interfacial stabilization by facile core-shell curcumin complexation

The role of facile curcumin dispersion and its hydrophobic complexation onto GLP, in the form of shell (GLPC-E), core (GLPE-C) and with synergy (GLP-ECE), on the protein interfacial and emulsion stabilization was investigated. Turbiscan instability index, microrheological elasticity, viscosity and solid-liquid balance values showed that the O/W emulsion stability was in the order of GLP-E < GLPC-E < GLPE-C < GLP-ECE. GLP-ECE also gave the most reduced D [4, 3] (8.11 ± 0.14 μm) with lowest indexes of flocculation (2.80 ± 0.05 %) and coalescence (2.83 ± 0.10 %) at day 5. Interfacial shear rheology suggested the GLP-curcumin complexation fortified the GLP interfacial gelling and then the efficiency as steric stabilizer, especially of core-shell complexation (14.2 mN/m) that showed the most sufficient in-plane protein interaction against strain. Dilatational elasticity and desorption observation revealed the synergistic curcumin complexation facilitated GLP unfolding and macromolecular association at O/W interface, as was also verified from SEM image and surface hydrophobicity (from 36.23 to 76.04). Overall, this study firstly reported the facile curcumin bi-physic dispersion and GLP complexation in improving the emulsion stabilizing efficiency of the protein by advancing its interfacial stabilization.

Carboxymethylcellulose-induced depletion attraction to stabilize high internal phase Pickering emulsions for the elderly: 3D printing and β-carotene delivery

In this study, a carboxymethylcellulose (CMC) induced depletion attraction was developed to stabilize high internal phase Pickering emulsions (HIPPEs) as age-friendly 3D printing inks. The results demonstrated that depletion force induced the adsorption of yolk particles at the droplet interface and the formation of osmotic droplet clusters, thereby increasing the stability of HIPPEs. In addition, the rheological properties and nutrient delivery properties of HIPPEs could be adjusted by the mass ratio of yolk/CMC. The HIPPEs stabilized at yolk/CMC mass ratio 20:7.5 showed optimal printability, viscoelastic, structural recovery, and swallowability. HIPPEs have been applied to 3D printing, International Dysphagia Dietary Standardization Initiative (IDDSI) test, and in vitro digestive simulation in the elderly, indicating their attractive appearance, safe swallowability, and enhanced bioaccessibility of β-carotene. Our work provides new ideas for developing age-friendly foods with plasticity and nutrient delivery capacity by depletion attraction stabilizing HIPPEs.

Intrinsic dynamics of emulsions: Experiments in microgravity on the International Space Station

HYPOTHESIS

In order to understand the basic mechanisms affecting emulsion stability, the intrinsic dynamics of the drop population must be investigated. We hypothesize that transient ballistic motion can serve as a marker of interactions between drops. In 1G conditions, buoyancy-induced drop motion obscures these interactions. The microgravity condition onboard the International Space Station enable this investigation.

EXPERIMENTS

We performed Diffusing Wave Spectroscopy (DWS) experiments in the ESA Soft Matter Dynamics (SMD) facility. We used Monte Carlo simulations of photon trajectory to support data analysis. The analysis framework was validated by ground-based characterizations of the initial drop size distribution (DSD) and the properties of the oil/water interface in the presence of surfactant.

FINDINGS

We characterized the drop size distribution and found to be bi-disperse. Drop dynamics shows transient ballistic features at early times, reaching a stationary regime of primarily diffusion-dominated motion. This suggests different ageing mechanisms: immediately after emulsification, the main mechanism is coalescence or aggregation between small drops. However at later times, ageing proceeds via coalescence or aggregation of small with large drops in some emulsions. Our results elucidate new processes relevant to emulsion stability with potential impact on industrial processes on Earth, as well as enabling technologies for space exploration.

Novel a-linolenic acid emulsions stabilized by octenyl succinylated starch -soy protein-epigallocatechin-3-gallate complexes: Characterization and antioxidant analysis

In this study, octenyl succinylated starch (OSAS)-soy protein (SP)-epigallocatechin-3-gallate (EGCG) complexes were designed to enhance the physical and oxidative stability of α-linolenic acid emulsions. Formations of OSAS-SP-EGCG complexes were confirmed via particle size, ξ-potential, together with fourier transform infrared (FTIR). A mixing ratio of 1:2 for OSAS to SP-EGCG resulted in ternary complexes with the highest contact angle (59.69°), indicating the hydrophobicity. Furthermore, the characteristics of α-linolenic acid emulsions (oil phase volume fractions (φ) of 10% and 20%) stabilized by OSAS-SP-EGCG complexes were investigated, including particle size, ξ-potential, emulsion stability, oxidative stability, and microstructure. These results revealed exceptional physical stability together with enhanced oxidative stability for these emulsions. Particularly, emulsions utilizing complexes having a 1:2 OSAS to SP-EGCG ratio exhibited superior emulsion stability. These findings provide theoretical support to the development of emulsions containing high levels of α-linolenic acid and for the broader application of α-linolenic acid in food products.

Food-derived peptides unleashed: emerging roles as food additives beyond bioactivities

Innovating food additives stands as a cornerstone for the sustainable evolution of future food systems. Peptides derived from food proteins exhibit a rich array of physicochemical and biological attributes crucial for preserving the appearance, flavor, texture, and nutritional integrity of foods. Leveraging these peptides as raw materials holds great promise for the development of novel food additives. While numerous studies underscore the potential of peptides as food additives, existing reviews predominantly focus on their biotic applications, leaving a notable gap in the discourse around their abiotic functionalities, such as their physicochemical properties. Addressing this gap, this review offers a comprehensive survey of peptide-derived food additives in food systems, accentuating the application of peptides' abiotic properties. It furnishes a thorough exploration of the underlying mechanisms and diverse applications of peptide-derived food additives, while also delineating the challenges encountered and prospects for future applications. This well-time review will set the stage for a deeper understanding of peptide-derived food additives.

Effect of xanthan gum (XG) and carrageenan (CG) ratio on casein (CA)-XG-CG ternary complex: Used to improve the stability of liquid diabetes formula food for special medical purposes

Poor storage stability limits the application of liquid diabetes formula food for special medical purposes (L-D-FSMP) in maintaining blood sugar stability in diabetic patients. This work aims to improve the stability of L-D-FSMP by adjusting the ratio of xanthan gum (XG) and carrageenan (CG) in casein (CA)-XG-CG ternary complex. The centrifugal sedimentation rate results showed that the compound ratio of XG and CG had a greater impact on L-D-FSMP storage stability. Transmission electron microscopy (TEM) results showed that the combination of CA, XG and CG occurred. Fourier transform infrared spectroscopy (FTIR) results showed that CA, XG and CG were mainly combined through hydrogen bonds and ionic bonds to form a CA-XG-CG ternary complex. When the ratio of XG and CG was 1:1, the number of disulfide bonds was the largest. The results of three-phase contact angle and emulsifying ability confirmed that when the ratio of XG and CG was 1:1, CA-XG-CG had the strongest emulsifying ability. The particle size distribution and zeta-potential results showed that when the ratio of XG and CG was 1:1, L-D-FSMP had the narrowest particle size distribution range and the strongest stability. These results may provide valuable information for the production of stable L-D-FSMP.

Effects of calcium chloride on the gelling and digestive characteristics of myofibrillar protein in Litopenaeus vannamei

In this study, the effects of CaCl2 (0, 25, 50, 75, and 100 mM) on the gelling and digestive properties of the myofibrillar protein (MP) in Litopenaeus vannamei were investigated. The results showed that increasing CaCl2 concentration led to changes in the tertiary structure of MP. Specifically, compared with the control group, a 64.31 % increase in surface hydrophobicity and a 45.90 % decrease in the sulfhydryl group were observed after 100 mM CaCl2 treatment. Correspondingly, the water holding capacity and strength of the MP gel increased by 24.46 % and 55.99 %, respectively. These changes were positively correlated with the rheological properties, microstructure pore size, and content of non-flowable water. The mechanical properties of MP gel were improved, and the microstructure became more compact with the increase in CaCl2 concentration. Furthermore, the particle size of the digested MP gels decreased in the presence of CaCl2, which improved the digestion characteristics of MP gels.

Encapsulation of grape seed oil in oil-in-water emulsion using multilayer technology: Investigation of physical stability, physicochemical and oxidative properties of emulsions under the influence of the number of layers

Many studies have shown that grape seed oil (GSO) is one of the vegetable fats that are plentiful in essential fatty acids and can be used as a fat substitute or to modify fat in food products to reduce saturated fatty acids. However, due to its low solubility and high sensitivity to oxidation, it is necessary to develop delivery systems that can distribute GSO in food more effectively. Recently, the preparation of emulsions using the layer-by-layer (LBL) method has many advantages in delivering lipid-soluble functional compounds. This research was used to check the formation of GSO oil-loaded primary, secondary and tertiary multilayer emulsions stabilized by mixture of anionic gelatin, cationic chitosan, and anionic basil seed gum (BSG) as the aqueous phase at pH 5, prepared using a layer-by-layer electrostatic deposition technique. Multilayer emulsions prepared by GSO and a mixture of gelatin, chitosan, and BSG as the aqueous phase at pH 5. Finally, the effect of the number of layers on the physicochemical properties (particle size, viscosity, turbidity, refractive index, and physical stability) and oxidative stability (peroxide value, thiobarbituric acid value, and fatty acid profile) during the storage time (30 days) at two temperatures 25 °C & 4 °C was investigated. Also, the zeta potential and Fourier transform infrared spectroscopy (FTIR) of mono-layer and multi-layer emulsions were investigated. The results revealed that by increasing the number of layers of multi-layer emulsion of GSO, the stability has improved. Thus, the tertiary emulsion has been more effective than the other two emulsions in maintaining the physicochemical characteristics and stability over time (P < 0.001). Morphological characterization and FTIR spectroscopy results confirmed that gelatin, chitosan, and BSG were successfully loaded into the LBL emulsions. This study can improve the original percept of multilayer emulsions and promulgate their potential applications for the entire encapsulation of essential fatty acids to enrich and prevent peroxide attack.

The evaluation of mixed-layer emulsions stabilized by myofibrillar protein-chitosan complex for delivering astaxanthin: Fabrication, characterization, stability and in vitro digestibility

Muscle protein based functional foods have been attracted great interests in novel food designing. Herein, myofibrillar protein (MP)-chitosan (CH) electrostatic complexes were employed to fabricate mixed-layer emulsions to protect and deliver astaxanthin. The MP/CH complex fabricated mixed-layer emulsions displayed higher stability against pH and temperature changes, exhibiting smaller droplet and homogenous distributions. After UV-light irradiation for 8 h, the mixed-layer emulsions had higher astaxanthin retention (69.11 %, 1:1 group). During storage, a lower degree of lipid oxidation, protein oxidation and higher astaxanthin retention were obtained, indicating desirable protections of mixed-layer emulsions. The vitro digestion reveled the mixed-layer emulsions could decrease the release of free fatty acids. Meanwhile, the bioaccessibility of astaxanthin was higher (30.43 %, 2:1 group) than monolayer emulsion. In all, the MP/CH prepared mixed-layer emulsions could protect and deliver fat-soluble bioactive compounds, and contributed to develop muscle protein based functional foods to meet the needs of slow and controlled release.

Oil-water interface and emulsion stabilising properties of rapeseed proteins napin and cruciferin studied by nonlinear surface rheology

HYPOTHESIS

Two major protein families are present in rapeseed, namely cruciferins and napins. The structural differences between the two protein families indicate that they might behave differently when their mixture stabilises oil-water interfaces. Therefore, this work focuses on elucidating the role of both proteins in interface and emulsion stabilisation.

EXPERIMENTS

Protein molecular properties were evaluated, using SEC, DSC, CD, and hydrophobicity analysis. The oil-water interface mechanical properties were studied using LAOS and LAOD. General stress decomposition (GSD) was used as a novel method to characterise the nonlinear response. Additionally, to evaluate the emulsifying properties of the rapeseed proteins, emulsions were prepared using pure napins or cruciferin and also their mixtures at 1:3, 1:1 and 3:1 (w:w) ratios.

FINDINGS

Cruciferins formed stiff viscoelastic solid-like interfacial layers (Gs' = 0.046 mN/m; Ed' = 30.1 mN/m), while napin formed weaker and more stretchable layers at the oil-water interface (Gs' = 0.010 mN/m; Ed' = 26.4 mN/m). As a result, cruciferin-formed oil droplets with much higher stability against coalescence (coalescence index, CI up to 10%) than napin-stabilised ones (CI up to 146%) during two months of storage. Both proteins have a different role in emulsions produced with napin-cruciferin mixtures, where cruciferin provides high coalescence stability, while napin induces flocculation. Our work showed the role of each rapeseed protein in liquid-liquid multiphase systems.

Fish oil-loaded multicore submillimeter-sized capsules prepared with monoaxial electrospraying, chitosan-tripolyphosphate ionotropic gelation, and Tween blending

In order to load fish oil for potential encapsulation of fat-soluble functional active substances, fish oil-loaded multicore submillimeter-sized capsules were prepared with a combination method of three strategies (monoaxial electrospraying, chitosan-tripolyphosphate ionotropic gelation, and Tween blending). The chitosan-tripolyphosphate/Tween (20, 40, 60, and 80) capsules had smaller and evener fish oil cores than the chitosan-tripolyphosphate capsules, which resulted from that Tween addition induced smaller and evener fish oil droplets in the emulsions. Tween addition decreased the water contents from 56.6 % to 35.0 %-43.4 %, increased the loading capacities from 10.4 % to 12.7 %-17.2 %, and increased encapsulation efficiencies from 97.4 % to 97.8 %-99.1 %. In addition, Tween addition also decreased the highest peroxide values from 417 meq/kg oil to 173-262 meq/kg oil. These properties' changes might result from the structural differences between the chitosan-tripolyphosphate and chitosan-tripolyphosphate/Tween capsules. All the results suggested that the obtained chitosan-tripolyphosphate/Tween capsules are promising carriers for fish oil encapsulation. This work also provided useful knowledge to understand the preparation, structural, and physicochemical properties of the chitosan-tripolyphosphate capsules.

Enhanced environmental stress resistance and functional properties of the curcumin-shellac nano-delivery system: Anti-flocculation of poly-γ-glutamic acid

Curcumin was widely designed as nanoparticles to remove application restrictions. The occurrence of flocculation is a primary factor limiting the application of the curcumin nano-delivery system. To enhance the environmental stress resistance and functional properties of shellac-curcumin nanoparticles (S-Cur-NPs), γ-polyglutamic acid (γ-PGA) was utilized as an anti-flocculant. The encapsulation efficiency and loading capacity of S-Cur-NPs were also improved with γ-PGA incorporation. FTIR and XRD analysis confirmed the presence of amorphous characteristics in S-Cur-NPs and the combination of γ-PGA and shellac was driven by hydrogen bonding. The hydrophilic, thermodynamic, and surface potential of S-Cur-NPs was improved by the incorporation of γ-PGA. This contribution of γ-PGA on S-Cur-NPs effectively mitigated the flocculation occurrence during heating, storage, and in-vitro digestive treatment. Furthermore, it was revealed that γ-PGA enhanced the antibacterial and antioxidant properties of S-Cur-NPs and effectively protected the functional activity against heating, storage, and in-vitro digestion. Release studies conducted in simulated gastrointestinal fluids revealed that S-Cur-NPs have targeted intestinal release properties. Overall, the design of shellac with γ-PGA was a promising strategy to relieve the application stress of shellac and curcumin in the food industry.

Ovotransferrin Fibril-Gum Arabic Complexes as Stabilizers for Oleogel-in-Water Pickering Emulsions: Formation Mechanism, Physicochemical Properties, and Curcumin Delivery

This project aimed to explore the influence of the interaction between ovotransferrin fibrils (OTF) and gum arabic (GA) on the formation mechanism, physicochemical properties, and curcumin delivery of the oleogel-in-water Pickering emulsion. Cryo-scanning electron microscopy results showed that OTF-GA complexes effectively adsorbed on the oil-water interface, generating spatial hindrance to inhibit droplet coalescence. The texture analysis also proved that OTF-GA complexes endowed oleogel-in-water Pickering emulsion with preferable springiness (0.49 ± 0.03 mm), chewiness (0.43 ± 0.07 mJ), and adhesion (0.31 ± 0.01 mJ). By exploring the coalescence stability, droplet size, and rheological properties of OTF-GA complexes-stabilized oleogel-in-water Pickering emulsion (OGPE), the higher coagulation stability, larger average droplet size (46.22 ± 0.08 μm), and stronger gel strength were observed. The microrheological results also exhibited stronger attraction between the OGPE droplets, a more pronounced solid-like structure, and a slower speed of movement than OTF-stabilized oleogel-in-water Pickering emulsion (OPE). Meanwhile, OGPE significantly enhanced the extent of lipolysis, stability, and bioaccessibility of curcumin, suggesting that it possessed superior performance as a delivery system for bioactive substances. This project provided adequate theoretical references for protein-polysaccharide complexes-stabilized oleogel-in-water Pickering emulsion, and contributed to expanding the application of oleogel-in-water Pickering emulsion in the food industry.

Physicochemical properties and stability of oil-in-water emulsions stabilized by soy protein isolate and xanthan gum

The aim of this work was to determine rheological and disperse characteristics and stability of oil-in-water emulsions stabilized by soy protein isolate (SPI) and xanthan gum (XG), as natural components. The effects of their combination on emulsion stabilization have not been investigated yet. The existence of interactions between the two macromolecules were indicated by the influence of XG on SPI surface hydrophobicity and surface tension values. Increase in SPI concentration from 1 to 3 % shift of distribution curves towards smaller particle size, while the opposite effects of further increase of SPI was obtained. The emulsions stabilized by SPI showed shear-thinning flow behavior, which changed to thixotropic at 5 % of SPI concentration. The presence of XG in emulsions at low concentrations did not affect the size distribution of the droplets, while at 0.1 % of XG Sauter mean diameter value raised and distribution curves were shifted towards a higher particle size. The presence of XG at higher concentration resulted in thixotropic flow behavior of emulsions. Also, increase in XG concentration led to the increase in consistency index and extent of non-Newtonian behavior of emulsions and enhanced the influence of the elastic modulus and creaming stability of the systems.

From isolated polyelectrolytes to star-like assemblies: the role of sequence heterogeneity on the statistical structure of the intrinsically disordered neurofilament-low tail domain

Intrinsically disordered proteins (IDPs) are a subset of proteins that lack stable secondary structure. Given their polymeric nature, previous mean-field approximations have been used to describe the statistical structure of IDPs. However, the amino-acid sequence heterogeneity and complex intermolecular interaction network have significantly impeded the ability to get proper approximations. One such case is the intrinsically disordered tail domain of neurofilament low (NFLt), which comprises a 50 residue-long uncharged domain followed by a 96 residue-long negatively charged domain. Here, we measure two NFLt variants to identify the impact of the NFLt two main subdomains on its complex interactions and statistical structure. Using synchrotron small-angle x-ray scattering, we find that the uncharged domain of the NFLt induces attractive interactions that cause it to self-assemble into star-like polymer brushes. On the other hand, when the uncharged domain is truncated, the remaining charged N-terminal domains remain isolated in solution with typical polyelectrolyte characteristics. We further discuss how competing long- and short-ranged interactions within the polymer brushes dominate their ensemble structure and, in turn, their implications on previously observed phenomena in NFL native and diseased states.

Microfluidization of soybean protein isolate-tannic acid complex stabilized emulsions: Characterization of emulsion properties, stability and in vitro digestion properties

Emulsion stability and sustained-release can be improved with a non-covalent complexing of a soybean protein isolate (SPI) with -tannic acid (TA) and dynamic high-pressure microfluidization (DHPM). The microstructure, physicochemical properties, and interfacial properties were investigated. The properties of the DHPM-treated emulsions were improved significantly, with the 120 MPa DHPM-treated SPI-TA emulsion (SPI-TA 120) having the best microstructure. The highest interface protein content, viscosity and viscoelasticity at 120 MPa of pressure facilitated the stability of the emulsion. The oxidation kinetics of emulsions was established. It was demonstrated that the oxidation stability of SPI-TA 120 was higher than SPI and SPI-TA emulsions without DHPM treatment. In addition, DHPM-treated SPI-TA emulsions showed the most positive effect on the slow release of curcumin compared to the control group. The formation of non-covalent protein complexes with polyphenols and DHPM treatment effectively increases the stability of emulsions.

Effects of limited enzymatic hydrolysis and polysaccharide addition on the physicochemical properties of emulsions stabilized with duck myofibrillar protein under low-salt conditions

This study aimed to investigate the role of hydrolysis and guar gum (GG) participation on the emulsification of the duck myofibrillar protein (MP) and the related stability of oil-in-water emulsion in low-salt condition. Emulsions were prepared using one of each or both treatments, and that prepared with trypsin hydrolysis and GG (T-GG) exhibited the highest stability. FTIR analysis confirmed the hydrogen bond interactions between the system components. T-GG treatment improved emulsion properties and decreased oil droplet size. Moreover, CLSM indicated that aggregation of T-GG oil droplets was prevented. Physical stability was assessed such as Turbiscan stability index, creaming index, and rheological properties. The adsorbed percentage for T-GG was the lowest. However, interfacial tension, droplet size, stability, and peroxide value analyses indicated that a denser interfacial membrane structure is formed with T-GG. Thus, T-GG treatment could be applied in the food industry, such as in nutrient delivery systems and fat mimetics.

Combination of carrageenan with sodium alginate, gum arabic, and locust bean gum: Effects on rheological properties and quiescent stabilities of partially crystalline emulsions

In the present study, carrageenan (CG) was combined with sodium alginate (SA), gum arabic (GA), and locust bean gum (LBG) to obtain four gum combinations (CG, CG + SA, CG + GA, and CG + LBG). The effects of different combinations on rheological properties and quiescent stabilities of PCEs were systematically investigated through characterization of fresh emulsion related parameters (rheological properties, forces between proteins, zeta potentials, surface tensions, interfacial adsorption properties, and multiple light scattering) and storage related parameters (visual appearance, creaming index, viscosities, particle sizes, and microscopic morphology). Rheological results indicated that CG PCEs had the highest apparent viscosities of 7.77-41.91 Pa·s at 0.01 s-1, followed by CG + SA PCEs (2.35-30.62 Pa·s), CG + GA PCEs (2.37-21.16 Pa·s), and CG + LBG PCEs (2.06-19.93 Pa·s). At low thickener concentration (0.02 %), CG PCE exhibited weak gel structure due to higher G' than G″ at all frequencies, while CG + SA, CG + GA, and CG + LBG PCEs had entangled network due to intersection between G' and G″. After three months of storage, CG + SA PCEs showed the lowest creaming index values (11.47-17.75 %), which were significantly lower than CG PCEs (15.35-20.85 %), CG + GA PCEs (15.97-24.42 %), and CG + LBG PCEs (17.13-21.71 %). Meanwhile, all the samples except for 0.02 % CG + SA PCE completely lost fluidity, and their viscosities were above 14,000 mPa·s. It was further found that CG stabilized emulsions showed severe droplet flocculation induced by hydrophobic interactions among adsorbed proteins. Combination of CG with SA, GA, and LBG, especially CG + SA, formed strong network structure and reduced contribution of hydrophobic interactions, which effectively inhibited flocculation of fat droplets, thereby improving rheological properties and storage stabilities of PCEs.

Efficient Demulsification Performance of Emulsified Condensate Oil by Hyperbranched Low-Temperature Demulsifiers

Focusing on the problem of poor demulsification performance of light crude oil emulsions in low-permeability oilfields at low temperatures, the composition of the emulsion samples, clay particle size distribution, and the viscosity-temperature relationship curve of samples were analyzed. Based on the results of emulsion composition analysis and characteristics, the bottle test method was used to analyze the demulsifying effect of different commercial types of demulsifiers, revealing the demulsification mechanism. The field tests confirm the demulsification capabilities of Polyoxyethylene polyoxypropylene quaternized polyoxyolefins surfactants (PR demulsifiers). The results reveal that PR demulsifiers combine the features of decreasing the interfacial tension between oil and water and adsorbing SiO2, allowing for quick demulsification and flocculation at low temperatures. This research serves as a theoretical and practical foundation for the study and advancement of low-temperature demulsification technology in oilfields.

Ultrasonic and homogenization: An overview of the preparation of an edible protein-polysaccharide complex emulsion

Emulsion systems are extensively utilized in the food industry, including dairy products, such as ice cream and salad dressing, as well as meat products, beverages, sauces, and mayonnaise. Meanwhile, diverse advanced technologies have been developed for emulsion preparation. Compared with other techniques, high-intensity ultrasound (HIUS) and high-pressure homogenization (HPH) are two emerging emulsification methods that are cost-effective, green, and environmentally friendly and have gained significant attention. HIUS-induced acoustic cavitation helps in efficiently disrupting the oil droplets, which effectively produces a stable emulsion. HPH-induced shear stress, turbulence, and cavitation lead to droplet disruption, altering protein structure and functional aspects of food. The key distinctions among emulsification devices are covered in this review, as are the mechanisms of the HIUS and HPH emulsification processes. Furthermore, the preparation of emulsions including natural polymers (e.g., proteins-polysaccharides, and their complexes), has also been discussed in this review. Moreover, the review put forward to the future HIUS and HPH emulsification trends and challenges. HIUS and HPH can prepare much emulsifier-stable food emulsions, (e.g., proteins, polysaccharides, and protein-polysaccharide complexes). Appropriate HIUS and HPH treatment can improve emulsions' rheological and emulsifying properties and reduce the emulsions droplets' size. HIUS and HPH are suitable methods for developing protein-polysaccharide forming stable emulsions. Despite the numerous studies conducted on ultrasonic and homogenization-induced emulsifying properties available in recent literature, this review specifically focuses on summarizing the significant progress made in utilizing biopolymer-based protein-polysaccharide complex particles, which can provide valuable insights for designing new, sustainable, clean-label, and improved eco-friendly colloidal systems for food emulsion. PRACTICAL APPLICATION: Utilizing complex particle-stabilized emulsions is a promising approach towards developing safer, healthier, and more sustainable food products that meet legal requirements and industrial standards. Moreover, the is an increasing need of concentrated emulsions stabilized by biopolymer complex particles, which have been increasingly recognized for their potential health benefits in protecting against lifestyle-related diseases by the scientific community, industries, and consumers.

Multivariable analysis of egg white protein-chitosan interaction: Influence of pH, temperature, biopolymers ratio, and ionic concentration

The influence of pH, temperature, biopolymer ratio, total concentration, and ionic concentration on the interaction between egg white protein (EWP) and chitosan (CS) was investigated through turbidity, zeta potential, and state diagram in our research. In addition, phase behavior was observed under various conditions. The turbidity of EWP remained low (turbidity < 0.03) and basically unchanged at a wide range of pH (4.0-8.0), while the turbidity of CS was slightly higher (turbidity < 0.2) after pH 7.0 than before. Moreover, under the same conditions, a sharply rising peak pattern was observed for the complex between EWP and CS. The maximum turbidity value was observed at 55 °C, and the temperature had a mild effect on turbidity. The optimum EWP to CS ratio was found to be 12:1 based on the turbidity curves and state diagrams influenced by different biopolymer mixing ratios. With the enhanced concentrations of total biopolymer, the maximum turbidity rose insignificantly above 0.1%.

Emulsifying properties of plant-derived polypeptide and their conjugates: a self-consistent-field calculation study of the impact of hydrolysis

By considering the hydrolysates of soy protein produced by trypsin as an example, the emulsion stabilizing properties of plant-based protein fragments have been investigated theoretically. We apply Self-Consistent-Field (SCF) calculations to determine the colloidal interactions induced between a pair of droplets stabilized by adsorbed layers of various soy protein fragments. The study is extended to conjugates of such polypeptides, formed by covalent bonding with a suitable hydrophilic sidechain (e.g. a polysaccharide). Our results show that the relatively longer fragments, with a greater number of hydrophobic amino acids, will display a stronger degree of adsorption affinity compared to the smaller hydrolysates, even where the latter may have a higher overall ratio of hydrophobic residues. This suggested that the degree of protein hydrolysis should be carefully controlled and limited to modest values to avoid the generation of a large number of short polypeptides, while still sufficient to improve solubility. While the emulsion stabilizing performance of a protein fragment type is strongly dependent on the conformation it adopts on the interface, we find this to be less critical for the conjugated polypeptides. However, we argue that with increasing degree of hydrolysis, many small fragments will not have the chance to form bonds with polysaccharides. It is demonstrated that the abundance of these unreacted polypeptides in the system severely reduces the efficiency of the conjugated longer protein fragments, preventing their presence on the surface of the droplets through competitive adsorption process.

Effects of ultrasonic and steam-cooking treatments on the physicochemical properties of bamboo shoots protein and the stability of O/W emulsion

In this study, the effects of ultrasonic and steam-cooking treatments on the physicochemical and emulsifying properties of bamboo shoots protein (BSP) were investigated. The particle size and the polydispersity index (PDI) of U-BSP (ultrasonic-BSP) both decreased. Fourier transform infrared spectroscopy (FTIR) showed that the secondary structure of U-BSP was more loose. Furthermore, X-ray diffraction (XRD) and thermogravimetric (TGA) analysis suggested that crystallinity amd thermal stability of U-BSP both deceased. The water and oil holding capacity (WHC/OHC) of U-BSP increased, while steam-cooking treatment had the reverse effect. We also investigated the effects of ultrasonic and steam-cooking treatments on BSP-stabilized emulsions. The viscosity of emulsion stabilized by U-BSP increased and the distribution of emulsion droplets was more uniform and smaller. The results showed that ultrasonic treatment significantly improved the stability of BSP-stabilized emulsions, while steam-cooking treatment had a significant negative impact on the stability of BSP-stabilized emulsions. The work indicated ultrasonication is an effective treatment to improve the emulsifying properties of BSP.

Polysaccharide-addition order regulates sonicated egg white peptide stabilized nanoemulsions and β-carotene digestion in vitro

In this paper, the effects of the polysaccharide-addition order (before and after homogenisation) on the stability of nanoemulsion stabilised by sonicated egg white peptides and the in vitro digestive behaviour of loaded β-carotene were investigated. The pyrene fluorescence results showed that the concentration of micelles formed by flaxseed gum (FG) in complex with peptides was significantly higher than that of peach gum (PG). The order of polysaccharide-addition affected the emulsion properties and stability; adding polysaccharides before homogenisation led to protein bridging flocculation, low polysaccharide coverage and a higher interfacial adsorbed protein content of the emulsion. PG enhanced potential spatial resistance and electrostatic repulsion, effectively prevented emulsion flocculation and improved electrostatic stability. After homogenisation, FG was added to emulsions to improve environmental stability, including ionic, temperature and storage stability. Due to the viscosity of polysaccharides and the formed polysaccharide-protein-lipid aggregates, the increasing degree of bridging flocculation promoted the prominent of apparent viscosity, and the G' and G'' exhibited a frequency-dependent increase. The polysaccharide type and mode changed the surface loading charge and droplet interface thickness, delayed the destruction of the droplet structure by protease, and slowed the release of β-carotene to form micelles. In this study, a stable emulsion system and an efficient emulsion transport system for bioactive substances were obtained by regulating polysaccharides adding order, which is significant for constructing an efficient food emulsion delivery system.

Construction of vitamin D delivery system based on pine nut oil Pickering emulsion: effect of phenols

BACKGROUND

The food industry has begun to develop foods fortified with unsaturated fatty acids; however, the susceptibility of pine nut oil to oxidation and other properties limits its use in food production. Researchers often inhibit the oxidation of oil by adding antioxidants. After the combination of polyphenols and proteins, the complex formed can improve or enhance the performance of the emulsion when it stabilizes the emulsion. Encapsulating, protecting, and controlling the release behavior of vitamin D (V_D ) during digestion through an emulsion delivery system can effectively overcome limitations such as easy degradation during processing and storage. This research uses tannic acid, gallic acid, tea polyphenol, and vanillic acid to prepare Pickering emulsions, and the type of phenolic compound is explored by multi-dimensional characterization and the amount of emulsion.

RESULTS

The influence of traits, microstructure, stability, V_D load application, and effect on the emulsion matrix's encapsulation rate and bioaccessibility is studied. A method was investigated to enhance the oxidative stability of whey protein isolate-stabilized emulsions by introducing phenol. Pickering emulsions could be obtained in the presence of phenol, while the type of phenol played a relatively important role, probably because the mechanism involved interactions between particles. Viscosity and creaming stability of emulsions increased with crosslinking of phenol in emulsions. In addition, the presence of phenol in emulsions significantly increased the bioaccessibility of encapsulated V_D after in vitro digestion.

CONCLUSION

The method presented in this study was important for improving the oxidative stability of pine nut oil emulsions, expanding the application of pine nut oil in the food industry, and providing the theoretical and application basis of application and active substance emulsion delivery systems. © 2022 Society of Chemical Industry.

Assessment of Soy Protein Acid Hydrolysate-Xanthan Gum Mixtures on the Stability, Disperse and Rheological Properties of Oil-in-Water Emulsions

There is a growing need for natural ingredients that could be utilized for the production of food, pharmaceutical, and cosmetic emulsions. Soy protein acid hydrolysate (SPAH) is a plant-based additive used in the food industry mainly as a flavor enhancer. For the purpose of this work, however, it was mixed with a well-known natural polysaccharide, xanthan gum (XG), to produce stable 30% (w/w) sunflower oil-in-water emulsions using a rotor-stator homogenizer. In order to assess the emulsifying properties of the SPAH and its mixtures with XG, the surface tension properties of their water solutions, particle size, creaming stability, and rheological properties of the emulsions were investigated. Since the emulsions prepared using only SPAH, in various concentrations, were not stable, systems containing 5% of SPAH and 0.1, 0.2, 0.3, 0.4, or 0.5% of XG were then studied. The increase in concentration of the macromolecule led to an increase in creaming stability. The emulsions with 5% SPAH and 0.5% XG were stable for at least 14 days. The increase in XG concentration led to a decrease in d_4,3, while consistency index and non-Newtonian behavior increased. The systems containing SPAH, in the absence of XG, showed shear-thinning flow behavior, which was changed to thixotropic with the addition of XG. Viscoelastic properties of emulsions containing over 0.2% of XG were confirmed by oscillatory rheological tests, demonstrating the dominance of elastic (G') over viscous (G") modulus.

Oil body extraction from high-fat and high-protein soybeans by laccase cross-linked beet pectin: physicochemical and oxidation properties

BACKGROUND

Soybean oil bodies (SOB) are droplets of natural emulsified oil. Soybean oil emulsifies well but it is easily oxidized during storage. Beet pectin is a complex anionic polysaccharide, which can be adsorbed on the surface of liposomes to improve their resistance to flocculation. Laccase can covalently cross-link ferulic acid in beet pectin, and its structure is irreversible, which can improve the stability of polysaccharides.

RESULTS

At pH 2.5, laccase cross-linked beet pectin high-oil soybean oil body (HOSOB) and high-protein soybean oil body (HPSOB) emulsions showed obvious aggregation and severe stratification, and the oxidation of the emulsions was also high. The flocculation of emulsions decreased with an increase in the pH. The effect of pH on the flocculation of emulsion was confirmed by confocal laser electron microscopy. The ζ potential, emulsification, and rheological shear force increased with increasing pH whereas the particle size and surface hydrophobicity decreased with increasing pH.

CONCLUSION

This experiment indicates that the physicochemical stability of the two composite emulsions was strongly affected under acidic conditions but stable under neutral and weakly alkaline conditions. Under the same acid-base conditions, the degree of oxidation of HPSOB composite emulsion changes substantially. The results of this study can provide a basis for the design of very stable emulsions to meet the demand for natural products. © 2023 Society of Chemical Industry.

W/O/W emulsions stabilized with whey protein concentrate and pectin: Effects on storage, pasteurization, and gastrointestinal viability of Lacticaseibacillus rhamnosus

Probiotics have demonstrated various bioactive functions but poor storage and application stability, and encapsulation a promising method of increasing its viability. In this study, whey protein concentrate (WPC) and pectin (PEC) formed non-covalent complexes through electrostatic interaction at pH 3.0. The formed WPC-PEC complexes showed superior particle size, absolute potential, emulsification properties, and structural changes when PEC concentration was >0.8 % (w/v). This made them appropriate as a hydrophilic emulsifier to stabilize W/O/W emulsions. Then, Lacticaseibacillus rhamnosus, one representative of probiotics, was encapsulated in the internal aqueous phase of W/O/W emulsions. We obtained higher encapsulation efficiency (78.49 %) and smaller D_4,3 (9.72 μm) with 0.8 % (w/v) PEC concentration. Encapsulation of Lacticaseibacillus rhamnosus in W/O/W emulsions improved its viability under harsh conditions, including 28 days storage at 4 °C, simulated pasteurization, and simulated gastrointestinal digestion. W/O/W emulsions stabilized by WPC-PEC non-covalent complexes further improved the survival of Lacticaseibacillus rhamnosus against various adverse conditions as compared to WPC. These findings suggest that the studied W/O/W emulsions systems have the potential to deliver probiotics in food substrates to enhance their viability during production processing, storage transportation, and digestion.

Segregative phase separation of gelatin and tragacanth gum solution and Mickering stabilization of their water-in-water emulsion with microgel particles prepared by complex coacervation

This study aimed to investigate the segregative interaction of gelatin (G) and tragacanth gum (TG) and the stabilization of their water-in-water (W/W) emulsion by G-TG complex coacervate particles. Segregation was studied at different pHs, ionic strengths and biopolymer concentrations. Results showed that incompatibility was affected by increasing the biopolymer concentrations. So, three reigns were demonstrated in the phase diagram of the salt-free samples. NaCl significantly changed the phase behavior via enhancement of self-association of polysaccharide and changing solvent quality due to the charge screening effect of ions. The W/W emulsion prepared from these two biopolymers and stabilized with G-TG complex particles was stable for at least one week. The microgel particles improved emulsion stability by adsorption to the interface and creating a physical barrier. A fibrous and network-like structure of the G-TG microgels was observed by scanning electron microscopy images suggesting the Mickering emulsion stabilization mechanism. It was confirmed that the bridging flocculation between the microgel polymers led to phase separation after the stability period. Biopolymer incompatibility investigation is a useful tool to obtain beneficial knowledge for preparation new food formulation, especially no contain oil emulsions for low- calorie diets.

Degradation kinetics of rutin encapsulated in oil-in-water emulsions: impact of particle size

BACKGROUND

Rutin is a natural bioactive flavonoid that is poor in water solubility and chemical stability. Encapsulation can be used to protect bioactive molecules from chemical or physical decomposition during food processing and storage. Thus, the effect of initial particle size on the ability of oil-in-water emulsions to retain rutin during storage was investigated.

RESULTS

Rutin was encapsulated in oil-in-water emulsions with different mean surface-weighted diameters: d_3,2  = 0.56 μm (small), 0.73 μm (medium), and 2.32 μm (large). As expected, the resistance of the emulsions to coalescence and creaming during storage increased as the particle size decreased due to weakening of the colloidal and gravitational forces acting on the droplets. The concentration of rutin in the emulsions decreased during storage (28 days), which was mainly attributed to photodegradation of the flavonoid. The loss of rutin from the emulsions during storage was fitted using a second-order equation. The rutin degradation rate constant k decreased and the half-life t_1/2 increased with decreasing droplet size, which was attributed to the stronger encapsulation and light scattering by smaller oil droplets reducing the amount of light that can penetrate into the emulsions.

CONCLUSION

This study has important implications for the design of more efficacious emulsion-based delivery systems for incorporating health-promoting nutraceuticals into foods. © 2022 Society of Chemical Industry.

Conformation changes and emulsifying properties of myofibrillar proteins in water: Effects of electrostatic interaction with chitosan

Great interests have been attracted toward muscle protein in a water-soluble state with improved functionality for further designing meat protein fortified low-salt functional foods. In the present study, electrostatic interaction of chitosan (CH) with myofibrillar proteins (MP) in water aqueous solution was investigated, and the linked structure changes and emulsion stabilization of MP were studied. Results showed that the electrostatic interaction inhibited MP aggregation, and smaller particle size complexes were formed at pH 6.0, leading to the loss of β-sheet contents and recovery of α-helix contents with decreasing MP/CH mixing ratio (5:1 and 1:1). The tertiary structure confirmed the conformation changes of MP in which more hydrophobic groups and active sulfhydryl groups were exposed (P < 0.05), and the fluorescence was also quenched. With decreasing mixing ratio, the droplet size of emulsion decreased (P < 0.05), while the absorbed protein content increased (P < 0.05). After 7 d of storage, complex at a ratio of 1:1 displayed desirable emulsion stability, which could be due to the improved emulsifying capacity, enhanced electrostatic repulsion and steric effects. These findings provide a better understanding of conformation changes of MP in water aqueous solution induced by electrostatic interactions at mild acidic pH and help to fabricate stable protein/polysaccharide emulsification systems for further developing meat protein-based functional food to deliver health.

Artificial Neural Networks to Optimize Oil-in-Water Emulsion Stability with Orange By-Products

The use of artificial neural networks (ANNs) is proposed to optimize the formulation of stable oil-in-water emulsions (oil 6% w/w) with a flour made from orange by-products (OBF), rich in pectins (21 g/100 g fresh matter), in different concentrations (0.95, 2.38, and 3.40% w/w), combined with or without soy proteins (0.3 and 0.6% w/w). Emulsions containing OBF were stable against coalescence and flocculation (with 2.4 and 3.4% OBF) and creaming (3.4% OBF) for 24 h; the droplets' diameter decreased up to 44% and the viscosity increased up to 37% with higher concentrations of OBF. With the protein addition, the droplets' diameter decreased by up to 70%, and flocculation increased. Compared with emulsions produced with purified citrus pectins (0.2 and 0.5% w/w), OBF emulsions exhibited up to 32% lower viscosities, 129% larger droplets, and 45% smaller Z potential values. Optimization solved with ANNs minimizing the droplet size and the emulsion instability resulted in OBF and protein concentrations of 3.16 and 0.14%, respectively. The experimental characteristics of the optimum emulsion closely matched those predicted by ANNs demonstrating the usefulness of the proposed method.