Surface Of Oil Droplets Research Articles

Lima bean (Phaseolus lunatus Linn.) protein isolate as a promising plant protein mixed with xanthan gum for stabilizing oil-in-water emulsions.

Lima bean protein isolate (LPI) is an underutilized plant protein. Similar to other plant proteins, it may display poor emulsification properties. In order to improve its emulsifying properties, one effective approach is using protein and polysaccharide mixtures. This work investigated the structural and emulsifying properties of LPI as well as the development of an LPI/xanthan gum (XG)-stabilized oil-in-water emulsion. The highest protein solubility (84.14%) of LPI was observed and the molecular weights (Mw ) of most LPI subunits were less than 35 kDa. The enhanced emulsifying activity index (15.97 m2 g-1 ) of LPI might be associated with its relatively high protein solubility and more low-Mw subunits (Mw < 35 kDa). The effects of oil volume fraction (ϕ) on droplet size, microstructure, rheological behavior and stability of emulsions were investigated. As ϕ increased from 0.2 to 0.8, the emulsion was arranged from spherical and dispersed oil droplets to polyhedral packing of oil droplets adjacent to each other, while the LPI/XG mixtures changed from particles (in the uncrowded interfacial layer) to lamellae (in the crowded interfacial layer). When ϕ was 0.6, the emulsion was in a transitional state with the coexistence of particles and lamellar structures on the oil droplet surface. The LPI/XG-stabilized emulsions with ϕ values of 0.6-0.8 showed the highest stability during a 14-day storage period. This study developed a promising plant-based protein resource, LPI, and demonstrates potential application of LPI/XG as an emulsifying stabilizer in foods. © 2023 Society of Chemical Industry.

Study on the Stability Mechanism of Peanut OBs Extracted with the Aqueous Enzymatic Method.

In this study, the internal relationships among oil bodies (OBs), the protein-phospholipid interactions in aqueous phase, oil-water interface behavior, and the stability of reconstituted OBs were analyzed from the bulk phase, interface, and macro perspectives, and the stability mechanism of OBs was discussed. OB proteins and phospholipids were combined through hydrophobic and electrostatic interactions, resulting in the stretching of protein conformation. OB proteins and phospholipids act synergistically to increase interface pressure and the rate of increase in interface pressure with relatively stable elastic behavior, which is beneficial to the formation and stability of interfacial films. When OBs were reconstituted by an OB protein-phospholipid complex system, phospholipids bound to OB proteins through hydrophobic and electrostatic interactions. OB proteins and phospholipids uniformly covered the oil droplet surface of reconstituted OBs to form a stable interfacial film, which maintained the stability of OBs. The addition of phospholipids significantly reduced the particle size of OBs prepared by OB proteins in a dose-dependent manner, and particle size decreased with the increase in phospholipid content (p < 0.05). Phospholipids increased the net surface charge, enhanced electrostatic repulsion, and improved the physicochemical stability of reconstituted OBs. The stability mechanism elucidated in this study provides a theoretical basis for the demulsification of peanut OBs.

Oil dispersing and adsorption by carboxymethyl cellulose–oxalate nanofibrils/nanocrystals and their kinetics

AbstractThe aim of our work is the preparation of cellulose nanofibrils or nanocrystals made from cellulose that is recovered from sugarcane bagasse agricultural waste (SC) as a dispersant instead of commercial cellulose for oil spill cleanup. In the current study, carboxymethyl cellulose was prepared by cellulose mercerization, which was then esterified by oxalic acid to create nanocellulose. Incorporation of oxalate into carboxymethyl cellulose (CMC) was verified by 1H‐NMR spectroscopy by the appearance of a new peak at 8.15 ppm for CMC–oxalate. The degree of substitution (DS) of oxalate was 0.17. The synthesized nanocellulose formed particles were roughly the same size and shape as both cellulose nanofibrils (CNFs) and cellulose nanocrystals (CNCs): measuring 321–480 nm in length and 4–5 nm in width. Emulsions of paraffins made from CMC–oxalate are stable up to 10 months without undergoing precipitation. CMC–oxalate had great thermal stability and worked well as a paraffin oil dispersant. CMC–oxalate provided a barrier around the oil droplet surface, which prevented droplets from coalescing. This hypothesis is supported by the contact angle measurement for the O/W emulsion formed by CMC–oxalate being 0°, which is lower than the value for emulsions formed by underivatized CMC, 37.20°. From transmission electron microscopy observations, O/W emulsions of paraffin oil were spherical in shape, and separated from each other by a distance of 30–100 nm. This study shows that CMC–oxalate can be prepared by a low‐cost method, yielding nanocellulose with characteristics that resemble CNFs and CNCs, thereby opening up new potential applications for cellulose nanomaterials.

Development of oil-in-water emulsion gels enriched with barley β-glucan as potential solid fat substitute and evaluation of their physical properties

Emulsion gels are considered as an innovative approach to substitute shortenings and margarine in food formulations, e.g., bakery products. Cereal β-glucans are fiber-type constituents, well-known for their human health promoting effects, but also as effective viscosifiers for stabilization of emulsions and aqueous dispersions of solid particles. Barley emulsion gels (BEGs) were formulated with varying weight proportions of β-glucan-enriched (∼27%) barley flour/olive oil/water (from 13/10/77 to 31/30/39) and their physicochemical properties and microstructure as potential solid fat replacers in food formulations were examined. Changes in physical properties and structure of BEGs were monitored using dynamic rheometry, large deformation mechanical testing, differential scanning calorimetry and confocal microscopy during storage (4 °C for 7 days). The rheological tests showed a typical solid-like character for all BEGs (i.e., G' was greater than G'') without oil exudation. The gel strength of BEGs increased upon storage, whereas the thermal properties were dependent on composition and application of heat treatment during BEGs production. Moreover, the microstructure of BEGs revealed that protein particles are located around the surface of oil droplets in the 13/10/77 gels, while in the 31/30/39 formulation, both oil droplets and proteins were entrapped within a more compact hydrated β-glucan-starchy network matrix. The molecular weight of β-glucans (SEC-HPLC) isolated from BEGs was lower than that of β-glucan isolate obtained from the native barley flour. Overall, the multi-instrumental analytical approach employed herein was a suitable framework for evaluation of the physical properties of BEGs as potential solid fat substitutes in the production of healthier formulated products.

Enhanced stabilization of oil-in-water (O/W) emulsions by fibrillar gel particles from lentil proteins

Pulse proteins as a sustainable protein source have attracted increasing interest in food development, but pulse proteins are generally less surface active than dairy proteins. This work introduces lentil protein (LP)-based fibrillar gel particles (FGPs) fabricated from heat-induced LP fibrillar aggregates by 1, 4, 8, and 16 h of heating, followed by particle reduction using sonication. The heating time significantly impacts the FGPs particle size and surface hydrophobicity. The FGP prepared by 4 h of heating (FGP-4) showed a small size (<200 nm) and homogeneous size distribution while possessing significantly increased surface hydrophobicity compared to untreated LP. Such structural features made FGP-4 better adsorb at the O/W interface and then completely covered the oil droplet surface, leading to homogeneous emulsions of small size (22.33 μm) and superior long-term stability without creaming for 30 days. In addition, the dispersed FGP in the bulk phase could develop interactions among each other, leading to improved emulsion viscosity and texture without oil droplet size change. This finding suggests that constructing fibril-type gel particles can provide a new strategy for forming superior O/W emulsions with improved stability from plant proteins.

Contactless Interfacial Thin‐Film Breaking Caused Splash‐Like Demulsification of Floating Micron Emulsions via Ionic Wind

AbstractEmulsified oil leakage onto the bulk water surface causes severe issues on global ecology and health. Developing efficient, rapid, and universal separation methods of emulsions has been a significant topic in scientific studies. However, a contactless and additive‐free strategy to achieve continuous floating emulsion separation and oil collection remains to be discovered. Herein, a universal contactless demulsification, transportation, and collection method to dispose floating emulsions by ionic wind, which contains active charged particles generated by corona discharge is reported. The splash‐like demulsification process of floating emulsions is attributed to the rupture of water film enveloped on oil droplet surface, simultaneously and respectively. The evidence of this process recorded by a high‐speed camera with 20 000 fps has a referential significance for other works. This study may clean up universal floating emulsions discharged on water in real situations such as oil stations, chemical plants, and restaurants, and furthermore increase the potential of remote control in liquid dynamics by corona discharge.

Demulsification of o/w emulsion produced by polymer flooding injecting anionic polymeric surfactant

Anionic amphiphilic polymers (polymeric surfactant) have been applied in polymer flooding to improve its adaptability to reservoirs of low permeability, high salinity and high temperature. Some pilot and extended polymer flooding projects injecting anionic polymeric surfactants with interfacial activities produced very stable o/w emulsion, bringing about high oil carry-over in produced water which was very difficult to remove to meet re-injection specifications. Factors contributing to the stability of o/w emulsion produced by a polymer flooding project injecting an anionic amphiphilic polymer were investigated by means of phase separation test, interfacial tension and Zeta potential measurements, emulsion microscopic structure observation and determination, and identification of interfacial active species. Major mechanisms hindering the aggregation and coalescence of oil droplets in the stable o/w emulsion were identified as the electrostatic repulsion and steric repulsion exerted by the polymer coils attached to the surfaces of oil droplets. A novel combination of a nonionic block polyether SP-2002 and a low molecular weight anionic surfactant AS-2001was designed to effectively demulsify the stable o/w emulsion produced by the polymer flooding project. Field trial of SP-2002 and AS-2001, together with a chelating agent WS-2001, brought about much looser o/w emulsion and significantly reduced oil carry over in produced water separated by field 3-phase production separators and skim tanks. The average OIWs of produced water dropped from 790 ppm before the trial to 482 ppm during the second stage of the trial. OIW of the produced water at the end of the trial dropped from 426 ppm to 90 ppm after 24 h static settling at 35 °C and further reduced to 17 ppm after bench-top media filtration.

Phase Diagram of Pickering Emulsions Stabilized by Cellulose Nanocrystals.

Cellulose is a promising renewable and biocompatible biopolymer for stabilizing Pickering emulsions (PEs). In the present study, PEs were produced by low-frequency ultrasounds with cellulose nanocrystals (CNCs) and caprylic/capric triglycerides. Phase diagrams allowed to understand mechanisms of formation and long-term stabilization of PEs. Emulsion type, continuous phase viscosity, and yield of oil incorporation were studied after PEs formation. Droplet size, oil release, and stability were measured weekly up to 56 days of storage. Results showed that oil mass fraction above 70% w/w led to unstable W/O PEs. Lower oil mass fraction formed O/W PEs of stability depending on CNC content and oil mass fraction. Droplet size stability increased with CNCs/oil ratio. A very low CNCs/oil ratio led to phase separation and oil release. High CNC content stabilized oil droplets surface, increased aqueous phase viscosity, and prevented creaming. Highly stable PEs were produced for CNC content above 3% (w/w) and oil mass fraction below 50% (w/w). Mechanisms for PEs formation and stabilization were proposed for various CNC contents and oil mass fractions.

Properties of Pickering emulsions stabilized by cellulose nanocrystals extracted from litchi peels

The development of Pickering emulsions which are applicable to the food industry still remains challenges due to the limited availability for biocompatible, edible and natural emulsifiers. The purpose of this study was to extract cellulose nanocrystals from litchi peels (LP-CNCs), and evaluate their emulsifying properties. The results showed that the LP-CNCs were needle-like and they possessed high crystallinity (72.34 %) and aspect ratio. When the concentrations of LP-CNCs were >0.7 wt% or the contents of oil were no >0.5, stable Pickering emulsions were obtained. The microstructures of emulsions confirmed that LP-CNCs formed dense interfacial layers on the surface of oil droplets, which functioned as barriers to prevent aggregation and flocculation among droplets. Rheological results showed that the emulsions exhibited typical shear thinning behavior. The elastic of emulsions was dominant, and their gel strength could be enhanced by regulating the contents of emulsifiers or oil. Additionally, the Pickering emulsions stabilized by LP-CNCs showed extremely high pH, ionic strength, and temperature tolerance. This strategy provides an innovative alternative to tackle the dilemma of preparing highly stable Pickering emulsions using natural particles in food products.

Pickering emulsions synergistically stabilized by sugar beet pectin and montmorillonite exhibit enhanced storage stability and viscoelasticity

Sugar beet pectin (SBP) is a naturally occurring emulsifying type of pectin fabricated into nanocomposites with montmorillonite (MMT) and then introduced as a stabilizer for high internal phase emulsions (HIPEs). SBP-MMT composites performed well in emulsifying medium-chain triglyceride with an oil volume fraction (φ) of 0.1–0.85 and SBP/MMT mass ratios of 1:0.1–1:0.75. The two representative high internal phase emulsions stabilized by SBP-MMT composites at different SBP/MMT mass ratios exhibited good stability against creaming and coalescence. In these emulsion systems, SBP and MMT formed a network in the continuous phase that markedly improved the rheological properties, including the storage modulus (by 3 orders of magnitude). Confocal light scattering microscopy analysis indicated that a fraction of MMT could work synergistically with SBP in adsorbing on oil droplet surfaces, enhancing stability. SBP-MMT composites stabilized high internal phase emulsions destabilized after the freeze-thaw treatment (−40 °C for 20 h and 25 °C for 4 h) but could be facilely re-emulsified via high-speed shearing. The gastrointestinal digestion behaviors were also modified by stabilizing SBP and MMT. Overall, this work reveals a hitherto undocumented strategy for fabricating highly stable emulsions based on SBP-MMT composites which have huge prospects for application in the food and related industries.

Analysis of the Emulsifying Capacity of Low Methyl-Esterified Citrus Pectin in the Presence of Calcium Cations from Its Aggregates: Micelles

In this study, pectin was considered a soft matter, and the emulsification of low methyl-esterified citrus pectin (LMCP) was analyzed in the presence of calcium cations (Ca2+). The formulation of LMCP aggregates was called micelles, and they could be regarded as granular emulsifiers. The size and morphology of LMCP micelles were affected by the concentration of Ca2+, and this changed the emulsifying properties of LMCP. The particle size distribution range in LMCP solutions was first decreased and then increased with increasing Ca2+ concentrations from 0.00 to 10.00 mM. The concentration of Ca2+ affected the creaming index (CI) of emulsions and the size distribution of the emulsion droplets significantly. Tiny particles and cavities being detected on the oil droplet surface in cryo-scanning electron microscopy (SEM) micrographs illustrated that the stable emulsion could be considered a Pickering emulsion when different concentrations of Ca2+ were brought into the LMCP solution for the preparation of the emulsion.

Construction of spherical cellulose nanocrystals synergized with graphene oxide to stabilize Pickering emulsions

In this study, we prepared spherical cellulose nanocrystals (S-CNCs) and stabilized n-hexadecane Pickering emulsions in conjunction with graphene oxide (GO), exploring the interaction between S-CNCs and GO in the emulsions. Both S-CNCs and GO are amphiphilic and synergistically stabilize Pickering emulsions by adhering to the surface of oil droplets and within the emulsion space through hydrogen bonding. GO's two-dimensional sheets assemble into a 3D network structure, further improving the stability of Pickering emulsions. Consequently, the stability of Pickering emulsions can be adjusted by altering the S-CNCs/GO ratio, modifying the spatial distribution relationship of stabilizers in the emulsions. At an S-CNCs concentration of 1 g/L and a GO concentration of 3 g/L, the Pickering emulsion demonstrated excellent stability and exhibited no delamination after 31 days of storage. Thus, the S-CNCs/GO combination serves as an effective Pickering emulsion stabilizer, utilizing the synergistic effect between the two components.

Synergistic effects of psyllium husk powder and different levels of methylcellulose on the storage stability of sodium caseinate emulsion.

The study investigated the effects of compound fibers composed of psyllium husk powder (PHP, 0.3%) and methylcellulose (MC, 0, 0.3, 0.6, 0.9, and 1.2%) on the storage stability, rheology, and microstructure of sodium caseinate emulsions. Results showed that the emulsion stability was enhanced with the increased concentrations of MC, especially at the concentration of 1.2%. The oil droplet size in the emulsions was decreased as the concentrations of compound fibers increased, which was further confirmed by the optical microscope analysis. The rheological measurements and cryo-scanning electron microscopy results indicated that compound fibers improved the viscosity of the emulsions, and formed a strong three-dimensional network structure. The results of confocal laser scanning microscope and surface protein concentration measurements showed that compound fibers were evenly distributed into the oil droplet surface. The above results demonstrate that compound fibers are an effective thickener and emulsifier in enhancing the stability properties of oil-in-water (O/W) emulsions stabilized by sodium caseinate.

Impact of interactions between peanut protein isolate and cellulose nanocrystals on the properties of Pickering emulsions: Rheological properties and physical stabilities

The interactions between cellulose nanocrystals and proteins can regulate the interfacial properties of Pickering emulsions, which plays a leading role in the stabilities of Pickering emulsions. In this work, oil-in-water (O/W) Pickering emulsions with different oil-water ratios were prepared using peanut protein isolate modified by cellulose nanocrystals (PPI/CL-CNCs). The distributions of PPI/CL-CNCs at the oil-water interfaces and the microstructures of Pickering emulsions were observed by CLSM and cryo-SEM. The results showed that stable complexes PPI/CL-CNCs formed thick and dense interface layers on the surface of oil droplets. The results of rheological tests clarified that the Pickering emulsions showed an elastic and gel texture, and their gel strength could be enhanced by regulating the oil-water ratios from 3:7 to 7:3. In addition, after one month of storage, the EI of all emulsions remained above 92 % with no obvious phase separation or demulsification. These results suggested that the PPI/CL-CNCs-stabilized Pickering emulsions showed good physical stabilities. The study on the rheological properties and physical stabilities of PPI/CL-CNCs-based Pickering emulsions provided novel insights on developing highly stable Pickering emulsions.

Pickering emulsion: A multi-scale stabilization mechanism based on modified lotus root starch/xanthan gum nanoparticles

New Pickering emulsion stabilizer LS/XG-NPs (Lotus root starch/xanthan gum nanoparticles) was prepared via autoclaving-cooling method followed by combination with XG. The LS/XG-NPs showed uniform and stable particles with particle size <500 nm, PDI <30, and zeta potential 30–40. The autoclaving-cooling treatment completely changed the crystalline form (from A-type to B-type) and structure of starch; hydrogen bonding and electrostatic interactions were proved to be existed between starch and XG in LS/XG-NPs. The addition of XG increased the contact angle of LS/XG-NPs from 58.79° to 85.42°. In the prepared Pickering emulsion, the LS/XG-NPs adsorbed well on the oil droplets surface, forming a three-dimensional gel network with evenly distributed oil droplets. The Pickering emulsion prepared with LS/XG-NPs showed excellent storage stability and auto-oxidation resistance; the EPA + DHA content in the emulsion remained at 92.46 % after 5 d of storage. The results of this study suggest that LS/XG-NPs have the potential to be food-grade Pickering emulsifiers that not only stabilize emulsions but also prevent emulsion oils from oxidizing.

Enhancement of emulsification properties by modulation of egg white protein fibril structure with different heating times

Egg white protein (EWP) has poor emulsification ability due to the hydrophobic groups buried in the molecular structure. In contrast, the protein fibrils produced by acidic heat treatment are able to expose the hydrophobic groups and firmly adsorb to the surface of oil droplets. Therefore, the preparation of egg white protein fibrils (EWPF) can broaden the range of applications of EWP, such as low-fat emulsion-based foods. Since the heating time affects the growth condition of the fibrils and thereby the properties of their stabilized emulsions. The effect of treatment time on the structure properties and emulsification properties of EWP during fibrillation, also the effect of different environments on the stability of EWPF emulsion were investigated. The EWPF content increased with heating time. During the heating of EWP under acidic condition, proteins were hydrolyzed into peptides, subsequently peptides aggregated unidirectionally to form fibrils due to electrostatic repulsive forces at low pH. Compared with EWP, EWPF had larger particle size, higher ζ-potential, higher β-sheet content and greater surface hydrophobicity. In addition, the emulsifying activity and emulsification stability of the EWPF emulsion increased nearly two-fold compared with that of the EWP emulsion. Furthermore, it had smaller droplets, higher ζ-potential, and better thermal and ionic stability. This study could provide insights into the improvement of EWP emulsifying properties and fibril-modified EWP as stabilizing ingredients for emulsion-based foods. • EWP rich in acidic amino acids is an excellent material for fibrils preparation. • EWPF morphology gradually prolonged and aggregated with heating time. • The fine curled structure of EWPF can better encapsulate the oil droplets. • EWPF had the best emulsification properties when heated for 8 h. • Thermal stability and ionic stability of emulsion with EWPF were increased.

Quaternary ammonium siloxane-decorated magnetic nanoparticles for emulsified oil-water separation

Rapid demulsification of “oil-in-water” (O/W) and “water-in-oil” (W/O) emulsions is extremely important for oil utilization and environmental protection. Although some siloxane-modified magnetic nanoparticles (MNPs) are applicable to separate oil–water mixture, there is no report on the demulsification performance of quaternary ammonium siloxane-coated MNPs in O/W or W/O emulsion. Herein, a series of dimethyloctadecyl [3-(trimethoxysilyl) propyl] ammonium chloride (DOTAC)-modified magnetic nanoparticles (MNPs) has been successfully synthesized and results showed that the optimized MNPs exhibited higher demulsification efficiency than our previously reported siloxane-modified MNPs. The synthetic MNPs were characterized in detail and their wettability and surface charge were facilely regulated by just adjusting DOTAC anchoring density on Fe3O4@SiO2 surface. Demulsification performance in O/W emulsion was enhanced at first and then declined with increasing DOTAC anchoring density at various pH levels. When the MNPs were weakly positively charged, both electrostatic attraction and hydrophobic interactions could promote the nanoparticle adsorption on oil droplet surface, thereby accelerating subsequent magnetic flocculation and separation. Specifically, M3-DOTAC 0.06, M3-DOTAC 0.12 and M3-DOTAC 0.6 exhibited best demulsification performance at pH 4.0, 7.0 and 10.0, respectively. The oil removal efficiency exceeded 94 % when 200 mg/L of MNPs introduced. Moreover, its demulsification performance was degraded with increasing surfactant concentration, and declined at first and then enhanced with increasing salinity. In W/O emulsion, demulsification effect was gradually increased with increasing DOTAC anchoring density. For an extremely stable W/O emulsion, dehydration efficiency of the optimized M3-DOTAC 1.8 exceeded 93% at 20 g/L of MNPs. Furthermore, the synthetic MNPs with suitable DOTAC anchoring density exhibited good recyclability in either O/W or W/O emulsion. Considering its simple synthetic procedure and high demulsification efficiency, DOTAC-coated MNPs could potentially find practical applications in demulsifying O/W or W/O emulsion.

Interfacial behavior of cyclodextrins at the oil-water interface of Pickering emulsion

An oil-in-water (O/W) Pickering emulsion stabilized by cyclodextrins (CDs), including α-, β-, γ-CD, and the hydroxypropyl (HP) derivatives, was prepared by high-speed homogenization. The interfacial behavior of CDs was studied by the contact angle, surface tension, interface tension, and adsorption kinetics. The physicochemical properties of CD Pickering emulsion were characterized by adsorption content, microstructure, rheology, and instability index. The results showed that the contact angles (85.30° and 75.93°), diffusion rates (−0.2481 and −0.1285), and adsorption rates (−0.0045 and −0.0028) of α-CD and β-CD were significantly higher than those of HP-CD derivatives, and emulsions possessed smaller droplet size (both about 7.5 μm) and better stability compared with HP-CDs derivatives. The formation of Pickering emulsion was attributable to the interfacial adsorption layer structure at the oil-water interface formed by the self-assembly of CD. Subsequent studies on the physiochemical properties of emulsion showed that Pickering emulsions stabilized by α-CD and β-CD had better storage modulus, loss modulus, viscosity, storage stability, and centrifugal stability. HP-α-CD, HP-β-CD, and HP-γ-CD stabilized emulsions delaminated and sedimented within a short time. The amorphous HP-α-CD, HP-β-CD, and HP-γ-CD were difficult to form stable interfacial layers and adsorb on the surface of oil droplets due to their high-water solubility and poor crystallinity. • Interfacial behavior of cyclodextrins in the Pickering emulsion was investigated. • α-CD, β-CD, and γ-CD formed rigid interfacial adsorption layer structure, the emulsions exhibited small droplet size and high apparent viscosity. • HP-α-CD, HP-β-CD, and HP-γ-CD were difficult to form stable interfacial layer, the emulsions exhibited low moduli and poor stability.

Influences of the different chemical components in soybean soluble polysaccharide on the emulsifying performance of its conjugates formed with soybean protein isolate

SummaryThis work aimed to elucidate the relationship between the chemical components of soybean soluble polysaccharide (SSPS) and its Maillard reaction with soybean protein isolate (SPI). Enzymatic hydrolysis was used to specifically cleave the chemical components of SSPS. Neutral sugar side chain regions of SSPS were easier to conjugate with SPI than the backbone containing galacturonic acid. The modified SSPS with higher content of arabinose showed the highest degree of glycosylation (46.8%). SSPS‐SPI conjugates exhibited lower interfacial tension than SPI, fabricating emulsion with smaller droplets size and better emulsion stability. The improved emulsifying properties could be ascribed to two aspects: (i) a higher percentage of adsorbed protein at the interface to cover more oil droplet surface; (ii) thicker adsorbed layer thickness onto the droplet surface to provide stronger steric‐hindrance effect to prevent droplet coalescence.

Structure and properties of Pickering emulsions stabilized solely with novel buckwheat protein colloidal particles

In this paper, buckwheat protein colloidal particles (BPCPs) were prepared by heat treatment to stabilize oil-water interface. The results of particle size, surface hydrophobicity and wettability indicated that the prepared BPCPs could be used as novel Pickering emulsifier. The effects of BPCPs concentration, ionic strength and heat treatment on the structure and properties of Pickering emulsions were explored. The microstructure results showed that BPCPs could tightly coated on the surface of oil droplets to form a tight interfacial film, confirming that BPCPs could be used as an effective Pickering-like stabilizer. With the increase of BPCPs concentration, the droplet size of the Pickering emulsion gradually decreased, and the viscoelasticity and storage stability of the emulsion were effectively improved. Different from the effect of ionic strength, heat treatment was beneficial to increasing the viscoelasticity of BPCPs-stabilized Pickering emulsion. The Pickering emulsions exhibited certain flocculation at different temperatures and ionic strengths, while still maintained good solid-like behavior. These results suggest that the structure and properties of BPCPs-stabilized Pickering emulsion could be regulated by changing the ionic strength and temperature.