Development of antioxidant Pickering high internal phase emulsions (HIPEs) stabilized by protein/polysaccharide hybrid particles as potential alternative for PHOs

Effects of different solid particle sizes on oat protein isolate and pectin particle-stabilized Pickering emulsions and their use as delivery systems

Oat protein isolate (OPI)/high methoxyl pectin (HMP) complexes (OPP) were prepared to stabilized Pickering emulsions and applied as nutraceutical delivery systems. The different mass ratios and pH changed the interactions between OPI and HMP that caused the different size of OPP. Specifically, smaller particle size of OPP (125.7-297.6 nm) were formed when hydrophobic interactions along with electrostatic forces predominant in OPP (OPI:HMP = 3:1, pH 4, 5). Among these particles, OPP-2 could stabilize Pickering emulsion efficiently through formation of dense interfacial film, which exhibited the highest apparent viscosity and the smallest average droplet size (23.39 μm). Moreover, OPP-2 stabilized Pickering emulsions with superior stability not only exhibited higher encapsulation efficiency of 85.63%, but also could control curcumin release in simulated gastrointestinal fluids to improve curcumin's bioaccessibility. These results verified the possibility of OPP to be a Pickering emulsions stabilizer, and also identified its potential to be a stable delivery system for bioactive compounds.

Characteristics of Pickering emulsions stabilized by microgel particles of five different plant proteins and their application

Pickering emulsions stabilized by protein particles are of great interest for use in real food systems. This study was to investigate the properties of microgel particles prepared from different plant proteins, i.e., soybean protein isolate (SPI), pea protein isolate (PPI), mung bean protein isolate (MPI), chia seed protein isolate (CSPI), and chickpea protein isolate (CPI). MPI protein particles had most desirable Pickering emulsion forming ability. The particles of SPI and PPI had similar particle size (316.23 nm and 294.80 nm) and surface hydrophobicity (2238.40 and 2001.13) and emulsion forming ability, while the CSPI and CPI particle stabilized emulsions had the least desirable properties. The MPI and PPI particle stabilized Pickering emulsions produced better quality ice cream than the one produced by SPI particle-stabilized emulsions. These findings provide insight into the properties of Pickering emulsions stabilized by different plant protein particles and help expand their application in emulsions and ice cream.

Toward Diverse Plant Proteins for Food Innovation

This review highlights the development of plant proteins from a wide variety of sources, as most of the research and development efforts to date have been limited to a few sources including soy, chickpea, wheat, and pea. The native structure of plant proteins during production and their impact on food colloids including emulsions, foams, and gels are considered in relation to their fundamental properties, while highlighting the recent developments in the production and processing technologies with regard to their impacts on the molecular properties and aggregation of the proteins. The ability to quantify structural, morphological, and rheological properties can provide a better understanding of the roles of plant proteins in food systems. The applications of plant proteins as dairy and meat alternatives are discussed from the perspective of food structure formation. Future directions on the processing of plant proteins and potential applications are outlined to encourage the generation of more diverse plant-based products.

Spray drying the Pickering emulsions stabilized by chitosan/ovalbumin polyelectrolyte complexes for the production of oxidation stable tuna oil microcapsules

The microencapsulation of polysaturated fatty acids by spray drying remains a challenge due to their susceptibility to oxidation. In this work, antioxidant Pickering emulsions were attempted as feeds to produce oxidation stable tuna oil microcapsules. The results indicated that the association between chitosan (CS) and ovalbumin (OVA) was a feasible way to fabricate antioxidant and wettable complexes and a high CS percentage favored these properties. The particles could yield tuna oil Pickering emulsions with enhanced oxidation stability through high-pressure homogenization, which were successfully spray dried to produce microcapsules with surface oil content of 8.84 % and microencapsulation efficiency of 76.65 %. The microcapsules exhibited significantly improved oxidation stability and their optimum peroxide values after storage at 50 °C, 85 % relative humidity, or natural light for 15 d were 48.67 %, 60.07 %, and 39.69 % respectively lower than the powder derived from the OVA-stabilized emulsion. Hence, Pickering emulsions stabilized by the CS/OVA polyelectrolyte complexes are potential in the production of oxidation stable polyunsaturated fatty acid microcapsules by spray drying.

Effect of zein-pectin composite particles on the stability and rheological properties of gelatin/hydroxypropyl methylcellulose water-water systems

To improve the compatibility of gelatin (GA) and hydroxypropyl methylcellulose (HPMC), we investigated the effects of zein-pectin composite particles (ZCPs) with various zein/pectin ratios (1:0, 1:0.5, 1:1, 1:1.5, and 1:2) on the physical stability, microstructure, and rheological properties of the GA/HPMC water-water systems. With increasing pectin ratio, the particle size of the composite particles increased from 234.53 ± 1.48 nm to 1111.00 ± 26.91 nm, and their zeta potential decreased from 20.60 mV to below -34.77 mV. Macroscopic and microstructure observations indicated that pectin-modified ZCPs could effectively inhibit phase separation behavior between GA and HPMC. Compared to pure HPMC, the GA/HPMC water-water systems possessed a higher viscosity and dynamic modulus at room temperatures but lower gel temperatures (reduction of about 11 %). The viscosity and modulus of the water-water systems increased with increasing pectin ratio in ZCPs. However, the ratio had no impact on the gel-sol (sol-gel) transition temperatures (not statistically significant (P < 0.05)). This study may serve as a reference for advancing the processability of HPMC.

Lentil protein isolate (Lens culinaris) subjected to ultrasound treatment combined or not with heat-treatment: structural characterization and ability to stabilize high internal phase emulsions

This study evaluated the effect of ultrasound treatment combined or not with heat treatment applied to lentil protein isolate (LPI) aiming to enhance its ability to stabilize high internal phase emulsions (HIPE). LPI dispersion (2%, w/w) was ultrasound-treated at 60% (UA) and 70% (UB) amplitude for 7 min; these samples were subjected to and then heat treatments at 70 °C (UAT70 and UBT70, respectively) or 80 °C (UAT80 and UBT80, respectively) for 20 min. HIPEs were produced with 25% untreated and treated LPI dispersions and 75% soybean oil using a rotor-stator (15,500 rpm/1 min). The LPI dispersions were evaluated for particle size, solubility, differential scanning calorimetry, electrophoresis, secondary structure estimation (circular dichroism and FT-IR), intrinsic fluorescence, surface hydrophobicity, and free sulfhydryl groups content. The HIPEs were evaluated for droplet size, morphology, rheology, centrifugal stability, and the Turbiscan test. Ultrasound treatment decreased LPI dispersions' particle size (∼80%) and increased solubility (∼90%). Intrinsic fluorescence and surface hydrophobicity confirmed LPI modification due to the exposure to hydrophobic patches. The combination of ultrasound and heat treatments resulted in a reduction in the free sulfhydryl group content of LPI. HIPEs produced with ultrasound-heat-treated LPI had a lower droplet size distribution mode, greater oil retention values in the HIPE structure (> 98%), lower Turbiscan stability index (< 2), and a firmer and more homogeneous appearance compared to HIPE produced with untreated LPI, indicating higher stability for the HIPEs stabilized by treated LPI. Therefore, combining ultrasound and heat treatments could be an effective method for the functional modification of lentil proteins, allowing their application as HIPE emulsifiers.

Synergistic stabilization of high internal phase Pickering emulsions by peanut isolate proteins and cellulose nanocrystals for β-carotene encapsulation

In this study, high internal phase Pickering emulsions (HIPPEs) were stabilized by the complexes of peanut protein isolate (PPI) and cellulose nanocrystals (CNCs) for encapsulation β-carotene to retard its degradation during processing and storage. CNCs were prepared by H2SO4 hydrolysis (HCNCs), APS oxidation (ACNCs) and TEMPO oxidation (TCNCs), exhibiting needle-like or rod-like structures with nanoscale size and uniformly distributed around the spherical PPI particle, which enhanced the emulsifying capability of PPI. Results of optical micrographs and droplet size measurement showed that Pickering emulsions stabilized by PPI/ACNCs complexes exhibited the most excellent stability after 30 days of storage, which indicated that ACNCs had the most obvious effect to improve emulsifying capability of PPI. HIPPEs encapsulated β-carotene (βc-HIPPEs) were stabilized by PPI/ACNCs complexes and showed excellent inverted storage stability. Moreover, βc-HIPPEs exhibited typical shear thinning behavior investigated by rheological properties analysis. During thermal treatment, ultraviolet radiation and oxidation, the retentions of β-carotene encapsulated in HIPPEs were improved significantly. This research holds promise in expanding Pickering emulsions stabilized by proteins-polysaccharide particles to delivery systems for hydrophobic bioactive compounds.

Research progress on plant-based protein Pickering particles: Stabilization mechanisms, preparation methods, and application prospects in the food industry

At present, there have been many research articles reporting that plant-based protein Pickering particles from different sources are used to stabilize Pickering emulsions, but the reports of corresponding review articles are still far from sufficient. This study focuses on the research hotspots and related progress on plant-based protein Pickering particles in the past five years. First, the article describes the mechanism by which Pickering emulsions are stabilized by different types of plant-based protein Pickering particles. Then, the extraction, preparation, and modification methods of various plant-based protein Pickering particles are highlighted to provide a reference for the development of greener and more efficient plant-based protein Pickering particles. The article also introduces some of the most promising applications of Pickering emulsions stabilized by plant-based protein Pickering particles in the food field. Finally, the paper also discusses the potential applications and challenges of plant-based protein Pickering particles in the food industry.

High-internal-phase emulsions stabilized by alkali-extracted green tea polysaccharide conjugates for curcumin delivery

Exploring the emulsification capabilities of tea polysaccharide conjugates (TPCs) in high-internal-phase emulsions (HIPEs) would further expand the utilization value of TPCs. This study aimed to prepare 0.1-0.5 wt% alkali-extracted green tea polysaccharide conjugate (gTPC-A)-stabilized HIPEs containing 75-87 wt% medium chain triglycerides (MCTs) to investigate their stability, rheology, microstructure, and loading and protective effects on curcumin. The findings revealed that only 0.1 wt% of gTPC-A could stabilize HIPEs containing 85 wt% oil for 30 days. HIPEs had better storage stability in a weakly acidic environment at pH 5.0-6.0 and at temperatures less than 70 °C. HIPEs could load curcumin and protect it from ultraviolet (UV) radiation and in vitro digestion. The half-life of curcumin loaded in HIPEs was 65 h under UV radiation. The curcumin bioaccessibility of HIPEs (56.29 %) was higher than that in MCT (8.73 %). These results provided a theoretical basis for the extensive use of TPCs.

Progress of Drug Nanocrystal Self-Stabilized Pickering Emulsions: Construction, Characteristics In Vitro, and Fate In Vivo

A drug nanocrystal self-stabilized Pickering emulsion (DNSPE) is a novel Pickering emulsion with drug nanocrystals as the stabilizer. As a promising drug delivery system, DNSPEs have attracted increasing attention in recent years due to their high drug loading capacity and ability to reduce potential safety hazards posed by surfactants or specific solid particles. This paper comprehensively reviews the progress of research on DNSPEs, with an emphasis on the main factors influencing their construction, characteristics and measurement methods in vitro, and fate in vivo, and puts forward issues that need to be studied further. The review contributes to the advancement of DNSPE research and the promotion of their application in the field of drug delivery.

Tannic acid-enriched nanocellulose hydrogels improve physical and oxidative stability of high-internal-phase Pickering emulsions

A cellulose suspension and tannic acid (TA) were co-sonicated to prepare TA-incorporated nanocellulose hydrogels with the aim of improving the physical and oxidative stability of high-internal-phase emulsions (HIPEs). Cellulose nanocrystal (CNC) hydrogels were used to stabilize HIPEs, relying on the interfacial adsorption behavior of CNCs and the reversible gelation properties of hydrogels. TA was incorporated due to its ability to improve emulsification performance and antioxidant properties. Introducing TA enhanced the gel strength of hydrogels by decreasing the interfibrillar distance. The utilization of CNC-TA hydrogels effectively improved physical properties of HIPEs. This improvement included a reduction in droplet size from the initial 103.41 μm to 39.66 μm, an enhancement of the gel structure, and an improvement in storage stability. A denser and orderly interfacial structure was formed in CNCs-TA hydrogel stabilized HIPEs due to anchoring TA at the interface driven by the hydrogen-bonding interaction between CNCs and TA. This densely interfacial layer with good antioxidant activity markedly enhanced the oxidative stability of emulsions, as evidenced by the low level of oxidation products in HIPEs. This study has the potential to extend the utilization of CNC-stabilized emulsions to new applications in the food, cosmetic, and pharmaceutical industries.

Microfluidized hemp protein isolate: an effective stabilizer for high-internal-phase emulsions with improved oxidative stability

BACKGROUND

Hemp protein isolates (HPIs), which provide a well-balanced profile of essential amino acids comparable to other high-quality proteins, have recently garnered significant attention. However, the underutilized functional attributes of HPIs have constrained their potential commercial applications within the food and agriculture field. This study advocates the utilization of dynamic-high-pressure-microfluidization (DHPM) for the production of stable high-internal-phase emulsions (HIPEs), offering an efficient approach to fully exploit the potential of HPI resources.

RESULTS

The findings underscore the effectiveness of DHPM in producing HPI as a stabilizing agent for HIPEs with augmented antioxidant activity. Microfluidized HPI exhibited consistent adsorption and anchoring at the oil-water interface, resulting in the formation of a dense and compact layer. Concurrently, the compression of droplets within HIPEs gave rise to a polyhedral framework, conferring viscoelastic properties and a quasi-solid behavior to the emulsion. Remarkably, HIPEs stabilized by microfluidized HPI demonstrated superior oxidative and storage stability, attributable to the establishment of an antioxidative barrier by microfluidized HPI particles.

CONCLUSION

This study presents an appealing approach for transforming liquid oils into solid-like fats using HPI particles, all without the need for surfactants. HIPEs stabilized by microfluidized HPI particles hold promise as emerging food ingredients for the development of emulsion-based formulations with enhanced oxidative stability, thereby finding application in the food and agricultural industries. © 2023 Society of Chemical Industry.

Glycation-induced enhancement of yeast cell protein for improved stability and curcumin delivery in Pickering high internal phase emulsions

Pickering high internal phase emulsions (HIPEs) have gained significant attention for various applications within the food industry. Yeast cell protein (YCP), derived from spent brewer's yeast, stands out as a preferred stabilizing agent due to its cost-effectiveness, abundance, and safety profile. However, challenges persist in utilizing YCP, notably its instability under high salt concentration, thermal processing, and proximity to its isoelectric point. This study aimed to enhance YCP's emulsifying properties through glycation with glucose and evaluate its efficacy as a stabilizer for curcumin (CUR)-loaded HIPEs. The results revealed that glycation increased YCP's surface hydrophobicity, exposing hydrophobic groups. This augmentation, along with steric hindrance from grafted glucose molecules, improved emulsifying properties, resulting in a thicker interfacial layer around oil droplets. This fortified interfacial layer, in synergy with steric hindrance, bolstered resistance to pH changes, salt ions, and thermal degradation. Moreover, HIPEs stabilized with glycated YCP exhibited reduced oxidation rates and improved CUR protection. In vitro digestion studies demonstrated enhanced CUR bioaccessibility, attributed to a faster release of fatty acids. This study underscores the efficacy of glycation as a strategic approach to augment the applicability of biomass proteins, exemplified by glycated YCP, in formulating stable and functional HIPEs for diverse food applications.

Pickering emulsions stabilized by ternary complexes involving curcumin-modified zein and polysaccharides with different charge amounts for encapsulating β-carotene

In this research, zein was modified with curcumin to obtain covalent and non-covalent complexes. They were further covered with polysaccharides (gum arabic or gum karaya) possessing different surface charge amounts to obtain ternary nanoparticles for preparing novel antioxidant Pickering emulsions. The addition of curcumin to the zein-polysaccharide system significantly retarded the UV degradation of the encapsulated β-carotene (maximum retention ∼ 97%) and effectively inhibited the lipid oxidation of the emulsions. In vitro gastrointestinal digestion assays showed that gum karaya significantly delayed the release of free fatty acids, thereby improving the bioaccessibility of β-carotene (the highest bioavailability ∼ 38%). By comparing the performance of the complex particles, the weakly charged polysaccharides were superior to the highly charged ones, while zein-curcumin covalent binding was superior to non-covalent binding in the above experiments. This study provides innovative perspectives on the use of novel Pickering emulsions to provide ideal protection and bioavailability of lipophilic nutraceuticals.

Composite formation of whey protein isolate and OSA starch for fabricating high internal phase emulsion: A comparative study at different pH and their application in biscuits

The composites formed by whey protein isolate (WPI) and octenyl succinate anhydride (OSA)-modified starch were characterized with a focus on the effect of pH, and their potential in fabricating high internal phase emulsions (HIPEs) as fat substitutes was evaluated. The particles obtained at pH 3.0, 6.0, 7.0, and 8.0 presented a nanosized distribution (122.04 ± 0.84 nm-163.24 ± 4.12 nm) while those prepared at pH 4.0 and 5.0 were remarkably larger. Results from the shielding agent reaction and Fourier transform infrared spectroscopy (FT-IR) showed that the interaction between WPI and OSA starch was mainly hydrophobic at pH 3.0-5.0, while there was a strong electrostatic repulsion at pH 6.0-8.0. A quartz crystal microbalance with dissipation (QCM-D) study showed that remarkably higher ΔD and lower Δf/n were observed at pH 3.0-5.0 after successive deposition of WPI and OSA starch, whereas slight changes were noted for those made at higher pH values. The WPI-OSA starch (W-O) composite-based HIPEs made at pH 3.0 and 6.0-8.0 were physically stable after long-term storage, thermal treatment, or centrifugation. Incorporation of HIPE into the biscuit formula yielded products with a desirable sensory quality.

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

BACKGROUND

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.

RESULTS

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.

CONCLUSION

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.

Zein/hyaluronic acid nanoparticle stabilized Pickering emulsion for astaxanthin encapsulation

Pickering emulsions have attracted considerable attention owing to the stability and functionality. In this study, zein/hyaluronic acid (ZH) nanoparticles were prepared and applied for stabilizing astaxanthin encapsulated Pickering emulsions. By non-covalent interaction between Zein and hyaluronic acid (HA), the conformation of zein changed and therefore improved the wettability of ZH nanoparticles. Unlike the spherical zein nanoparticles, ZH nanoparticles possessed a cross-linked structure with rough surface. Confocal laser scanning microscopy indicated that the nanoparticles accumulated at the oil-water interface. The Pickering emulsion stabilized by ZH nanoparticles exhibited high viscoelasticity and a solid-like behavior, as well as excellent stability during the storage. In vitro digestion results revealed that the presence of HA coating prevented the emulsion from pepsin hydrolysis and achieved efficient delivery of astaxanthin. This work confirmed that Pickering emulsion stabilized by ZH nanoparticles could be used as an effective deliver system for bioactive substances.

Edible polysaccharide-based oleogels and novel emulsion gels as fat analogues: A review

Polysaccharide-based oleogels and emulsion gels have become novel strategies to replace solid fats due to safe and plentiful raw material, healthier fatty acid composition, controllable viscoelasticity, and more varied nutrition/flavor embedding. Recently, various oleogelation techniques and novel emulsion gels have been reported further to enrich the potential of polysaccharides in oil structuring, in which a crucial step is to promote the formation of polysaccharide networks determining gel properties through different media. Meanwhile, polysaccharide-based oleogels and emulsion gels have good oil holding, nutrient/flavor embedding, and 3D food printability, and their applications as fat substitutes have been explored in foods. This paper comprehensively reviews the types, preparation methods, and mechanisms of various polysaccharide-based oleogels and emulsion gels; meanwhile, the food applications and new trends of polysaccharide-based gels are discussed. Moreover, some viewpoints about potential developments and application challenges of polysaccharide-based gels are mentioned. In the future, polysaccharide-based gels may be flexible materials for customized nutritional foods and molecular gastronomy. However, it is still a challenge to select the appropriate oleogels or emulsion gels to meet the requirements of the products. Once this issue is addressed, oleogels and emulsion gels are anticipated to be used widely.

Optimization and antifungal efficacy against brown rot fungi of combined Salvia rosmarinus and Cedrus atlantica essential oils encapsulated in Gum Arabic

The stability, sensitivity, and volatility of essential oils are some of their most serious limitations, and nanoencapsulation has been considered one of the most effective techniques for solving these problems. This research aimed to investigate the incorporation of Salvia rosmarinus Speen and Cedrus atlantica Manetti (MEO) essential oil mixture in Gum Arabic (GA) and to evaluate nanoencapsulation's ability to promote antifungal activity against two brown rot fungi responsible for wood decay Gloeophyllum trabeum and Poria placenta. The optimization of encapsulation efficiency was performed using response surface methodology (RSM) with two parameters: solid-to-solid (MEO/GA ratio) and solid-to-liquid (MEO/ethanol). The recovered powder characterization was followed by various techniques using a scanning electron microscope (SEM), X-ray diffractometry (XRD), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), and thermo-gravimetric analysis (TGA). The optimal nanoencapsulating conditions obtained from RSM were ratios of MEO/GA of 1:10 (w/w) and MEO/ethanol of 10% (v/v), which provided the greatest encapsulation efficiency (87%). The results of SEM, XRD, DLS, FTIR, and TGA showed that the encapsulation of MEO using GA modified particle form and molecular structure and increased thermal stability. An antifungal activity assay indicated that an effective concentration of MEO had an inhibitory effect on brown rot fungi. It had 50% of the maximal effect (EC50) value of 5.15 ± 0.88 µg/mL and 12.63 ± 0.65 µg/mL for G. trabeum and P. placenta, respectively. Therefore, this product has a great potential as a natural wood preservative for sustainable construction and green building.

High internal phase emulsion stabilized by sodium caseinate:quercetin complex as antioxidant emulsifier

High internal phase emulsion (HIPE) was produced and stabilized using a novel antioxidant emulsifier formed by the complexation between sodium caseinate (SC) and quercetin (Q). Colloidal complexes, produced via an alkaline process, showed great ability to reduce the interfacial tension between oil-water phases, promoting stabilization of the HIPEs even at low concentrations (1.5% w/v in the aqueous fraction). HIPEs at 0.80 volume fraction of dispersed phase presented remarkable viscosity due to the high-packing network of oil droplets surrounded by a thin liquid layer. Moreover, the emulsions showed a gel-like behavior and kinetic stability for 45-days at 25 °C. The approach of SC:Q complexes on HIPEs development is promising to reduce lipid oxidation, translated by the formation of hydroperoxides and malondialdehyde during storage, especially for the complex formed with the highest amount of the phenolic compound. In this study, the development of HIPEs with outstanding kinetic and oxidative stability is reported as a potential alternative for the development of healthier products with reduced saturated and trans-fat content.

Thermal Stability Improvement of Core Material via High Internal Phase Emulsion Gels

Biocompatible particle-stabilized emulsions have gained significant attention in the biomedical industry. In this study, we employed dynamic high-pressure microfluidization (HPM) to prepare a biocompatible particle emulsion, which effectively enhances the thermal stability of core materials without the addition of any chemical additives. The results demonstrate that the HPM-treated particle-stabilized emulsion forms an interface membrane with high expansion and viscoelastic properties, thus preventing core material agglomeration at elevated temperatures. Furthermore, the particle concentration used for constructing the emulsion gel network significantly impacts the overall strength and stability of the material while possessing the ability to inhibit oxidation of the thermosensitive core material. This investigation explores the influence of particle concentration on the stability of particle-stabilized emulsion gels, thereby providing valuable insights for the design, improvement, and practical applications of innovative clean label emulsions, particularly in the embedding and delivery of thermosensitive core materials.

Combination modes impact on the stability of β-carotene-loaded emulsion constructed by soy protein isolate, β-glucan and myricetin ternary complex

A β-carotene rich emulsion with improved physical and chemical stability was obtained in this study, using different types of protein-polysaccharide-polyphenol ternary complexes as novel emulsifiers. The ternary complexes were prepared by covalent or non-covalent binding of soy protein isolate (SPI), β-glucan (DG) and myricetin (MC), which were evidenced to be stable. It was indicated that the emulsion stabilized by covalent complex of SPI, DG and MC, exhibited higher zeta-potential and smaller particle size than those stabilized by non-covalent complex. Furthermore, the covalent complexes prepared from different addition sequences showed different efficiencies in stabilizing the emulsion, in which SPI-DG-MC and SPI-MC-DG-stabilized emulsions possess better stability, emulsifying activity and storage resistance under adverse environmental treatment, with CI values of 62.7% and 64.3% after 25 days, respectively. According to oxidative stability and rheology analysis of the emulsions, it was found that the SPI-MC-DG complex prepared at the ratio of 4:2:1 was more stable with relatively less lipid oxidation products and a tighter stacking structure, and the final LH value was 39.98 mmol/L and the MDA value was 6.34 mmol/L. These findings implied that the ternary complex has the potential to deliver fat-soluble active ingredient by means of emulsion, but which depends on the mode and sequence of the molecular interactions.

Soy protein isolate-citrus pectin-gallic acid ternary composite high internal phase Pickering emulsion for delivery of β-carotene: Physicochemical, structural and digestive properties

The structure properties, stability and β-carotene slow-release mechanism of soybean protein isolate-citrus pectin-gallic acid complex (SPI-CP-GA) stabilized high-internal phase Pickering emulsion (HIPPE) were investigated. The results showed that compared with the SPI-CP binary complex, the turbidity of the SPI-CP-GA ternary complex increased from 2.174 ± 0.001 to 3.027 ± 0.001, the surface wettability was increased, the infrared peaks was blue-shifted, changed from hydrophilic to hydrophobic, and the equilibrium interfacial tension of particles increased from 10.77 ± 0.02 mN/m to 13.46 ± 0.03 mN/m, the complex was more stable. When the GA was 2.0 mg/mL, the encapsulation efficiency of β-carotene was higher. With increased GA concentration and oil phase volume fraction (φ), the apparent viscosity and viscoelastic behavior of HIPPE performed well, forming a stable gel network structure. After 30 days of storage, there was no oil separation in the sample group with GA concentration of 2.0 mg/mL and φ = 0.7, and the stability was strong. After gastrointestinal digestion, the particle size of the HIPPE decreased from 13.51 ± 0.86 μm to 7.70 ± 0.68 μm, the free fatty acid (FFA) release rate was 22.03%, and the bioaccessibility of β-carotene was 6.67 ± 0.19%, and the sustained-release effect was obvious. These results indicated that the SPI-CP-GA ternary complex is a potential stabilizer for HIPPE, and providing theoretical guidance for the design of protein-polysaccharide-polyphenol stabilized HIPPE.

Research Progress of Quinoa Seeds (Chenopodium quinoa Wild.): Nutritional Components, Technological Treatment, and Application

Quinoa (Chenopodium quinoa Wild.) is a pseudo-grain that belongs to the amaranth family and has gained attention due to its exceptional nutritional properties. Compared to other grains, quinoa has a higher protein content, a more balanced amino acid profile, unique starch features, higher levels of dietary fiber, and a variety of phytochemicals. In this review, the physicochemical and functional properties of the major nutritional components in quinoa are summarized and compared to those of other grains. Our review also highlights the technological approaches used to improve the quality of quinoa-based products. The challenges of formulating quinoa into food products are addressed, and strategies for overcoming these challenges through technological innovation are discussed. This review also provides examples of common applications of quinoa seeds. Overall, the review underscores the potential benefits of incorporating quinoa into the diet and the importance of developing innovative approaches to enhance the nutritional quality and functionality of quinoa-based products.

Pickering emulsions stabilized with a spirulina protein-chitosan complex for astaxanthin delivery

Astaxanthin (AXT) is a lipid-soluble carotenoid with good anti-oxidation, hepatic steatosis reduction, anti-inflammation, and intestinal microbiota regulation ability, whose poor stability and pH vulnerability limit its bioavailability. Spirulina protein (SP) derived from spirulina has good emulsifying ability with potential application in nutraceuticals, medicines, and cosmetics. In this study, Pickering emulsions were prepared using a SP-chitosan (CS) complex as an emulsifier. The particle size, zeta potential, and three-phase contact angle of the SP-CS complex with different SP to CS ratios were investigated. A mass ratio of 1 : 2.5 SP-CS complex showed a good emulsifying ability in preparing Pickering emulsion. A higher storage modulus and viscoelasticity were observed with higher SP-CS complex concentrations and oil fractions. The SP-CS Pickering emulsion significantly improved the stability of AXT in different environments. The lipid release rate and AXT bioavailability after digestion of 3 wt% SP-CS complex-stabilized Pickering emulsion reached 70.54 ± 1.59% and 36.60 ± 3.44%, respectively. The results indicated that the SP-CS complex could act as a Pickering emulsion stabilizer and had the potential to deliver protective hydrophobic AXT.

Chitosan-based Pickering emulsion: A comprehensive review on their stabilizers, bioavailability, applications and regulations

BACKGROUND

Chitosan-based particles are one of the most promising Pickering emulsions stabilizers due to its cationic properties, cost-effective, biocompatibility, biodegradability. However, there are currently no comprehensive reviews analyzing the role of chitosan to develop Pickering emulsions, and the bioavailability and multiple uses of these emulsions.

SCOPE AND APPROACH

This review firstly summarizes the types, preparation and functional properties of chitosan-based Pickering emulsion stabilizers, followed by in vivo and in vitro bioavailability, main regulations, and future application and trends.

KEY FINDINGS AND CONCLUSIONS

Stabilizers used in chitosan-based Pickering emulsions include 6 categories: chitosan self-aggregating particles and 5 types of composites (chitosan-protein, chitosan-polysaccharide, chitosan-fatty acid, chitosan-polyphenol, and chitosan-inorganic). Chitosan-based Pickering emulsions improved the bioavailability of different compounds compared to traditional emulsions. Current applications include hydrogels, microcapsules, food ingredients, bio-based films, cosmeceuticals, porous scaffolds, environmental protection agents, and interfacial catalysis systems. However, due to current limitations, more research and development are needed to be extensively explored to meet consumer demand, industrial manufacturing, and regulatory requirements. Thus, optimization of stabilizers, bioavailability studies, 3D4D printing, fat substitutes, and double emulsions are the main potential development trends or research gaps in the field which would contribute to increase adoption of these promising emulsions at industrial level.

Storage stability and interfacial rheology analysis of high-internal-phase emulsions stabilized by soy hull polysaccharide

High-internal-phase emulsions (HIPEs) are more promising candidates for development to replace hydrogenated fatty acids, yet the current HIPEs are limited for stabilizers require very high surface activity. This study showed that HIPEs could be prepared with 1.0-2.2 wt% soy hull polysaccharide (SHP) and the related stability indicators of HIPEs were analyzed. The plasticity, stress resistance, stability of the HIPEs were positively correlated with the SHP content. The interfacial adsorption experiments showed that SHP had the good ability to reduce interfacial tension and formed an elastic interfacial layer. Dilatational rheological results showed the interfacial film reached jammed saturation at about 1.8 wt% of SHP concentration, and the zeta potential results were consistent. This study demonstrated that SHP was an efficient stabilizer of HIPEs, which was useful both for the preparation of HIPEs and for developing uses for SHP.

Recent Trends in Improving the Oxidative Stability of Oil-Based Food Products by Inhibiting Oxidation at the Interfacial Region

In recent years, new approaches have been developed to limit the oxidation of oil-based food products by inhibiting peroxidation at the interfacial region. This review article describes and discusses these particular approaches. In bulk oils, modifying the polarity of antioxidants by chemical methods (e.g., esterifying antioxidants with fatty alcohol or fatty acids) and combining antioxidants with surfactants with low hydrophilic–lipophilic balance value (e.g., lecithin and polyglycerol polyricinoleate) can be effective strategies for inhibiting peroxidation. Compared to monolayer emulsions, a thick interfacial layer in multilayer emulsions and Pickering emulsions can act as a physical barrier. Meanwhile, high viscosity of the water phase in emulsion gels tends to hinder the diffusion of pro-oxidants into the interfacial region. Furthermore, applying surface-active substances with antioxidant properties (such as proteins, peptides, polysaccharides, and complexes of protein-polysaccharide, protein-polyphenol, protein-saponin, and protein-polysaccharide-polyphenol) that adsorb at the interfacial area is another novel method for enhancing oil-in-water emulsion oxidative stability. Furthermore, localizing antioxidants at the interfacial region through lipophilization of hydrophilic antioxidants, conjugating antioxidants with surfactants, or entrapping antioxidants into Pickering particles can be considered new strategies for reducing the emulsion peroxidation.

The stability mechanism of Pickering emulsions fabricated by multi-functional amylose-based nanoparticles in a delivery system

In this work, multi-functional amylose-based nanoparticles (OSA-AM-9/VE NPs) were fabricated via simple and sustainable esterification, encapsulation, and co-precipitation processes of amylose (AM), octenyl succinic anhydride (OSA), and vitamin E (VE). These nanoparticles showed a nanometer size of 243.2 nm and a regular spherical shape which contributed to their excellent physical and oxidative stability and the outstanding pH-responsive performance of a Pickering emulsion. Compared with OSA-AM-9 and OSA-AM-9 NPs, the Pickering emulsion stabilized by OSA-AM-9/VE NPs presented higher stability and stronger antioxidant capacity. The delivery system of the OSA-AM-9/VE NP stabilized emulsion could protect fish oil from gastric juice and then was digested to facilitate the absorption of ω-3 polyunsaturated fatty acids in the intestine due to the pH-induced protonation/deprotonation of carboxyl groups in OSA-AM-9/VE NPs.

Stability of protein particle based Pickering emulsions in various environments: review on strategies to inhibit coalescence and oxidation

The emerging research interests in fabrication of protein particles as soft-particle emulsifiers show the prospective potential of using protein particles in novel poly-phase dispersing food systems. This review first provides a comprehensive summary and analysis on the dominant role of key physicochemical properties of protein particles including wettability, morphology, surface charge and protein concentration on their emulsifying abilities to construct Pickering emulsions. It was found that the constructed emulsions showed high sensitivity to changes in pH, ionic strength and temperature (thermal and freeze-thaw treatment). Moreover, oxidation remains as a challenge for protein particle based Pickering emulsions during prolonged storage, reducing their acceptance in food products. Current strategies for improving the stability of these emulsions to variable aqueous conditions and variable temperatures, and restricting oxidation event are summarized. In summary, an "ideal" protein particle-based Pickering emulsion system is proposed, encompassing aspects of interfacial property, emulsion network and texture, and antioxidant enrichment, thus promoting industrial translation into novel food and nutraceutical products.

Biopolymer-based pickering high internal phase emulsions: Intrinsic composition of matrix components, fundamental characteristics and perspective

Pickering HIPEs have received tremendous attention in recent years due to their superior stability and unique solid-like and rheological properties. Biopolymer-based colloidal particles derived from proteins, polysaccharides and polyphenols have been demonstrated to be safety stabilizers for the construction of Pickering HIPEs, which can meet the demands of consumers for "all-natural" products and provide "clean-label" foods. Furthermore, the functionality of these biopolymers can be further extended by forming composite, conjugated and multi-component colloidal particles, which can be used to modulate the properties of the interfacial layer, thereby adjusting the performance and stability of Pickering HIPEs. In this review, the factors affecting the interfacial behavior and adsorption characteristics of colloidal particles are discussed. The intrinsic composition of matrix components and fundamental characteristics of Pickering HIPEs are emphatically summarized, and the emerging applications of Pickering HIPEs in the food industry are reviewed. Inspired by these findings, future perspectives concerning this field are also put forward, including (1) the exploration of the interactions between biopolymers used to produce Pickering HIPEs and target food ingredients, and the influence of the added biopolymers on the flavor and mouthfeel of the products, (2) the investigation of the digestion properties of Pickering HIPEs under oral administration, and (3) the fabrication of stimulus-responsive or transparent Pickering HIPEs. This review will give a reference for exploring more natural biopolymers for Pickering HIPEs application development.

Pickering emulsion stabilized by modified pea protein-chitosan composite particles as a new fat substitute improves the quality of pork sausages

Pickering emulsion is a potential substitute for animal fat due to high stability and solid-like properties. Therefore, the effect of replacing 25%-100% pork backfat with Pickering emulsion (75% corn oil volume fraction) stabilized by modified pea protein-chitosan composite particles on the quality of sausages was studied. All meat pastes exhibited a strong gel-like rheological character (G' > G"). The incorporation of Pickering emulsion in sausages enhanced the textural properties (hardness, springiness, chewiness, cohesiveness and resilience) and the uniformity and compactness of micromorphology, as well as suppressed the cooking loss and TBARS content. In particular, the sausages with a backfat substitution ratio of 100%, showing a similar overall sensory acceptability to the backfat sausage, revealed the best rheological properties, texture properties and micromorphology and the lowest cooking loss and fat oxidation (P < 0.05). The results showed that Pickering emulsion stabilized by modified pea protein-chitosan composite particles is a potential fat substitute for meat products with the desirable characteristics.

An "intelligent -responsive" bactericidal system based on OSA-starch Pickering emulsion

Pickering emulsion based on OSA-starch was developed in this study as an intelligent delivery system for the application of thymol against foodborne pathogens. Morphology and microstructure characterization showed that the Pickering emulsion was an O/W type emulsion and stayed stable at starch concentration of 200 mg/mL and oil fraction at 30 % with particle size of 10 μm and absolute Zeta potential of -12.5 mV. Low field nuclear magnetic resonance and rheology experiments indicated that a denser network structure was formed in this stable Pickering emulsion. Besides, the Pickering emulsion could endure long-time storage, low pH (3,5) and additional NaCl (50, 100, 200, 400 mM) and it showed enhanced bactericidal effects against Escherichia coli, Staphylococcus aureus (thymol =1.48 μmol/L) and Aspergillus flavus (thymol = 0.624 μmol/L) by inducing ROS eruption, membrane lipid peroxidation and cell shrink. Moreover, the bactericidal assay demonstrated that thymol could be intelligently released and a considerable 75 % timely bactericidal effect was detected after 9 days' intermittently exposing to E. coli, S. aureus and A. flavus in vitro, by comparison thymol alone showed only 20 % bactericidal effect due to its volatility. The results are of great importance to offer an intelligent delivery system of bio-actives defending foodborne pathogens.

Formulation and stabilization of high internal phase emulsions: Stabilization by cellulose nanocrystals and gelatinized soluble starch

In this work, high internal phase emulsions (HIPEs) stabilized by naturally derived cellulose nanocrystals (CNC) and gelatinized soluble starch (GSS) were fabricated to stabilize oregano essential oil (OEO) in the absence of surfactant. The physical properties, microstructures, rheological properties, and storage stability of HIPEs were investigated by adjusting CNC contents (0.2, 0.3, 0.4 and 0.5 wt%) and starch concentration (4.5 wt%). The results revealed that CNC-GSS stabilized HIPEs exhibited good storage stability within one month and the smallest droplets size at a CNC concentration of 0.4 wt%. The emulsion volume fractions of 0.2, 0.3, 0.4 and 0.5 wt% CNC-GSS stabilized HIPEs after centrifugation reached 77.58, 82.05, 94.22, and 91.41 %, respectively. The effect of native CNC and GSS were analyzed to understand the stability mechanisms of HIPEs. The results revealed that CNC could be used as an effective stabilizer and emulsifier to fabricate the stable and gel-like HIPEs with tunable microstructure and rheological properties.

Protein-Based High Internal Phase Pickering Emulsions: A Review of Their Fabrication, Composition and Future Perspectives in the Food Industry

Protein-based high internal phase Pickering emulsions (HIPEs) are emulsions using protein particles as a stabilizer in which the volume fraction of the dispersed phase exceeds 74%. Stabilizers are irreversibly adsorbed at the interface of the oil phase and water phase to maintain the droplet structure. Protein-based HIPEs have shown great potential for a variety of fields, including foods, due to the wide range of materials, simple preparation, and good biocompatibility. This review introduces the preparation routes of protein-based HIPEs and summarizes and classifies the preparation methods of protein stabilizers according to their formation mechanism. Further outlined are the types and properties of protein stabilizers used in the present studies, the composition of the oil phase, the encapsulating substances, and the properties of the constituted protein-based HIPEs. Finally, future development of protein-based HIPEs was explored, such as the development of protein-based stabilizers, the improvement of emulsification technology, and the quality control of stabilizers and protein-based HIPEs.

Naturally occurring protein/polysaccharide hybrid nanoparticles for stabilizing oil-in-water Pickering emulsions and the formation mechanism

In this study, we reported for the first time that the natural protein/polysaccharide hybrid nanoparticles (PPH NPs) with a diameter of ∼ 129 nm, originating from Lactobacillus plantarum fermented cheese whey, could act as green-based NPs for stabilizing Pickering emulsions. Characterizations of PPH NPs showed that the negative-charged PPH NPs were composed of ∼ 37.7% total protein and ∼ 7.3% polysaccharide bearing several functional groups, such as -OH, -NH, -COOH, etc.; and displayed excellent emulsifying capacity in preparing oil-in-water Pickering emulsions. The obtained emulsions exhibited gel-like behavior with excellent stability against the variation of pH, ionic strength, and temperature. Confocal observations showed that PPH NPs effectively adsorbed and anchored at the oil-water interface, thus creating the steric hindrance to inhibit droplet coalescence. This research is of importance in developing novel and biocompatible Pickering stabilizers with outstanding performance, as well as enable a versatile design of stable Pickering emulsions suitable for food industries.

Fabrication and stabilization mechanisms of Pickering emulsions based on gliadin/arabinoxylan complexes

In the present work, the Pickering emulsions with enhanced oxidation stability were fabricated using gliadin (G)/arabinoxylan nanoparticles (GANPs). The influence of different G/AX ratios on the properties of GANPs and corresponding physicochemical characteristics of Pickering emulsions were investigated. Results indicated that the droplet size and ζ-potential of Pickering emulsions declined with the decrease of G/AX ratios. Pickering emulsion with the smallest G/AX ratio (1:4) exhibited excellent oxidative and coalescence stability due to the formation of viscoelastic gel network, which was supported by confocal laser scanning microscopy (CLSM) images. Furthermore, the increase of salt ions in a lower concentration (0-0.2 M) was conducive to the flocculation of the droplets, while further increasing the NaCl concentration impaired the emulsion stability. Such elements revealed that G/AX complex is a promising stabilizer of Pickering emulsions with prominent antioxidant activity, which have favorable potential applications in protecting the functional properties of polyunsaturated fatty acids (PUFAs).