Phytoparticles for the stabilization of Pickering emulsions in the formulation of novel food colloidal dispersions

Quercetin encapsulation and release using rapid CO2-responsive rosin-based surfactants in Pickering emulsions

Emulsion-based delivery systems are extensively employed for encapsulating functional active ingredients, protecting them from degradation, and enhancing bioavailability and release efficiency. Here, a CO2-responsive surfactant synthesized from rosin displays rapid responsiveness to CO2 at room temperature, transitioning reversibly switches between active and inactive states multiple times. The dual tertiary amines on the rosin rigid structure contributes to its CO2 sensitivity. When in its active cationic form, in conjunction with silica nanoparticles, it exhibits desired Pickering emulsification performance across various oil phases. In the Pickering emulsion loaded with quercetin, the encapsulation efficiency and loading efficiency reached 80.50% and 0.69%, respectively, with stability lasting at least 30 days. The system provides robust protection for quercetin against external factors, such as UV and heat, revealing sustained release effects. This study investigated the potential of using rosin-based CO2-responsive surfactants alongside nanoparticles to design stable Pickering emulsion systems for active substance encapsulation and sustained release.

A crystal engineering approach for rational design of curcumin crystals for Pickering stabilization of emulsions

Emulsions stabilized via Pickering particles are becoming more and more popular due to their high stability and biocompatibility. Hence, developing new ways to produce effective Pickering particles is essential. In this work, we present a crystal engineering approach to obtain precise control over particle properties such as size, shape, and crystal structure, which may affect wettability and surface chemistry. A highly reproducible synthesis method via anti-solvent crystallization was developed to produce sub-micron sized curcumin crystals of the metastable form III, to be used as Pickering stabilizers. The produced crystals presented a clear hydrophobic nature, which was demonstrated by their preference to stabilize water-in-oil (W/O) emulsions. A comprehensive experimental and computational characterization of curcumin crystals was performed to rationalize their hydrophobic nature. Analytical techniques including Raman spectroscopy, powder X-ray diffraction (PXRD), Solid-State Nuclear Magnetic Resonance (SSNMR), scanning electron microscopy (SEM), Differential Scanning Calorimetry (DSC), confocal fluorescence microscopy and contact angle measurements were used to characterize curcumin particles in terms of shape, size and interfacial activity. The attachment energy model was instead applied to study relevant surface features of curcumin crystals, such as topology and facet-specific surface chemistry. This work contributes to the understanding of the effect of crystal properties on the mechanism of Pickering stabilization, and paves the way for the formulation of innovative products in fields ranging from pharmaceuticals to food science.

Emerging encapsulation strategies for vitamin A fortification in food sector: an overview

Micro- and nano-encapsulation techniques, such as microfluidization, spray drying, and centrifugal extrusion, have been widely utilized in various industries, including pharmaceuticals, food, cosmetics, and agriculture, to improve the stability, shelf life, and bioavailability of active ingredients, such as vitamin A. Emulsion-based delivery platforms offer feasible and appropriate alternatives for safeguarding, encapsulating, and transporting bioactive compounds. Therefore, there is a need to enrich our basic diet to prevent vitamin A deficiency within a population. This review focused on addressing vitamin A shortages, encapsulation techniques for improving the delivery of vital vitamins A and their food applications. Additionally, more studies are required to guarantee the security of nano-delivery strategies, as they proliferate in the food and beverage sector.

Graphical Abstract

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.

Novel nutraceutical delivery system utilizing a bigel formulated with sesame oil, kokum butter, and pectin

This study delineates biobased foods. Curcumin (CRU) delivery modules were studied using pectin gel, Sesame oil (SO), and Kokum butter (KB) oleogel (OG). SB1, the control, has 10% OG. The pectin gel between 10 and 50% oleogel were emulsified by 2.5% tween 80. Surface, physical, chemical, and physiochemical properties of prepared bigels were examined. Microscopic studies show biphasic feature. With OG content, FTIR shows hydrogen bonding increasing and decreasing. XRD confirmed gel amorphousness. Stress relaxation indicated 10% control bigel had considerably less strength. Bigel impedance factors increased considerably with OG content, according to impedance profiles. The moisture study found that replacing hydro phase with OG phase in formulations reduced moisture content from 10 to 50%. Less CRU released from 20 to 50% bigel matrices than 10% during in vitro studies. Acidic pH hindered polymer relaxation, altering release behaviour. Overall, the bigels were studied and shown to regulate oral CRU administration.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-024-01559-3.

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

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

Wide pH, Adaptable High Internal Phase Pickering Emulsion Stabilized by a Crude Polysaccharide from Thesium chinense Turcz

The ultrasound-assisted extraction conditions of Thesium chinense Turcz. crude polysaccharide (TTP) were optimized, and a TTP sample with a yield of 11.9% was obtained. TTP demonstrated the ability to stabilize high-internal-phase oil-in-water emulsions with an oil phase volume reaching up to 80%. Additionally, the emulsions stabilized by TTP were examined across different pH levels, ionic strengths, and temperatures. The results indicated that the emulsions stabilized by TTP exhibited stability over a wide pH range of 1-11. The emulsion remained stable under ionic strengths of 0-500 mM and temperatures of 4-55 °C. The microstructure of the emulsions was observed using confocal laser scanning microscopy, and the stabilization mechanism of the emulsion was hypothesized. Soluble polysaccharides formed a network structure in the continuous phase, and the insoluble polysaccharides dispersed in the continuous phase, acting as a bridge structure, which worked together to prevent oil droplet aggregation. This research was significant for developing a new food-grade emulsifier with a wide pH range of applicability.

A comprehensive review of processing, functionality, and potential applications of lentil proteins in the food industry

There is a pressing need for sustainable sources of proteins to address the escalating food demands of the expanding global population, without damaging the environment. Lentil proteins offer a more sustainable alternative to animal-derived proteins (such as those from meat, fish, eggs, or milk). They are abundant, affordable, protein rich, nutritious, and functional, which makes them highly appealing as ingredients in the food, personal care, cosmetics, pharmaceutical and other industries. In this article, the chemical composition, nutritional value, and techno-functional properties of lentil proteins are reviewed. Then, recent advances on the extraction, purification, and modification of lentil proteins are summarized. Hurdles to the widespread utilization of lentil proteins in the food industry are highlighted, along with potential strategies to surmount these challenges. Finally, the potential applications of lentil protein in foods and beverages are discussed. The intention of this article is to offer an up-to-date overview of research on lentil proteins, addressing gaps in the knowledge related to their potential nutritional benefits and functional advantages for application within the food industry. This includes exploring the utilization of lentil proteins as nanocarriers for bioactive compounds, emulsifiers, edible inks for 3D food printing, meat analogs, and components of biodegradable packaging.

Preparation and Properties of Walnut Protein Isolate-Whey Protein Isolate Nanoparticles Stabilizing High Internal Phase Pickering Emulsions

To enhance the functional properties of walnut protein isolate (WalPI), hydrophilic whey protein isolate (WPI) was selected to formulate WalPI-WPI nanoparticles (nano-WalPI-WPI) via a pH cycling technique. These nano-WalPI-WPI particles were subsequently employed to stabilize high internal phase Pickering emulsions (HIPEs). By adjusting the mass ratio of WalPI to WPI from 9:1 to 1:1, the resultant nano-WalPI-WPI exhibited sizes ranging from 70.98 to 124.57 nm, with a polydispersity index of less than 0.326. When the mass ratio of WalPI to WPI was 7:3, there were significant enhancements in various functional properties: the solubility, denaturation peak temperature, emulsifying activity index, and emulsifying stability index increased by 6.09 times, 0.54 °C, 318.94 m2/g, and 552.95 min, respectively, and the surface hydrophobicity decreased by 59.23%, compared with that of WalPI nanoparticles (nano-WalPI), with the best overall performance. The nano-WalPI-WPI were held together by hydrophobic interactions, hydrogen bonding, and electrostatic forces, which preserved the intact primary structure and improved resistance to structural changes during the neutralization process. The HIPEs stabilized by nano-WalPI-WPI exhibited an average droplet size of less than 30 μm, with droplets uniformly dispersed and maintaining an intact spherical structure, demonstrating superior storage stability. All HIPEs exhibited pseudoplastic behavior with good thixotropic properties. This study provides a theoretical foundation for enhancing the functional properties of hydrophobic proteins and introduces a novel approach for constructing emulsion systems stabilized by composite proteins as emulsifiers.

Pickering emulsions stabilized by prolamin-based proteins as innovative carriers of bioactive compounds

Pickering emulsions (PEs) can be used as efficient carriers for encapsulation and controlled release of different bioactive compounds. Recent research has revealed the potential of prolamins in development of nanoparticle- and emulsion-based carriers which can improve the stability and bioavailability of bioactive compounds. Prolamin-based particles have been effectively used as stabilizers of various PEs including single PEs, high internal phase PEs, multiple PEs, novel triphasic PEs, and PE gels due to their tunable self-assembly behaviors. Prolamin particles can be fabricated via different techniques including anti-solvent precipitation, dissolution followed by pH adjustment, heating, and ion induced aggregation. Particles fabricated from prolamins alone or in combination with other hydrocolloids or polyphenols have also been used for stabilization of different PEs which were shown to be effective carriers for food bioactives, providing improved stability and functionality. This article covers the recent advances in various PEs stabilized by prolamin particles as innovative carriers for bioactive ingredients. Strategies applied for fabrication of prolamin particles and prolamin-based carriers are discussed. Emerging techno-functional applications of prolamin-based PEs and possible challenges are also highlighted.

Multiple Pickering emulsions stabilized by food-grade particles as innovative delivery systems for bioactive compounds

The most common carrier for encapsulation of bioactive components is still simple emulsion. Recently, bio-based novel emulsion systems such as multiple emulsions (MEs) and Pickering emulsions (PEs) have been introduced as innovative colloidal delivery systems for encapsulation and controlled release of bioactive compounds. Multiple PEs (MPEs), which carries both benefit of MEs and PEs could be fabricated by relatively scalable and simple operations. In comparison with costly synthetic surfactants and inorganic particles which are widely used for stabilization of both MEs and PEs, MPEs stabilized by food-grade particles, while having health-promoting aspects, are able to host the "clean label" and "green label" attributes. Nevertheless, in achieving qualified techno-functional attributes and encapsulation properties, the selection of suitable materials is a crucial step in the construction of such complex systems. Current review takes a cue from both MEs and PEs emulsification techniques to grant a robust background for designing various MPEs. Herein, various fabrication methods of MEs and PEs are described comprehensively in a physical viewpoint in order to find key conception of successful formulation of MPEs. This review also highlights the link between the underlying aspects and exemplified specimens of evidence which grant insights into the rational design of MPEs through food-based ingredients to introduces MPEs as novel colloidal/functional materials. Their utilization for encapsulation of bioactive compounds is discussed as well. In the last part, instability behavior of MPEs under various conditions will be discussed. In sum, this review aims to gain researchers who work with food-based components, basics of innovative design of MPEs.

Recent progress on Pickering emulsion stabilized essential oil added biopolymer-based film for food packaging applications: A review

Nowadays food safety and protection are a growing concern for food producers and food industry. The stability of food-grade materials is key in food processing and shelf life. Pickering emulsions (PEs) have gained significant attention in food regimes owing to their stability enhancement of food specimens. PE can be developed by high and low-energy methods. The use of PE in the food sector is completely safe as it uses solid biodegradable particles to stabilize the oil in water and it also acts as an excellent carrier of essential oils (EOs). EOs are useful functional ingredients, the inclusion of EOs in the packaging film or coating formulation significantly helps in the improvement of the shelf life of the packed food item. The highly volatile nature, limited solubility and ease of oxidation in light of EOs restricts their direct use in packaging. In this context, the use of PEs of EOs is suitable to overcome most of the challenges, Therefore, recently there have been many papers published on PEs of EOs including active packaging film and coatings and the obtained results are promising. The current review amalgamates these studies to inform about the chemistry of PEs followed by types of stabilizers, factors affecting the stability and different high and low-energy manufacturing methods. Finally, the review summarizes the recent advancement in PEs-added packaging film and their application in the enhancement of shelf life of food.

Plant gums in Pickering emulsions: A review of sources, properties, applications, and future perspectives

Recently, there has been an increasing research interest in the development of Pickering emulsions stabilized with naturally derived biopolymeric particles. In this regard, plant gums, obtained as plant exudates or from plant seeds, are considered promising candidates for the development of non-toxic, biocompatible, biodegradable and eco-friendly Pickering stabilizers. The main objective of this review article is to provide a detailed overview and assess the latest advances in the formulation of Pickering emulsions stabilized with plant gum-based particles. The plant gum sources, types and properties are outlined. Besides, the current methodologies used in the production of plant gum particles formed solely of plant gums, or through interactions of plant gums with proteins or other polysaccharides are highlighted and discussed. Furthermore, the work compiles and assesses the innovative applications of plant gum-based Pickering emulsions in areas such as encapsulation and delivery of drugs and active agents, along with the utilization of these Pickering emulsions in the development of active packaging films, plant-based products and low-fat food formulations. The last part of the review presents potential future research trends that are expected to motivate and direct research to areas related to other novel food applications, as well as tissue engineering and environmental applications.

Influence of varying oil phase volume fractions on the characteristics of flaxseed-derived diglyceride-based Pickering emulsions stabilized by modified soy protein isolate

This research aimed to create Pickering emulsions using modified soy protein isolate (SPI) as a stabilizer and flaxseed-derived diglyceride (DAG) as an oil phase. The SPI was modified through a process involving both heating and ultrasound treatment. The result indicated that the droplet size of emulsions increased with the increase in oil content (p < 0.05). For instance, the largest droplet size (23 µm) was observed at an oil-to-SPI dispersion ratio of 4:1 ratio (φ = 80), whereas the smallest droplet size (6.39 µm) was noticed at the 1:4 ratio. During the 7-day storage period, the emulsions with a 4:1 ratio (φ = 80) showed the lowest droplet size increase (from 23 µm to 25.58 µm). In contrast, the emulsions with a 1:1 ratio displayed the highest increase (from 19.39 µm to 74.29 µm). Creaming index results revealed that emulsions with a 4:1 ratio (φ = 80) showed no signs of creaming and phase separation than all other treatments (p < 0.05). Backscattering fluctuations (ΔBS) and turbiscan stability index (TSI) showed that emulsions with 4:1, 2:1, and 1:1 oil-to-SPI dispersion ratios had consistent ΔBS curves with higher and TSI curves with lower values. Optical microscopy, confocal laser scanning, and cryo-scanning electron microscopy revealed that emulsions with oil-to-SPI dispersion ratios of 4:1 and 2:1 had well-organized structures with no visible coalescence. Macromorphological and microrheological investigations demonstrated that emulsions with 80% oil content had the highest viscosity, both moduli, elasticity index, macroscopic viscosity index, and the lowest fluidity index and solid-liquid balance values. Moreover, these emulsions were more resistant to centrifugation and storage environments. In conclusion, the study determined that flaxseed-derived DAG-based high internal phase Pickering emulsions (φ = 80) had superior stability, improved viscoelasticity, and better rheological properties.

Comparative study on the in vitro digestion of different lipids in starch-based Pickering emulsions

Starch-based Pickering stabilizer has attracted more attentions due to its health-friendly attribute. Lipid digestion in Pickering emulsion is the key to its delivery ability for active substances. Herein, in vitro oral-gastric-intestinal digestions of Pickering emulsions stabilized by starch particles with different oil phases (e.g., coconut, corn, olive, and sunflower oils) were investigated. The highest rate of lipid digestion was coconut oil (25.71 %), followed by olive (12.64 %), corn (11.16 %), and sunflower (8.99 %) oils. The lipid digestibility was influenced by saturation of fatty acids: coconut (91.41 %)>olive (16.58 %)>corn (14.63 %)>sunflower (10.85 %) oils. The increase of starch concentration (0.5 % - 4.0 %, w/w) had positive effects, while the increase of oil fraction (25 % - 70 %, v/v) had negative impacts on free fatty acid release due to the formation of different initial droplet sizes. The microstructures observed using confocal laser scanning microscope indicated that starch-based Pickering emulsion possessed super stability against oral and gastric digestions, which made it a superior delivery system for lipophilic active substances under severe gastric environment. These results may promote the design of functional food emulsions stabilized by starch particles which can regulate digestion of triglycerides.

Preparation of Lignin-Based Nanoparticles with Excellent Acidic Tolerance as Stabilizer for Pickering Emulsion

In this work, novel lignin-based nanoparticles (LβNPs) with high acidic tolerance were successfully prepared via electrostatic interaction between β-alanine and lignin nanoparticles. The effects of the mass ratio of lignin nanoparticles to β-alanine and pH value on the morphology and particle sizes of LβNPs were investigated with the aim of obtaining the ideal nanoparticles. The optimized LβNPs were spherical in shape with an average particle size of 41.1 ± 14.5 nm and exhibited outstanding structure stability under high acidic conditions (pH < 4). Subsequently, Pickering emulsions stabilized by LβNPs were prepared using olive oil as the oil phase. Additionally, the effects of pH value, droplet size, morphology, and storage stability on Pickering emulsions were also analyzed. The emulsions displayed excellent stability, and were stable against strongly acidic conditions (pH < 4) after 30 days of storage. The study presented a promising approach to preparing lignin-based nanoparticles with high acidic tolerance (an ideal type of stabilizer to prepare emulsions), and exhibited extremely high potential application values in the fields of drug delivery, food additives, and oily wastewater treatment.

Strategies for improving loading of emulsion-based functional oil powder

Functional oil is type of oil that is beneficial to human health and has nutritional value, however, functional oils are rich in bioactive substances such as polyunsaturated fatty acids which are sensitive to environmental factors and are susceptible to oxidation or decomposition. Construction of emulsion-based oil powder is a promising approach for improving the stability and solubility of functional oils. However, the low effective loading of oil in powder is the main challenge limiting encapsulation technology. This manuscript focuses on reviewing the current research progress of emulsion-based functional oil powder construction and systematically summarizes the processing characteristics of emulsion-based oil powder with high payload and summarizing the strategies to enhance the payload of powder in term of emulsification and drying, respectively. The impact of emulsion formation on oil powder production is discussed from different characteristics of emulsions, including emulsion composition, emulsification methods and emulsion types. In addition, the current status of improving material loading performance by various modifications to the drying technology is discussed, including the addition of drying processing additives, changes in drying parameters and the effect of innovative technological means.

Nutritional Value and Structure Characterization of Protein Components of Corylus mandshurica Maxim

Alternative protein sources for the human diet may help overcome the growing food pressure. Plants with abundant resources and high protein content are potential sources. In this article, graded proteins and isolated proteins from Corylus mandshurica Maxim kernels were extracted by the Osborne procedure and the alkali-solution and acid-isolation method, respectively, and the contents of the five proteins, and the differences in nutritional value and structural properties of the main proteins, were investigated. Amino acid analysis revealed that the total essential amino acids in the five proteins ranged from 249.58 to 324.52 mg/g. The essential amino acid profiles in the proteins were similar to those of FAO/WHO except for the alcohol-soluble protein. The essential amino acid indices ranged from 58.59 to 72.19 and the biological values ranged from 52.16 to 66.99, and the highest nutritional indices were found for the isolate and water-soluble protein, which were 41.68 and 55.78, respectively. The molecular weight pattern distribution of the protein isolates of the Corylus mandshurica Maxim kernel was more similar to that of the water-soluble proteins by SDS-PAGE. The β-sheet and α-helix were the main secondary structures in the two protein fractions. The fluorescence spectra showed that the maximum fluorescence intensity of the two proteins and their λmax were also somewhat different. From the perspective of microscopic morphology, the two proteins are mainly compact and irregular lamellar structures, but the surface of the water-soluble protein is more flat and regular. Both proteins have good solubility, and the water-soluble protein has higher solubility. In general, the protein isolates of the Corylus mandshurica Maxim kernel and the water-soluble protein showed their potential as plant protein resources.

Sustainable Isolation of Bioactive Compounds and Proteins from Plant-Based Food (and Byproducts)

Plant-based food produces significantly less greenhouse gases, and due to its wealth of bioactive components and/or plant-based protein, it becomes an alternative in a sustainable food system. However, the processing and production of products from plant sources creates byproducts, which can be waste or a source of useful substances that can be reused. The waste produced during the production and processing of food is essentially nutrient- and energy-rich, and it is recognized as an excellent source of secondary raw materials that could be repurposed in the process of manufacturing and preparing food, or as feed for livestock. This review offers an overview of the sources and techniques of the sustainable isolation of bioactive substances and proteins from various sources that might represent waste in the preparation or production of food of plant origin. The aim is to uncover novel approaches to use waste and byproducts from the process of making food to provide this waste food an additional benefit, not forgetting the expectations of the end user, the consumer. For the successful isolation of bioactive ingredients and proteins from food of plant origin, it is crucial to develop more eco-friendly and efficient extraction techniques with a low CO2 footprint while considering the economic aspects.

Banana biomass waste: A prospective nanocellulose source and its potential application in food industry - A review

Bananas are among the most produced and consumed fruit all over the world. However, a vast amount of banana biomass is generated because banana trees bear fruit only once in their lifetime. This massive amount of biomass waste is either disposed of in agricultural fields, combusted, or dumped at plantations, thus posing environmental concerns. Nanocellulose (NC) extraction from this source can be one approach to improve the value of banana biomass. Owing to its superb properties, such as high surface area and aspect ratio, good tensile strength, and high thermal stability, this has facilitated nanocellulose application in the food industry either as a functional ingredient, an additive or in food packaging. In this review, two different applications of banana biomass NC were identified: (i) food packaging and (ii) food stabilizers. Relevant publications were reviewed, focusing on the nanocellulose extraction from several banana biomass applications as food additives, as well as on the safety and regulatory aspects. Ultimately, further research is required to prompt a perspicuous conclusion about banana biomass NC safety, its potential hazards in food applications, as well as its validated standards for future commercialization.

Antibacterial Pickering emulsions stabilized by bifunctional hairy nanocellulose

HYPOTHESIS

Pickering emulsions, defined as emulsions that are stabilized by colloidal particles, provide dispersion stability by preventing coalescence of the dispersed phase. In this study, we used a bifunctional hairy nanocellulose (BHNC) bearing both aldehyde and carboxylic acid groups as an stabilizer. We hypothesize that these particles as Pickering stabilizers can effectively reside at the oil-water interface, better than hairy nanocelluloses containing only carboxyl groups or aldehyde groups, and provide long-term stability without the need of any surfactants.

EXPERIMENTS

Varying concentrations of BHNC were tested to explore the optimal concentration that provides emulsion stability. The effects of various preparation conditions such as salt and pH were also studied. Finally, carvacrol, an antibacterial essential oil, was loaded in the oil phase to develop antibacterial emulsions.

FINDINGS

It was shown that a 1% BHNC suspension provides 90% and 80% stability for a duration of 30 and 60 days, respectively. A theoretical model using nuclear magnetic resonance relaxometry data is developed to prove that only a monolayer of BHNC covers oil droplets. Increasing the concentration of BHNC decreased the size of oil droplets, which as a result increases the surface area available for monolayer coverage. It was also shown that the antibacterial emulsions are highly effective against Gram-negative (i.e. E. coli) and Gram-positive (i.e. S. aureus) bacteria. Accordingly, BHNC as a highly functionalized bio-derived colloidal particle opens new opportunities for engineering highly stable Pickering emulsions.

Preparation and Characterization of a Novel Natural Quercetin Self-Stabilizing Pickering Emulsion

In contrast to their well-known physiological properties, phytochemicals, such as flavonoids, have been less frequently examined for their physiochemical properties (e.g., surface activity). A natural quercetin self-stabilizing Pickering emulsion was fabricated and characterized in the present study. The antisolvent precipitation method was used to modify quercetin (in dihydrate form), and the obtained particles were characterized by light microscope, atom force microscope, XRD, and contact angle. The antisolvent treatment was found to reduce the particle size, crystallinity, and surface hydrophobicity of quercetin. We then examined the effects of the antisolvent ratio, particle concentration, and oil fraction on the properties of the quercetin particle-stabilized emulsions. In addition, increasing the antisolvent ratio (1:1~1:10) effectively improved the emulsification performance of the quercetin particles. The emulsion showed good storage stability, and the particle size of the emulsion decreased with the rising particle concentration and increased with the rising oil phase ratio. The findings indicate that natural quercetin treated with antisolvent method has a good ability to stabilize Pickering emulsion, and this emulsion may have good prospective application potential for the development of novel and functional emulsion foods.

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.

Bacterial Cellulose Nanofibril-Based Pickering Emulsions: Recent Trends and Applications in the Food Industry

The Pickering emulsion stabilized by food-grade colloidal particles has developed rapidly in recent decades and attracts extensive attention for potential applications in the food industry. Bacterial cellulose nanofibrils (BCNFs), as green and sustainable colloidal nanoparticles derived from bacterial cellulose, have various advantages for Pickering emulsion stabilization and applications due to their unique properties, such as good amphiphilicity, a nanoscale fibrous network, a high aspect ratio, low toxicity, excellent biocompatibility, and sustainability. This review provides a comprehensive overview of the recent advances in the Pickering emulsion stabilized by BCNF particles, including the classification, preparation method, and physicochemical properties of diverse BCNF-based particles as Pickering stabilizers, as well as surface modifications with other substances to improve their emulsifying performance and functionality. Additionally, this paper highlights the stabilization mechanisms and provides potential food applications of BCNF-based Pickering emulsions, such as nutrient encapsulation and delivery, edible coatings and films, fat substitutes, etc. Furthermore, the safety issues and future challenges for the development and food-related applications of BCNFs-based Pickering emulsions are also outlined. This work will provide new insights and more ideas on the development and application of nanofibril-based Pickering emulsions for researchers.

Effects of Concentration of Soybean Protein Isolate and Maltose and Oil Phase Volume Fraction on Freeze-Thaw Stability of Pickering Emulsion

There is growing interest in enhancing the freeze-thaw stability of a Pickering emulsion to obtain a better taste in the frozen food field. A Pickering emulsion was prepared using a two-step homogenization method with soybean protein and maltose as raw materials. The outcomes showed that the freeze-thaw stability of the Pickering emulsion increased when prepared with an increase in soybean protein isolate (SPI) and maltose concentration. After three freeze-thaw treatments at 35 mg/mL, the Turbiscan Stability Index (TSI) value of the emulsion was the lowest. At this concentration, the surface hydrophobicity (H₀) of the composite particles was 33.6 and the interfacial tension was 44.34 mN/m. Furthermore, the rheological nature of the emulsions proved that the apparent viscosity and viscoelasticity of Pickering emulsions grew with a growing oil phase volume fraction and concentration. The maximum value was reached in the case of the oil phase volume fraction of 50% at a concentration of 35 mg/mL, the apparent viscosity was 18 Pa·s, the storage modulus of the emulsion was 575 Pa, and the loss modulus was 152 Pa. This research is significant for the production of freeze-thaw resistant products, and improvement of protein-stabilized emulsion products with high freeze-thaw stability.

Protein-Glutaminase Engineering Based on Isothermal Compressibility Perturbation for Enhanced Modification of Soy Protein Isolate

Protein-glutaminase plays a significant role in future food (e.g., plant-based meat) processing as a result of its ability to improve the solubility, foaming, emulsifying, and gel properties of plant-based proteins. However, poor stability, activity, high pressure, and high shear processing environments hinder its application. Therefore, we developed an application-oriented method isothermal compressibility perturbation engineering strategy to improve enzyme performance by simulating the high-pressure environment. The best variant with remarkable improvement in specific activity and half-time, N16M/Q21H/T113E, exhibited a 4.28-fold increase compared to the wild type in specific activity (117.18 units/mg) and a 1.23-fold increase in half-time (472 min), as one of the highest comprehensive performances ever reported. The solubility of the soy protein isolate deaminated by the N16M/Q21H/T113E mutant was 55.74% higher than that deaminated by the wild type, with a tinier particle size and coarser texture. Overall, this strategy has the potential to improve the functional performance of enzymes under complex food processing conditions.

The Current Situation of Pea Protein and Its Application in the Food Industry

Pea (Pisum sativum) is an important source of nutritional components and is rich in protein, starch, and fiber. Pea protein is considered a high-quality protein and a functional ingredient in the global industry due to its low allergenicity, high protein content, availability, affordability, and deriving from a sustainable crop. Moreover, pea protein has excellent functional properties such as solubility, water, and oil holding capacity, emulsion ability, gelation, and viscosity. Therefore, these functional properties make pea protein a promising ingredient in the food industry. Furthermore, several extraction techniques are used to obtain pea protein isolate and concentrate, including dry fractionation, wet fractionation, salt extraction, and mild fractionation methods. Dry fractionation is chemical-free, has no loss of native functionality, no water use, and is cost-effective, but the protein purity is comparatively low compared to wet extraction. Pea protein can be used as a food emulsifier, encapsulating material, a biodegradable natural polymer, and also in cereals, bakery, dairy, and meat products. Therefore, in this review, we detail the key properties related to extraction techniques, chemistry, and structure, functional properties, and modification techniques, along with their suitable application and health attributes.

The effect of microfluidization pressure on the physical stability of vitamin A in oil-in-water emulsions

In this study, vitamin A was encapsulated within oil-in-water emulsions by high-pressure microfluidization prepared using phosphate buffer (90%), corn oil (10%), and whey protein isolate (2%) as an emulsifier. The influence of microfluidization pressure (10, 50, 100, 200 MPa) on the particle size, zeta potential, and the physical and chemical stability of emulsions was evaluated. The physical stability of emulsion was determined by multiple light scattering technique. The content of vitamin A was measured by HPLC–DAD during an accelerated storage test at 40 °C during 4 weeks. The color of the samples was monitored using a colorimeter. The results showed that the lowest particle size distribution and the highest absolute value of zeta potential on the droplets’ surface charge were obtained by applying a pressure of 100 MPa. Nanoemulsions prepared at 100 MPa also showed the highest colloidal stability. However, higher microfluidization pressure (up to 200 MPa) had a negative impact on the prepared emulsion’s stability. The results of chemical stability by HPLC measurements during storage time were in agreement with the results of physical stability and color change.

Egg Yolk-Free Vegan Mayonnaise Preparation from Pickering Emulsion Stabilized by Gum Nanoparticles with or without Loading Olive Pomace Extracts

The yolk-free mayonnaise was formed by Pickering emulsions stabilized by free and encapsulated olive pomace extracts (OPEs) in rocket seed [rocket seed gum nanoparticle (RSGNP)] and chia seed gum nanoparticles at different nanoparticle concentrations. The yolk-free mayonnaise and the control mayonnaise samples were compared in terms of appearance, microstructural, droplet size, emulsion stability, rheological, oxidative stability, and sensory properties. The droplet size decreased by increasing the nanoparticle concentration in yolk-free mayonnaise samples. The yolk-free mayonnaise samples prepared with OPE-loaded gum nanoparticle showed shear-thinning, solid-like and recoverable characteristics, which increased as the increase in the nanoparticle concentration. The emulsion stability and capacity increased by increasing the nanoparticle concentration in the yolk-free mayonnaise samples. OPE-loaded gum nanoparticle-stabilized yolk-free mayonnaise samples exhibited higher IP (induction period) values than the control samples. OPE-RSGNP 1% mayonnaise was observed to be the closest sample to the control sample with its sensory properties, general acceptability, and similar microstructural and rheological properties. The results of this study indicated that Pickering emulsions stabilized by gum nanoparticles could be used as healthy alternatives to the egg yolk in conventional mayonnaise.

Pickering Emulsions: A Novel Tool for Cosmetic Formulators

The manufacturing of stable emulsion is a very important challenge for the cosmetic industry, which has motivated intense research activity for replacing conventional molecular stabilizers with colloidal particles. These allow minimizing the hazards and risks associated with the use of conventional molecular stabilizers, providing enhanced stability to the obtained dispersions. Therefore, particle-stabilized emulsions (Pickering emulsions) present many advantages with respect to conventional ones, and hence, their commercialization may open new avenues for cosmetic formulators. This makes further efforts to optimize the fabrication procedures of Pickering emulsions, as well as the development of their applicability in the fabrication of different cosmetic formulations, necessary. This review tries to provide an updated perspective that can help the cosmetic industry in the exploitation of Pickering emulsions as a tool for designing new cosmetic products, especially creams for topical applications.

Oxidative stability of Pickering emulsions

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Oxidative stability of O/W Pickering emulsions depends on their interfacial layer.

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Solid particles can reduce Pickering emulsion oxidation by creating a thick interface.

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Manipulating the charge of the interface can control Pickering emulsion oxidation.

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Adding antioxidants to solid particles can reduce oxidation in Pickering emulsions.

In recent years, Pickering emulsions have been the focus of growing interest because of their possible role as alternatives to conventional emulsions. Some reviews have investigated the physical stability of Pickering emulsions, but the oxidative stability of these emulsions remains largely unexplored. In this review, the oxidation mechanism and factors affecting lipid oxidation rates in Pickering emulsions are discussed. Then, different food-grade solid particles are evaluated for their ability to stabilize Pickering emulsions. Finally, several strategies are reviewed for improving the oxidative stability of Pickering emulsions. These strategies are based on efforts to manipulate the physical and chemical properties of the interfacial layer, increase the concentration of antioxidants at the interfacial layer through incorporating them into solid particles, cause oil droplets to crowd at high packing fractions, trap oil droplets in a gel network and increase the viscosity of the continuous phase.

Whey Protein Isolate Nanofibers Prepared by Subcritical Water Stabilized High Internal Phase Pickering Emulsion to Deliver Curcumin

This study aimed to design a Pickering emulsion (PE) stabilized by whey protein isolate nanofibers (WPINs) prepared with subcritical water (SW) to encapsulate and prevent curcumin (Cur) degradation. Cur-loaded WPINs–SW stabilized PE (WPINs–SW–PE) and hydrothermally prepared WPINs stabilized PE (WPINs–H–PE) were characterized using the particle size, zeta potential, Congo Red, CD, and TEM. The results indicated that WPINs–SW–PE and WPINs–H–PE showed regular spherical shapes with average lengths of 26.88 ± 1.11 μm and 175.99 ± 2.31 μm, and zeta potential values were −38.00 ± 1.00 mV and −34.60 ± 2.03 mV, respectively. The encapsulation efficiencies of WPINs–SW–PE and WPINs–H–PE for Cur were 96.72 ± 1.05% and 94.07 ± 2.35%. The bio-accessibility of Cur of WPINs–SW–PE and WPINs–H–PE were 57.52 ± 1.24% and 21.94 ± 2.09%. In addition, WPINs–SW–PE had a better loading effect and antioxidant activities compared with WPINs–H–PE. SW could be a potential processing method to prepare a PE, laying the foundation for the subsequent production of functional foods.

The Potential Application of Pickering Multiple Emulsions in Food

Emulsions stabilized by adsorbed particles—Pickering particles (PPs) instead of surfactants and emulsifiers are called Pickering emulsions. Here, we review the possible uses of Pickering multiple emulsions (PMEs) in the food industry. Food-grade PMEs are very complex systems with high potential for application in food technology. They can be prepared by traditional two-step emulsification processes but also using complex techniques, e.g., microfluidic devices. Compared to those stabilized with an emulsifier, PMEs provide more benefits such as lower susceptibility to coalescence, possible encapsulation of functional compounds in PMEs or even PPs with controlled release, etc. Additionally, the PPs can be made from food-grade by-products. Naturally, w/o/w emulsions in the Pickering form can also provide benefits such as fat reduction by partial replacement of fat phase with internal water phase and encapsulation of sensitive compounds in the internal water phase. A possible advanced type of PMEs may be stabilized by Janus particles, which can change their physicochemical properties and control properties of the whole emulsion systems. These emulsions have big potential as biosensors. In this paper, recent advances in the application of PPs in food emulsions are highlighted with emphasis on the potential application in food-grade PMEs.

Development and characterization of medium and high internal phase novel multiple Pickering emulsions stabilized by hordein nanoparticles

Medium and high internal phase W₁/O/W₂ multiple Pickering emulsions (MPEs) were fabricated by physically-modified hordein nanoparticles. A triphasic system was developed at dispersed phase volume fraction (Φ) of 0.5 with an overrun value of ∼40%. No overrun was detected in high internal phase MPEs (Φ 0.8). Optical and confocal laser scanning microscopy confirmed the formation of MPEs. Monomodal droplet size distribution with a mean diameter of 32.90 and 21.48 μm was observed for MPEs at Φ 0.5 and Φ 0.8, respectively. Static multiple light scattering confirmed that creaming was the main mechanism behind the instability of MPEs. Both MPEs revealed pseudo-plastic behavior and predominant storage modulus (G') over the applied frequency range. The encapsulation efficiency of vitamin B₁₂ in MPEs was 98.3% and remained relatively constant during 28 d. These results suggested the excellent potential of hordein nanoparticles as appropriate candidate for designing multi-structural colloidal systems using plant proteins.

Pesticide-loaded colloidal nanodelivery systems; preparation, characterization, and applications

The fast developments in pesticide-loaded nanodelivery systems over the last decade have inspired many companies and research organizations to highlight potential applications by employing encapsulation approaches in order to protect the agricultural crops. This approach is being used to retard the indiscriminate application of conventional pesticides, as well as, to make ensure the environmental safety. This article shed light on the potential of colloidal delivery systems, particularly controlled releasing profiles of several pesticides with enhanced stability and improved solubility. Colloidal nanodelivery systems, being efficient nanoformulations, have the ability to boost up the pest-control competence for prolonged intervals thru averting the early degradation of active ingredients under severe ecofriendly circumstances. This work is thus aimed to provide critical information on the meaningful role of nanocarriers for loading of pesticides. The smart art of pesticide-loaded nanocarriers can be more fruitful owing to the use of lower amount of active ingredients with improved efficiency along with minimizing the pesticide loss. Also, the future research gaps regarding nano-pesticide formulations, such as role of nanomaterials as active ingredients are discussed briefly. In addition, this article can deliver valuable information to the readers while establishing novel pesticide-loaded nanocarriers for a wide range of applications in the agriculture sectors.

Enhancing bioaccessibility and bioavailability of carotenoids using emulsion-based delivery systems

The consumption of foods rich in antioxidants, vitamins, minerals including carotenoids etc. can boost the immune system to help fight off various infections including SARS- CoV 2 and other viruses. Carotenoids have been gaining attention particularly in food and pharmaceutical industries owing to their diverse functions including their role as pro-vitamin A activity, potent antioxidant properties, and quenching of reactive oxygen (ROS), such as singlet oxygen and lipid peroxides within the lipid bilayer of the cell membrane. Nevertheless, carotenoids being lipophilic, have poor solubility in aqueous medium and are also chemically instable. They are susceptible to degrade under stimuli environmental conditions during food processing, storage and gastrointestinal passage. They also exhibit poor oral bioavailability, thus, their applications in aqueous-based foods are limited. As a consequent, suitable delivery systems including colloids-based are needed to enhance the solubility, stability and bioavailability of carotenoids. This review presents challenges of incorporation and delivery of carotenoids focusing on stability and factors affecting bioavailability. Furthermore, designed factors impacting bioaccessibility and bioavailability of carotenoids using emulsion-based delivery systems are explicitly explained. Each delivery system exhibits its own advantages and disadvantages; thus, the delivery systems should be designed based on their targets and their further applications.

Applications of capsaicin in food industry: functionality, utilization and stabilization

As a bioactive component in Capsicum species, capsaicin is a compound of hot chili peppers which is known as the main substance responsible for the spiciness of these fruits. Besides its taste and physiological effects, it exhibits good antioxidant activity in food matrix and antimicrobial activity against foodborne pathogens and viruses. Considering its low stability and bioaccessibility, and also regarding its irritation, the entrapment methods of capsaicin are fully developed. To compensate the limitations of capsaicin, various encapsulation methods have been used so far, including coacervation, emulsion, spray chilling, and liposomal delivery. Capsaicin has been widely used as a flavoring and preservative agent in food formulations and even as an active compound in packaging film and functional foods. This review provides an overview of the techno-functional properties, stabilization procedures, and burgeoning usages of capsaicin in the latest studies of the food sector. So, it may introduce new windows for the application of this compound.

Tailored rigidity of W/O Pickering emulsions using diacylglycerol-based surface-active solid lipid nanoparticles

Pickering water-in-oil (W/O) emulsions were fabricated by using medium-long chain diacylglycerol (MLCD)-based solid lipid nanoparticles (SLNs) and the connection between the characteristics of the SLNs and the colloidal stability of the emulsions was established. Via melt-emulsification and ultrasonication, MLCD-based SLNs with particle sizes of 120-300 nm were obtained with or without other surfactants. The particle size of the SLNs was influenced by the chemical properties of the surfactants, and surfactants decreased the contact angle of SLNs at the oil-water interface. Gelation was observed in SLNs modified by sodium stearoyl lactylate and lecithin, whereas the addition of Tween 20 resulted in a homogeneous SLN solution. The adsorption of surfactants onto SLN surfaces caused the production of higher amounts of α crystals accompanied by delayed crystallization onset which contributed to the reduction of particle size, interfacial tension and oil wetting ability. The W/O emulsions with higher rigidity and physical stability can be obtained by varying surfactant types and by increasing SLN mass ratios to 60%, whereby more SLNs are adsorbed at the droplet surface as a Pickering stabilizer. This study provides useful insights for the development of diacylglycerol-based SLNs and Pickering W/O emulsions which have great potential for food, cosmetic and pharmaceutical applications.