Advances in emulsion stability: A review on mechanisms, role of emulsifiers, and applications in food

“The results showed that solid particles (10 nm to a few millimeters) and hydrocolloids (5 – 10 nm) had a significant advantage in forming thicker interfacial films compared to surfactants (0.5 – 1 nm) and proteins (1 – 5 nm) (Dickinson, 2009).”

“Emulsifiers commonly used in the food industry include proteins, polysaccharides, phospholipids, and small-molecule surfactants (McClements & Gumus, 2016).”

“This, in turn, affects the viscosity and textural properties of the system (Ravera et al., 2021).”

“When the catechin concentration in the complex was increased to 0.15 % ( w / v ), the zeta potential nearly doubled, resulting in the highest observed stability (Li et al., 2020).”

“Because particle adsorption at the interface is irreversible, Pickering emulsions exhibit greater stability than conventional emulsions (Xia, Xue, & Wei, 2021).”

“Larger droplets tend to flocculate or settle more rapidly, negatively impacting emulsion stability (Shao et al., 2020).”

“For example, casein tends to form a thick and low-viscoelastic interfacial layer that effectively stabilizes oil droplets, mainly due to its low hydrophobicity and high electrostatic charge (Kim, Wang, & Selomulya, 2020).”

“Chemically, phenolics are defined by the presence of at least one phenolic hydroxyl group, often linked to aromatic rings or conjugated sugars, which influence their bioactivity and functional properties (Liu et al., 2021).”

“For oil-in-water emulsions, a more hydrophilic inter-facial layer improves resistance to coalescence, as emulsifiers with higher water solubility better stabilize droplets in the aqueous continuous phase (Zembyla, Murray, & Sarkar, 2020).”

“In flocculation, the droplet radius remains unchanged, but the droplets come together to form clusters, which accelerates gravitational separation and compromises emulsion stability (Niu et al., 2023).”

“These influences mainly include the thickness and structural characteristics of the interfacial layer, the interaction between the emulsifier and the two phases, and the rheological properties of the interface (Cai et al., 2023).”

“Pickering emulsions are stabilized through three primary mechanisms: particle adsorption at the oil-water interface, network formation, (Lv et al., 2024; Nooshkam & Varidi, 2020). and steric hindrance (Tian et al., 2024) Fig.”

“…best emulsification activity index and emulsion stability index, especially GG-SPI, GG can stabilize the large interfacial area. physical stability (Zhang, Liang, & Li, 2022) Rice protein (RP) (solution) Gum Arabic (GA) (solution) noncovalent binding The ability to stabilize oil-in-water emulsions…”

“When the tea saponin concentration reached 1.0 %, the G ′ value stabilized, suggesting the formation of a uniform and stable emulsion structure (Yan et al., 2022).”

“Certain natural poly-saccharides, such as gum Arabic, pectin, and galactomannans, contain proteins or non-polar groups within their hydrophilic carbohydrate chains, which impart emulsifying properties (Zhang et al., 2020).”

“This dispersion stabilizes the emulsion, ensuring a smooth texture and preventing the separation of fat (oil) and water phases during storage (Akbari, Akbari, Eskandari, & Davoudi, 2019).”

“Methods for determining emulsion droplet size include particle size analyzing techniques such as diffraction-based particle sizing, Coulter counters, optical microscopy, and electron microscopy (Zhang et al., 2023).”

“Surface hydrophobicity, a critical parameter in emulsion science, can be measured using fluorescence spectroscopy with probes such as 1-naphthylamine naphthalene-8-sulfonic acid (ANS) and cis-naphthalenesulfonic acid (CPA) (Zhang et al., 2021).”

“(Yang et al., 2018) improved rheological properties, emulsification, foaming, and thermal stability compared to proteins or polysaccharides alone (Nooshkam & Varidi, 2020) Fig.”

“Covalent conjugates of protein-and phenolic compounds are stable and offer better protection against oxidation (e.g. of unsaturated fatty acids) compared to non-covalent complexes (Li et al., 2021).”

“Similarly, Feng et al. re-ported that ternary complexes prepared from pea protein isolate, high-methoxyl pectin, and epigallocatechin gallate effectively stabilized HIPE by forming smaller particle sizes, which contributed to improved emulsion stability (Feng et al., 2022).”

“The properties of plant protein-based emulsions are highly influenced by factors such as pH, ionic strength, temperature, and preparation methods, as these parameters affect the structure of proteins at the oil-water interface (Lima, Stephani, Perrone, & de Carvalho, 2023).”

“The presence of polyphenols has also been shown to improve surface wettability and hydrophobicity of proteins (Wang et al., 2022b).”

“The resulting emulsions exhibited improved stability and rheological properties (Chen et al., 2023).”

“The resulting complex co-acervates are widely applied to stabilize hydrophilic-hydrophobic interfaces, such as oil-water and air-water interfaces (Babu, Shams, Dash, Shaikh, & Kov ´ acs, 2024).”

“Emulsion systems are generally classified as oil-in-water (O/W) or water-in-oil (W/O) emulsions, depending on whether the dispersed phase is oil or water (Liu, Wu, Zhang, Yan, & Mao, 2024).”

“(Gao et al., 2023).”

“Their amphiphilic nature allows them to adsorb at the oil-water interface, with hydrophilic polysaccharide chains anchored in the aqueous phase and hydrophobic groups (e.g. methoxyl and acetyl groups) oriented toward the oil phase (Hu, Jiang, Du, & Meng, 2023).”

“This process increases the particle size distribution of the emulsion, leading directly to delamination or settling (Koroleva & Yurtov, 2021).”

“Over time, the effectiveness of emulsification decreases, and the oil phase rapidly leaks from the interfacial layer, leading to varying degrees of phase separation (Cheng et al., 2023).”

“The presence of polyphenols has also been shown to improve surface wettability and hydrophobicity of proteins (Wang et al., 2022b).”

“Conversely, increasing protein concentration in the continuous phase improved oxidative stability by enhancing interfacial protection and reducing oxidative reactions (Ries, Ye, Haisman, & Singh, 2010).”

“When the tea saponin concentration reached 1.0 %, the G ′ value stabilized, suggesting the formation of a uniform and stable emulsion structure (Yan et al., 2022).”

“The HBG concentration was 0.5 % (w/v), without NaCl (Li et al., 2024).”

“The HBG concentration was 0.5 % (w/v), without NaCl (Li et al., 2024).”

“By interacting with proteins, poly-phenols enhance the hydrophobicity of the complexes, thereby improving surface properties, rheological behaviour, and overall stability (Huang, Luo, Ning, Ye, & Liu, 2024).”

“The HBG concentration was 0.5 % (w/v), without NaCl (Li et al., 2024).”

“Since the mouth-feel of ice cream is closely associated with emulsion stability, its control during the manufacturing process is essential for ensuring product quality and consumer satisfaction (Hei et al., 2024).”

“For example, the heating of whey protein has been shown to produce stabilized nanoparticles and aggregates, which enhance emulsion stability by providing a protective interface and reducing droplet coalescence (Dybowska, 2011).”

“A higher viscosity in the continuous phase can slow down the settling or creaming rate of dispersed phase droplets, thereby enhancing emulsion stability (Zhang et al., 2025).”

“Since the mouth-feel of ice cream is closely associated with emulsion stability, its control during the manufacturing process is essential for ensuring product quality and consumer satisfaction (Hei et al., 2024).”

“Common biopolymers used for stabilization include proteins, polysaccharides, and other related compounds (Tamang et al., 2022).”

“The presence of polyphenols has also been shown to improve surface wettability and hydrophobicity of proteins (Wang et al., 2022b).”

“Additionally, the magnitude of the repulsive forces between droplets, as measured by zeta potential, serves as a key indicator of stability, with higher repulsion reducing the likelihood of coalescence or aggregation (Cao et al., 2023).”

“These parameters were optimized holistically, resulting in stable cream emulsions with smooth textures and desirable sensory properties (Wu et al., 2023).”

“This sharp reduction in surface hydrophobicity destabilizes protein-stabilized emulsions (Zhang & Lu, 2015).”

“This stabilization is particularly pronounced in the three-dimensional network structures formed by the modified HEC, which exhibit strong elastic properties (Akiyama et al., 2005).”

“In this regard, protein-polysaccharide complexes fare better, as the complexation of proteins with polysaccharides modulates hydrophilicity and enhances interfacial properties, making them suitable for Pickering stabilization(Wu et al., 2022).”

“Mayonnaise is a traditional and commercially successful O/W-type emulsion product that typically consists of oil (70 – 80 %), egg yolk, emulsifier, vinegar, sugar, and salt (Taslikh et al., 2022).”

“Food-grade particles mainly include protein/polysaccharide particles, lipid crystals, flavonoids, composite particles, food-grade waxes (Boostani et al., 2024).”

“The zeta potential of droplets and particles is determined by the type and concentration of surface charges and ions in the surrounding medium, which significantly influences emulsion stability (Collini & Jackson, 2023).”

“Modified proteins can be rapidly anchored to the droplet surface by their amphiphilic peptides (Xu et al., 2022).”

“It serves as an effective indicator of emulsification efficiency, emulsion stability, and the type of emulsion formed (W/O or O/W), particularly for Pickering emulsions (Erbil, 2021).”

“Various colloidal particles obtained from natural substances, including protein, polysaccharide, polyphenol, and their complexes, have shown that they can effectively stabilize Pickering emulsions (Najari, Dokouhaki, Juliano, & Adhikari, 2024).”

“The application of nanosized Pickering particles has been shown to significantly improve the stability of Pickering emulsions(Yan, Regenstein, Qi, & Li, 2023).”

“Oil is encapsulated in O/W, thus being more protected against oxidation (Chang et al., 2023).”

“The properties of the interfacial layer surrounding the dispersed phase droplets in an emulsion often determine its stability (Guan, Jiang, Lin, & Ngai, 2024).”

“It is measured using methods such as electrophoresis, electroosmosis, and electroacoustics (Bommakanti et al., 2022).”

“PPCs possess excellent amphiphilic properties, with a triple-phase contact angle close to 90 ◦ , enabling superior long-term storage stability, heat resistance, and suitability for 3D printing applications (Zong et al., 2022).”

“When the catechin concentration in the complex was increased to 0.15 % ( w / v ), the zeta potential nearly doubled, resulting in the highest observed stability (Li et al., 2020).”

“As shown in Table 2, These interactions can be classified as non-covalent or covalent, with binding mechanisms that include physical interaction, chemical cross-linking, enzymatic cross-linking, and the Maillard reaction (Wu et al., 2024).”

“In contrast, thinner interfacial layers, such as those formed by globular proteins, stabilize emulsion droplets through a combination of electrostatic interactions and spatial repulsive forces (Xu, Wang, Xin, Zhang, & Liu, 2025).”

“At the molecular level, the emulsifying ability of native pectin was attributed to its acetyl and methyl groups, while its stability was linked to monosaccharide side chains and ionized carboxyl groups (Liu et al., 2022).”

“4b. Covalent binding interactions are primarily achieved through protein glycosylation during the initial phase of the Maillard reaction (Ke, Zhang, Yang, & Li, 2024).”

“This self-arranging behaviour at the interface contributes to their effectiveness in preventing phase separation and maintaining emulsion stability (Lv et al., 2024) Fig.”

“The emulsification performance of high molecular weight pectin is better (Li et al., 2022).”

“The emulsification performance of high molecular weight pectin is better (Li et al., 2022).”

“An emulsion is a multiphase dispersion system that typically consists of two immiscible liquids, with one dispersed in the other as small droplets (Singh & Pulikkal, 2024).”

“Xanthan gum and similar hydrocolloids are widely used in O/W emulsions to modulate viscosity (Meng, Nicolai, Benyahia and Nicol, 2022).”

“Pickering emulsions are stabilized through three primary mechanisms: particle adsorption at the oil-water interface, network formation, (Lv et al., 2024; Nooshkam & Varidi, 2020). and steric hindrance (Tian et al., 2024) Fig.”

“The resulting emulsions exhibited improved stability and rheological properties (Chen et al., 2023).”

“The HBG concentration was 0.5 % (w/v), without NaCl (Li et al., 2024).”

“For instance, rapeseed protein-xanthan gum-based Pickering emulsions have been shown their potential to replace fat in meat products (Rezaee & Aider, 2023).”

“…/W emulsions formed by mixing polyethylene oxide (PEO) and dextran (DEX) are stable only when the contact angle with the continuous phase is less than 90 ◦ , confirming the hypothesis that the contact angle can indeed be a determining factor in the stability of W/W emulsions (Meng & Nicolai, 2023).”

“The emulsification performance of high molecular weight pectin is better (Li et al., 2022).”

“Droplet size and distribution are crucial for emulsion stability (Wang, Anton, Vandamme, & Anton, 2023).”

“…exhibiting moderate hydrophobicity in certain areas are particularly effective as emulsifiers, thereby improving the stability of the emulsion (Maaref, Kantzas, & Bryant, 2019). urface hydrophobicity plays an important role in determining the physicochemical properties and stability of…”

“For example, Xie et al. prepared Pickering emulsions stabilized by complex particles with pea isolate protein-zearaldehyde soluble protein (PPI-Zein) through hydrophobic interactions with good storage stability (Xie et al., 2024).”

“Methods for determining emulsion droplet size include particle size analyzing techniques such as diffraction-based particle sizing, Coulter counters, optical microscopy, and electron microscopy (Zhang et al., 2023).”

“…interfacial conformation at the oil-water interface, which is influenced by its micellar or sub-micellar coalescence behaviour in the aqueous phase (Yan et al., 2024). it is shown that all four types of casein could adsorb at the oil-water interface, forming interfacial layers with varying…”

“The presence of polyphenols has also been shown to improve surface wettability and hydrophobicity of proteins (Wang et al., 2022b).”

“However, synthetic surfactants are increasingly less preferred by consumers (Liu, He, Huang, Yin, & Nie, 2024).”

“For example, Othmeni et al. found that treatment of pea protein at pH 5 during preparation was the least effective in stabilizing the emulsion compared to untreated pea protein (Othmeni, Blecker, & Karoui, 2025).”

“The EAI measures the rapid adsorption capacity of surfactants at the water-oil interface, reflecting their ability to reduce interfacial tension effectively (Cao et al., 2024; Tian et al., 2023).”

“For example, researchers have used flaxseed oil and soy lecithin or saponin to prepare oil-in-water emulsions thickened with modified starch and have shown that lecithin-stabilized emulsions display a greater negative charge (Quezada, Urra, Mella, Zú ˜ niga, & Troncoso, 2024).”

“The stability of the cream was evaluated using key parameters such as whipping time, texture, storage stability, foam stabilization time, and microstructural analysis of its cross-section (Zhang et al., 2024).”

“This layer creates a spatial barrier on the particle surface, effectively preventing flocculation and agglomeration (Udomrati et al., 2020).”

“…interfacial conformation at the oil-water interface, which is influenced by its micellar or sub-micellar coalescence behaviour in the aqueous phase (Yan et al., 2024). it is shown that all four types of casein could adsorb at the oil-water interface, forming interfacial layers with varying…”

“For example, natural corn starch increases the viscosity of the emulsion, reducing droplet mobility and collision frequency (Yang et al., 2022).”

“The phospholipid-based functional ingredient used as an emulsifier in commercial products is often referred to as lecithin, which can be isolated from a variety of biological sources, the most common of which include soy, egg, milk, and rapeseed (Thy, Duy, & Dat, 2025).”

“To provide product diversity, Bi et al. developed a plant-based mayonnaise using a pea protein-xanthan gum complex, reportedly achieving a similar appearance, microstructure, and rheological properties to those of traditional mayonnaise (Bi, Bi, Qie, Liu, Gao, & Zhou, 2024).”

“The resulting coalescence, Ostwald ripening, flocculation, and phase separation pose challenges to the long-term stability of emulsion systems (Suzuki, Kobayashi, Yamazaki, Tsuji, & Arai, 2024).”

“They typically consist of flavoured or turbid oils as the dispersed phase, water as the continuous phase, and emulsifiers for stability (Devaki & Ghosh, 2024).”

“These polysaccharides also compensate for the reduced thickening properties associated with lower oil content in salad dressings (Bindereif, Karbstein, & van der Schaaf, 2023).”

“The HBG concentration was 0.5 % (w/v), without NaCl (Li et al., 2024).”

“Pickering emulsions are multiphase systems stabilized by solid particles that adsorb at the liquid-liquid interface, offering controllability and high stability (Hei et al., 2025).”

“For example, Yao et al. developed a low-energy emulsification method for the preparation of gelatin-stabilized emulsions with low oil-phase volume fractions by stirring only, and revealed that a change in pH improves the emulsification capacity of stirred gelatin (Yao et al., 2024).”

“Researchers have found that the emulsion stability of microalgal proteins (MP) is limited to strongly alkaline conditions; but by complexing with carboxymethyl chitosan (CMCS), complex-stabilized emulsions exhibit good stability at pH 2, 4, and 7 (Wang et al., 2024).”

“As shown in Table 2, These interactions can be classified as non-covalent or covalent, with binding mechanisms that include physical interaction, chemical cross-linking, enzymatic cross-linking, and the Maillard reaction (Wu et al., 2024).”

“In recent years, the development of enzymes biotechnology has been rapid, in and protein modification has become a key factor in promoting the progress of enzyme technology (Cheng et al., 2025).”