Droplet Aggregation Research Articles

Insights into the Pickering emulsions stabilized by yeast dietary fiber: Interfacial adsorption kinetics, rheological characteristics, and stabilization mechanisms

This study developed Pickering emulsions based on yeast dietary fiber (YDF) and investigated the interfacial adsorption kinetics of YDF, rheological properties and stabilization mechanisms of emulsions. Results indicated that increasing YDF concentration enhanced its diffusion and rearrangement at the oil-water interface. At a concentration of 8 %, YDF exhibited the highest diffusion rate (0.1406 mN·m−1·s-0.5) and rearrangement rate (18.8 s−1). The emulsion stabilized at this concentration had the smallest droplet size (1.55 μm) and the slowest droplet migration rate (0.34 mm/h), effectively suppressing droplet aggregation due to collisions and thereby improving the overall emulsion stability. Confocal laser scanning microscopy results confirmed that emulsion stability relied on the co-adsorption of proteins and polysaccharides from YDF at the interface, with proteins primarily adsorbed at the oil-water interface and polysaccharides responsible for the continuous phase network formation. This study demonstrates YDF's potential as an emulsion stabilizer and elucidates the stabilization mechanism of YDF-induced emulsion.

Study on the Anti-Atherosclerotic Mechanisms of Xin-Tong-Tai Granule Through Network Pharmacology, Molecular Docking, and Experimental Validation.

Xin-Tong-Tai Granule (XTTG), a Chinese medicine (CM) formula, has demonstrated significant therapeutic effects on atherosclerosis (AS) in both clinical and experimental settings. Nonetheless, the mechanisms underlying XTTG's efficacy remain largely unexplored. This study aimed to elucidate the mechanisms through which XTTG acts against AS, employing network pharmacology, molecular docking, and experimental validation techniques. Initially, target identification for the main chemical components of XTTG was conducted using database, followed by determining the intersection targets between these compounds and disease. Protein-protein interaction (PPI) network analysis, Gene Ontology (GO) enrichment, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were subsequently utilized to investigate the potential pathways through which XTTG exerts its effects on AS. Molecular docking was done to confirm the binding efficacy of XTTG's active components. Additionally, the effects of XTTG were evaluated in vitro using oxidized low-density lipoprotein (ox-LDL) induced human aortic vascular smooth muscle cells (HAVSMCs) and in vivo in apolipoprotein E gene knockout (ApoE-/-) mice fed a high-fat diet (HFD). 229 therapeutic targets were screened for PPI network and enrichment analysis. Notably, the nuclear factor kappa-B (NF-κB) signaling pathway, along with processes related to inflammation and autophagy, were significantly enriched, highlighting their importance. In vitro studies showed that XTTG repressed cell proliferation and lipid droplet aggregation in ox-LDL-induced HAVSMCs. It also decreased the ratio of phosphorylated NF-κB p65/ NF-κB p65, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels, and elevated microtubule-associated protein light chain 3 (LC3) and decreased p62 protein expression. In vivo, XTTG ameliorated blood lipid profiles and aortic pathology in HFD-fed ApoE-/- mice, reduced NF-κB p65 expression and serum levels of TNF-α and IL-6, increased the ratio of LC3II/LC3I while decreasing p62 protein expression. XTTG mitigates AS primarily through anti-inflammatory and autophagy-modulating mechanisms, particularly via inhibition of NF-κB p65 expression. These findings underscore the potential of CM in treating AS and support its further clinical exploration.

Pea Albumin Alleviates Oleic Acid-Induced Lipid Accumulation in LO2 Cells Through Modulating Lipid Metabolism and Fatty Acid Oxidation Pathways.

Excessive lipid accumulation in the liver can cause NAFLD, leading to chronic liver injury. To relieve liver lipid accumulation by dietary proteins, this study used oleic acid (OA) induction to establish a stable in vitro LO2 cell lipid accumulation model. This model was used to explore the mechanism by which pea albumin (PA) regulates lipid levels in LO2 cells. PA has been shown to ameliorate OA-induced lipid accumulation in LO2 cells by reducing the aggregation of intracellular lipid droplets and lowering cell TG and TC levels. In addition, it can alleviate OA-induced LO2 cell damage and oxidative stress, reduce cellular ALT and AST secretion, lower cellular MDA levels, and increase GSH-Px viability. Regulation of lipid metabolism in LO2 cells involves inhibiting the cellular lipid synthesis pathway and activating the expression of proteins related to the triglyceride catabolic and fatty acid oxidation pathways. PA contributes to regulating lipid accumulation in LO2 cells. This study provides new insights into alleviating liver fat accumulation and a theoretical basis for exploring the mechanism of protein regulation of liver cell lipid metabolism.

Effect of gene CRTC2 on the differentiation of subcutaneous precursor adipocytes in goats.

The aim of this study was to obtain goat CRTC2 gene sequence and elucidate its biological properties, and further study the impact of overexpression and interference of CRTC2 on the cell differentiation of goat subcutaneous precursor adipocytes. The sequence of goat CRTC2 was cloned by reverse transcription polymerase chain reaction (RT-PCR) and its molecular characterization was analyzed. The expression of CRTC2 gene in goat tissues and subcutaneous precursor adipocytes differentiated from 0 to 120 h was examined by quantitative real-time PCR (qRT-PCR). The effects of CRTC2 on the subcutaneous precursor adipocyte differentiation were investigated by using liposome transfection, Bodipy, Oil Red O staining and qPCR. The results showed that the cloned goat CRTC2 gene was 2363 bp long (coding sequence [CDS] 2082 bp), encoding 693 amino acids. The relative expression levels of CRTC2 gene were highest in liver and then in kidney (P < 0.05). During differentiation, the highest expression of CRTC2 in subcutaneous precursor adipocytes was observed at 120 of differentiating (P < 0.01). In addition, we found that overexpression of CRTC2 significantly increased the expression of lipid metabolism-related genes (C/EBPα, C/EBPβ, PPARγ, DGAT1, DGAT2, ACC, FASN, SREBP1，AP2，LPL，ATGL) and promoted lipid accumulation. We then chemically synthesized goat CRTC2 small interfering RNA and transfected it into goat subcutaneous precursor adipocytes. The results revealed that SiRNA-mediated interference with CRTC2 significantly inhibited its differentiation and suppressed lipid droplet aggregation. So, this study indicates that CRTC2 is a positive regulator that promoting cell differentiation of subcutaneous adipocyte in goats, which lays the foundation for an in-depth study of the role of CRTC2 in lipid deposition in goats.

Analysis of the motion and deformation of water-in-oil emulsion droplets under the action of an electric field

Molecular dynamics simulations are used to study the aggregation dynamics of water-in-oil emulsion droplets under an electric field, and to analyze the effects of electric field strength, type, droplet position, and ionic concentration on their kinematic properties. The best droplet aggregation is observed at E=0.03V/Å for DC field condition, and E=0.045V/Å - 80ps for rectangular AC field condition. The rectangular alternating current (AC) field is able to merge the droplets farther away from the center of mass, but the two fields are not able to merge when the angle between the center of mass of the droplets and the electric field force is ≥35.54°. For different ion concentrations, t40N < t20N < t60N < t0N in the DC field and t20N < t40N < t0N < t60N in the rectangular AC field, and for the same ion concentration, the rectangular AC field takes longer time to merge.

Fabrication and characterization of mayonnaise based on xanthan gum/lysozyme nanoparticles and konjac glucomannan as egg yolk substitutes under different temperature stresses

High cholesterol levels in mayonnaise pose a potential health threat to consumers, and there is an urgent need to develop cholesterol-reduced mayonnaise to meet consumer demand. Therefore, the aim of this study was to prepare a cholesterol-reduced Pickering emulsion mayonnaise (PEM) by replacing egg yolk with xanthan gum/lysozyme nanoparticles (XG/Ly NPs) and konjac glucomannan (KGM). In addition, the decorated appearance, droplet size, centrifugal stability, microstructure, and rheological properties of PEM were determined at different temperature fields (ambient, pasteurized, and refrigerated). The results showed that KGM provided additional network structure for PEM when the yolk substitution rate was no more than 40%, limiting oil droplet aggregation, as evidenced by the enhanced centrifugal stability and significantly reduced droplet size (P < 0.05). Moreover, the PEM supplemented with 0.2% KGM at 40% yolk substitution showed good viscoelasticity and small particle size (12.4 ± 0.7 μm) after pasteurization (65 °C for 30 min) and 30 days of refrigeration. Overall, XG/Ly NPs and KGM can be used as potential egg yolk substitutes and provide a new theoretical reference for the food industry to develop highly stable cholesterol-reduced mayonnaise.

Photofunctional gold nanocluster-based nanocomposite coating for enhancing anti-biofouling and anti-icing properties of flexible films

Elastomeric materials have garnered significant attention across biomedical and industrial fields. Multifunctionality and environmental stability are essential requirements for the application of these materials. Herein, we developed photofunctional gold nanocluster-based nanocomposites (SiO2-AuNC) and coated them on elastomeric polydimethylsiloxane (PDMS) films through one-step way to enhance anti-biofouling and anti-icing properties. The SiO2-AuNC coating, created by immobilizing ultra-small gold nanoclusters (AuNCs) onto hydrophobic silica nanoparticles surface using a gel-sol method, forms an island-like convex structure. The immobilization significantly enhanced radiative transitions and promoted the generation of reactive oxygen species of AuNCs, which provided robust anti-biofouling property through photosensitization to the films. Meanwhile, the rigid SiO2-AuNC nanocomposite markedly enhances the wear resistance of the films. Additionally, the hierarchical micro- and nanostructure of SiO2-AuNC coating increases the hydrophobicity of the films, effectively preventing the aggregation of supercooled water droplets, thereby providing superior and durably anti-icing properties. This one-step coating provides a simple and effective strategy for multifunctional surface modification with nanoparticles, showing potential biomedical and industrial applications.

The resistance of BSA-Dex conjugate nanoemulsions to depletion flocculation induced by excessive dextran in Maillard reaction

Protein nanoemulsions are excellent carriers of nutrients due to their unique surface activity and structural properties, however, poor stability has limited their application. The Maillard reaction can enhance protein emulsification, but an excess of dextran formed during the reaction can trigger detrimental effect. In this study, the influence of unbound dextran following the Maillard reaction on nanoemulsions composed of bovine serum albumin (BSA) and dextran conjugates was studied. The results showed that saturation grafting occurred at a 1:7 M ratio of BSA to dextran during the Maillard reaction. Rheological analysis revealed that the relative amount of difference between the loss modulus (G″) and storage modulus (G′) in the nanoemulsions was most pronounced within the ratio of 1:7–1:11. This difference decreased when the dextran content exceeded 1:11, indicating a reduction in the system’s ability to prevent aggregation. Nanoemulsions within the range of ratios 1:7–1:11 showed no droplet aggregation, particle size, or zeta-potential alterations after 3-months of storage. They remained stable at 90 °C, with NaCl concentrations within 75 mM, and at pH 3–8. Small amounts of free dextran remaining from the Maillard reaction are deemed acceptable in subsequent nanoemulsions preparation. This study offers a scientific foundation for devising cost-effective strategies in industrial production.

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.

Lipid digestion profiles of pickering emulsion gels stabilized by β-glucans microgel particles

Pickering emulsion gels (PEGs) stabilized by microgel particles (MPs) have a wide range of applications. However, the extent and mechanisms of lipid digestion in these PEGs are still unclear. In this study, we explored how the concentration of β-glucans MPs and different stabilizers influence the lipid digestion profiles. Our findings revealed a significant role of β-glucans MPs in modulating lipid digestion, with a reduction in lipid digestion rate and extent correlated with an increase in MPs concentration. Notably, compared to droplets stabilized by other agents, emulsions stabilized by β-glucans MPs exhibited the lowest initial release rate (0.81 ± 0.08 FFA%/min) and final degree of digestion (18.96% ± 0.42%) of free fatty acids. Lipid droplets stabilized by β-glucan MPs were able to effectively resist the effects of high ionic strength and complex components in the oral and gastric environments, maintaining their structural integrity and preventing droplet aggregation. Our results indicated that β-glucans MPs are not only effective stabilizers but also provide a novel approach to controlling lipid digestibility.

Physicochemical characterization of emulsions stabilized with polysaccharide conjugates extracted from Pu'er tea and their protective effect on curcumin

This study aimed to investigate the influence of different storage periods on the emulsifying properties of polysaccharide-protein complexes (pTPC) in Pu 'er tea through structural analysis and macroscopic characterization, and further explore the stability of pTPC-stabilized nano-emulsions in various environmental conditions. Through determination of chemical composition, interfacial tension, and infrared spectroscopy, it was found that compared to pTPC-13, the higher amino acid content of pTPC-18 led to enhanced hydrogen bonding and electrostatic interactions between intramolecular polysaccharides and polyphenols, thereby increasing its adsorption rate and interfacial film thickness. Additionally, the stability of pTPC-18 stabilized nano-emulsions showed no significant changes in zeta potential and particle size over 0–90 days of storage, pH 2.0–9.0, 25–100 °C, Na+ and Ca2+, whereas pTPC-13 stabilized emulsions exhibited noticeable droplet aggregation and layering instability under the same stress conditions. Furthermore, for curcumin encapsulation, pTPC-18 nano-emulsions (60%) demonstrated stronger protection of curcumin compared to pTPC-13 nano-emulsions (39%). These results suggest that during long-term storage, the relative increase in protein and polyphenol content within pTPC-18 enhances its emulsifying properties, providing new insights into the development of lipid-active substance delivery systems.

Preparation and characterization of pickering emulsions stabilized by zein/quercetin/quaternary ammonium chitosan composite nanoparticles with antibacterial effect

The role of nanoparticles in the stabilizing interface is very important in the preparation of stable Pickering emulsions. In this study, ternary composite nanoparticles (ZQ-HC) were synthesized by complexing zein-quercetin covalent complex (ZQ) with quaternary ammonium chitosan (HTCC) and subsequently stabilized Pickering emulsions (ZQ-HC) with antibacterial activity. Results revealed that HTCC covers the surface of ZQ nanoparticles successfully, which designates an effective improvement in the surface wettability of ZQ effectively. Among them, ZQ-HC2:1 possesses the closest three-phase contact angle of 90° and the highest emulsification activity and emulsion stability. The results of ultra-high resolution microscopy showed that ZQ-HC nanoparticles were adsorbed at the oil-water interface to prevent droplet aggregation and improved the pH, ionic strength, and storage stability of the prepared Pickering emulsions. ZQ-HC nanoparticles construct an antioxidant barrier at the oil-water interface, improving the lipid oxidation stability of the emulsion. The ZQ-HC2:1 stabilized Pickering emulsion exhibits the most superior stability and strongest antibacterial activity against other emulsions. The ZQ-HC stabilized Pickering emulsions prepared in this study exhibit potential for use as carriers of bioactive ingredients in food applications.

Effect of polysaccharide on structures and gel properties of microgel particle reconstructed soybean protein isolate/polysaccharide complex emulsion gels as solid fat mimetic

In this work, a soybean protein isolate (SPI)/polysaccharide microgel particle reconstructed emulsion gels (MPEG) were fabricated through heat-induced gel (HG)–microgel particle–transglutaminase (TG) induced gel process in the presence of four polysaccharides (κ-carrageenan, κC; konjac glucomannan, KGM; high-acyl gellan, HA and xanthan gum, XG). HG exhibited a higher springiness than that of pig back fat (PBF) regardless of polysaccharide type and concentration. After forming MPEG, the springiness was significantly lowered at ≥0.6 % κC, which made MPEG exhibit similar springiness of PBF; while SPI/KGM, SPI/XG and SPI/HA systems failed to regulate the springiness property. Rheological behavior revealed the loss in elasticity, the increase in the plastic deformation of SPI/κC MPEG, while KGM, XG and HA systems still exhibited elasticity dominated rheological properties. Compared with KGM, XG, the presence of excess κC and HA disturbed the continuous protein network structure, resulting to the aggregation of microgel particles and oil droplets. Disulfide bonds and hydrophobic interactions mainly contributed to the formation of MPEG, while the addition of κC weakened the contribution of them, which was not conducive to the formation of gel network. This study provides a guidance on the development of solid fat mimetic based on the microgel particle emulsion gels.

Effect of protein oxidation on the structure and emulsifying properties of fish gelatin

This study aimed to investigate the effect of oxidation on fish gelatin and its emulsifying properties. Fish gelatin was oxidized with varying concentrations of H2O2 (0–30 mM). Increased concentrations of the oxidant led to a decrease in amino acids in the gelatin, including glycine, lysine, and arginine. Additionally, the relative content of ordered secondary structure and triple helix fractions decreased. Zeta potential decreased, while particle size, surface hydrophobicity, and water contact angle increased. Regarding emulsifying behavior, oxidation promoted the adsorption of gelatin to the oil–water interface and reduced interfacial tension. With increased degrees of oxidation, the zeta potential and size of the emulsion droplets decreased. The oxidized gelatin exhibited better emulsifying activity but worse emulsifying stability. Based on these results, a mechanism for how oxidation affects the emulsifying properties of gelatin was proposed: the increase in gelatin’s hydrophobicity and the decrease in triple helix structure induced by oxidation reduced the interfacial tension at the oil–water interface. This promoted protein adsorption at the oil–water interface, allowing the formation of smaller oil droplets and enhancing gelatin’s emulsifying activity. However, the decrease in electrostatic repulsion between emulsion droplets and the decrease in solution viscosity increased the flocculation and aggregation of oil droplets, ultimately weakening the emulsifying stability of gelatin.

Lactic acid regulates lipid droplet aggregation through a microglia-neuron axis in neuroinflammation

Neuroinflammation, marked by the release of proinflammatory cytokines and resulting neuronal death, is a multifaceted process extending beyond traditional inflammatory pathways. Microglia, primary cells in the inflammatory response, rapidly activate during neuroinflammation and produce proinflammatory and cytotoxic factors that affect neuronal function. Recent evidence highlights the significant role of abnormal lipid droplet (LD) deposition in the pathogenesis of neuroinflammation. While microglia are known to influence LD aggregation during neuroinflammation, the regulatory mechanism within neurons is not well understood. Our study demonstrates that lipopolysaccharide-activated microglia induce the accumulation of LD in neurons, identifying microglial-derived lactic acid as a key mediator in this process. Excessive lipid accumulation threatens neuronal function, a phenomenon reversed by eliminating microglia. Our study demonstrates that lipopolysaccharide-activated microglia induce the accumulation of LD in neurons, identifying microglial-derived lactic acid as a key mediator in this process. Excessive lipid accumulation threatens neuronal function, a phenomenon reversed by eliminating microglia.

Oil in water emulsion stabilized by glycated rice bran protein aggregates: Effect on interfacial behavior and in vitro digestion of emulsion

To investigate the effect of molecular weight of saccharides and heating time on interfacial behavior of protein, glycated rice bran protein aggregates (gRBPAs) were obtained by incubating rice bran protein (RBP) with glucose (Glu), maltose (Mal) and dextran (Dex) via acid-heat treatment (pH 2.0, 90 °C). Subsequently, the stability and in vitro simulated digestion properties of oil in water (O/W) emulsion stabilized by gRBPAs were analyzed. Structural analysis (circular dichroism and fluorescence spectra) proved that the tertiary structure and secondary structure of RBP changed after glycation, and the contents of β-sheet structure of gRBPAs increased significantly. Besides, the glycation improved the interfacial activity and emulsification of protein obviously. Compared with Glu or Mal, the grafting of Dex could produce larger steric hindrance, which better inhibited the aggregation of emulsion droplets. Furthermore, glycation enhanced the pancreatic lipase (PL) inhibitory activity of gRBPAs obviously, and the emulsions stabilized by gRBPAs exhibited higher anti-digestion ability (62.12–75.00%) compared with RBP (95.27%). Moreover, the free fatty acid (FFA) rate of O/W emulsion was closely related to the surface hydrophobicity, degree of glycation, PL inhibitory activity and interfacial behavior of gRBPAs. Therefore, these findings would be enlightening to intuitively tailor the physicochemical stability and digestibility of O/W emulsion system according to heating time and molecular weight of saccharides. Meanwhile, this work would facilitate the application of O/W emulsion stabilized by glycated protein aggregates in functional foods.

(Non)linear Interfacial Rheology of Tween, Brij and Span Stabilized Oil-Water Interfaces: Impact of the Molecular Structure of the Surfactant on the Interfacial Layer Stability.

During emulsification and further processing (e.g., pasteurizing), the oil-water interface is mechanically and thermally stressed, which can lead to oil droplet aggregation and coalescence, depending on the interfacial properties. Currently, there is a lack of insights into the impact of the molecular structure (headgroup and FA chain) of low molecular weight emulsifiers (LME) on the resulting interfacial properties. Additionally, the crystallization/melting of the oil/the emulsifier is often neglected within interfacial rheological experiments. Within this study, the stability of interfaces formed by Tween, Span or Brij was determined as a function of their molecular structure, taking crystallization effects of the LME into account. The headgroup was kept constant while varying the FA, or vice versa. The interfacial film properties (viscoelasticity) were investigated at different temperatures using dilatational and interfacial shear rheology. Both the headgroup and the FA chain impacted the interfacial properties. For the same FA composition, a rather small hydrophobic headgroup resulted in a higher packed interface. The interfacial elasticity increased with increased FA chain length (C12 to C18). This seemed to be particularly the case when the emulsifier crystallized on the interface among cooling. In the case of a densely packed interface, network formation due to chain crystallization of the LME's FA chains occurs during the cooling step. The resulting interface shows predominantly elastic behavior.

Lipid accumulation drives cellular senescence in dopaminergic neurons.

Parkinson's disease (PD) is an age-related movement disorder caused by the loss of dopaminergic (DA) neurons of the substantia nigra pars compacta (SNpc) of the midbrain, however, the underlying cause(s) of this DA neuron loss in PD is unknown and there are currently no effective treatment options to prevent or slow neuronal loss or the progression of related symptoms. It has been shown that both environmental factors as well as genetic predispositions underpin PD development and recent research has revealed that lysosomal dysfunction and lipid accumulation are contributors to disease progression, where an age-related aggregation of alpha-synuclein as well as lipids have been found in PD patients. Interestingly, the most common genetic risk factor for PD is Glucosylceramidase Beta 1 (GBA), which encodes a lysosomal glucocerebrosidase (GCase) that cleaves the beta-glucosidic linkage of lipids known as glucocerebrosides (GluCer). We have recently discovered that artificial induction of GluCer accumulation leads to cellular senescence of DA neurons, suggesting that lipid aggregation plays a crucial role in the pathology of PD by driving senescence in these vulnerable DA neurons. Here, we discuss the relevance of the age-related aggregation of lipids as well as the direct functional link between general lipid aggregation, cellular senescence, and inflammaging of DA neurons. We propose that the expression of a cellular senescence phenotype in the most vulnerable neurons in PD can be triggered by lysosomal impairment and lipid aggregation. Importantly, we highlight additional data that perilipin (PLIN2) is significantly upregulated in senescent DA neurons, suggesting an overall enrichment of lipid droplets (LDs) in these cells. These findings align with our previous results in dopaminergic neurons in highlighting a central role for lipid accumulation in the senescence of DA neurons. Importantly, general lipid droplet aggregation and global lysosomal impairment have been implicated in many neurodegenerative diseases including PD. Taken together, our data suggest a connection between age-related lysosomal impairment, lipid accumulation, and cellular senescence in DA neurons that in turn drives inflammaging in the midbrain and ultimately leads to neurodegeneration and PD.

Regulating interfacial structure of fat globules based on milk fat globule membrane with milk phospholipids to improve physicochemical properties and fat digestion of infant formula emulsions

Modulation of a suitable proportion of milk fat globule membrane (MFGM) and milk phospholipid (MPL) at the lipid droplet interface could be an effective strategy to improve the physicochemical properties and digestibility of infant formula emulsion (FE) systems that contain milk protein. The results showed that the distribution of lipid droplets became more uniform, and the adsorption of MFGM and MPL with different thicknesses was observed at the interface by adding different ratios of MFGM and MPL. Meantime, the stability of the FE was significantly increased than FE prepared by only protein-coated oil core, especially FE4 prepared by adding MFGM and MPL (1:3, w/w) as membrane components, the emulsifying activity index (48.28 m2/g) and emulsion stability index (73.08 min) reached the maximum. The emulsion prepared by phospholipid (PL) encapsulation oil core (FE5) exhibited lipid droplet aggregation and poor emulsion dispersion. The results of lipid digestion indicated that FE obtained with MFGM and MPL encapsulated lipid droplets maintained more PL ring structure similar to human milk structure during gastric digestion, which in turn promotes intestinal digestion of lipids by preventing the formation of protein aggregation. At the end of intestinal digestion, FE4 exhibited the highest lipolysis rate (86.48%) and release of free fatty acids (92.05 μmol/mL). Overall, the addition of a suitable ratio of MFGM to MPL, especially MFGM/MPL (1:3, w/w), contributes to the creation of a thin PL interface structure similar to that of human milk. This could facilitate fat degradation and fatty acid release by regulating the lipid droplet interface.

Freeze-thaw stability of high-internal-phase emulsion stabilized by chickpea protein microgel particles and its application in surimi.

Future applications of high-internal-phase emulsions (HIPEs) are highly regarded, but poor freeze-thaw stability limits their utilization in frozen products. This study aimed to characterize the structure of chickpea protein microgel particles (HCPI) induced by NaCl and to assess its impact on the freeze-thaw stability of HIPEs. The results showed that NaCl induction (0-400 mmol L-1) increased the surface hydrophobicity (175.9-278.9) and interfacial adsorbed protein content (84.9%-91.3%) of HCPI. HIPEs prepared with HCPI induced by high concentration of NaCl exhibited superior flocculation index and centrifugal stability, and their freeze-thaw stability was better than that of natural chickpea protein. The increase in NaCl concentration reduced the droplet aggregation and coalescence index of the freeze-thaw emulsions, diminishing the precipitation of oil from the emulsion. Linear and nonlinear rheology showed that the strengthened gel structure (higher G' values) restricted water flow and counteracted the damage to the interfacial film by ice crystals at 100-400 mmol L-1 NaCl, thus improving the viscoelasticity of the freeze-thaw emulsions. Finally, the thawing loss of surimi gel with HCPI-200 HIPE was reduced by 2.04% compared to directly adding oil. This study provided a promising strategy to improve the freeze-thaw stability of HIPEs and reduce the thawing loss of frozen products. © 2024 Society of Chemical Industry.