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This study explored the relationship between the interfacial behavior of lactoferrin-(−)-epigallocatechin-3-gallate covalent complex (LF-EGCG) and the stability of high internal phase Pickering emulsions (HIPPEs). The formation of covalent bond between lactoferrin and polyphenol was verified by the increase in molecular weight. In LF-EGCG group, the surface hydrophobicity, interfacial pressure, and adsorption rate were decreased, while the molecular flexibility, interfacial film viscoelasticity, and interfacial protein content were increased. Meanwhile, LF-EGCG HIPPE possessed reduced droplet size, increased ζ-potential and stability. Rheology showed the viscoelasticity, structural recovery and gel strength of LF-EGCG HIPPE were improved, giving HIPPE inks better 3D printing integrity and clarity. Moreover, the free fatty acids (FFA) release of LF-EGCG HIPPE (62.6%) was higher than that of the oil group (50.1%). Therefore, covalent treatment effectively improved the interfacial properties of protein particles and the stability of HIPPEs. The macroscopic properties of HIPPEs were positively regulated by the interfacial properties of protein particles. The result suggested that the stability of emulsions can be improved by regulating the interfacial properties of particles. • Covalent treatment improved the interfacial properties of lactoferrin. • High internal phase Pickering emulsions (HIPPEs) combined with the covalent complex (LF-EGCG) increased stability. • HIPPEs stabilized with LF-EGCG had better rheological and 3D printing properties. • Lactoferrin-based particles stabilized HIPPEs across a wide pH range (pH 3.0–9.0). [ABSTRACT FROM AUTHOR]

In order to prevent the photooxidation of phytosterols, a new type of Pickering emulsion was developed by regulating the oriented distribution of antioxidants in colloidal lipid particles (CLPs) at the oil-water interface. High-melting-point and low-melting-point lipids were tested to modulate their protective effect against phytosterols photooxidation. Results showed that CLPs could stabilize Pickering emulsion and encapsulate antioxidants, providing a dual functional delivery system for phytosterols protection. The Pickering emulsion formed had a particle size of around 350–820 nm, and the crystallization and melting temperatures of tripalmitin particles were approximately 32 °C and 63.8 °C, respectively. The addition of tributyrin or tricaprylin reduced the crystallization and melting temperatures of Pal CLPs and improved the photooxidation emulsion stability. The prepared Pickering emulsion remained stable for a maximum of 12 days under accelerated light-induced oxidation. Among all formulations, the emulsion primarily composed of tripalmitin CLPs, with added tributyrin and resveratrol, exhibited the highest photooxidation stability. [Display omitted] • Emulsions stabilized with colloidal lipid particles had anti-photooxidation effect. • Low-melting-point lipid could modulate the ability of colloidal lipid particles. • Resveratrol had the highest anti-photooxidation ability in Pickering emulsions. • The colloidal lipid particles were distributed at the oil-water interface. [ABSTRACT FROM AUTHOR]

Phytosterol, recognized for its health benefits, is predominantly extracted from plants and exhibits significantly reduced stability under varying light conditions. Their photooxidation is significantly influenced by emulsion interfaces. This study examined the mechanism of interface structure on phytosterol photooxidation with unparalleled molecular precision, utilizing molecular dynamics simulations and experimental procedures. Hydrogen bonding between the hydroxyl group at the C3 position of phytosterols and water molecules, coupled with van der Waals forces between the hydrophobic regions and the oil phase, induced phytosterol molecules to disperse toward the interface. The elevated polarity of the oil phase, specifically in tributyrin, facilitated the permeation of water molecules into the oil phase. This was achieved by diminishing the emulsion's interfacial tension, thereby fostering the development of more interface or micelles, and accelerating the photooxidation process of phytosterols. These simulations unraveled that the preponderance of phytosterol distribution is localized and oxidized at the oil-water interface. [Display omitted] • Molecular dynamic indicated phytosterols were located at O/W emulsion interface. • Phytosterols were impelled toward the interface through hydrogen bond with water. • Low polarity oil form more robust van der Waals force with phytosterols. • Polar oil molecules culminate in a less stable emulsion interface. • Oil pahse with higher viscosity ensnared phytosterols and reduce oxidation rate. [ABSTRACT FROM AUTHOR]

The impacts of enzymatically produced acylglycerol and glycerin monostearate on the characteristics of gelatin-stabilized omega-3 emulsions and microcapsules were investigated. Tuna oil was enzymatically produced and the resulting acylglycerol was mixed with tuna oil at 12.5% (w /w) to prepare a novel oil phase. This oil phase was stabilized by gelatin to prepare oil-in-water emulsions and subsequent microcapsules via complex coacervation. The tuna oil with glycerin monostearate (GMS) at 1 and 2% (w /w) were used as controls. Results showed that both acylglycerol and GMS significantly reduced the emulsion droplet size and zeta potential, while increasing the viscoelasticity and stability. The diacylglycerol/monoacylglycerol were involved in the oil/water interfacial layer formation by lowering interfacial tension and increasing droplet surface hydrophobicity. Overall, the changed emulsion properties promoted the complex coacervation and contributed to the formation of microcapsules with improved oxidative stability. Therefore, enzymatically produced acylglycerol can develop high-quality stable omega-3 microencapsulated novel food ingredients. • Acylglycerol and GMS improved gelatin-based emulsion stability by competitive adsorption. • Acylglycerol and GMS promoted gelatin‑sodium hexametaphosphate complex coacervation. • Acylglycerol and GMS microcapsules showed better oxidative stability than microcapsules with tuna oil alone. • Acylglycerol was shown to be a beneficial additive to fish oil for microcapsule stability. [ABSTRACT FROM AUTHOR]

Soybean protein isolate was modified with polysaccharides and polyphenols to prepare a natural emulsifier with antioxidant capacity. Physicochemical, structural, interfacial, and functional properties of SPI-SSPS complex were investigated after covalent and non-covalent interacted with EGCG. SPI-SSPS-EGCG ternary complex with low EGCG concentrations (0.0625 and 0.125 mg/mL) showed a significant increase in absolute potential value and a decrease in turbidity. EGCG destroyed the original rigid structure of SPI-SSPS complex, and the covalent complexes had an ordered structure, while the non-covalent interaction resulted in disordered. The ternary complex with high EGCG concentrations (0.25 and 0.5 mg/mL) exhibited stronger EGCG binding capacity and lower surface hydrophobicity, which in turn affected its interfacial properties. The EAI and ESI of SPI-SSPS-EGCG covalent complex increased significantly, while the non-covalent complex had a significant change in EAI but no significant change in ESI with increasing EGCG concentration. The ternary complex showed significantly enhanced antioxidant capacity. The SPI-SSPS-EGCG ternary complex, with excellent antioxidant capacity and emulsifying property, making it suitable for emulsion delivery systems. [Display omitted] • SPI-SSPS-EGCG ternary covalent and non-covalent complexes were prepared. • EGCG destroyed the original rigid structure of the SPI-SSPS complex. • Covalent complexes had ordered structures, while non-covalent became disordered. • Covalent complexes with 0.5 mg/mL EGCG had excellent emulsifying property. • The complexes with high EGCG concentrations exhibited strong antioxidant capacity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Glycosylation tuned structural and interfacial properties of egg white proteins. • EWPG exhibited better interactions with aliphatic amino acids. • EWPG-stabilized HIPPEs demonstrated superior physical stability. • EWPG-stabilized HIPPEs could co-deliver anthocyanins and melatonin. • The FFA release of HIPPEs followed the first-order kinetic model. This study was oriented towards the impacts of unique interfacial networks, formed by glycosylated and non-glycosylated egg white proteins, on the characteristics of high internal phase Pickering emulsions (HIPPEs). Glycosylated egg white protein particles (EWPG) manifested a more compact protein tertiary structure and amplified surface hydrophobicity, forming durable coral-like networks at the oil-water interface. The non-glycosylated egg white protein particles (EWP) could form spherical cluster interfacial networks. Raman spectroscopy analysis illuminated that EWPG could exhibit better interactions with aliphatic amino acids via hydrogen bonds and hydrophobic interactions. The release of free fatty acid (FFA) from both HIPPEs followed the first-order kinetic model with a combination of diffusion. EWPG-stabilized HIPPEs demonstrated superior physical stability and cellular antioxidant activity. This research shed light on the promising prospects of HIPPEs as promising amphiphilic delivery systems with capabilities to co-deliver hydrophilic and hydrophobic nutraceuticals and amplify their intracellular biological potency. [ABSTRACT FROM AUTHOR]

A whey protein isolate–rhodamine B conjugate (WPI-RB) was synthesized to visualize changes in the location of a protein emulsifier in oil-in-water emulsions during digestion. An oil-soluble dye (Nile Red) was used to visualize changes in the lipid phase during digestion. Protein-labeled and lipid-labeled emulsions were passed through a simulated gastrointestinal tract consisting of mouth, stomach, and intestinal phases, and changes in protein and lipid location and morphology were monitored using confocal laser scanning microscopy. The proteins remained attached to the lipid droplet surfaces in the mouth and stomach, but formed large aggregates in the small intestine. The lipid droplets were highly flocculated in the mouth, highly coalesced in the stomach, and fully digested in the small intestine. Our results show that conjugation of fluorescence dyes to protein emulsifiers is useful for direct visualization of their location, as well as for understanding the behavior of food emulsions within the gastrointestinal tract. [ABSTRACT FROM AUTHOR]

• The retention rate of cinnamaldehyde was 15 %∼20 % higher than that of eugenol. • The Schiff base reaction led to formation of elastic-dominated interfacial layers. • The viscous dominant weak interfacial layers were formed in the presence of eugenol. The addition of tea seed oil improved storage stability and retention rate of HIPPEs. • Cinnamaldehyde-loaded HIPPEs had better storage stability than eugenol-loaded HIPPEs. This work aimed to investigate the encapsulation and stabilization mechanism of cinnamaldehyde and eugenol in high internal phase Pickering emulsions (HIPPEs) through regulating their interfacial rheological properties and interfacial microstructure. With the incorporation of cinnamaldehyde, the Schiff base reaction between the cinnamaldehyde and proteins favored the formation of the predominantly elastic and solid-like interfacial layers. In contrast, the hydrogen bonds between eugenol and proteins resulted in the transformation of interfacial layers to viscous dominant with weak viscoelastic responses. Thus, cinnamaldehyde-loaded HIPPEs had a better storage stability than eugenol-loaded HIPPEs, and the retention rate was increased by about 15 %∼20 %. The addition of tea camellia seed oil inhibited the mobility of immobilized water and improved the retention rates of cinnamaldehyde and eugenol by approximately 6 % and 12 % (30 days at 25 °C), respectively. These findings will be beneficial for the development and design of effective essential oil encapsulation systems in the food industry. [ABSTRACT FROM AUTHOR]

Ultra-High Pressure Homogenization (100–300 MPa) has great potential for technological, microbiological and nutritional aspects of fluid processing. Its effect on the oxidative stability and interfacial properties of oil-in-water emulsions prepared with 4% (w/v) of soy protein isolate and soybean oil (10 and 20%, v/v) were studied and compared to emulsions treated by conventional homogenization (15 MPa). Emulsions were characterized by particle size, emulsifying activity index, surface protein concentration at the interface and by transmission electron microscopy. Primary and secondary lipid oxidation products were evaluated in emulsions upon storage. Emulsions with 20% oil treated at 100 and 200 MPa exhibited the most oxidative stability due to higher amount of oil and protein surface load at the interface. This manuscript addresses the improvement in oxidative stability in emulsions treated by UHPH when compared to conventional emulsions. [ABSTRACT FROM AUTHOR]

• TC or citral addition improves the interfacial properties of CAS at O/W interfaces. • TC addition enhances the surface dilatational modulus of CAS interfacial film. • TC binding involves hydrogen bonding and CAS conformational changes. • The binding between CAS and TC seems to be spontaneous. The interactions between sodium caseinate (CAS) and two natural aldehydes (trans -cinnamaldehyde (TC) and citral) were studied by evaluating oil/water (O/W) interfacial and fluorescence quenching properties. A small amount of TC in the oily phase resulted in lower O/W interfacial tension (9.12 mN/m). Particularly, the use of TC developed a stronger interface with higher elastic moduli (∼16.21 mN/m). This was supported by the fluorescence measurements: the quenching effect of TC on CAS was more pronounced than that of citral. Kinetic analysis indicated that both dynamic and static quenching occurs. The large binding constant (1.78 × 105 M−1) at 25 °C suggests that TC has strong affinity for CAS. Meanwhile, this binding process seemed to be spontaneous and driven by hydrogen bond formation with unfavorable conformational changes. This work would provide guidance for using the binding properties of natural aldehydes to enhance the interfacial properties of proteins. [ABSTRACT FROM AUTHOR]

• Insoluble soy peptide aggregates were modulated by hydrophobic modification. • Insoluble soy peptide aggregates with near-neutral wettability were obtained. • The modified insoluble soy peptide aggregates prepared Pickering emulsion gels. • Pickering emulsion gels exhibited a long-term storage stability. In this work, a highly stable food-grade Pickering emulsion gels was successfully prepared by hydrophobically modified insoluble soybean peptide aggregates. The relationships between the surface properties of insoluble soybean peptide aggregates and Pickering emulsion gels characteristics were clarified. After modification, the insoluble soybean peptide aggregates with high surface hydrophobicity had small particle size (377 nm), near-neutral wettability (θ o/w = 92°) and strong interfacial adsorption capability. These allowed the modified insoluble soybean peptide aggregates to stabilize the oil-water interface and form continuous network surrounding oil droplets, leading to the formation of stable Pickering emulsion gels. Besides, Pickering emulsion gels prepared by insoluble soybean peptide aggregates with higher surface hydrophobicity had smaller droplet size and higher gel strength, and remained stable even after 60 days of storage. The findings suggest a preferable plant protein particle for the preparation of stable Pickering emulsion gels in food industry. [ABSTRACT FROM AUTHOR]

• Refolded proteins exposed more hydrophobic groups and free sulfhydryl groups. • The pH-shifting treatment increased adsorption of interfacial proteins. • Emulsions stabilized by refolded proteins exhibited dispersed particle distribution. • The pH shifting altered tertiary and secondary structures of interfacial proteins. • MPs treated by pH 12.0 → 7.0 exhibited a multiple protein layer on oil surface. The emulsion abilities of pale, soft, exudative (PSE)-like chicken breast protein are unsatisfied, which are urgently needed to be ameliorated. This study evaluated the improvement of pH-shifting (11.0-, 11.5- and 12.0–7.0) on emulsion properties of the PSE-like chicken breast myofibrillar proteins (MPs) and the underlined structure-driven interfacial mechanism. It was found pH-shifting promoted the exposure of buried hydrophobic groups and free sulfhydryl groups, and changed secondary structures. Emulsions stabilized by refolded MPs exhibited more uniform and dispersed distributions with more adsorbed proteins at the interface. Electrophorogram showed both disulfide and non-disulfide covalent bonds were involved during interfacial protein–protein interaction. The results from circular dichroism and front-surface fluorescence spectroscopy revealed interfacial MPs were exposed to a more hydrophobic environment and increased β-sheets enhanced their molecular interactions. In addition, interfacial proteins after pH-shifting was less likely to be replaced by Tween 20. [ABSTRACT FROM AUTHOR]

Highlights: [•] The review covers plant and animal protein stabilised emulsions. [•] The review covers protein dynamics and affinity to the oil–water interface. [•] The review discusses mechanisms of emulsion instability. [•] The review discusses the effect of polysaccharides on protein-stabilised emulsions. [ABSTRACT FROM AUTHOR]

• TAG and interfacial properties of goat milk fat globule were different from cow milk. • Effect of processing on goat milk fat globule digestion was different from cow milk. • TAG and interfacial properties both affected goat and cow milk fat globule digestion. • Mechanism of different digestion between goat and cow milk fat globule was clarified. The different TAG, interfacial properties and digestion rate between goat and cow milk fat globules were investigated. The mechanism of their different lipid digestion was also elucidated. Raw goat milk fat globules had smaller size, less large molecular weight and unsaturated TAG, larger liquid-ordered region and fewer glycoproteins, which contributed to the higher digestion rate than cow milk. After homogenization, the goat lipids also had higher digestion rate that was attributed to the special structure of easy-to-digest TAG and less glycosylated molecules not globule size. More integrated phospholipid layers and glycosylated molecules of HTST milk fat globules resulted in a lower lipid digestion rate than other processed milks. No difference in digestion rate between pasteurized goat and cow milk fat globules might be explained by the more denatured proteins and glycosylated molecules, respectively. Therefore, the TAG and interfacial properties contributed to different digestion between goat and cow milk fat globules. [ABSTRACT FROM AUTHOR]

[Display omitted] • A methanotrophic fermentation biomass was characterized by quantitative proteomics. • Emulsifier peptides were predicted from different sustainable protein sources. • Peptides from seaweed, microbial and potato proteins displayed emulsifying activity. • Interfacial conformation, length, and amphiphilicity affect emulsion stability. • Peptides showed emulsifying activity comparable to or better than sodium caseinate. Global focus on sustainability has accelerated research into alternative non-animal sources of food protein and functional food ingredients. Amphiphilic peptides represent a class of promising biomolecules to replace chemical emulsifiers in food emulsions. In contrast to traditional trial-and-error enzymatic hydrolysis, this study utilizes a bottom-up approach combining quantitative proteomics, bioinformatics prediction, and functional validation to identify novel emulsifier peptides from seaweed, methanotrophic bacteria, and potatoes. In vitro functional validation reveal that all protein sources contained embedded novel emulsifier peptides comparable to or better than sodium caseinate (CAS). Thus, peptides efficiently reduced oil–water interfacial tension and generated physically stable emulsions with higher net zeta potential and smaller droplet sizes than CAS. In silico structure modelling provided further insight on peptide structure and the link to emulsifying potential. This study clearly demonstrates the potential and broad applicability of the bottom-up approach for identification of abundant and potent emulsifier peptides. [ABSTRACT FROM AUTHOR]

• A co-product of hempseed called HM-PI was characterized as affected drying process. • HM-PI showed high protein concentration with good amino acid profile. • HM-PI exhibited functional characteristics that are common to protein ingredients. • HM-PI gastrointestinal digests have antioxidant and anti-inflammatory activities. Hempseed meal after protein isolation (HM-PI) is a co-product obtained from hempseed. The objectives were to characterize and determine the effect of drying on HM-PI. HM-PI was produced using three drying methods: freeze (FD), vacuum oven (VOD), and oven drying (OD). HM-PI contained over 70% protein and had similar or higher level of essential amino acids than recommended values for human adults. Osborne fractionation indicated that glutelin was the most dominant fraction in HM-PI. FD HMPI has a significant lower surface hydrophobicity and higher in vitro protein digestibility than OD and VOD HM-PI. FD HM-PI demonstrated better functional properties than OD and VOD HM-PI. Pepsin-pancreatin digestion of VOD, FD and OD resulted in comparable and considerable antioxidant and anti-inflammatory properties. This is the first report on the characterization of HM-PI, a co-product of hempseed processing. HM-PI could serve as a novel food protein ingredient resulting in increase utilization of hempseed. [ABSTRACT FROM AUTHOR]

• A Bacillus mojavensis strain producing exopolysaccharides was isolated from soil samples. • A high molecular weight levan was the main polysaccharide present. • Levan was structurally analyzed by NMR, SEM and methylation analyses. • Levan possessed interesting interfacial properties. • Levan could be a promising emulsifying agent to food industries. A strain with high exopolysaccharide (EPS) production was isolated from soil and identified as Bacillus mojavensis based on the 16S rRNA gene sequencing and biochemical properties. The EPS produced simultaneously with the growth phase reached a maximum of 22 g/L after attaining a stationary phase with sucrose used as sole carbon source. B. mojavensis EPS (BM-EPS) was recovered, fractionated by ethanol precipitation and analysed by NMR and methylation analyses. The BM-EPS was found to be composed of (β2 → 6)-Fru f residues, characteristic of a levan, with an average molecular weight of 2.3 MDa. A homogeneous micro-porous and rough structure matrix was observed by SEM of the freeze-dried powdered sample. A concentration-dependent water-soluble nature was observed, with good water (5.3 g/g) and oil (36 g/g) holding capacities. The levan displayed good emulsification activity with excellent stability against food grade oil, thus favoring it as a promising emulsifying agent to food industries. [ABSTRACT FROM AUTHOR]