Search

Fish oil contains omega-3 polyunsaturated fatty acids, but their poor oxidation stability and gastrointestinal digestion rate led to the low bioavailability. Oleogels could improve the stability of EPA and DHA, so the effect of beeswax (BW)-based fish oil oleogels (FOGs) on the stabilization mechanism and lipid digestion of bi-layer emulsions was investigated. The results showed that the enhanced BW crystals lowered the myofibrillar protein (MP) unfolding along with the decrease in β -sheets, hydrophobic force and disulfide bond, thus reducing the interfacial adsorption capacity and emulsion stability. The enhanced BW formed the rigid crystal network structure and improved the crystal size in the inner layer. The suitable FOG addition (4 wt%) enhanced the unfolding of advanced structures in the outer layer, and the exposure of more hydrophobic groups and disulfide bonds facilitated the interfacial adsorption, thus reducing the size. The final release rate of FFAs significantly decreased with the increasing BW, and significantly increased and decreased with the increasing FOG. BW and FOGs could induce the changes in spatial conformation, and the exposure of hydrophobic groups and disulfide bonds affected the lipase contact at the interface. BW and FOG could adjust the crystal network structure in the inner layer and spatial conformation in the outer layer, thus improving the stabilization and lipid digestion of bi-layer emulsions. This study can provide a theoretical basis for developing DHA and EPA food. [Display omitted] • Beeswax crystal lowered the protein unfolding and interfacial adsorption capacity. • FOGs facilitated the molecular interaction, thus improving the emulsion stability. • High hydrophobic forces and disulfide bonds delayed the lipid digestion. • Spatial conformation could adjust the interfacial stability and replacement. [ABSTRACT FROM AUTHOR]

pH-induced and ultrasound treatment can both adjust spatial conformation to improve the interfacial stability, and fish oil oleogel could be used to enhance oil binding capacity. The relationship between stabilization mechanism and lipid digestion was revealed, considering the protein conformation and interfacial characteristics. The results showed that pH-ultrasonic-induced myofibrillar proteins (MPs) at pH 7.0 had higher interfacial adsorption capacity and surface hydrophobicity as well as more stable secondary structures, which lowered the particle size and enhanced the interfacial stability. In the stomach, the particle size increased along with the decrease in electrostatic repulsion, and β -sheets significantly increased, which promoted aggregation and flocculation. In the small intestine, the reduction of β -sheets favored the interfacial replacement and facilitated the lipid digestion. Therefore, pH-ultrasonic-modified method improved the structure and function of MPs, facilitated the interfacial stability and intestinal digestion. [Display omitted] • pH-ultrasonic-induced MPs improved the stability of structured lipid emulsions. • pH-ultrasonic-induced treatment facilitated interfacial adsorption and unfolding. • The specific conformation facilitated the lipid digestion. • Hydrophobic forces and disulfide bonds affected the stability and lipid digestion. [ABSTRACT FROM AUTHOR]

Fish oil contains rich EPA and DHA, but their low absorption rate and bioavailability in the gastrointestinal tract limit their physiological activity. Ultrasonic treatments can modify the spatial structure of myofibrillar proteins and influence their function. The microstructure, viscoelastic properties, spatial conformation, size and charge, interfacial characteristics were investigated in the emulsions with fish oil oleogels to clarify the mechanism between emulsification stability and lipid digestion by ultrasonic treatment. The results showed that ultrasonic-treated (120 s or 150 W) fish myofibrillar protein had higher interfacial protein concentration and formed the more stable interfacial adsorption layer to wrap the fish oil oleogel with higher viscoelastic properties. The surface charge density was affected by adsorbed proteins, and higher interfacial adsorption capacity enhanced electrostatic repulsion and reduced the size. CLSM images also indicated that the droplet distribution was more uniform with smaller particle size. The increase in β -sheets facilitated interfacial adsorption and emulsion stability, and hydrophobic force and disulfide bonds promoted the interactions between myofibrillar protein and fish oil oleogel. In the stomach, the demulsification and flocculation occurred, and β -sheets increased along with hydrophobic forces and disulfide bonds, facilitating flocculation and aggregation as well as the increase in particle size. The electrostatic repulsion and spatial conformation altered the molecular interaction. In the intestine, the decreasing β -sheets, hydrophobic force and disulfide bonds were conducive to the adsorption of bile salts and lipase/colipase. Hence, ultrasonic treatments simultaneously enhanced emulsion stability and lipid digestion. [Display omitted] • The adjustment in electrostatic repulsion and particle size promoted the stability and digestion. • Ultrasound treatments facilitated interfacial re-arrangement, affecting the digestion. • The decreasing hydrophobic force and disulfide bonds improved the digestion. • The enhancement in emulsification stability facilitated the digestion by ultrasound treatment. [ABSTRACT FROM AUTHOR]

Glycerol acetonide, also termed solketal, which is chemically derived from bio-glycerol, was used as a combustion improver in the dispersed emulsion phase in this study. Nano-emulsions of ultra-low sulfur diesel (ULSD) containing nano-sized droplets of solketal were produced using microwave irradiation and compared with those produced by mechanical homogenizing. A non-ionic surfactant mixture of Tween 80 and Span 80, with a combined hydrophile-lipophile balance (HLB) adjusted to 10 by the weight proportion of the two surfactants was added to assist the emulsion formation. The characteristics of the emulsions produced using the two methods were analyzed and compared. The experimental results show that nano-emulsions can only form when up to 15 wt% of surfactant and no more than 5 wt% of solketal are added. The nano-emulsions from microwave irradiation had a larger mean droplet size, more concentrated one-peak distribution of droplet size, and lower kinematic viscosity and emulsification stability (ES) than those from the mechanical homogenizer. Higher solketal content in the emulsion increased the mean droplet size and kinematic viscosity of the nano-emulsions prepared using either method, and decreased the emulsification stability. The nano-emulsions with 3 wt% solketal in the dispersed phase also had superior characteristics including the lowest mean droplet size and highest ES. This is thus suggested to be the optimum composition. [ABSTRACT FROM AUTHOR]

[Display omitted] • A lysozyme (Lys)-oregano essential oil (OEO) antibacterial emulsion successfully inhibited the growth of E. coli and S. aureus. • Ultrasonic treatment improved the stability of Lys-OEO antibacterial emulsion. • The best dispersion and stability of emulsion were both achieved at 600 W. • CLSM image demonstrated the oil-in-water type of Lys-OEO antibacterial emulsion. A lysozyme-oregano essential oil (Lys-OEO) antibacterial emulsion was developed via ultrasonic treatment. Based on the general emulsion materials of ovalbumin (OVA) and inulin (IN), the addition of Lys and OEO successfully inhibited the growth of E. coli and S. aureus , two representatives of which were Gram-negative and Gram-positive bacteria respectively. The emulsion system in this study was designed to compensate for the limitation that Lys could only act on Gram-positive bacteria, and the stability of the emulsion was improved using ultrasonic treatment. The optimal amounts among OVA, Lys and OEO were found to be the mass ratio of 1:1 (Lys to OVA) and 20% (w/w) OEO. The ultrasonic treatment at the power of 200, 400, 600, and 800 W and time length of 10 min improved the stability of emulsion, in which the surface tension was below 6.04 mN/m and the Turbiscan stability index (TSI) did not exceed 10. The multiple light scattering showed that sonicated emulsions were less prone to delamination; salt stability and pH stability of emulsions were improved, CLSM image showed emulsion as oil-in-water type. In the meantime, the particles of the emulsions were found to become smaller and more uniform with ultrasonic treatment. The best dispersion and stability of the emulsion were both achieved at 600 W with a zeta potential of 7.7 mV, the smallest particle size and the most uniform particle distribution. [ABSTRACT FROM AUTHOR]

Tea polysaccharide conjugates (TPCs) are macromolecular polymers comprising polypeptides covalently bound to polysaccharides with a wide range of molecular weights that are found in tea leaves. We previously found that TPCs had emulsifying properties, but the difference in the emulsification stabilities between the high- and low-molecular-weight TPCs was unknown. In this study, the total polysaccharide conjugates (gTPC-T) with average molecular weight of 258,900 Da were extracted from low-grade green tea, from which two separate fractions with average molecular weights of 989,600 Da (22.43%) and 47,780 Da (77.57%), which were referred to as gTPC-1 and gTPC-2, respectively, were separated using an ultrafiltration membrane. The polypeptide chains of the three TPCs (gTPC-T, gTPC-1, and gTPC-2) contained 17 out of the 20 canonical amino acids. In addition, gTPC-1 had the highest acidic monosaccharide content. Circular dichroism (CD) an analysis showed that the secondary structures of the protein moieties of the three TPCs were dominated by α-helices. The nano-differential scanning calorimetry (Nano-DSC) results showed that the transition midpoints (T m) of the three samples were 86.69, 59.53, and 68.59 °C, respectively. The zeta potential of gTPC-T at weakly acidic or neutral pH (4.0–7.0) was the highest, followed by gTPC-1 and then gTPC-2. Of all three gTPCs, gTPC-1 had the smallest interfacial tension, the highest interfacial pressure, and the best interfacial activity. In addition, gTPC-T slightly better-stabilized the MCT oil-in-water emulsions than gTPC-1, while the emulsification stability of gTPC-2 was the worst. This trend was likely attributed to the synergistic effect between gTPC-1 and gTPC-2. [Display omitted] • Polysaccharide conjugates (gTPC-T) with average molecular weight of 258,900 Da were prepared from low-grade green tea. • gTPC-T was isolated two fractions of TPC by ultrafiltration membrane, named as gTPC-1(989,600 Da) and gTPC-2 (47,780 Da). • The physicochemical properties of gTPC-T, gTPC-1 and gTPC-2 were characterized. • gTPC-1 has stronger emulsifying ability than gTPC-2. [ABSTRACT FROM AUTHOR]

Abstract: In order to improve the oil–water separation of wastewater produced in polymer flooding of oil field, the emulsification stability of wastewater was investigated by using laser particle-size distribution analyzer, potential measurement and flocculation test. The influences of polymer, water treatment agent, solution viscosity and temperature on emulsification stability were analyzed. The experimental results show that the emulsification stability is mainly determined by the size distribution of oil droplets in wastewater. The addition of polymer will enhance steric hindrance among oil droplets and decrease the efficiency of collision of oil droplets, which results in lower size of oil droplet and slower floating speed. The higher the polymer concentration, the more stable the emulsion. Therefore, the key for improving the efficiency of oil–water separation is to decrease the activation energy barrier for oil droplets coalescence, which can promote the coalesce of tiny oil droplets to from large ones. [Copyright &y& Elsevier]

• The ultrasonic power of 400 W can unfold the structure of CBTMP significantly. • Emulsification was improved by CBTMP especially for 400 W. • Interfacial properties were enhanced by ultrasonic pretreatment. • Rheology behavior of CBTMP emulsions was promoted by ultrasonic treatment. Clanis Bilineata Tingtauica Mell Protein (CBTMP) is a naturally high-quality insect protein resource, while its poor emulsification has limited its application in food industry. In order to change the present situation, in this research, the ultrasonic pretreatment (0 W, 200 W, 400 W, 600 W, and 800 W) method was used to improve the emulsification properties of CBTMP. Results indicated that ultrasound treatment especially at 400 W could significantly change the particle sizes, further increase the content of sulfhydryl group and surface hydrophobicity. The emulsification properties of emulsions were enhanced (from 4.16 ± 1.07 m2/g to 27.62 ± 2.20 m2/g) by sonicated CBTMP solution. Moreover, the physical stability of the emulsions to salt stress and centrifugation treatment was also promoted. Additionally, rheology revealed that a stronger network was formed at 400 W and all samples exhibited frequency-dependent and amplitude-dependent properties. The experiment demonstrated that ultrasound pretreatment was an effective means to improve the emulsification properties of CBTMP and it could provide a promising perspective for the application of CBTMP in food industry. [ABSTRACT FROM AUTHOR]

[Display omitted] • Small and uniform (su) OVA solution was obtained by ultrasound especially at 300 W. • Emulsification properties of OVA-PES-PSO emulsions were enhanced by suOVA particles. • Interface and rheology properties of OVA-PEC-PSO emulsions were promoted by suOVA. • Antioxidant activity of OVA-PEC-PSO emulsion were improved by suOVA particles. • The oxidation of pumpkin seed oil was delayed in suOVA-PEC-PSO emulsion. Pumpkin seed oil (PSO), which is a valuable compound with high nutritional value used for the prevention of various chronic diseases, is prone to oxidation. In this work, small and uniform (su) ovalbumin (OVA) and pectin (PEC) were used to stabilize PSO in the form of an emulsion. The results showed that suOVA-PEC-PSO emulsion with a droplet size of 9.82 ± 0.05 μm was successfully self-assembled from PSO, PEC, and suOVA solution (with a droplet size of 230.13 ± 14.10 nm) treated with 300 W ultrasound, owing to the formation of a more stable interfacial film on the surface of droplets. The interfacial, rheological, emulsifying, and antioxidant properties of the suOVA-PES-PSO emulsions were excellent, owing to the synergistic effects between PEC and suOVA solution. Moreover, the physical stability of the suOVA-PEC-PSO emulsions to salt stress, a freeze-thaw cycle, and heat treatment was also increased and the oxidation of linolenic acid was notably delayed. These results have extended the food-related applications of OVA and PSO, and provide a promising foundation for further exploration of the self-assembly of composite emulsions by small and uniform proteins. [ABSTRACT FROM AUTHOR]

[Display omitted] • The stimulus-responsiveness of surfactin to acetoin were disclosed. • Acetoin changed the interfacial assembly conformation of surfactin. • Acetoin decreased the surfactin solution wettability to silicate surface. • The crude oil-washing performance of surfactin was obviously inhibited by acetoin. Due to its special structure, the cyclic lipopeptide surfactin showed remarkable responsiveness to stimuli such as pH, temperature and metal ions. However, few studies investigated the effect of fermented by-products on the conformational change and interfacial assembly of surfactin. Here, the effect of acetoin, a primary metabolite of Bacillus subtilis , on the conformational change and interfacial assembly of surfactin was studied in detail. Surface tension measurements showed that the critical micelle concentration (CMC) of surfactin increased from 1.14 × 10−5 to 4.32 × 10−5 M in the presence of acetoin. Moreover, acetoin has increased the interfacial tension of surfactin aqueous solution-crude oil from 1.08 mN/m to 3.01 mN/m. Circular dichroism (CD) spectra and dynamic light-scattering (DLS) further demonstrated that acetoin had induced the conformational transition of surfactin from β-sheet to β-turn structure, and caused surfactin forming some larger micelle aggregations. Afterwards, it was further found that acetoin decreased the oil sand cleaning efficiency of surfactin from 59.7% to 6.6%, and deteriorated the O/W emulsion stability and altered the silicate wettability toward less water wet state. Based on the experimental results, a possible mechanism of the interaction between surfactin and acetoin was proposed. [ABSTRACT FROM AUTHOR]