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Summary: Bighead carp has the largest production amount among freshwater fish in China, but its physicochemical properties change rapidly with the denaturation of their myofibril protein (MP). The protein–polysaccharide complexes have shown interesting physicochemical properties as stabilisers and emulsifiers. In this study, arabinoxylans (AXs) were prepared and mixed with bighead carp MP to form a composite gel. The effect of AXs on the thermal stability, emulsification and emulsion stability of the composite gel was investigated. The results showed that fraction precipitated by 60% ethanol (F60) and by 90% (F90) improved the denaturation temperature of bighead carp MP from 65.99 °C to 67.39 °C and 68.22 °C, respectively. The emulsifying capacity of F60 (0.54 m2 g−1) was similar to that of sucrose (0.52 m2 g−1). The effect of F90 on the emulsion stability of bighead carp MP was better than that of F60. The elasticity of bighead carp MP was improved by F60 and F90. The hydroxyl group interactions, hydrophobic interactions and electrostatic forces exist between the macromolecules. AXs of fresh maize bran could prevent protein denaturation and improve the emulsion capacity and gel properties of bighead carp MP. [ABSTRACT FROM AUTHOR]

Emulsified meat products are key deep-processing products due to unique flavor and high nutritional value. Myosin dissolves, and protein aggregation and heat-induced gelation occur after myosin unfolds and hydrophobic groups are exposed. Myosin could form interfacial protein membranes and wrap fat globules. Emulsified fat globules may be filled in heat-induced gel networks. Therefore, this review intends to discuss the influences of heat-induced gelation and interfacial adsorption behavior on oil and water retention. Firstly, the mechanism of heat-induced gelation was clarified from the perspective of protein conformation and micro-structure. Secondly, the mechanism of emulsification stability and its factors affecting interfacial adsorption were demonstrated as well as limitations and challenges. Finally, the structure characteristics and application of multi-layer hydrogels in the gelation and emulsification were clarified. It could conclude that the characteristic morphology, spatial conformation and structure adjustment affected heat-induced gelation and interfacial adsorption behavior. Spatial conformation and microstructure were adjusted to improve the oil and water retention by pH, ionic strength, amino acid, oil phase characteristic and protein interaction. Multi-layer hydrogels facilitated oil and water retention. The comprehensive review of gelation and emulsification mechanisms could promote the development of meat products and improvement of meat processing technology. [ABSTRACT FROM AUTHOR]

The emulsification stability of microalgae protein (MP) is limited to strongly alkaline conditions, restricting its applications in food processing. This study aims to investigate the capability of carboxymethyl chitosan (CMCS) to improve MP's emulsification stability over a wider pH range. Results indicated soluble MP-CMCS complexes formed at pH 2, 4, and 7, while aggregation of the complexes occurred at pH 8. The complexes stabilized emulsions exhibited smaller droplet sizes and higher absolute zeta potential at pH 2, 4, and 7 compared to pH 8. After 2 weeks of storage, emulsions remained stable at pH 2, 4, and 7, with significant delamination at pH 8. Laser confocal microscopy confirmed uniform droplet distribution at pH 2 and 7, with slight fusion at pH 4. The complexes stabilized emulsions exhibited higher viscosity and shear stress than MP stabilized emulsions at pH 2, 4, and 7. The stronger viscoelastic properties and higher storage moduli (G') values of MP-CMCS complexes under acidic and neutral conditions indicated stronger intermolecular interactions compared to alkaline conditions. The increase in G' and loss moduli (G'') values for emulsions at pH 8 under stress highlighted the significant impact on network structure strength and viscosity in these emulsions. This study elucidated the binding interactions between MP and CMCS under various pH conditions, and demonstrated a feasible approach to improving MP's emulsification stability over a wider pH range.

The development of oil and gas resources in low-permeability reservoirs is being paid more and more attention. Moreover, oil and gas resources in low-permeability reservoirs are affluent, and the water cut of the medium permeability layer is so high that the injection capacity has decreased significantly. Therefore, it is of great importance to address the issues of injectability and enhance oil recovery in low-permeability reservoirs. Given the existing conditions of low permeability and high water cut in Daqing Oilfield, the synthesis of an in situ emulsified associative polymer (ISEPAM) is the focus of the research. The polymer was prepared by micellar polymerization, ensuring a molecular weight of 5 × 106 Dalton. A series of experiments were conducted to investigate its dissolution filtration property, viscosifying, emulsification, anti-adsorption, conductivity, and oil displacement capacity. The experimental results show that ISEPAM has more significant properties than the polymeric surfactant (HB) used in Daqing Oilfield. The ISEPAM solution has significant filterability (filter factor is 1.1), viscosifying (38.66 mPa·s), emulsification (the water evolution rate of ISEPAM was only 4.4% for 60 min at 90% water cut), and good anti-adsorption property (after five adsorptions, still has a viscosity retention rate of 65%) in a specific concentration (1000 mg/L) and the field water in Daqing Oilfield (salinity is 4996.3 mg/L). The reason for this is due to the presence of dynamic reversible networks in the ISEPAM solution, and there are no cationic functional groups on the polymer chain. The conductivity of ISEPAM was tested using a homogeneous square core with 48.1 mD permeability, and the results show that the viscosity retention rate of the effluent can reach 90% and excellent injection property can be achieved. In the oil displacement test, ISEPAM presents excellent sweep efficiency and enhanced oil recovery by about 25% under 50 mD permeability. Under low permeability conditions, the ISEPAM exhibits better injectability and excellent oil displacement capacity. The related findings can provide an important idea and reference for the design and development of EOR polymers in the reservoirs with low permeability or high water cut. [ABSTRACT FROM AUTHOR]

In this experiment, Forsythia suspensa was used as raw material to extract insoluble dietary fiber (IDF) by double enzyme method, and then the extracted IDF was chemically modified by carboxymethylation (CM), hydroxypropylation (HP) and cross-linking (CL), and their physicochemical properties, structure and emulsifying properties were analyzed. The results showed that the modified treatment reduced the water holding capacity of Forsythia suspensa IDF and significantly increased the oil holding capacity by 21%~53.0% (P

In this study, Tartary buckwheat starch was modified to different degrees of substitution (DS) with octenyl succinate anhydride (OS-TBS) in order to explore its potential for stabilizing Pickering nanoemulsions. OS-TBS was prepared by reacting Tartary buckwheat starch with 3, 5 or 7% (w/v) octenyl succinate in an alkaline aqueous solution at pH 8.5. Fourier-transform infrared spectroscopy gave peaks at 1726 cm−1 (C=O) and 1573 cm−1 (RCOO−), indicating the formation of OS-TBS. We further studied the physicochemical properties of the modified starch as well as its emulsification capacity. As the DS with octenyl succinate anhydride increased, the amylose content and gelatinization temperature of the OS-TBS decreased, while its solubility increased. In contrast to the original Tartary buckwheat starch, OS-TBS showed higher surface hydrophobicity, and its particles were more uniform in size and its emulsification stability was better. Higher DS with octenyl succinate led to better emulsification. OS-TBS efficiently stabilized O/W Pickering nanoemulsions and the average particle size of the emulsion was maintained at 300–400 nm for nanodroplets. Taken together, these results suggest that OS-TBS might serve as an excellent stabilizer for nanoscale Pickering emulsions. This study may suggest and expand the use of Tartary buckwheat starch in nanoscale Pickering emulsions in various industrial processes. [ABSTRACT FROM AUTHOR]

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]

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.

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]

In this study, the effect of various heating temperatures (61–70 °C) and times (1–10 min) on physical and chemical properties of liquid egg yolk (LEY) and mayonnaise were investigated. Initially, we found that the increase of LEY protein denaturation was highly correlated with the increase of temperature and time, without causing either protein degradation or aggregation. In addition, the viscosity and particle size of LEY were significantly increased with greater heating temperature and time. Furthermore, the emulsification stability of mayonnaise prepared from thermally processed LEY were significantly better than that of the unheated control group, in particular, the emulsion stability of mayonnaise was higher at a temperature ranging from 62 °C to 68 °C, whereas the emulsion stability decreased above 69 °C. A rheological analysis showed that mayonnaise prepared from thermally processed LEY has higher shear stress when compared with the control group. Indeed, a sharp increase in the shear stress was observed when LEY was heated above 67 °C. Results from storage behavior analysis suggest that mayonnaise prepared from thermally processed LEY failed to affect the chemical qualities of mayonnaise, as evidenced by the fact that acid values and TBA values were not statistically significant with the unheated control group. Microscopic observation indicates that the number of complete oil droplets were significantly reduced at higher heating (70 °C/5 and 10 min) conditions. Finally, the sensory evaluation results suggest that mayonnaise prepared from thermally processed LEY does not influence the appearance, aroma, taste, greasy feeling, and overall acceptance of mayonnaise, as indicated by there being no significant differences between the experimental group and the control group (p > 0.05). We conclude from our study that a combination of heating conditions over 67 °C/5 min can allow the mayonnaise to retain better quality in terms of stability. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Northwest A & F University - Natural Science Edition is the property of Editorial Department of Journal of Northwest A&F University (Natural Science Edition) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The differences of emulsion properties between normal colour chicken livers (NCCLs) and discolouration chicken livers (DCCLs) were evaluated. Compared with NCCLs, the L* and b*-value of DCCLs were extremely higher (p

In this study, Tartary buckwheat starch was modified to different degrees of substitution (DS) with octenyl succinate anhydride (OS-TBS) in order to explore its potential for stabilizing Pickering nanoemulsions. OS-TBS was prepared by reacting Tartary buckwheat starch with 3, 5 or 7% (w/v) octenyl succinate in an alkaline aqueous solution at pH 8.5. Fourier-transform infrared spectroscopy gave peaks at 1726 cm−1 (C=O) and 1573 cm−1 (RCOO−), indicating the formation of OS-TBS. We further studied the physicochemical properties of the modified starch as well as its emulsification capacity. As the DS with octenyl succinate anhydride increased, the amylose content and gelatinization temperature of the OS-TBS decreased, while its solubility increased. In contrast to the original Tartary buckwheat starch, OS-TBS showed higher surface hydrophobicity, and its particles were more uniform in size and its emulsification stability was better. Higher DS with octenyl succinate led to better emulsification. OS-TBS efficiently stabilized O/W Pickering nanoemulsions and the average particle size of the emulsion was maintained at 300–400 nm for nanodroplets. Taken together, these results suggest that OS-TBS might serve as an excellent stabilizer for nanoscale Pickering emulsions. This study may suggest and expand the use of Tartary buckwheat starch in nanoscale Pickering emulsions in various industrial processes.

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.

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.

Polysaccharides are macromolecules used for food development, and their further separation into different molecular weights allows their broader application in the food industry. Here, we performed microwave-assisted ammonium oxalate extraction of soy hull polysaccharide (SHP; MASP), followed by their separation and purification using membrane-separation technology and analyses of the emulsifying stability and MASP mechanism at different molecular weights. Additionally, we compared the composition and structural differences in SHP components and evaluated the separation and grading-emulsification stability properties of the membrane-emulsified components. The results showed improved emulsification stability properties of high molecular weight SHPs that had been separated and purified by membrane separation, with the formed emulsion exhibiting a high degree of viscosity, uniform particle-size distribution, smaller particle size, less interfacial tension, and a high Zeta potential. Moreover, the chemical composition, monosaccharide composition, and molecular weight of SHP were different. [ABSTRACT FROM AUTHOR]

In this study, the effect of various heating temperatures (61–70 °C) and times (1–10 min) on physical and chemical properties of liquid egg yolk (LEY) and mayonnaise were investigated. Initially, we found that the increase of LEY protein denaturation was highly correlated with the increase of temperature and time, without causing either protein degradation or aggregation. In addition, the viscosity and particle size of LEY were significantly increased with greater heating temperature and time. Furthermore, the emulsification stability of mayonnaise prepared from thermally processed LEY were significantly better than that of the unheated control group, in particular, the emulsion stability of mayonnaise was higher at a temperature ranging from 62 °C to 68 °C, whereas the emulsion stability decreased above 69 °C. A rheological analysis showed that mayonnaise prepared from thermally processed LEY has higher shear stress when compared with the control group. Indeed, a sharp increase in the shear stress was observed when LEY was heated above 67 °C. Results from storage behavior analysis suggest that mayonnaise prepared from thermally processed LEY failed to affect the chemical qualities of mayonnaise, as evidenced by the fact that acid values and TBA values were not statistically significant with the unheated control group. Microscopic observation indicates that the number of complete oil droplets were significantly reduced at higher heating (70 °C/5 and 10 min) conditions. Finally, the sensory evaluation results suggest that mayonnaise prepared from thermally processed LEY does not influence the appearance, aroma, taste, greasy feeling, and overall acceptance of mayonnaise, as indicated by there being no significant differences between the experimental group and the control group (p > 0.05). We conclude from our study that a combination of heating conditions over 67 °C/5 min can allow the mayonnaise to retain better quality in terms of stability.

The differences of emulsion properties between normal colour chicken livers (NCCLs) and discolouration chicken livers (DCCLs) were evaluated. Compared with NCCLs, the L* and b*-value of DCCLs were extremely higher (p <.05), but the a*-value, cooking loss and emulsification stability were lower (p <.05). The elasticity and cohesiveness of two kinds of livers had significant difference (p <.05) after 45 °C. The particle size and optical morphology of the emulsion prepared with NCCLs were significantly smaller than that of the emulsion prepared with DCCLs (p <.05), and the emulsion of NCCLs was stable and uniform distribution. Overall, the NCCLs presented more stable emulsification properties than DCCLs, and the formed emulsion was exquisite and uniform. The results indicated that in order to obtain high quality emulsified chicken liver products, it might be necessary to select the NCCLs instead of DCCLs as raw material to process. The NCCLs could be great feasible and potential application in the development of emulsified chicken liver paste products. NCCLs had better emulsifying stability, cohesiveness and elasticity than DCCLs. Emulsion prepared with NCCLs presented stable and uniform distribution. NCCLs could be feasible to develop emulsified chicken liver paste products. [ABSTRACT FROM AUTHOR]

Solketal is a promising oxygenate additive that can be chemically derived from bioglycerol. Emulsification by a microwave-irradiating method was used to prepare the micro- and nanoemulsions of solketal dispersed in continuous ultra-low sulfur diesel (ULSD) due to the immiscibility of solketal with ULSD. The emissions from a direct-injection, four-stroke and naturally aspirated diesel engine fueled with each of these emulsions, and with neat ULSD, were analyzed and compared. The experimental results show that the nanoemulsion and microemulsions were successfully produced. In addition, an increasing engine speed resulted in lower NOx, CO and O2 but higher CO2 emissions. The nanoemulsion was found to produce the lowest NOx emission while neat ULSD produced the highest NOx emission among these three test fuels. The lowest CO emission was formed by fueling the micro-emulsion of dispersed solketal-in-ULSD. Moreover, the burning of the nanoemulsion in the diesel engine formed the highest CO2 along with the lowest O2 emissions. Hence, the nanoemulsion had the highest burning efficiency among the three test fuels for the diesel engine. [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]

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Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The heavy molecular bonds of liquid fuels can be broken with the assistance of a nitromethane fuel additive by virtue of its explosive and flammable properties to obtain greater heat release. Because of the immiscibility between nitromethane and petro-diesel, two-phase emulsions of nitromethane dispersed in the oil phase of a mixture of diesel and biodiesel were prepared. The experimental results show that microwave irradiation produced an emulsion with a larger number of dispersed nitromethane droplets in the continuous oil mixture, a smaller mean droplet size, and lower turbidity than magnetic stirring, and thus was a better method for preparation of the two-phase emulsion. The increase in the nitromethane weight fraction increased the number of dispersed nitromethane droplets and the emulsion turbidity. In addition, allowing the emulsion preparation to remain motionless for a longer period of time after either method resulted in an obvious reduction in the emulsification stability (ES). [ABSTRACT FROM PUBLISHER]

Sorry, this article has been withdrawn of Orbital journal because its content was previously published in another scientific journal! Dr. Adilson Beatriz Editor-in-Chief of the Orbital – The Electronic Journal of Chemistry

Sodium 4,6-(2-( N, N-bis-ethylhexylamino)-1,3,5-triazine-4,6-yl-amino) ethane sulfonate (IXC), Sodium 4,6-(2-( N, N-bis-octylamino)-1,3,5-Triazine-4,6-yl-amino) ethane sulfonate (XC) and 2,2′-(6,6′-(ethane-1,2-diylbis(azanediyl) bis(4-(octylamino)-1,3,5-triazine-6,2-diyl)) bis(azanediyl))diethane sulfonate (C-2-C) were synthesized from cyanuric chloride. The surface activity and application properties of these surfactants (XC, IXC and C-2-C) were discussed. The values of CMC, γ, pC, Γ, and A calculated from surface tension measurement at 30 °C indicate that the surface activity of IXC, which has two branched hydrophobic carbon chains, has lower γ (26.8 mN m) than the other investigated surfactants and excellent wetting ability. [ABSTRACT FROM AUTHOR]

Biosurfactant-producing Halomonas sp. MB-30 was isolated from a marine sponge Callyspongia diffusa, and its potency in crude oil recovery from sand pack column was investigated. The biosurfactant produced by the strain MB-30 reduced the surface tension to 30 mN m in both glucose and hydrocarbon-supplemented minimal media. The critical micelle concentration of biosurfactant obtained from glucose-based medium was at 0.25 mg ml at critical micelle dilution 1:10. The chemical structure of glycolipid biosurfactant was characterised by infrared spectroscopy and proton magnetic resonance spectroscopy. The emulsification activity of MB-30 biosurfactant was tested with different hydrocarbons, and 93.1 % emulsification activity was exhibited with crude oil followed by kerosene (86.6 %). The formed emulsion was stable for up to 1 month. To identify the effectiveness of biosurfactant for enhanced oil recovery in extreme environments, the interactive effect of pH, temperature and salinity on emulsion stability with crude oil and kerosene was evaluated. The stable emulsion was formed at and above pH 7, temperature >80 °C and NaCl concentration up to 10 % in response surface central composite orthogonal design model. The partially purified biosurfactant recovered 62 % of residual crude oil from sand pack column. Thus, the stable emulsifying biosurfactant produced by Halomonas sp. MB-30 could be used for in situ biosurfactant-mediated enhanced oil recovery process and hydrocarbon bioremediation in extreme environments. [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]

[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]