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In this paper, the effects of three cations, Ca2+, Mg2+, and Na+, on the stability of APG foams were investigated experimentally. The results show that cations can slow down the process of liquid drainage and coarsening of APG foam, which is beneficial to the stability of the foam. The salt resistance mechanism of nonionic surfactant (APG) was investigated by molecular dynamics simulation and compared with that of anionic surfactant (SDS) foam. Firstly, the distribution characteristics of cations in APG foam and SDS foam were explored. It was found that the cations in the APG foam were mainly distributed in the water layer away from the head groups, and the cations in the SDS foam were more likely to appear near the head groups. Then, the hydration of the head groups and the cation was investigated. The results show that cations have little effect on the number of water molecules in the hydration layer of APG head groups but will reduce the diffusion capacity of water molecules and increase the water retention capacity of the foam film, thereby enhancing the foam stability. The addition of cations will reduce the water retention capacity of the SDS foam film. In addition, the behavior of surfactant head and tail groups was also analyzed. It was found that the cations made the head groups of APG more inclined to be aligned perpendicular to the liquid interface, and the tail groups were more inclined to realize a cross-arrangement and cover the gas–liquid interface. This can not only slow down the gas phase mass transfer process of the adjacent foam and slow down the coarsening process of the foam but also increase the viscoelasticity and anti-disturbance ability of the foam film. The cations will weaken the staggered arrangement of the SDS molecular tail groups, and at the same time, will cause the SDS molecules to aggregate, which greatly reduces the stability of the foam. [ABSTRACT FROM AUTHOR]

Foams are essential in many food applications and require surface‐active ingredients such as proteins for formation and stabilization. We investigated the influence of high‐pressure homogenization on foaming properties of insoluble pea protein dispersions (5% w/w) at pH 3 and 5. Unhomogenized insoluble pea protein dispersions did not foam at either pH 3 or 5, as they consisted of large insoluble pea protein aggregates with limited surface activity. At pH 3, the homogenized pea protein dispersions generated foams due to higher protein solubility and surface activity through disruption of large protein aggregates into smaller particles. The foam stability decreased with increasing homogenization pressure and number of cycles due to a reduction in continuous phase viscosity. At pH 5, the insoluble pea proteins foamed when the homogenization resulted in formation of aggregates made of smaller protein entities, which was the case for homogenization ≥ 100 MPa and three cycles. In general, the foam capacity (amount of formed foam) was higher at pH 3 due to improved protein solubility and surface activity that facilitated incorporation of air, while the foam stability (resistance against foam collapse) was better at pH 5 because of the presence of larger protein aggregates that formed thicker and more viscous films around the air bubbles benefitting retention of gas bubbles. Overall, homogenization improved the foaming properties of insoluble pea proteins at pH 3 and 5. Practical Application: Insoluble pea protein dispersions formed foams at pH 3 and 5 after homogenization highlighting the potential of this processing step for the food industry. The improvement in functionality of plant‐derived ingredients helps to increase their use for consumer goods, thereby supporting the transition to more sustainable food system. [ABSTRACT FROM AUTHOR]

BACKGROUND: In this study, the foamability and foam stability of nitrogen‐infused cold brew coffee, as affected by coffee variety (Arabica and Robusta), degree of roast (light, medium, dark), brewing temperature (4, 20, 35 °C), brew ratio (1:5–1:15 w/w; coffee/water), ground particle size (712, 647 and 437 μm volume mean diameter) and beverage temperature (4, 20 and 35 °C), were investigated. RESULTS: Dynamic surface tension of cold brew, as determined from bubble tensiometry, decreased from 65–70 mN m−1 to about 60 mN m−1 as the bubble lifetime increased from 0.1 s to 1 s. Infusing the cold brew coffee (70 mL) with nitrogen gas for 30 s at 50 mL min−1 generated 30–40 mL of foam head. At the same degree of roast, brews prepared from Arabica beans had more stable foam than those from Robusta. Foam stability increased with increasing degree of roast, increasing brewing temperature, decreasing particle size, and decreasing the beverage temperature. By contrast, brew ratio had relatively less effect on foaming properties. Nitrogen‐containing constituents present in the 80% (v/v) ethanol‐soluble fraction (55.9% of total dissolved solids) of the brew samples were important contributors to foaming, while the 80% (v/v) ethanol‐insoluble fraction (42.3% of total dissolved solids) that contained polysaccharides was important in stabilizing the foam. CONCLUSION: The foamability and foam stability of cold brew coffee are significantly affected by coffee variety, degree of roast, brewing temperature, ground particle size, and beverage temperatures. The foam properties are dictated by the low‐molecular‐weight nitrogen‐containing compounds and high‐molecular‐weight polysaccharides present in the cold brew coffee. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Different combinations of nano-particles and surfactants are selected to prepare foam fracturing fluid for tight gas reservoirs fracturing. The thermal stability of foam fracturing fluid is improved by adding nano iron oxide particles. Adding (w)0.5% nano iron oxide as foam stabilizer to the mixture of surfactant(SDBS and CAPB) can improve the rheology of the foam and increase its thermal stability at 80 °C by 52%. The apparent viscosity of the optimized foam system is affected by the foam stability. The elasticity of the foam fluid is dominant in viscosity, which can help to improve the proppant suspension ability. It can effectively transport the proppant through the foam fluid, which can better meet the requirements of the allowable proppant settling rate and be used in the fracturing process of tight gas reservoirs. [ABSTRACT FROM AUTHOR]

Food allergies and intolerances have challenged the food industry to create alternatives for allergenic ingredients replacement. Furthermore, meeting vegan diet patterns is even more complicated due to the limited functional properties and sensory characteristics. This study aimed to develop a vegetable powder for egg replacement (VP) for gluten-free cake (GFC) using aquafaba powder (AP), lentil protein (LP), and citric acid (CA) according to a mixture design (MD) with lower and upper restrictions. Three mixtures were chosen based on responses foaming capacity (FC) and foam stability (FS). They were applied as eggs substitute in GFC. The dough physical parameters, proximal composition, microbiological quality, and sensory acceptance of GFC were determined. The AP utilization as raw material in VP is suitable, and mixtures containing 66% to 71.5% of AP, 20% of LP, and 8.5% to 14% of CA were considered suitable for GFC egg replacement. Although the physical characteristics were slightly below the control, GFC with VP had higher fiber content, lower lipid and carbohydrate content, and sensory characteristics as accepted as the control.

This paper deals with the potential of aggregates of surfactant and SiO2 nanoparticles as foam stabilizers for practical applications. The effects of different chain lengths and concentrations of the cationic surfactant CnTAB on the performance of CnTAB–SiO2 nanofluids are examined to gain a comprehensive understanding of their ability to stabilize foam. The results indicate enhanced foam stability in the presence of SiO2 nanoparticles. These findings help to better understand foam stabilization and its potential in various industrial applications such as enhanced oil recovery and foam-based separation processes.

• The foam and its history in various industries are thoroughly described, providing detailed information. • A discussion of the properties of foam and its limitations is included. • The parameters and mechanisms influencing foam stability are thoroughly examined. • A summary update of the foam laboratory studies is provided. Foam finds applications in various industries such as wastewater treatment, enhanced oil recovery, and the manufacturing of food, medicine, and cosmetics, as well as in firefighting. Therefore, having a thorough comprehension of foam and the challenges it presents is crucial. This comprehensive review article offers a detailed analysis of the processes involved in foam generation, stability, and rupture, emphasizing the influence of physical and chemical parameters. With their intricate structure and unique characteristics, foams play a crucial role in a wide range of industrial sectors including oil and gas, food production, healthcare, and pharmaceuticals. The stability of foams is influenced by various factors such as the type of gas, solution composition (including surfactants, pH, polymers, and nanoparticles), and operational conditions (e.g., temperature and injection pressure). Each of these factors can impact foam stability by modifying the physical and chemical properties of the liquid and gas phases. The review thoroughly examines the role of surfactants in reducing surface tension, the use of nanoparticles to enhance foam structure, and the function of polymers as thickeners and stabilizers. These materials improve foam stability by regulating the behavior of the liquid phase, reducing drainage rates, and preventing bubble coalescence. Furthermore, this review critically evaluates the impact of operational variables like temperature and injection pressure on foam stability. Higher temperatures can lead to increased liquid drainage and bubble coalescence, but these negative effects can be mitigated by using suitable compounds such as thermally resistant surfactants and nanoparticles, along with increased injection gas pressure. In addition, the salt content and pH of the solution significantly influence foam stability by altering the electrostatic properties of the liquid phase. The conclusions drawn from this review highlight the effectiveness of optimizing the combination of materials and process conditions to enhance foam stability. This study lays a solid groundwork for future research aimed at improving and developing highly stable foams and can serve as a valuable reference for engineers and researchers seeking to optimize foam-related processes. [ABSTRACT FROM AUTHOR]

We analyze the heat transfer between the melt pool and the layer of reacting materials called cold cap, which is the determining factor for the glass production rate in Joule-heated air-bubbled nuclear waste glass melters. We consider the effects of bubbling rate, melt viscosity, melt thermal conductivity, conversion kinetics, and shear rate at the cold-cap bottom, and develop simple relationships for the cold-cap bottom temperature and glass production rate. We show that the melt convection enhances the heat transfer to the cold cap by suppressing the thermal boundary layer and primary foam, while the conversion kinetics opposes these effects. Additionally, we mention how dissolving silica particles affects the primary foam stability and discuss the limitations of the presented approach for vigorously foaming feeds. [ABSTRACT FROM AUTHOR]

The thermal insulation performance of curing foam is a critical factor affecting fire extinguishing efficiency. In this study, sodium dodecyl sulfate was used as the foaming agent, and then combined with foam stabilizers, foam thickeners and inorganic powders to prepare the curing foam extinguishing agents. The result demonstrated that the addition of PEG and Xanthan gum could prolonge the 50 % drainage time of foam solution to 1.98 times compared with the foam solution without foam additives. The composite powders imparts an excellent thermal insulation and high-temperature stability to curing foam, especially the mass fractionratio of loess to cement equals to 4:6 and the water cement ratio is 0.7. Moreover, the thermal insulation tests showed that when the test temperature equalled 500 °C, the curing foam could reduce the temperature of the covered surface by 234.2 °C. Compared with the water-based foam, the thermal insulation performance was improved by 58.1 %. Finally, fire extinguishing test showed that the fire extinguishing time of curing foam is 0.47 s and 33.99 s shorter than that of water-based foam and water, respectively. The consumption of water-based foam and water fire extinguishing consumption is 1.46 times and 4.37 times that of curing foam, respectively. The excellent structural stability is due to the addition of Xanthan gum and PEG additives, which provide a more uniform distribution of bubbles and denser pores. At the same time, the mixture of loess and cement acts as a skeleton in curing foam thereby improving the stability of the integral structure and further preventing the heat transfer. [Display omitted] • The mixture of PEG and xanthan gum can prolong the 50 % drainage time of foam liquid to 1.98 times. • When the mass ratio of loess to cement is 4:6 and the water cement ratio is 0.7, the curing foam does not collapse. • The mixture of loess and cement acts as a skeleton in curing foam, which improves the thermal insulation. [ABSTRACT FROM AUTHOR]

• Summarizes recent advances in foam EOR, focusing on mixed surfactants, NPs, and surface-modified NPs to foam stabilization in EOR. • Discusses key factors affecting foam stability, including foam morphology, gas type, injection rates, foam quality, and reservoir conditions. • Offers an in-depth discussion of the synergistic effects and stabilization mechanisms of surfactant-NP's foams and their applications. Different enhanced oil recovery (EOR) methods have been implemented in oil fields over the past decades. Gas flooding is widely used, but its effectiveness is hindered by mobility control issues and often leads to problems such as viscous fingering and gravity segregation. This review examines the challenges in gas flooding and advocates for the utilization of foam. Foam offers enhanced mobility control compared to gas flooding, mitigating gas channeling and improving sweep efficiency. However, foam flooding also encounters significant challenges under different reservoir conditions. A thorough understanding of the mechanisms responsible for foam stabilization and propagation at the reservoir scale is essential for its effective utilization. Therefore, this review focuses on the application of surfactants, polymers, nanoparticles, or their combinations, assessing their effectiveness in foam flooding in oil reservoirs. The study delves into the critical parameters influencing foam stability and quality, offering insights to aid in the selection of foam stabilizers and the design of foam flooding operations. Parameters such as foam stabilizer type and concentration, gas type, reservoir conditions, and the properties of reservoir rock and fluids are thoroughly analyzed. Additionally, it comprehensively examines emerging foam stabilizers, including the incorporation of nanoparticles and nanocomposites. The mechanisms underlying nanoparticle-induced foam stabilization are explored in detail. Through a review of available laboratory and field results, the potential of these foam stabilizers is illustrated. Lastly, future directions for development and conclusions are drawn based on reported research in the relevant field. [ABSTRACT FROM AUTHOR]

This study investigates the effect of Iron Oxide Nanoparticles (IONPs) on the stability of a class A foam. IONPs are synthesised via two different pathways, namely the reflux and the hydrothermal methods. The synthesised nanoparticles are then added to the foam solution at different concentrations, applying various techniques to test how they affect properties and processes such as particle size distribution, surface tension, and coalescence. Results show that (i) the addition of IONPs improves the foam stability by reducing the bubble coarsening and disproportionation; (i i) the IONPs assemble at the plateau borders and nodes of the bubbles creating a protective layer on the gas–liquid interface, which delays foam drainage hence improving foam stability; and (i i i) stability is also improved by the increase in the foam half-life due to the accumulation of nanoparticles on the surface of the bubble. IONPs obtained using the reflux method are shown to affect the firefighting foam more positively. [Display omitted] • Iron Oxide Nanoparticles (IONPs) improve foam stability by altering bubble structure. • IONPs also improve foam stability by altering surface tension. • Reflux is more cost-effective and practical than hydrothermal synthesis in the lab. • X-ray Diffraction (XRD) analysis confirms crystalline structure of synthesised IONPs. • A crystalline structure is indicative of their potential to enhance foam stability. [ABSTRACT FROM AUTHOR]

Liquid foams, as colloidal systems comprising a dispersed gas phase within a continuous liquid medium, exhibit unique structural and rheological properties beneficial for various industrial and environmental applications. This review synthesizes current knowledge on the fundamentals, stability mechanisms, and practical applications of liquid foams. We first discuss foam structures, transitioning from ball to wet and dry foams, influenced by the liquid fraction and surfactant presence, which also influence the foam's mechanical and stability properties. We further describe the mechanisms of foam generation (for confined foams), stability, and decay, highlighting the roles of snap-off, lamellae division, and leave-behind in foam formation and the adverse effects of coarsening, gravity drainage, and collapse on foam stability. Additionally, the review covers the rheological behavior of foams under shear stress, illustrating their complex viscoelastic or viscoplastic nature. Finally, we review recent studies of foam injection and displacement in porous structures, utilizing Hele–Shaw cells and microfluidics. [Display omitted] [ABSTRACT FROM AUTHOR]

• Nanoparticles functionalized with carboxyl groups were prepared. • Foam stability was improved significantly by using the prepared nanoparticles. • The complete structure of bubbles was observed in the presence of divalent ions. Aqueous foams are thermodynamically unstable systems, and their instability increases with temperature and salinity. In this study, we successfully synthesized an amphiphilic polyhedral oligomeric silsesquioxane, POSS-NH 2 -BTCA, featuring phenyl and carboxyl groups, through a substitution reaction. Highly stable foams were prepared under temperatures conditions ranging from 50 to 90 °C and salinity levels between 20 and 80 g/L. Rheological tests and scanning electron microscopy analysis show that the interactions between divalent ions and carboxyl groups improve the film strength. However, the half-life of the drainage only increased from 38 s to 55 s. Therefore, the enhancement in foam stability is believed to be caused by the inhibition of coarsening and coalescence rather than the suppression of drainage. The strategy for fabricating amphiphilic nanoparticles can serve as a reference for designing new foam stabilizers for high temperature and salinity conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Increasing CCNF concentration improves the foam stability of SDS and CTAB solutions. • The foaming ability of CTAB solution is more affected by CCNF than SDS solution. • The foam stability enhancement of CTAB solution is due to the formation of aggregates and the increase of viscosity. • The foam stability enhancement of SDS solution is dominated by viscosity. Synergistic effects and stability mechanism of carboxylated cellulose nanofiber (CCNF) and hydrocarbon surfactants on the environmentally friendly foam are investigated in this work. Higher concentrations of CCNF decelerate the bubble coarsening and liquid drainage processes, consequently enhancing foam stability. Increasing viscosity is the primary cause of foam stability enhancement for all surfactant solutions. However, the generation of aggregates is still another reason for the enhanced stability of CTAB/CCNF foam. In addition, CCNF diminishes the foaming ability of all surfactants. Furthermore, as CCNF exceeds 0.8 wt.%, the foaming ability of all surfactants diminishes noticeably, with CTAB solution experiencing a more pronounced reduction. In SDS solutions, the foaming ability is governed by viscosity, whereas in CTAB solutions, it is influenced by adsorption kinetics and viscosity. [ABSTRACT FROM AUTHOR]

• Duomeen TTM exhibited poor foam stability, which significantly improved with decreasing GLDA pH. • Armovis VES demonstrated remarkable CO 2 foam performance, with half-life times exceeding 240 min. • Reducing the GLDA pH enhanced the CO 2 -VES faomability. • Combining Duomeen TTM and Armovis VES yielded the highest foam viscosity due to a synergistic interaction between the surfactants. The injection of CO 2 foam into the carbonate reservoir for enhanced oil recovery (EOR) has attracted special interest in the last decades; nevertheless, the understanding of the effect of liquid solution chemistry on foam stability at high temperatures and salinities is limited. Hence, this paper fully investigates the effect of chelating agents L-glutamic acid-N, N-diacetic acid (GLDA) pH, and hydrochloric acid (HCl) on the stability and viscosity of generated CO 2 foam for heterogeneous carbonate formation under reservoir conditions. In this paper, Duomeen TTM and Armovis VES surfactants were utilized due to their capabilities to produce viscous CO 2 foam under harsh conditions. The foamability, foam stability, and foam structure were studied at 100 °C and 1000 psi using a high-temperature and high-pressure (HPHT) foam analyzer. The measurement of CO 2 foam viscosity was determined at 100 °C, 1000 psi, and 70 % foam quality using the HPHT foam rheometer. Rheology experiments and dynamic light scattering investigated the micelle's size or aggregation behavior of surfactants. The obtained results showed that the Duomeen TTM generated unstable foam; however, foam stability and foamability improved with the decrease in GLDA pH. Armovis VES showed excellent CO 2 foam performance, where the foam half-life time of Armovis VES systems was 240 min. The liquid drainage and bubble coarsening were delayed due to the formation of the viscoelastic liquid phase. The foamability of Armovis VES was improved as the GLDA pH decreased. Furthermore, the addition of HCl to Armovis VES solution presented the highest foamability. The outcomes of the HPHT foam analyzer and HPHT viscometer proved that as the pH of Armovis VES solution decreased, higher foamability was produced. The highest foam viscosity was obtained using the synergic effect of 0.5 wt% Duomeen TTM and 0.5 wt% Armovis VES (39 cp at 100/s). In comparison, 1 wt% Armovis VES presented the lowest foam viscosity (30 cp at 100/s). The outcomes of this research can provide insight into the effect of chemistry on CO 2 foam and extend its application in oilfield development. This work broadens the design of novel CO 2 foam formulation, leading to the improvement of sweep efficiency in CO 2 -EOR methods and enhance the gas trapping in carbon storage. [ABSTRACT FROM AUTHOR]

Protein aggregates are known to enhance foam stability by either increasing the thin film viscosity or by blocking the lamellae of a foam. In this study, we produced a mung bean protein colloids mixture (MPCM) by heating protein coacervates that were formed by liquid-liquid phase separation. The functionality of MPCM was compared to a mildly purified mung bean protein extract (MIL). The MPCM showed extraordinary foaming properties, much better than MIL, with foamability of 324 % and a half-life time of 400 min. This work focused on elucidating the exact interface and foam stabilising mechanism of the MPCM by separating the colloids (COL) from the supernatant/continuous phase of the MPCM (SUP). Their interfacial properties were studied by performing surface dilatational rheology and microstructure analysis. Finally, foaming properties, such as foamability, foam stability, and air bubble size, were studied. It was found that the highest foam capacity was observed for the SUP fraction by generating stiffer interfaces. This fraction also contributed to the high foam stability of the MPCM. The COL fraction was found to form a viscoelastic thin film between air bubbles, thereby decreasing the drainage rate of the foam. In brief, SUP and COL fractions co-operate in the formation of highly stable MPCM foam, leading to a promising plant-derived candidate for producing stable foams in food products. [Display omitted] • Protein colloid mixture had 8x higher foam stability than a protein concentrate. • The mixture was separated into non-aggregated proteins and colloids. • The non-aggregated proteins form and stabilize the air-water interface. • The colloids further increase foam stability by pinning in the thin films. • The non-aggregated proteins and colloids show synergy in foam stabilisation. [ABSTRACT FROM AUTHOR]

For many dairy products such as cappuccino-style beverages, the top foam layer determines the overall product quality (e.g. their appearance, texture, mouthfeel and coffee aroma release rate) and the consumer acceptance. Proteins in milk are excellent foaming agents, but the foaming properties of milk are greatly affected by several factors such as the protein content, ratio of caseins to whey proteins, casein micelle size, pH, minerals, proteolysis, presence of low molecular weight compounds (lipids and their hydrolyzed products) and high molecular weight compounds (polysaccharides); milk processing conditions (e.g. homogenization, heat treatment and aging); and foaming method and temperature. These factors either induce changes in the molecular structure, charge and surface activity of the milk proteins; or interfere and/or compete with milk proteins in the formation of highly viscoelastic film to stabilize the foam. Some factors affect the foamability while others determine the foam stability. In this review, functionality of milk proteins in the production and stabilization of liquid foam, under effects of these factors is comprehensively discussed. This will help to control the foaming process of milk on demand for a particular application, which still is difficult and challenging for researchers and the dairy industry. [ABSTRACT FROM AUTHOR]

Foam flooding is an important pathway for enhanced oil recovery. However, the evaluation of foam properties is usually carried out in free space, which can not accurately reflect the performance of foam in porous oil formation. In the present work, by investigating the foamability and stability of foam systems in sand‐pack models with average pore throat radius from 1.24 μm to 4.28 μm, the effects of porous media on foam properties are studied. Compared with foam systems in free space, foam systems in porous media have longer foam half‐life, longer drainage half‐life, and higher foam comprehensive index. The foam volume of foam systems in porous media could be higher or lower than that in free space, depending on the average pore throat radius of the porous media. Generally, in porous media, with the decreasing of pore throat radius, the foamability of the foam systems gradually decreases while the foam stability gradually increases. Moreover, the bubble size and liquid film thickness also decrease with the decreasing of pore throat radius of the porous media. Above all, the behaviors of foams are significantly affected by porous media. When investigating a foam system to evaluate its performance for foam flooding in oil recovery or other applications in porous media, porous models which could reflect the target conditions should be considered to obtain more trustable results. [ABSTRACT FROM AUTHOR]

Inorganic electrolytes are assumed to significantly impact the flotation performance of graphite resources; however, the underlying mechanism is still unclear. In this work, the effect of three inorganic salts, including KCl, MgCl2, and AlCl3, was studied on the flotation of graphite. Flotation results indicated significantly increased graphite recovery with the addition of KCl regardless of pulp pH. MgCl2 improved the flotation performance under acidic and slightly alkaline conditions, while AlCl3 had a better activation on graphite flotation under strong acidic and alkaline conditions. Contact angle and Zeta potential results confirmed that electrolytes substantially reduced the absolute value of surface charge and the hydration of graphite surface, thus improving the hydrophobicity. Froth stability studies indicated that multivalent Al3+ and Mg2+ ions exhibit superior foaming performance than K+ ions and contribute to more stable and abundant foam. Additionally, these salt ions increased the surface tension and prevented bubble coalescence, contributing to nanobubble formation. Therefore, adding MgCl2 and KCl is of great significance for improved graphite flotation under neutral conditions. [ABSTRACT FROM AUTHOR]

As the demand for new protein sources increases, research is needed to extract and develop protein isolates with desirable functional properties. Sesame protein can be used as a new plant protein source due to its high amino acid content. In this study, the effect of sodium chloride salt concentration (0, 18 and 22% w / v) and drying temperature (25, 45 and 180 °C) as two important parameters affecting the functional properties of protein isolates extracted from sesame were investigated. Protein solubility tests at pH 4, 5, 7, 9 and 11, foam stability and emulsion stability at pH 11 and water holding capacity (WHC) and oil holding capacity (OHC) were performed. The lowest protein solubility was observed at pH 5 and with increasing pH, protein solubility increased. With increasing temperature from 45 to 180 °C at constant salt concentration, protein solubility and foam and emulsion stability increased and WHC and OHC decreased. An increasing in salt concentration from 18 to 22% at constant temperature caused to increase in protein solubility and decrease in WHC and OHC. Foam and emulsion stability was lowest at 18% of salt concentration. In general, drying temperature of 45 degrees Celsius and salt concentration of 18% for preparation of protein isolate with maximum water and oil holding capacity and drying temperature of 180 °C and salt concentration of 22% for production of sesame protein isolate with maximum solubility, Emulsion stability and foam stability are recommended. [ABSTRACT FROM AUTHOR]

Foam‐mat drying is an alternative dehydration technique to tray, drum, freeze, and spray drying. Foam‐mat drying can be used to obtain high‐quality powders from fruit juices and other heat‐sensitive food products which are difficult to dry using traditional drying techniques. In foam‐mat drying, the product to be dried is first converted into a stable foam by whipping, bubbling, or shaking in the presence of a foaming agent and foam stabilizer. The foam has been significantly increased the surface area of the product and thereby decreasing the time, temperature, and cost needed for drying. The selection of a foaming agent, foam stabilizer, foaming technique, and drying method is crucial in determining the final quality of the dried product. Due to its simplicity, faster drying, cost‐effectiveness, and improved product quality, foam‐mat drying is getting attention from researchers and industrialists worldwide. In this context, this review aims to present an overview of the recent advances in foam‐mat drying along with its cost economics and industrial potential. [ABSTRACT FROM AUTHOR]

Copyright of Industrial Minerals & Processing / Huagong Kuangwu yu Jiagong is the property of Industrial Minerals & Processing Editorial Office 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.)

Foams are increasingly popular in the field of dermatology due to their many advantages such as easy spreading, good skin sensation, and applicability in special skin conditions. One of the critical points of foam formulation is the choice of the appropriate stabilizing ingredients. One of the stability-increasing strategies is retarding the liquid drainage of liquid films from the foam structure. Therefore, our aim was the application of different hydrogel-forming polymers in order to retain the stabilizing liquid film. Dexpanthenol and niacinamide-containing foams were formulated, where xanthan gum and hyaluronic acid were used as foam-stabilizing polymers. Amplitude (LVE range) and frequency sweep (G', G", tanδ, and frequency dependency) were applied as structure- and stability-indicating rheological parameters. The rheological data were compared with the results of the cylinder method, microscopical images, and the spreadability measurements. The application of the gel-forming polymers increased the stability of the dermal foams (increased LVE range, G' values, and decreased frequency dependency). These results were in correlation with the results of the cylinder and spreadability tests. It was concluded that in terms of both foam formation and stability, the combination of xanthan gum and dexpanthenol can be ideal. [ABSTRACT FROM AUTHOR]

The world is rich in heavy oil resources, however, the recovery difficulty and cost are both higher than that of conventional crude oil. To date, the most common method of recovering heavy oil is steam flooding. However, once the steam breaks through the geological formation, gas channeling readily occurs, which leads to a rapid decrease of the steam drive efficiency. To improve the swept volume of steam in the geological formation, a series of hydrophobic silica particles for stabilizing foam was synthesized. This kind of particles used hydrophilic nano silica particles as reactant. Hydrophobic groups with cationic long carbon chains were grafted onto the surface of hydrophilic silica particles by synthetic silane quaternary ammonium salt. When the quantity of silane quaternary ammonium salt used in the modification reaction is different, the product had various degrees of wettability. The hydrophobic particles with the contact angle closest to 90° had the best foam stabilization effect on the betaine zwitterionic surfactant LAB. For LAB solution with mass fraction of 0.3%, the half-life of foam was extended into 160% when the mass fraction of particles was 0.5%. The higher the gas-liquid ratio, the better the plugging effect of foam agent with hydrophobic particles presented in porous media. The adsorption test of hydrophobic particles indicated that hydrophobic particles improved the stability of foam liquid membrane by improving the adsorption capacity of surfactant molecules. The thermal stability of hydrophobic silica particles exceeded 200°C, and the good foam stability made it a potential additive for foam oil displacement in high-temperature geological formation.

In recent years, there has been increased interest in studies on the stabilization of liquid foams with solid particles. In such three-phase foams it is possible to completely stop the process of syneresis, reduce coalescence and diffusion of gas. The presence of particles can significantly increase the time of the foam lifetime. Such Pickering foams are also of interest as an environmentally friendly and cost-effective alternative to surfactants and high molecular weight foaming agents. This work is focused on investigating the foam stability containing SDS-PVA SDS–PVA composite foaming agents with bentonite clay particles. Foam stability was characterized via the time of foam drainage. The stability of foams of SDS-PVA SDS–PVA mixtures in absence and presence of bentonite particles was determined. The stability of foams is higher in presence of the bentonite particles.

AlCa75 with equal Ca content was used to replace pure Ca for the preparation of AlSi12 foam in a stable pore structure after foaming for 20 min. The stability mechanism was studied based on the comparison between the macroscopic pore structure evolution and the second phase composition of AlCa75 and pure Ca aluminum foam. It was found that the porosity and average pore size of the AlSi12 foam with AlCa75 were stable without any abnormal large pores, and the foaming stage was prominent. The stability of AlSi12 foam with pure Ca is inferior. After 20 min of foaming, the foam bursts in the center. Combined with the microscopic characteristic analysis, it could see that the second phase produced by AlCa75 is mainly Al2Si2Ca, which can be uniformly dispersed in the matrix. The addition of pure Ca reduces the amount of the second phase and the main phase Al4Ca is easy to agglomerate. The stability mechanism shows that the Al2Si2Ca second phase, formed by AlCa75, demonstrates a better stabilizing effect in different foaming stages. Due to the premature agglomeration caused by Al4Ca and the low content of the second phase, the AlSi12 foam with pure Ca is challenging to long-term stability.

To get a deeper understanding on the synergistic enhancement effect of low frequency artificial seismic wave on foam stability, a micro-kinetic model of enhanced foam stability under low frequency artificial seismic wave is established based on a vertical liquid film drainage model and elastic wave theory. The model is solved by non-dimensional transformation of the high order partial differential equations and a compound solution of implicit and explicit differences and is verified to be accurate. The foam film thickness, surfactant concentration distribution and drainage velocity under the action of low frequency artificial seismic wave are quantitatively analyzed. The research shows that low-frequency vibration can reduce the difference between the maximum and minimum concentrations of surfactant in the foam liquid film at the later stage of drainage, enhance the effect of Marangoni effect, and improve the stability of the foam liquid film. When the vibration frequency is close to the natural frequency of the foam liquid film, the vibration effect is the best, and the best vibration frequency is about 50 Hz. The higher the vibration acceleration, the faster the recovery rate of surfactant concentration in the foam liquid film is. The higher the vibration acceleration, the stronger the ability of Marangoni effect to delay the drainage of foam liquid film and the better the foam stability is. It is not the higher the vibration acceleration, the better. The best vibration acceleration is about 0.5 times of gravity acceleration. Reasonable vibration parameters would greatly enhance the effect of Marangoni effect. The smaller the initial concentration of surfactant, the better the vibration works in enhancing Marangoni effect.

Summary: The purpose of this study was to expound on the correlation between foaming properties and physicochemical characteristics of rice bran protein (RBP) samples. RBP nano‐particles (RBPNs) were prepared by acidic–thermal treatment under different RBP solution concentrations and treated times at 90 °C, and then the foaming properties were measured at pH 7.0 and pH 2.0. Compared to RBP, the foaming properties of RBPNs were increased at pH 7.0, and RBPNs could have better foam capacity but have no obvious changes in foam stability at pH 2.0. The results of Pearson correlation showed that the foaming properties were closely correlated with ζ potential, contact angle, and surface hydrophobicity for RBP and RBPNs, and a strong correlation between foaming capacity and surface hydrophobicity was shown for RBPNs. Additionally, the result of TEM images confirmed that RBPNs were inclined to form associated aggregates which may affect the physicochemical characteristics of RBPNs. [ABSTRACT FROM AUTHOR]

Copyright of Fire Safety Science is the property of Fire Safety Science Editorial Office 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.)

Copyright of Food & Machinery is the property of Food & Machinery Editorial Office 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.)

Lyotropic liquid crystal prepared by triethanolamine oleate and p.xylene. The texture of liquid crystal was observed macroscopically by polarized light microscope. The viscosity of the system and the rheological behavior of the lyotropic liquid crystal were measured by steady state rheology. The foam properties of lyotropic liquid crystals were studied by the variation of gas content, half-life and foam height with time. The results show that triethanolamine oleate/p-xylene lyotropic liquid crystal exhibits the texture of lamellar liquid crystal. The lyotropic liquid crystal system behaves as a non-Newtonian fluid and has obvious yield value and shear diluency. When the mass fraction of triethanolamine oleate is 87%, the foam is the most stable, and the complete decay can reach 21 h, indicating that the lyotropic liquid crystal foam has excellent stability. [ABSTRACT FROM AUTHOR]

The environmentally-friendly foam extinguishing agent was prepared by using sodium alpha-ole-fin sulfonate (AOS), phosphate betaine silicone (PPSS) and polysaccharide polymer as surfactants and foam stabilizer, respectively. The effect of polysaccharide polymers on viscosity, foaming ability and foam stability of foam was investigated. The results showed that the viscosity and the 25% drainage time of foam solutions increase with the increasing the concentration of polysaccharide polymers. Foaming ability analysis shows that both xanthan gum and sodium alginate decrease the foaming ability of foam solution while the gelatin improves the foaming ability of it. The addition of individual polysaccharide polymer cannot effectively improve the foam properties, while the combination of xanthan gum and gelatin can effectively balance the foaming ability and foam stability of foam extinguishing agents. The combination of xanthan gum and gelatin can effectively balance the foaming ability and foam stability of foam extinguishing agent, which is ascribed to the formation of hydrogen bonds that enhances the surface strength of foam liquid film and decreases the diffusion of water in the liquid film, thus effectively slowing down the drainage rate and bubbles coarsening of foam. When the concentration ratio of xanthan gum to gelatin is 1: 5, the resulting foam exhibits the optimal foam properties, corresponding to the foam height of 123. 0 mm and 25% drainage time of 128. 1 s, which is related to the fact that the xanthan gum and gelatin compound system can slow down the rate of liquid evolution and bubble coarsening. [ABSTRACT FROM AUTHOR]

Natural gas foam can be used for mobility control and channel blocking during natural gas injection for enhanced oil recovery, in which stable foams need to be used at high reservoir temperature, high pressure and high water salinity conditions in field applications. In this study, the performance of methane (CH4) foams stabilized by different types of surfactants was tested using a high pressure and high temperature foam meter for surfactant screening and selection, including anionic surfactant (sodium dodecyl sulfate), non‐anionic surfactant (alkyl polyglycoside), zwitterionic surfactant (dodecyl dimethyl betaine) and cationic surfactant (dodecyl trimethyl ammonium chloride), and the results show that CH4‐SDS foam has much better performance than that of the other three surfactants. The influences of gas types (CH4, N2, and CO2), surfactant concentration, temperature (up to 110°C), pressure (up to 12.0 MPa), and the presence of polymers as foam stabilizer on foam performance was also evaluated using SDS surfactant. The experimental results show that the stability of CH4 foam is better than that of CO2 foam, while N2 foam is the most stable, and CO2 foam has the largest foam volume, which can be attributed to the strong interactions between CO2 molecules with H2O. The foaming ability and foam stability increase with the increase of the SDS concentration up to 1.0 wt% (0.035 mol/L), but a further increase of the surfactant concentration has a negative effect. The high temperature can greatly reduce the stability of CH4‐SDS foam, while the foaming ability and foam stability can be significantly enhanced at high pressure. The addition of a small amount of polyacrylamide as a foam stabilizer can significantly increase the viscosity of the bulk solution and improve the foam stability, and the higher the molecular weight of the polymer, the higher viscosity of the foam liquid film, the better foam performance. [ABSTRACT FROM AUTHOR]

Copyright of China Surfactant Detergent & Cosmetics (1001-1803) is the property of China Surfactant Detergent & Cosmetics Editorial Office 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 technique of dry hopping is used to produce many different beer styles with various alcohol contents. Information about the alcohol-dependent behaviour of hop components after dosing is crucial to control the resulting flavour and ensure consistent beer quality. This systematic pilot-scale study was therefore performed using standardised procedures by only varying the alcohol content in the beer samples in four steps from 0.5 % to 10.5 % alcohol by volume (ABV). A commercially available alcohol-free wheat beer was used as a base beer to adjust the alcohol concentrations while keeping the hop dosing rate consistent at 250 g/hl using Type 90 Pellets of the variety Solero. After a semi-static contact time of 14 days, the following attributes were analysed: hop-derived bitter and aroma compounds, polyphenol content, nitrates, foam stability and pH value. The conclusions for the non-volatile attributes are as follows: iso-alpha acids, humulinones, polyphenols and foam stability remained unchanged with varying ABV. In contrast, increasing the alcohol content improved the transfer and solubility of hydrophobic alpha and beta acids as well as xanthohumol, resulting in higher concentrations. Increasing the alcohol also caused lower quantities of nitrates to be transferred. Foam stability was negatively affected when more ethanol was added, but this drop in stability was compensated by more foam-positive alpha acids introduced. The beer pH showed very little increase and was hardly influenced by the ABV. For the hop-derived volatile substances, the conclusions are as follows: The terpene alcohols displayed very good solubility with the ABV having hardly any impact. The transfer of hop esters was only somewhat ABV-dependant and the presence of alcohol above 0.5 % further increased the solubility to finally reach a certain plateau. Ketone concentration did depend on the ABV. Mono- and sesquiterpenes are most clearly influenced by the alcohol content and the highest concentrations were reached at the highest ethanol addition. [ABSTRACT FROM AUTHOR]

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Water-based fracturing fluids are among the most common fluid types used in hydraulic fracturing operations. However, these fluids tend to cause damage in water-sensitive formations. Foam comprises a small amount of base fluid, and compressible gas such as carbon dioxide and nitrogen has emerged as a more ecologically friendly option to fracture such formations. Foam is an attractive option since it has a low density and high viscosity. The applicability of foamed frac fluid is characterized by foam stability and rheology, encompassing the viscosity and proppant carrying ability. The foam quality, pressure and temperature affect the foam rheology. Generally, foam viscosity and stability increase with pressure but decrease when the temperature increases. Hence, it is essential to preserve foam stability in high pressure and high temperature (HPHT) reservoir conditions. The addition of nanoparticles could increase the thermal stability of the foam. This article provides the basis of foam-based fracturing fluid characterization for an optimal application in HPHT reservoir conditions. Then, focusing on improving thermal stability, it reviews the research progress on the use of nanoparticles as foam stabilizing agent. This paper also sheds light on the literature gaps that should be addressed by future research. [ABSTRACT FROM AUTHOR]

Screening proteins for their potential use in foam applications is very laborious and time consuming. It would be beneficial if the foam properties could be predicted based on their molecular properties, but this is currently not possible. For protein-stabilized emulsions, a model was recently introduced to predict the emulsion properties from the protein molecular properties. Since the fundamental mechanisms for foam and emulsion formation are very similar, it is of interest to determine whether the link to molecular properties defined in that model is also applicable to foams. This study aims to link the exposed hydrophobicity with the foam ability and foam stability, using lysozyme variants with altered hydrophobicity, obtained from controlled heat treatment (77 °C for 0–120 min). To establish this link, the molecular characteristics, interfacial properties, and foam ability and stability (at different concentrations) were analysed. The increasing hydrophobicity resulted in an increased adsorption rate constant, and for concentrations in the protein-poor regime, the increasing hydrophobicity enhanced foam ability (i.e., interfacial area created). At higher relative exposed hydrophobicity (i.e., ~2–5 times higher than native lysozyme), the adsorption rate constant and foam ability became independent of hydrophobicity. The foam stability (i.e., foam collapse) was affected by the initial foam structure. In the protein-rich regime—with nearly identical foam structure—the hydrophobicity did not affect the foam stability. The link between exposed hydrophobicity and foam ability confirms the similarity between protein-stabilized foams and emulsions, and thereby indicates that the model proposed for emulsions can be used to predict foam properties in the future. [ABSTRACT FROM AUTHOR]

Aqueous Extract of Acanthophyllum laxiusculum root (AE) exhibited remarkable foaming profile, emulsification properties and antifungal activity due to the presence of high concentration of total saponins. Total phenolic compounds, another main component, accounted for the AE antioxidant activity. Spray drying of AE, as a thermal process, did not affect the foaming indices of A. laxiusculum Spray-dried Extract (SE) and is a recommended alternate for convenient application in food industry. Addition of SE to the malt extract at accepted levels of total saponin daily intake (below 50 mg/kg) showed positive attribution of malt and carbonation on the foaming quality of SE. Meanwhile, antioxidant activity of commercial malt beverage was enhanced by addition of phenolic compounds containing SE. The 20–60% antifungal inhibitory ratio of the SE developed here is within the applied range of total saponin that supports its application to inhibit the growth of Saccharomyces cerevisiae after malt beverage production. The bitter taste of SE was not sensed in malt beverage at 30 mg/kg total saponin content and suggested A. laxiusculum root extract as a natural additive in malt industry. [ABSTRACT FROM AUTHOR]

In the present study, SiO2 nanoparticles were first hydrophobically modified and then added into anionic surfactant sodium dodecyl sulfate (SDS) stabilized water-based foam to improve the foam stability. The foam stability was experimentally evaluated by measuring surface tension, Zeta potential and half-life of the foam. The foam stabilizing mechanism was also studied from a micro perspective by molecular dynamics simulation through analyzing the equilibration configuration and MSD curve of both SDS surfactant and water molecules. The results show that foam exhibits an optimal stability when SiO2 concentration is 0.35 wt% under a specific surfactant concentration (0.5 wt%) in this work. The addition of SiO2 nanoparticles with suitable concentration could improve the adsorption between SDS molecules and nanoparticles, thus limiting the movement of SDS and restricting the movement of surrounding water molecules, which is beneficial to enhance the foam stability.

Purpose. To establish the relationship between the foam expansion rate and stability of low-expansion air-mechanical foam generated in deflector type sprinklers for automatic extinguishing systems. To develop a methodology and carry out field tests of foam and foam-water sprinklers. To compare the extinguishing efficiency of the tested sprinklers basing on the results of field tests. Methods. The method of regression analysis was used to establish the dependence of the foam stability on its expansion rate. The assessment of the extinguishing efficiency of the sprinklers was carried out experimentally, and the processing of the obtained experimental data was carried out using the method of estimation and expression of measurement uncertainty. Findings. A linear relationship has been established between the expansion rate K and stability C of the low-expansion air-mechanical foam: C = γ·K, where γ is an empirical coefficient depending on the physicochemical properties of the foaming agent. The empirical dependences C = f(K) were obtained for brand of the foaming agents PO-6RZ (6 %). The methodology was developed and field tests of four deflector type sprinklers (V2 sprinkler with optimized geometry on the foam expansion rate, TY 3251 (USA), DPU-15 (Russia) and DVN-11 (Belarus)) were carried out. To compare the extinguishing efficiency of the sprinklers, the extinguishing efficiency indicator Et was used. This indicator takes into account the extinguishing time of the model fire site and the discharge rate of the extinguishing agent. In the result of field tests, it was found that the V2 sprinkler has at least 2.5 times better extinguishing efficiency compared to other tested sprinklers. Application field of research. The obtained empirical dependence C = γ·K can be used to predict the stability of the foam based on its expansion rate value and vice versa. The developed methods of field testing and evaluating the extinguishing efficiency of foam and foam-water deflector type sprinklers can be implemented for the development of standards, as well as for the study of other sprinklers in conditions close to a real fire.

The foam performance in the presence of oil plays an essential role in foam application in enhancing oil recovery. This study systematically investigated whey protein isolate (WPI), the effectiveness of foam generation, the effect of three types of crude oil, surfactant concentration on foam performance and oil-water interfacial tension (IFT). The extraction of WPI was compared to sodium dodecyl sulfate (SDS) at the microscopic foam images to have a better understand of foaming in terms of performance. The results showed that the WPI lowers the surface tension, which also tends to disclose and stabilize the interface by forming a viscoelastic network. SDS reduced the surface tension compared to the WPI but did not produce a high modulus interface. WPI generated a more stable foam in oil than SDS foam. The WPI improved foam stability by increasing the gas-water interface dilatational viscoelasticity layers. WPI solution decreases bubble sizes and prevents oil from spreading at the foam lamellae. The WPI foam exhibits higher stability in Libya crude oil when the oil saturation is between 0–20%. WPI foam reduces fluid loss and hinders the movement of oil droplets within the lamella, the significant viscosity contrast between oil and WPI-CO2. Waxy oil is detrimental to both SDS and WPI foam, while waxy oil can harm WPI foam in some specific cases. The oil-water IFT was reduced to extremely low levels by WPI. As a result, WPI's interfacial tension values with Sharara oil were (21 mN/m) and SDS's were (44.5 mN/m).

An interface can be delicately designed using interactions between nanoparticles and surfactants by controlling surface properties such as activity and charge equilibrium. This study seeks to provide insights into how surfactant concentration impacts the stability and dynamics of nanoparticle-surfactant interfaces, with potential applications in material science and interface engineering. This study investigates the interactions between Graphene Function (Gr, Graphene function in this text refers to functionalizing the graphene sheets with -COOH groups via acidic reactions.), Polystyrene sulfonate (PSS), and the surfactant Cetyl trimethylammonium bromide (CTAB) at the air/water interface. We examined various ratios of CTAB to Gr-PSS to determine the effects of surfactant concentration, focusing on conditions up to the critical micelle concentration (CMC). Specifically, we utilized different concentrations of CTAB ranging from 0 to 1 CMC (0.82 mM), while the concentration of Gr-PSS varied between 0 and 1 wt% and 20-50 ppm. To analyze the dynamic interfacial properties, including dynamic surface tension and dilational viscoelasticity, we employed drop profile analysis tensiometry (PAT) to measure area perturbation frequency at the air/water interface. The study aimed to elucidate the behavior of the CTAB/Gr-PSS complex at this interface. We discussed the adsorption of the CTAB/Gr-PSS complex on the droplet surface and its varying roles by examining surface pressure across different area change domains and conducting elasticity measurements. The results indicate that the attachment of CTAB molecules to Gr particles and PSS leads to the formation of surface-active complexes. As the surfactant concentration increases, excess CTAB monomers compete with the CTAB/Gr-PSS complexes for access to the interfaces, causing the larger complexes to migrate into the liquid bulk, as confirmed by elasticity assessments., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Mahmoodreza Khadangi reports article publishing charges, equipment, drugs, or supplies, and writing assistance were provided by Islamic Azad University Quchan Branch. Mahmoodreza Khadangi-Mahrood reports a relationship with 10.13039/501100002660Islamic Azad University Quchan Branch that includes: board membership, consulting or advisory, employment, and funding grants. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

The stability of foam during injection into oil reservoirs is critical, especially under high-temperature and high-salinity conditions. This study formulates foam stabilizers using one polymer, two surfactants, and six types of nanoparticles (NPs). Foam stability was assessed with a static setup, examining factors such as interfacial tension (IFT), bubble characteristics, and solution viscosity through dimensionless numbers: Bond number (Bo), Worthington number (We), and Neumann number (Ne). A new formula for dimensionless electrical conductivity was also introduced. Results showed that at optimal concentrations of the four additives, foam stability improved with NPs due to enhanced surface charge from in situ physiochemical reactions, promoting their migration to the fluid interface. Notably, Ne proved more effective than Bo and We in describing foam stability as it accounts for droplet height's impact on IFT. Acidic NPs demonstrated greater electrostatic force than amphoteric NPs, correlating with improved foam stability reflected in a downward trend in the Ne plot. Additionally, we analyzed the coarsening rate of foam bubbles over time and its relationship to stability. Our findings suggest that dimensionless numbers serve as valuable benchmarks for evaluating foam stability across various additive mechanisms., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

High-temperature steam injection is a primary method for viscosity reduction and recovery in heavy oil reservoirs. However, due to the high mobility of steam, channeling often occurs within the reservoir, leading to reduced thermal efficiency and challenges in enhancing oil production. Foam fluids, with their dual advantages of selective plugging and efficient oil displacement, are widely used in steam-injection heavy oil recovery. Nonetheless, conventional foams tend to destabilize under high-temperature conditions, resulting in poor stability and suboptimal plugging performance, which hampers the efficient development of heavy oil resources. To address these technical challenges, this study introduces a foam system reinforced with Janus nano-graphite, a high-temperature stabilizer characterized by its small particle size and thermal resistance. The foaming agents used in the system are sodium α-olefin sulfonate (AOS), an anionic surfactant, and octadecyl hydroxylpropyl sulfobetaine (OHSB), a zwitterionic surfactant. Under conditions of 250 °C and 5 MPa, the foam system achieved a half-life of 47.8 min, 3.4 times longer than conventional foams. Janus nano-graphite forms a multidimensional network structure in the liquid phase, increasing internal friction and enhancing shear viscosity by 1.2 to 1.8 times that of conventional foams. Furthermore, the foam gel system demonstrated effective steam-channeling control in heterogeneous heavy oil reservoirs, particularly in reservoirs with permeability differentials ranging from 3 to 9. These findings suggest that the Janus nano-graphite reinforced foam system holds significant potential for steam-channeling mitigation in heavy oil reservoirs.

Gliadin nanoparticle (GNP) is a promising foaming agent, but its application is hindered by the limited foam stability under low acidic conditions. Herein, we attempted to tune the foam stability of GNP by coating it with flaxseed gum (FG) and investigated the structure, interfacial behaviors, and foam functionality of gliadin-FG (GFG) particles at pH 4.5. Results showed that the formation of GFG complex particles was driven by an electrostatic interaction between positive charge patches on the surface of GNP (~17 mV) and negative charges in FG molecule (~-13 mV) at all tested ratios. The addition of appropriate amounts of FG (1:0.05) effectively improved the foam stability of GNP. This was because GFG with larger sizes and lower surface charge possessed higher rigidity after coating with FG. When they adsorbed at the air/water interface, their deformation process was slower than that of GNP, as indicated by interfacial dilatational rheology and cryo-SEM, and the covered particles seemed to be more closely distributed to form solid-like and dense interfacial films. Notably, the addition of FG at a higher ratio (1:0.3) promoted the foam stability of GNP by about five folds because the larger GFG with suitable flexibility and wettability could form a stiff interface layer with more significant elastic response, and the unabsorbed particles and FG could form a gel-like network structure in the continuous phase. These characteristics effectively prevented foam disproportionation and coalescence, as well as retard the drainage. Our findings demonstrate that coating GNPs with FG is an effective approach to improve their application in foamed foods.

The increasing global population and consumer demand for protein pose a serious challenge to the provision of protein-rich diets. Insect farming has been suggested to have a lower environmental impact than conventional animal husbandry which makes insect consumption a more sustainable solution to meet the growing world population's protein requirements. However, there is a reluctancy in the adoption of insect protein especially in the Western diets as whole insect consumption is often met with disgust and resentment. To mitigate against the feeling of disgust and resentment, there have been suggestion to include insects as an ingredient in product development. However, for this to be successfully carried out, the techno-functional properties of insect protein need to be characterised. Therefore, the aim of this study was to isolate and characterise proteins from nine edible insect species. Protein was isolated from nine edible insect species and characterised in terms of the protein content and molecular weight distribution. As crickets are the most common insect food source, the functional characterisation (foaming and emulsification) of protein extracted from house cricket (HC) supernatant protein (SP) was investigated in comparison to commercial whey protein (WP) and pea protein isolate (PPI). The protein content of the buffalo worms and yellow meal worms was significantly ( P  = 0.000) higher than other insect species such as wild black ants, queen leaf cutter ants, and flying termites. The molecular weight distribution of the nine edible insect species varied from ~ 5 to 250 kDa. HC SP foaming capacity was fourfold and threefold higher than that of WP and PPI respectively. The emulsification potential of HC SP was 1.5 × higher than PPI. The HC protein extract shows promising potential for use in the food industry and represents a potential vehicle for the introduction of insect protein into the diet of societies that are not accustomed to eating insects., Competing Interests: Conflict of interestThere are none to declare., (© Association of Food Scientists & Technologists (India) 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)