Gel Viscosity Research Articles

Properties of Rennet Gels from Retentate Produced by Cold Microfiltration of Heat-Treated and Microfiltered Skim Milk.

This study investigated the production of rennet gels from β-casein-depleted retentates obtained through cold microfiltration (MF) of skim milk (SM) that was treated beforehand to ensure microbial safety. The treatments included thermization (65 °C, 20 s), pasteurization (72 °C, 15 s), and microfiltration (50 °C; 1.4 μm pore size). The reduction in β-casein content was 0.98, 0.51 and 0.90%, respectively. All treatments resulted in the partial aggregation of serum proteins, which were slightly concentrated in the retentates obtained post cold MF process. This aggregation, along with concentration effect, likely inhibited β-casein dissociation from casein micelles and permeation, particularly in pasteurized milk. Renneting and coagulation properties of the retentates were comparable to those of the respective SM samples, with no significant differences in syneresis, water-holding capacity, or protein hydration. Notably, the retentate from thermized SM, which showed the best performance with the highest β-casein reduction (0.98%), demonstrated shorter coagulation time compared to retentate from pasteurized milk or the corresponding unfiltered SM. Textural analysis revealed greater firmness, cohesiveness, and viscosity of retentate-based rennet gels compared to gels made from unfiltered SM, attributed to protein concentration during cold MF. Overall, this study successfully produced rennet gels from cold MF retentates without compromising their physicochemical properties.

Water as Dual-Function Plasticizer and Cosolvent in Gel Electrolytes for Dye-Sensitized Solar Cells.

This study presents a novel approach to developing eco-friendly dye-sensitized solar cells (DSSCs) using natural and renewable materials for gel polymer electrolytes (GPEs), reducing reliance on unsustainable solvents. Water is added to polar aprotic solvents, specifically ethylene carbonate/propylene carbonate (EC/PC), across various mass fractions (0:100 to 100:0). An amphiphilic hydroxypropyl cellulose (HPC) natural polymer is employed to formulate GPEs within this water-EC/PC cosolvent system, achieving successful gelation up to 50:50 mass fractions. Incorporating water reduced the gel strength and viscosity of the GPEs. Water acted as a plasticizer, enhancing the polymer chains mobility, and creating a more flexible and permeable structure. This increased ion diffusion coefficients and ion mobility, resulting in a maximum ionic conductivity of 18.17 mS cm-1. The highest efficiency achieved in DSSCs using these GPEs is 5.81%, with elevated short-circuit current density and reduced recombination losses. However, some compositions experienced syneresis, affecting their stability. The GPE with a 40:60 mass fraction exhibited superior long-term stability because it is free from syneresis, though it achieved a lower efficiency (4.83%), making it the best-performing sample. This work demonstrates the feasibility and benefits of using gel polymer electrolytes in an aqueous system, improving DSSC efficiency and sustainability.

Synthesis of vitamin D3 loaded ethosomes gel to cure chronic immune-mediated inflammatory skin disease: physical characterization, in vitro and ex vivo studies

The purpose of the current work was to develop and characterize ethosomes of vitamin D3 gel that could more effectively work against psoriasis. Psoriasis is a chronic immune-mediated inflammatory skin disease. Due to vitamin D3 role in proliferation and maturation of keratinocytes, it has become an important local therapeutic option in the treatment of psoriasis. In this research we have initiated worked on ethosomes gels containing vitamin D3 to treat psoriasis. Soya lecithin 1–8% (w/v), propylene glycol and ethanol were used to create the formulations, which were then tested for vesicle size, shape, surface morphology, entrapment effectiveness, and in vitro drug permeation. The drug encapsulation efficiency of ethosomes was 96.25% ± 0.3. The particle sizes of the optimized ethosomes was 148 and 657 nm, and the PDI value was 0.770 ± 0.12 along with negative charge − 14 ± 3. Fourier transform infrared (FT-IR) spectroscopy and differential scanning calorimetry (DSC) along with thermogravimetric analysis (TGA) studies confirmed the absence of interactions between vitamin D3 and other ingredients. It was determined that the total amount of medication that penetrated the membrane was 95.34% ± 3. Percentage lysis was very negligible for all strengths which were found less than 15%. Based on our research, ethosomes appear to be safe for use. The vitamin D3 ethosomal gel order, description, pH, and viscosity were all within the specified ranges, according to the findings of a 6-month investigation into the stability profile of the completed system. In this research, we successfully prepared ethosomes loaded with vitamin D3 and then converted it into gel for patients’ easy applications.

Effect of three polysaccharides with different charge characteristics on the properties of highland barley starch gel

Highland barley, a nutritious whole grain, faces limited market utilization due to the poor heating stability of its starch. The aim of this study was to investigate the effects of three differently charged ionic polysaccharides—guar gum (GG), xanthan gum (XG), and carboxymethyl chitosan (CMC)—on the gel properties of highland barley starch (HBS). GG and XG notably increased pasting viscosity, viscoelasticity, hardness, and strength of HBS gels. Conversely, CMC resulted in decreased gel properties. All three polysaccharides enhanced OH tensile vibration (3000–3800 cm−1), with GG and XG promoting denser honeycomb network structures and lower spin–spin relaxation time (T2), indicating improved structural integrity. In contrast, low concentrations of CMC led to disorder and loose structure. Hydrogen bonding and electrostatic interactions were the main forces by which polysaccharides influenced the properties of starch gels. This research contributes to enhancing the properties of HBS gel during heating and expanding its commercial applications. It also provides some insights to understand the interaction between different charged polysaccharides and starch.

Chitosan gel loaded with carbon dots and mesoporous hydroxyapatite nanoparticles as a topical formulation for skin regeneration: An animal study

BackgroundCarbon dots (CDs) are the research hotspots in antimicrobial applications. Also, due to the importance of calcium ions in skin regeneration, mesoporous hydroxyapatite nanoparticles (mHAP NPs) were prepared. This study aimed to evaluate the wound healing efficiency of both CD and mHAP NPs simultaneously. MethodsWe doped Fluorine (F) and Copper (Cu) in CDs to prepare Cu*F-doped CDs (Cu.CDs). For the rapid release of calcium ions, a novel double-surfactant system (CTAB/F-127) was used for the synthesis of mHAP NPs. Then, we loaded both Cu.CDs and mHAP NPs simultaneously into the chitosan (CTS) gel. ResultsThe released calcium for mHAP NPs prepared using CTAB/F-127 was proved about 30 % higher than that prepared using only CTAB, after one day. The BET-specific surface area for mHAP NPs prepared using CTAB/F-127 was 23.17 % more than that prepared using only CTAB. This high porosity improves wound exudate absorption. Rheological analysis showed that the addition of both mHAP NPs and Cu.CD decreases the viscosity of CTS gel and thereby makes it suitable for topical applications. CTS gel containing mHAP + Cu.CDs indicated exceptional antibacterial properties even without light and/or H2O2 with an inhibition zone diameter of 35 and 17 mm for E. coli and S. aureus species, respectively. CTS gel containing mHAP + Cu.CDs also showed significantly higher wound closure efficacy, greater inflammation inhibition, and better re-epithelialization than the other groups in rats with full-thickness skin wounds. ConclusionThe CTS gel containing both Cu.CD and mHAP NPs can be proposed as a new therapeutic gel for wound healing.

Pasting, structural properties, and in vitro digestibility of water chestnut (Eleocharis dulcis Burm. f., Cyperaceae) starch co-gelatinized with different hydrocolloids

Hydrocolloids have been widely used to modulate the processing properties of native starch, this study aimed to investigate the effects of carrageenan (KC), tamarind seed polysaccharide (TSP), and xanthan gum (XG) on the pasting, rheology, structural properties, and in vitro digestibility of water chestnut starch (WCS). The pasting results showed that XG increased the peak viscosity (PV), trough viscosity (TV), final viscosity (FV) and breakdown viscosity (BD) of WCS gel, but decreased the setback (SB), TSP significantly increased SB. The rheological data found that KC, TSP and XG increased the apparent viscosity and storage modulus (G') and loss modulus (G'') of WCS, which gradually increased by the concentration gradient of hydrocolloids. The hardness of starch with KC increased from 171.52g to 323.36g, and the addition of 0.3% KC and 0.5% KC enhanced the thermal stability. Furthermore, XG significantly increased the resistant starch (RS) content and decreased the hydrolysis rate of starch. These results will provide theoretical references for expanding the application range of WCS.

Study on preparation and performance of bagasse/sodium carboxymethyl cellulose gel for inhibiting coal spontaneous combustion

In order to effectively prevent and control coal spontaneous combustion and improve the safety of coal mining, bagasse carboxymethy cellulose (BCC) prepared from bagasse (BS) and sodium carboxymethyl cellulose (CMC) were used as the substrates. A gel (BCC-CMC) for inhibiting coal spontaneous combustion was prepared using a chemical crosslinking method involving zirconium citrate crosslinking and glucono-delta-lactone (GDL) modification. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy were utilized to characterize both the crystal and molecular structure of bagasse and its derived bagasse carboxymethyl cellulose. The results indicated that new carboxymethyl groups were introduced into bagasse during the treatment, facilitating the successful extraction and preparation of sodium carboxymethyl cellulose. The results of viscosity and bonding tests demonstrated that the concentration and dosage of CMC had the most significant influence on the gel viscosity, which remained higher and more stable at room temperature. The coal bonded by the gel coal mixture can effectively seal surface cracks, with a bonding degree of up to 70.72 %. TG-DTG, temperature-programmed oxidation experiment and FTIR analyses revealed that, compared to raw coal, coal samples treated with gel exhibited improved stability, fewer active groups, and fewer oxygen-containing functional groups, effectively inhibiting coal’s low temperature oxidation and reducing the risk of spontaneous combustion. The gel is environmentally friendly, cost-effective, and exhibits good flame retardant properties. This study is of great significance for preventing and controlling coal spontaneous combustion, effectively ensuring the safe production of coal resources and the safety of mine workers, achieving the green sustainable development of the mine.

Formulation Development of Mucoadhesive Vaginal Gel of Secnidazole and Voriconazole.

Purpose: Over the preceding decades, developing conventional drug delivery in to modified form has acquired importance in the pharmaceutical industry. Vaginal drug delivery system offers localized drug administration of drug and also avoids unwanted side effects of oral drug delivery. Vaginal drug delivery system has significant role in medical practice. Even though VDDS has a lot of advantages over the other routes of administration. The goal of developing the Mucoadhesive Vaginal Gel was to achieve the synergistic effect of voriconazole and secnidazole in the treatment of bacterial and fungal vaginal infections. Method: Mucoadhesive antimicrobial vaginal gel was optimised using Design expert software using Carbopol 934, HPMC K4M polymers. Result: Formulation was evaluated for various rheological parameters ,antimicrobial activity, invitro drug release and stability study. The spreadability and pH was found to be 5.5 to 7.4 cm and 4.12. Its compatible with vaginal pH. The selected optimized F8 formulation is the best formulation and the drug ratio is 2:1. and optimum gel viscosity is 1874 cps. antimicrobial study revealed that faster drug release of test formulation was compared to marketed product. It indicates as inhibition zone. Conclusion: The combination of drugs can serves as better option for treating vaginitis, compared to single drug formulation. Mucoadesion increases contact time of drug with affected area which rendered formulation more effective.

Preparation and In vitro/Ex vivo Evaluation of Nanoemulsion-Based in Situ Gel for Intranasal Delivery of Lasmiditan

Lasmiditan (LAS) was formulated as a nanoemulsion based in situ gel (NEIG)with the aim of improving its oral bioavailability via application intranasally. The solubility of LAS in oils, emulsifiers, and co-emulsifiers was determined to identify nanoemulsion (NE)components. Phase diagrams were constructed to identify the area of nanoemulsification. LAS NE was formulated using the spontaneous nanoemulsification method. Four NEs (F19, F24, F31, and F34) containing 7-15 % oleic acid (OA) as an oily phase, 40-55% labrasol (LR), and transcutol (TC) as emulsifier mixture at (1:1), (2:1), (3:1), and (1:2) ratio with 30-53 % (w/w) aqueous phase, having suitable optical transparency of 95–98%, globule size of 104-140 nm and polydispersity of 0.253–0.382 were selected for ex vivo permeation study. F31 with the highest flux value (2.32 ± 0.01 mg/cm2.min) relative to the other NEs. It achieves an enhancement ratio of 3.3 as compared to LAS aqueous suspension (8% LAS) also it achieves a significantly higher value of permeability coefficient. F31 was selected for the incorporation of different percentages of pH-sensitive in situ gelling polymer (Carbopol 934) to prepare NEIGs 4,5 and 6. The gel strength, pH, gelation time, and viscosity were predicted for the prepared NEIGs. In vitro release and ex vivo, nasal permeation were determined for NEIG5, which exerts comparable release and permeation values as F31 with more residence time in order to overcome the normal nasal physiological clearance.

Sustainable valorisation of freshwater fish by‐products to gelatin and fish oil by hydrothermal extraction

SummaryThis study explores the potential of hydrothermal extraction as an innovative valorisation method for the simultaneous production of gelatin and fish oil from fish byproducts. It offers an environmentally friendly alternative to conventional solvent‐based techniques by minimising the use of chemical solvents and water. We researched various major commercial freshwater fish species: striped catfish, catfish, and tilapia, and achieved a gelatin product that reflects commercial standards in chemical structure, gel strength, and pH level. The striped catfish gelatin showed the highest gel strength and viscosity (66.01 ± 0.83 g bloom and 15.3 ± 0.1 cP), but was produced at a lower yield than the catfish gelatin. On the other hand, striped catfish produced the highest yield of fish oil (13.56 ± 0.21%) and has the highest omega 3 content (3.72 ± 0.02%) than other fish oil. This innovative study demonstrates the potential of hydrothermal extraction as a sustainable method for producing gelatin and fish oil, offering eco‐friendly and nutritional benefits across a range of applications.

Effects of glycation modifications of different glycosylating agents on the molecular structure and gel properties of sheep's hoof gelatin

In this study, we utilized sheep's hoof gelatin as a raw material to modify gelatin by non-enzymatic glycation reactions using five different monosaccharides (D-glucose, D-sorbose, D-fructose, D-ribose, and D-erythrose) and five different polysaccharides (pectin, inulin, carrageenan, xanthan gum, and konjac glucomannan) and comparatively analyzed the properties (rheological properties, textural properties, and thermal stability) of differently glycosylated sheep's hoof gelatin to determine the mechanism of different glycosylating agents on the molecular properties and gel performance of sheep's hoof gelatin. The results showed that the reactivity (DG value) and phase transition temperature (Td value) of gelatin modified with monosaccharide glycosylates were notably higher (p < 0.05) compared to those modified with polysaccharides, resulting in a micro-network structure with finer pore size. Conversely, polysaccharide glycosylation significantly enhanced the mechanical properties and rheological characteristics of gelatin (p < 0.05). The formation of a mosaic network structure in the polysaccharide-glycosylated gelatin group played a pivotal role in enhancing gel properties. Notably, the gel strength (584.62 ± 6.34 g), viscosity (η-value), and gel melting temperature (37.85 ± 0.20 °C) of the polysaccharide S-PEC were significantly higher than the other treatment groups (p < 0.05). This research not only provides a new perspective for modifying gelatin derived from sheep's hooves but also offers an important theoretical basis for the exploration and application of gelatin materials in the food industry.

Preparation and flame retardant properties of new mining fireproof gel

Coal spontaneous combustion (CSC) brings great danger to mine safety. Although traditional colloidal fire-fighting materials can reside at high fire source points, their permeability and fluidity are poor, and such materials focus on their water absorption, but pay less attention to water retention and resistance, which makes their fire-fighting effect not good. This paper proposed a new type of mining fire prevention colloid material (CPS-α), which had good solid water gel formation, viscosity, fluidity, and blocking properties to compensate for traditional colloids' shortcomings. According to the single-factor experiment, polymeric polyacrylamide (PAM) as the base material, sodium carboxymethyl cellulose (CMC) as the coagulant, modified starch (SS) as the flame retardant and reduced ascorbic acid were determined. After gel treatment, compared with raw coal, the critical temperature point of spontaneous combustion of coal was increased by about 28 °C, the time to reach the critical temperature point was delayed by 190s, and the characteristic temperature points were significantly increased; the overlap area of coal and water increases by about 20 % after adding gel, and the change slope of the diffusion coefficient of water decreases, which indicated that CPS-α had good flame retardant effect.

Effect of branch length of cluster dextrin on the textural and rheological properties of κ-carrageenan emulsion gels

In this paper, a range of novel cluster dextrins (CDs) with high molecular weight (∼105 g/mol) and narrow molecular weight distribution were fabricated by α-amylase and branching enzyme (BE, EC 2.4.1.18). The influence of CDs on the physicochemical properties of κ-carrageenan (KC) emulsion gels was investigated. The average particle size of the composite emulsion gels containing CD was decreased by 7.85–12.66 μm, and the gel network was more uniform and denser, owing to stronger non-covalent interactions in the composite sample system. Textural results demonstrated that the composite emulsion gels exhibited higher hardness and springiness, but lower cohesiveness. CDs hindered the formation and aggregation of KC double helices, as evidenced by reducing the intensity of the sulfate group peak at 1223 cm−1. Furthermore, CDs increased the apparent viscosity, storage modulus (G'), and melting temperature (Tm) of emulsion gels, based on rheological results. CDs with longer branch lengths were more prone to entangle with KC chains to optimize the gel structure, exhibiting a more significant effect on the physicochemical properties of emulsion gels. The present study provided a new insight for constructing a new energy delivery system.

A mechanism – based perspective on the interplay of new drug candidate with biomolecules

This research deals with the synthesis and analysis of a novel Pd(II) compound, [Pd(dach)(SA)], featuring 1,2-diaminocyclohexane (dach) and salicylic acid (SA). The compound's structure was refined and its electronic properties including HOMO-LUMO energies, molecular electrostatic potential and natural bond analysis were calculated using B3LYP functional of DFT. Biologically, the compound demonstrated significant antitumor efficacy against the K562 leukemia cell line (IC50 = 37 μM). In-silico methods predicted the favorable characteristics and low risks of new compound. Interactions with DNA and serum albumin were explored using both experimental and computational techniques, revealing that the compound binds through hydrogen bonds and van der Waals forces having Kb,DNA = 1.7 × 105, ΔG°DNA = - 7.32 kcal/mol, Kb,BSA = 1.25 × 106 and ΔG°BSA = - 8.36 kcal/mol, as indicated by fluorescence spectroscopy. UV–Vis spectroscopy showed a reduction in the absorption spectra of both DNA and BSA upon interaction. DNA binding affinity was confirmed via gel electrophoresis and viscosity measurements. Molecular docking suggested the groove binding with DNA, and site I of BSA, primarily through hydrogen binding. The stability and conformational changes of these interactions over the time were affirmed by molecular dynamics simulations and QM/MM calculations. These comprehensive studies underscore the potential of [Pd(dach)(SA)] complex as a candidate for cancer therapy, highlighting its strong binding interactions with crucial biomolecules.

Research on the Effect of Static Pressure on the Rheological Properties of Waxy Crude Oil

In this paper, with the application of a MARS 60 high-pressure rheometer, experimental tests are conducted on Shengli crude oil to test its gel point, viscosity and thixotropy under different static pressures. Consequently, the effect of static pressure on the rheological parameters of waxy crude oil is revealed. It is proven that with the increase in the static pressure, the gel point of Shengli crude oil increases linearly, and the viscosity also gradually increases. The power law equation is employed to describe the relationship between the apparent viscosity and shear rate of Shengli crude oil under different static pressures. With the increase in the static pressure, the consistency coefficient (K) increases linearly, and the rheological index (n) decreases linearly. The relationship between the viscosity of Shengli crude oil and the static pressure and shear rate can be obtained. The Cross thixotropic model is used to describe the thixotropic curve of Shengli crude oil under different static pressures. With the increase in the static pressure, the thixotropic coefficient of consistency (ΔK) and the structure fracture constant (b) increase linearly. This is because a high pressure results in high structure strength and strong non-Newton rheological behavior in gelled crude oil and also causes remarkable structure fracture in crude oil. The results in this paper can provide an important theoretical basis for crude oil production and transportation.

Effect of different chain-length fatty acids on the retrogradation properties of rice starch

In order to delay the retrogradation of rice starch, the effects of three different chain length fatty acids (lauric acid, myristic acid and palmitic acid) on rice starch were studied. The fatty acids with longer carbon chains had strong steric hindrance and hydrophobicity, which formed a more compact structure in the helical cavity of amylose, and significantly reduced degree of expansion, migration of water, short-range ordered structure, number of double helical structures and crystallinity. These structural changes endowed the rice starch-long chain fatty acid complexes with better gel viscosity, liquid fluidity and thermal stability than in the rice starch-short chain fatty acid complexes. The results showed that fatty acids with longer chain length inhibited the retrogradation of rice starch, most obviously when 5% palmitic acid was added. This study provides an important reference for the processing of rice starch-based foods.

Enhancing temperature resistance of polymer gel fracturing fluids: The role of alcohol

The temperature resistance of polymer gel fracturing fluids is the key to ensure its application in deep oil and gas reservoirs. Currently, the methods to improve the temperature resistance of polymer gel fracturing fluids are mainly based on the additives commonly used in fracturing fluids, but rarely studied on improving the strength of crosslinked systems by strengthening its non-covalent interactions. Herein, we separately introduce ethanol and glycol into the partially hydrolyzed polyacrylamide (HPAM) crosslinked zirconium polymer gels to form the fracturing fluid system with higher temperature-resistant ability. The concentrations of the HPAM and crosslinking agent are all 0.6 wt%. After shearing at 120 °C and 170 s−1 for 1 h, the addition of ethanol and glycol can increase the retention viscosity of the polymer gels from 43 mPa s to 148 mPa s and 204 mPa s, respectively. Microscopic characterization demonstrates that the addition of ethanol and glycol makes the polymer gels more dense “honeycomb” and “dendritic” structures, which may be the main reasons for the temperature resistance enhancement of the system. Additionally, the molecular dynamics simulations show that the supramolecular interaction in the polymer gel system is greatly enhanced by the formation of hydrogen bonds when the alcohol is added at low concentrations. Meanwhile, the zirconium ions play a bridging role in connecting oxygen atoms in the carboxyl group in HPAM and oxygen in the alcohol hydroxyl group. The hydrogen bonds and O-Zr-O bridges can strengthen the non-covalent interactions of the system, inhibiting the destruction of polymer gel structure at high temperatures and enhancing its temperature resistance. However, when the alcohol concentration of the system is too high, the crosslinking strength of the polymer gels is weakened to different degrees due to the competitive effect of the alcohol on the crosslinking agent. Both experimental results and theoretical simulation further deepen the understanding of alcohol to improve the temperature resistance of polymer gels, and can promote the subsequent application of alcohol to polymer gel fracturing fluids for property enhancement.

A systematic study of the effect of nano-additives on the functional characteristics of hydraulic fracturing gels

Currently, the main technique for the development of low-permeability reservoirs is hydraulic fracturing technology. To further enhance its efficiency and reduce costs, it is necessary to improve the formulations and properties of liquids used for hydraulic fracturing. The use of nanoparticles for these purposes may become one of the promising directions. In this paper, for the first time, the effect of concentration, size, material and form of nano-additives on colloidal stability, viscosity, wetting characteristics and filtration losses of cross-linked gels for hydraulic fracturing were studied systematically. In the preparation of cross-linked gels, a guar gum biopolymer was used as a typical gel-forming agent and sodium tetraborate in glycerin was applied as a cross-linker. Spherical nanoparticles of silicon oxide and aluminum oxide, single-walled carbon nanotubes, and aluminum oxide nanofibers were employed as nano-additives. The average size of the nanoparticles varied from 11 to 216 nm. The concentration of nano-additives in the gels ranged from 0.01 to 0.8 wt%. The temperature was changed from 25 to 70 °C. The research has shown that the dependences of the functional characteristics of nano-modified gels on the concentration and size of nano-additives are non-monotonic in nature. The optimal concentration of nanoparticles to control the properties of the gel is in the range of 0.05–0.2 wt%, and the optimal average size is 70–80 nm. With these parameters, nanomaterial additives can radically change the properties of hydraulic fracturing gels (increase the effective viscosity several times, reduce filtration losses tenfold and significantly change the hydrophobicity).

Numerical simulations of secondary atomization characteristics of shear-thinning kerosene gels

Owing to their unique non-Newtonian characteristics, gel propellants have become a new type of fuel with promising applications in the aerospace industry. However, the complex rheological properties and high viscosity of gels pose significant challenges for flow control in gel engines, particularly in terms of fuel atomization and combustion efficiency. Focusing primarily on kerosene gel, this study investigates the secondary atomization characteristics of shear-thinning droplets, where the volume of fluid method is employed to capture interface dynamics on adaptive grids, and the viscosity of the gel is described by a power-law model. The accuracy of the numerical model is validated by comparing it with the experimental observations of the breakup process of 1% silica kerosene gel droplets. Numerical simulations are conducted to analyze the droplet breakup processes and formation mechanisms under bag, multimode, and shear breakup. Compared to kerosene, the apparent viscosity distribution inside the kerosene gel droplets is non-uniform, and the inhibition of viscous force delays the breakup time and reduces the droplet deformation, thereby affecting the transition of the breakup mode. By varying the Weber number, We, the rheological parameters, and the density ratio, the quantitative effects of these factors on droplet deformation, centroid velocity, average viscosity, the breakup time, etc. are revealed. The results indicate that the breakup becomes more severe with increasing We number, resulting in larger deformation and a greater number of smaller droplets; the rheological parameters significantly affect the droplet breakup by altering the fluid viscosity; moreover, under the same flow condition, the higher the density ratio, the more difficult it is for the droplet to break up; however, on dimensionless scales, the effect of density ratio appears weak. Additionally, a breakup regime diagram is constructed in the We–Oh (Ohnesorge) number space for low Weber numbers. This study validates the numerical method for simulating the secondary atomization of kerosene gel propellants, providing a thorough analysis of three breakup mechanisms and the impact of key parameters on kerosene gel droplets. These insights offer a theoretical foundation for the optimization of gel propellants, aiding in the development of efficient and stable propulsion systems.

Interaction of anthocyanins, soluble dietary fiber and waxy rice starch: Their effect on freeze-thaw stability, water migration, and pasting, rheological and microstructural properties of starch gels

This study aimed to investigate the effect of the interaction of black rice anthocyanins (BRA), soluble dietary fiber from extruded rice bran (ES) and waxy rice starch (WRS) on the physicochemical properties of starch gels, including gelatinization properties, rheological properties, freeze-thaw stability, water migration, molecular structure and gel microstructure. The results showed that the pasting temperature (PT) of the mixtures was increased, and the peak viscosity (PV), trough viscosity (TV), final viscosity (FV) and setback viscosity (SV) were significantly reduced when ES and BRA were added to WRS in different proportions (ES:BRA, 4:0, 4:0.4, 4:1, 4:2, 8:0, 8:0.8, 8:2, 8:4). Both ES and BRA could enhance the viscosity of WRS gels, and ES exhibited strong ability on improving the strength of gels. The presence of ES and BRA improved the water retaining capacity of WRS gels, but weakened the freeze-thaw stability. ES, BRA and WRS formed non-covalent bonds (hydrogen bonds) through hydrophilic groups during gelatinization, which improved the gel properties. In addition, the steric hindrance formed by ES and BRA inhibited starch retrogradation. These results might contribute to the development of starch-based food formulations with good quality.