Stability Of Gels Research Articles

Effects of konjac glucomannan as a freeze-denaturation inhibitor or binder on the physiochemical properties of heat-induced gel of freeze-dried duck blood.

During freeze-drying, the degradation or eutectic melting of duck blood proteins can reduce the quality of duck blood gels. However, the interaction between proteins and polysaccharides during drying can improve protein-based gel quality. Therefore, here, we investigated the physicochemical properties of heat-induced gels of freeze-dried duck blood (FDB) and FDB with different proportions of the polysaccharide konjac glucomannan (KG), which serves as a freeze-denaturation inhibitor agent (FDA) or binder (BG). The pH and water-holding capacity (WHC) of FDB + KG gels were higher than those of FDB gel without KG (control). Especially, the WHC increased from 11.00% for control to 55.65% for FDB gel with 1% KG as a BG. Consequently, cooking loss and texture parameters of FDB + KG gels decreased. The hardness of control was 2.14kg, which significantly reduced to 0.12-0.87kg with KG addition. The highest carbonyl content was observed in control gel, and the thiobarbituric acid reactive substance content was reduced by the addition of 1% KG as an FDA (T1) or 0.8% KG as an FDA with 0.2% KG as a BG (T2) (p<0.05). These changes might be induced by the alteration of tertiary structure and thermodynamic stability of gels. In conclusion, 1% KG can be used as an FDA to improve the quality and physicochemical properties of heat-induced gels of FDB. Optimized FDB gels with KG can be used as an innovative food ingredient to fortify nutrition and develop special dietary purposes.

Development of environmentally friendly lubricant using natural resources: Layered double hydroxide gels

The development of a sustainable and environmentally friendly alternative to petroleum-based lubricants is a major challenge. In this study, layered double hydroxide (LDH) vegetable oil gels were prepared from stearic-acid-intercalated LDH (LDH-SA) and vegetable oil. The effects of content of LDH-SA and types of vegetable oils on the rheological properties of the gels were studied. The effects of several plant-derived antioxidants on the oxidative stability of LDH-SA gels were also investigated. Further, the tribological properties of LDH-SA gels were studied and compared with those of a lithium grease under the same conditions. The results showed that LDH-SA gels exhibit the typical rheological properties of grease, such as viscoelasticity, shear thinning, and structural thixotropy. Tocopherols, tea polyphenol, gallic acid, and their combinations can enhance the oxidative stability of LDH-SA gels. The tribological experiments showed that LDH-SA gels maintained the inherent excellent tribological properties of their corresponding vegetable oil. LDH-SA gels provide a new idea for the development of environmentally friendly lubricants.

Effectiveness of plant-based hand sanitizer incorporating Quercus infectoria gall extract.

Quercus infectoria (Qi), a traditional herbal plant with broad-spectrum of activities on multidrug-resistant bacteria has been develop as hand sanitizer applications. Antimicrobial activity was evaluated using agar-well diffusion and broth microdilution method. Bactericidal activity was determined following the European Standard 1276 antibacterial suspension test. Neutralization assay was performed to assess anti-respiratory syncytial virus. Safety, stability, and skin permeation of Qi hand gel was investigated. Qi hand sanitizer gel inhibited microorganisms ranging from 99.9-99.999% against Enterococcus faecalis, Staphylococcus aureus, methicillin-resistant S. aureus, S. epidermidis, S. pseudintermedius, S. saprophyticus, Streptococcus pyogenes, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Candida albicans. A significant reduction in main human dermatophytes including Microsporum canis, Microsporum gypseum, and Talaromyces marneffei of approximately 50% was observed (p<0.05). Qi hand sanitizer gel inactivated more than 99% viral particles entering human laryngeal epidermoid carcinoma cells in a dose-dependent manner. Scanning electron micrographs further illustrated that Qi hand sanitizer gel disrupted microbial cell membrane after 1-min contact time resulting in cell death. Qi hand sanitizer gel delivered emollient compounds through simulated human skin layers and showed no cytotoxicity on fibroblast cells. Moreover, Qi hand sanitizer gel demonstrated stability under extreme conditions. Qi hand sanitizer gel was able to inhibit various microorganisms including bacteria, dermatophytes, and virus.

Gelation melioration with synergistic interaction between κ-carrageenan and senna tora gum mixed gel

This study aimed to explore the synergistic effect between κ-carrageenan (KC) and senna tora gum (STG). Firstly, we found that the texture parameters, freeze-thaw stability and viscosity of KC-STG mixed gel were obviously improved compared with KC and STG. After that, the Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) results showed that KC's structure is the main one in the KC-STG mixed gel, and the hydrogen bonding force between KC and STG molecules was enhanced. The results of thermal analysis showed a high gel-sol transition temperature in the KC-STG mixed gel. A reduction in the mobility of water molecules and a more uniform distribution of water in the KC-STG mixed gel could be observed in the low-field nuclear magnetic resonance (LF-NMR) consequences. Finally, the microstructure of the gel was observed by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM), in which the STG network acted as a scaffold to fill in between the multilayered sheets of KC. The above results suggested an obvious synergistic effect between KC and STG.

Rheological and textural properties of sohphlang (Flemingia vestita) starch gels as affected by heat moisture treatment and annealing

Sohphlang being a tuberous crop exhibits rheological properties, which are expected to change with treatment. The main aim was to study the influence of heat-moisture treatment (HMT) and annealing (ANN) on rheological properties of sohphlang starch. HMT was done for 16 h using 20 %, 25 % and 30 % moisture levels, while ANN was performed at 70 %, 75 % and 80 % moisture levels for 24 h at 50 °C. Both HMT and ANN enhanced gel formation capacity and firmness. Starch gels presented a reduced apparent viscosity with an increase in shear rate, exhibiting shear thinning behavior. Frequency tests were well described by Power law and both HMT and ANN increased the structural gel strength. Starch gels containing 10 % of HMT-30 starch exhibited an improved elastic behavior (4289.79 Pa). Irrespective of starch concentration and for all samples, G′ > G″ was observed on heating beyond Tgel and during cooling, indicating the formation of rigid gel network. Gels prepared from 15 % of HMT-30 starch showed the highest resistance to temperature than other gels. HMT-30 showed more pronounced and significant changes in properties than ANN-80. The thermal stability of sohphlang starch gels may extend its application in foods requiring severe processing conditions such as pasteurized foods.

Characterization and stability of low-oil emulsion gels with newly shaped droplets stabilized by camellia saponin and k-carrageenan

In this study, low oil emulsion gels stabilized by camellia saponin (CS) and different concentrations of carrageenan (KC) were prepared, and the particle size, microstructure, rheology, and stability of the samples were investigated. The experimental results show that the average particle size of emulsion droplets decreased with the increase in KC concentration because adding KC increases the continuous phase's viscosity and prevents the oil droplets from approaching and fusing after homogenization. In addition, the shape of the oil droplets exhibited the formation of a spindle shape. Because the KC forms a spiral as it cools, pulling the sugar chains of the CS adsorbed at the droplet interface toward the ends. As KC formed strong intermolecular hydrogen bonds with the sugar chains in CS, it increased the strength of the fibrous interfacial membrane formed by CS self-assembly, resulting in good solid-like properties and excellent stability of the samples. These results suggest that emulsion gels co-stabilized with CS and KC have great potential for solid fat replacement in low-saturated and trans-fat-free foods.

The Effect of Polymer Mixing Time on the Strength of HPAM-Cr(III) Gels

The dissolution of hydrolyzed polyacrylamide, commonly used in gel treatments for enhanced oil recovery, takes between 2‒3 to over 24 h at 20‒25 °C. The duration is influenced by factors such as polymer molecular weight and brine salinity. In injection/production wells, gel treatments often involve injecting 50‒150 m3 of polymer solution within 1‒2 days, resulting in the injection of partially dissolved polymer. This raises concerns about the stability and strength of gels containing partially dissolved polymer particles. This study demonstrates that when undissolved polymer particles are kept suspended during the gelation process, there is no significant visual distinction between gels obtained from 30 min or 12 h of polymer mixing. Additionally, viscometer measurements reveal that gels formed with shorter polymer mixing times exhibit higher resistance to shearing. This observation supports the concept that undissolved polymer particles act as a composite material, improving the gel strength. This paper does not advocate for the use of partially dissolved polymer gelants. Undissolved polymer particles cannot effectively penetrate porous media. Gelants containing such particles are primarily suited for addressing fracture conformance issues. Therefore, future research will focus on examining the impact of polymer mixing time on gel syneresis and resistance to washout from fractures.

Excessive free radical grafting interferes with the macromolecular association and crystallization of brined porcine myofibrils during heat-set gelatinization

Free radical grafting and oxidative modification show superiority in myofibrillar protein (MP) aggregation patterns during salting process, but their consequent formation mechanisms of protein hydration network require further evaluation. Herein, we explored the effect of salt-curing (0, 1, 3 and 5 %) on MP protein polymer substrate, water-protein interaction, crystallization events and thermal stability under H2O2/ascorbate-based hydroxyl radical (•OH)-generating system (HRGS) (1, 10, 20 mM H2O2). Results showed that moderate salting (≤3%) favored the water binding of MP gels during the oxidation course. Accordingly, the maximum thermal stability (Tm) of MP gels was obtained at 3 % salting could be greatly attributed to the protein chain solubilization and refolding process. However, 5 % salt synergized with •OH oxidation intensified diffraction peak 2 (the most striking diffraction feature). Microstructural analysis validated a maximum compactness of MP gel following brining with 5 % salt at potent oxidation strength (20 mM H2O2). This study maybe promises efficient strategy to the myogenetic fibril products and biomaterials.

Thrombin-Free Fibrillogenesis and Gelation of Fibrinogen Triggered by Magnesium Sulfate.

Self-assembly of the blood protein fibrinogen is a highly relevant topic in materials science and medical research. This originates from fibrinogen's beneficial material properties such as cell interaction and biocompatibility. Within recent decades, several enzyme-free strategies to create fibers and hydrogels out of fibrinogen have been presented, broadening the spectrum of fibrinogen-based material enormously. Herein, we describe a further method to obtain such a material by adding specifically MgSO4 to fibrinogen. The key of this material is the combination of Mg2+ and a kosmotropic anion, for example sulfate or (hydrogen)phosphate. This effect is most likely related to occupancy of fibrinogen's well-known binding sites for Mg2+, resulting in a significant increase in fiber yield and gel stability. Here, we shine light on the question of how electrostatic interactions via Mg2+ enhance fibrillogenesis and the gelation of fibrinogen and discuss first insights into the material's properties.

Effect of konjac glucomannan with different degrees of deacetylation on the gel behavior of transglutaminase induced soybean protein isolate emulsion gels

In this study, the effect of konjac glucomannan (KGM) with different degrees of deacetylation (DD) on the gel properties of transglutaminase induced soybean protein isolate (SPI) emulsion gel was investigated. It was found that the three kinds of KGM increased the breaking force and water holding capacity, enhanced the freeze-thaw stability of the SPI emulsion gel, while KGM with DD of 59% (DKGM1) improved these properties to the largest extent. This was because SPI-DKGM1 had the lowest oil water interfacial tension, resulting in the formation of the most uniform and the smallest oil droplets, which then led to the formation of much denser gel network. Moreover, the hydrophobic interaction and hydrogen bonding between DKGM1 and SPI were the strongest compared with that of other KGM. Besides, FTIR results showed that SPI-DKGM1 emulsion gel had higher β-sheet content, which was conductive to the formation of a stable three-dimensional network structure. However, the combination of SPI and KGM with high DD (DKGM2, DD = 92%) destroyed the gel structure to some extent and resulted in emulsion gel with weakened gel properties compared with that of DKGM1. Therefore, KGM with proper DD was conducive to the formation of more ordered and much denser gel network structure, which then resulted in SPI emulsion gel with the best gel properties.

Physical Stability of Gel of Read Algae (Eucheuma spinosum) Extract and Evaluation of its Antioxidant effect

Physical Stability of Gel of Read Algae (Eucheuma spinosum) Extract and Evaluation of its Antioxidant effect

Thermal Stability Improvement of Core Material via High Internal Phase Emulsion Gels.

Biocompatible particle-stabilized emulsions have gained significant attention in the biomedical industry. In this study, we employed dynamic high-pressure microfluidization (HPM) to prepare a biocompatible particle emulsion, which effectively enhances the thermal stability of core materials without the addition of any chemical additives. The results demonstrate that the HPM-treated particle-stabilized emulsion forms an interface membrane with high expansion and viscoelastic properties, thus preventing core material agglomeration at elevated temperatures. Furthermore, the particle concentration used for constructing the emulsion gel network significantly impacts the overall strength and stability of the material while possessing the ability to inhibit oxidation of the thermosensitive core material. This investigation explores the influence of particle concentration on the stability of particle-stabilized emulsion gels, thereby providing valuable insights for the design, improvement, and practical applications of innovative clean label emulsions, particularly in the embedding and delivery of thermosensitive core materials.

Highly-branched cyclic dextrin for improvement in mechanical properties and freeze-thaw stability of κ-carrageenan gels

Highly-branched cyclic dextrin (HBCD) is a novel dextrin with promising applications in functional foods. In this study, the influence of HBCD on physiochemical properties of κ-carrageenan (KC) gels was determined by rheological measurements, thermal analysis, spectral analysis, micromorphology observation, and freeze-thaw cycle test. The results revealed that the addition of HBCD at a concentration of 2% (w/v) significantly enhanced the storage modulus and freeze-thaw stability of KC gels. During the gelation, HBCD prompted the uniform distribution of KC chains and facilitated the aggregation of KC helixes to form a compact network, enhancing the mechanical properties of KC gels. Meanwhile, the small pores within the compact network contributed to reduced water loss from the KC gels. Comparatively, the syneresis of KC gels with 2% HBCD was 19.80% after the first freeze-thaw cycle and 46.51% after complete cycles (five times), much lower than that observed in pure KC gels (66.50% after the first cycle and 68.15% after the fifth cycle). Furthermore, the attachment of HBCD to the network wall strengthened hydrogen-bonding interactions, thereby enhancing the thermal reversibility of KC gels. Overall, this research provides valuable insights and a theoretical foundation for the potential applications of HBCD in KC gels.

Characterization of the thermal behavior and structural properties of a commercial high-solids confectionary gel made with gelatin

Gelatin plays a critical role in controlling the stability and texture of high-solids gels (HSGs), widely used in confectionery products and nutrient delivery systems. Most gelatin studies have been done on dilute solutions and films, rather than HSGs. Thus, the objectives of this study were to determine the: 1) thermal and structural characteristics of gelatin in a high-solids confectionary gel, 2) effect of renaturation temperature on reformation of gelatin helical structure, and 3) effect of time on loss and reformation of gelatin helical structure. Gelatin HSGs thermal and structural characteristics were investigated using differential scanning calorimetry (DSC), powder x-ray diffraction, and powder x-ray diffraction with total scattering pair distribution function analysis, respectively. The gelatin HSG DSC thermogram exhibited two thermal events: a glass transition and an endothermic peak associated with the helix-coil transition. Based on these results, the helix-coil transition was identified as a thermal denaturation event, not a melting event. The effect of renaturation temperature on gelatin reformation and the effect of time on the loss and reformation of triple-helix gelatin structure were determined using isothermal-DSC. Onset and peak denaturation temperatures increased with renaturation temperature, whereas the amount of triple-helix structure reformed increased with renaturation temperature up to 22 °C, then decreased. Both loss and renaturation of triple-helix structure were time-dependent processes. These results support the development of gelatin HSGs with controlled thermal stability and textural properties and contribute to solving the technical challenges associated with replacing gelatin in HSGs through enhanced understanding, obtained herein, of gelatin's thermal and structural characteristics.

Waxy maize starch incorporated (−)-epigallocatechin-3-gallate can stabilize emulsion gel and improve antioxidant activity

A food-grade emulsion gel was stabilized using waxy maize starch (WS) incorporated (−)-epigallocatechin-3-gallate (EGCG) at different ratio (from 5 % to 20 %, w/w). The microstructure, rheological behavior, physical stability and antioxidant activity of emulsion gels were investigated using confocal laser scanning microscopy (CLSM), cryo-scanning electron microscopy (cryo-SEM), and rheometer, etc. The results suggested that incorporated EGCG obviously affected the spatial configuration of WS hydrogel. The WS/EGCG hydrogels presented an excellent lipophilic capacity characterized by tightly adhering to linseed oil droplets in the emulsion gels. Moreover, the viscosity, viscoelasticity and physical stability of the emulsion gels stabilized by the WS/EGCG hydrogel matrices were significantly enhanced. The emulsion gel stabilized by the WS/EGCG hydrogel matrix (15 % EGCG) had long-term emulsifying stability because its emulsified phase volume fraction (77.14 %) remained stable for 30 days. Compared with typical natural and synthetic antioxidants in food and pharmaceutical processing, the emulsion gels stabilized by the WS/EGCG hydrogel matrices showed significant stronger DPPH (97.45 %) and ABTS•+ (97.97 %) free radical scavenging activity. These results demonstrate that WS/EGCG hydrogels can not only be used in food-grade matrix materials to stabilize emulsion gels but also improve the antioxidant activity of the emulsion gels.

Experimental research on bimetallic ion crosslinked gel to inhibit the spontaneous combustion of coal

To address the environmentally friendly issue of fire prevention and extinguishing materials in coal mines, a new type of mine fire prevention and extinguishing gel was prepared using sodium carboxymethyl cellulose (CMC) as the matrix, ferro aluminum citrate (Fe-AlCit) as the cross-linking agent, and gluconic acid-δ-lactone (GDL) as the pH modifier. The preferred ratio was 2.5 % CMC + 4 % Fe-AlCit + 2 % GDL of No. 23 gel material by gelation time, thermal stability, strength, and permeability performance tests. The results show that the gelation time of No. 23 gel was 10 min, and its complete water loss time was 1.97 times that of water at a high temperature of 180 °C. The gel for sealing the surface of the coal body still maintained good stability after two weeks. Furthermore, A metal coordination bond favorable to the stability of gel is formed by the carboxylate ion in CMC and the double high-valent metal ions Fe3+ and Al3+ ionized by Fe-AlCit. No. 23 gel exhibits excellent fire prevention and extinguishing properties. The temperature-programmed test showed that the CO and C2H4 gas inhibition rate of the coal sample treated with No. 23 gel reached 33.42 % and 56.86 % at 220 ℃, and the activation energy growth rate reached 26.5 % and 21.1 % in the first and second stages, respectively. The fire extinguishing test indicated that No. 23 gel can significantly reduce the temperature of the coal sample and extinguish the coal fire quickly. The study is useful to develop efficient and environmentally friendly coal mine fire prevention and extinguishing materials.

Aggregation-induced electrochemiluminescence enhancement of Ag-MOG for amyloid β 42 sensing

This study aimed to introduce an immunosensor for measuring amyloid β 42 (Aβ42) levels by aggregation-induced enhanced electrochemiluminescence (ECL). Metal–organic gels (MOGs) are novel soft materials with advantages such as high gel stability, good light-emitting properties, and easy preparation. This study used silver nanoparticle metal–organic gel (Ag-MOG) as a substrate to connect Aβ42-Ab2 and the cathodoluminescent probe. Potassium persulfate was used as a co-reactant that could emit a high ECL signal. CuS@Au had the benefits of a relatively large surface area with excellent carrier function; therefore, it was used as a substrate to load a large amount of Aβ42-Ab1, significantly improving the immunosensor sensitivity. The ECL intensity of Aβ42 was linear in the range of 0.01 pg/mL to 250 ng/mL with a detection limit of 2.2 fg/mL (S/N = 3) under optimized detection conditions. This ECL immunosensor has been successfully applied to detect Aβ42 in human serum with the advantages of excellent stability and high selectivity. This method not only expands the potential applications of ECL immunosensors based on biological testing and clinical diagnosis but also provides a viable approach to basic clinical testing.

Improvement effect of different protein powder on cooking characteristics of gluten‐free pasta and the establishment of quality evaluation based on principal component analysis

SummaryImproving the edible quality and nutrition of gluten‐free (GF) products is vital for patients to improve their coeliac disease (CD). This study explored the effect of the addition of soybean protein isolate (SPI), ovalbumin (OVA), and whey protein (WP) on the cooking characteristics of rice‐maize‐potato (RMP) GF pasta and made a comprehensive evaluation of the quality of GF pasta. The addition of SPI at higher concentrations would seriously increase the cooking loss of GF pasta. In contrast, the addition of OVA and WP could improve the cooking stability of GF pasta. The amount of OVA and WP powder in GF flour was positively correlated with gelatinization and gel stability, and negatively correlated with cooking loss. Moreover, the addition of OVA to GF flour improved the chewiness, hardness, elasticity and tensile properties of GF pasta based on texture profile analysis. Furthermore, 13 GF pasta with different additions of protein powder were studied based on principal component analysis to evaluate the comprehensive quality of GF pasta. The consistent results of GF pasta cooking characteristics and their ranking in comprehensive quality evaluation verified the reliability of this method. This study provides a reasonable instruction for quality improvement of GF pasta and a theoretical basis for the comprehensive quality evaluation of GF pasta, which could facilitate the development of foods with high cooking characteristics and nutrition suitable for patients with CD.

Characterization of sacha inchi (Plukenetia volubilis) and taro (Colocasia esculenta) flours with potential application in the preparation of both gluten-free and high protein foods.

Background: Interest in alternative sources of tubers and legumes has increased in recent years because of the constant search for raw materials that provide bioactive compounds with antioxidant potential benefits for consumers. The functionality of new raw materials is sought through physical and/or chemical modifications to develop and innovate new foods. The objective of this study was to characterize taro (TF) (Colocasia esculenta) and sacha inchi (Plukenetia volubilis) flours, obtained by the wet (SIF-WM) and defatted method (SIF-DM), as an alternative for the formulation of new functional foods. Methods: The free polyphenols of the different mixtures were analyzed, and the antioxidant properties of the extracts obtained were measured using ABTS.* (2,2′-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid). The ABTS radical method, which reacts with the phenolic compounds of the food matrix, using Trolox as a standard. The blends were subjected to pasting analysis, flow profile tests, determination of viscoelastic properties (temperature sweep). Characterization of common microorganisms in these foods was performed. Results: The highest protein value was obtained in the sacha inchi flour obtained by the defatted method (72.62). The majority of components in taro were carbohydrates (85.4%). About antioxidant and determination of free polyphenols, taro flour obtained values of 2.71 µmol ET/g and 7.47 mg EAG/g, higher than Sacha inchi flours. In the rheological analysis (pasting properties, flow profile, and viscoelasticity), we observed that adding taro flour in different mixtures increases the viscosity peak and a lower breakdown, while there was an increase in setback. Except for defatted sacha flour, the others presented a flow index &gt;1 before heating, showing a dilatant fluid behavior. The presence of Taro flour improves gel formation and stability. Staphylococcus aureus and Salmonella were present in the taro flour. Conclusions: The flours analyzed represent a raw material with great potential for the development of gluten-free foods with functional properties.

Effect of palm oil content and melting point on the freeze-thaw stability of fat substitutes

Animal or plant-based meat products are typically stored and transported using freezing. Freezing-thawing cycles can lead to detrimental changes in the texture, appearance, and mouthfeel of fat substitutes, thus affecting their quality. In this work, a protein/polysaccharide composite emulsion gel was created by emulsifying soybean isolate protein (SPI) and palm oil (PO), and incorporating curdlan (CL). It can serve as a potential replacement for animal fat in meat products, such as sausage, and plant-based meat. The study aimed to investigate the stability of the complex fat substitutes during freeze-thaw at various melting points and palm oil content. The results showed that the 52°C-palm oil samples were the most freeze-thaw stable compared to samples with other melting points. 52°C-palm oil samples were tested for texture and water holding capacity (WHC), increasing the oil content from 5g/100g–20g/100g improved the gel strength and WHC after freeze-thaw. The samples containing high melting point palm oil were less affected by temperature changes and showed higher stability as detected by low-field NMR and differential calorimetric scanning. The confocal laser scanning and rheological detection further confirmed the enhanced structural strength and freeze-thaw stability of the emulsion gels containing solid fat particles with high melting points.