Characteristics Of Gels Research Articles

Multi-dimensional analysis of heat-induced soybean protein hydrolysate gels subjected to ultrasound-assisted pH pretreatment

This study aimed to evaluate the gelation characteristics of soybean protein hydrolysate (SPH) extracted by enzyme-assisted aqueous extraction. Specifically, the changes in gelation behaviors for heat-induced (95 °C, 20 min) SPH dispersions treated with pH (pH 3, 5, 9; pH 7 as control) and ultrasound (U; 240 W, 30 min) were investigated. The results showed that typical gel behavior with high elastic nature in the viscoelasticity and network structures were observed during the heating process, where the disulfide bond played a dominant role in the gel network formation of all the samples. Notably, the heat-induced aggregation in the SPH gels was mainly formed by the association of the basic B polypeptide in 11S and β subunit in 7S. The most superior SPH gel was formed at pH 7 when assisted by ultrasonication during the heating process. This as-synthesized gel showed a uniform filamentous structure and exhibited the more excellent textural, rheological and thermal properties than those of the samples formed under acidic and alkaline conditions. These results are of great value in revealing the gelation mechanism of SPH.

Effect of high‐content ultrasonically emulsified lard on the physicochemical properties of surimi gels from silver carp enhanced by microbial transglutaminase

SummaryThe objective of this study was to investigate the effect of ultrasonically emulsified lard combined with microbial transglutaminase (MTGase) on the physicochemical characteristics of surimi gel from silver carp. Surimi gel with ultrasonically emulsified lard had higher whiteness, gel strength and water‐holding capacity. Storage modulus and loss modulus decreased with the addition of lard or ultrasonically emulsified lard to the surimi. However, the gel strength and WHC presented a decreasing tendency in surimi gels with more addition of ultrasonically emulsified lard, because the gel network could not overcome the damaging effect of higher ultrasonically emulsified lard (>6 g 100 g−1). MTGase increased the cross‐linking degree of gels (P < 0.05) regardless of the presence or absence of lard or ultrasonically emulsified lard. MTGase provided a denser and stronger gel network to ensure the stability of oil droplets. In general, the combination of ultrasonically emulsified lard and MTGase could effectively improve the color, textural and rheological characteristics of surimi‐based products.

Acid-induced Poria cocos alkali-soluble polysaccharide hydrogel: Gelation behaviour, characteristics, and potential application in drug delivery

Poria cocos alkali-soluble polysaccharide (PCAP), a water-insoluble β-glucan, is the main component of the total dried sclerotia of Poria cocos. However, its gelation behaviour and properties have yet to be comprehensively studied. In this study, an acid-induced physical hydrogel based on natural PCAP is fabricated. The acid-induced gelation in PCAP is explored with respect to the pH and polysaccharide concentration. PCAP hydrogels are formed in the pH range of 0.3–10.5, and the lowest gelation concentration is 0.4 wt%. Furthermore, dynamic rheological, fluorescence, and cyclic voltammetry measurements are performed to elucidate the gelation mechanism. The results reveal that hydrogen bonds and hydrophobic interactions play a dominant role in gel formation. Subsequently, the properties of the PCAP hydrogels are investigated using rheological measurements, scanning electron microscopy, gravimetric analysis, free radical scavenging, MTT assays, and enzyme-linked immunosorbent assays. The PCAP hydrogels exhibit a porous network structure and cytocompatibility, in addition to good viscoelastic, thixotropic, water-holding, swelling, antioxidant, and anti-inflammatory activities. Furthermore, using rhein as a model drug for encapsulation, it is demonstrated that its cumulative release behaviour from the PCAP hydrogel is pH dependent. These results indicate the potential of PCAP hydrogels for application in biological medicine and drug delivery.

Optimization of The Combination of CMC-Na and Glycerin in Tobacco (Nicotiana tabacum L.) Hand Sanitizer Gel Using The Simplex Lattice Design

Tobacco leaves have active compounds such as phenols and alkaloids that can be used as antibacterial and antiseptic because they can damage the cell components of microorganisms. Tobacco leaf extract in hand sanitizer gel has been shown to have antibacterial activity against Staphylococcus aureus and Eschericia coli bacteria at a minimum concentration of 0.25%. Hand sanitizer is an antiseptic product that is used to clean hands and is preferred because it is practical, has a cooling and dries quickly when compared to hand soap. To make hand sanitizer products that are safe for the skin, various chemical compounds are used as building blocks, including CMC-Na and glycerin. CMC-Na acts as a gelling agent and glycerin has a role as a vehicle. This study aims to obtain the optimum formula for hand sanitizer gel preparations with variations in the concentration ratio of CMC-Na and glycerin using Simplex Lattice Design (SLD) and to determine the effect of variations in the concentration ratio of CMC-Na and glycerin on physical, chemical, and microbiological characteristics of the results of the optimum formula for hand sanitizer gel preparations. The research method used in this study is a type of laboratory experiment using Completely Randomized Design (CRD). The data obtained from the research results were processed using Analysis of Variance (ANOVA) with a 95% confidence level and continued with Duncan's Multiple Range Test at a significance level of 5%. The results showed that there were 3 optimum formulas for hand sanitizer gel of tobacco leaf extract based on the desirability value, 0.912 (Formula 1), 0.457 (Formula 4) and 0.653 (Formula 5). The variation of the concentration ratio of CMC-Na and glycerin in the optimum formula showed that CMC-Na had the most dominant influence on physical (homogeneity), chemical (total flavonoid) and microbiological (antibacterial and antiseptic) characteristics. Meanwhile, glycerin has the most dominant influence on product viscosity stability. The three optimum formulas have homogeneous gel characteristics.

Gelation properties of silver carp (Hypophthalmichthys molitrix) surimi as affected by phenolic compounds in lotus root knot extract

ABSTRACT The objective of this study was to investigate the effects of aqueous extract of lotus root knot (AELRK) on the gel characteristics of silver carp surimi. Gel strength, storage modulus, and disulfide bond of surimi gels were significantly increased with the addition of the AELRK (p < 0.05), especially at 10% AELRK (p < 0.05), where gel strength and disulfide bond were enhanced by 14.7% and 41.6%, respectively, but decreased in expressible moisture content, ionic bond, hydrogen bond and hydrophobic interaction. Adding 10% AELRK could enhance cross-linking degree surimi gels with the denser and smoother microstructure. There was the reduction in myosin heavy chain but not significant change in actin. More addition of the AELRK significantly decreased in L* and whiteness of surimi gels (p < 0.05) but increased in a * . Therefore, there would be a potential to utilize the phenolic compounds from lotus root to improve the quality of silver carp surimi.

Impact of pin‐to‐plate cold plasma depolymerization on the gelation and functional attributes of guar galactomannan

AbstractThe present study aimed to investigate the impact of pin‐to‐plate cold plasma on the gelation and functional attributes of guar seed galactomannan. The guar galactomannan was subjected to 170 and 230 V treatment for 30 and 60 min and investigated for the gel characteristics and functional properties. The cold plasma treatment incurred galactomannan chain depolymerization with a reduction in the degree of polymerization (DP) ranging from 7.33% to 48.99%. The water contact angle (WCA) reduced from 110.93° to 95.54°, thus increasing the hydration capacity (36.73–45.90 g/g). These mechanisms diminish the gel viscosity (from 798. 227 cP of UT to 334.65 cP at 230‐60) and the viscoelastic moduli (G′ andG″) indicating the low strength of gels from plasma‐treated galactomannan (PT‐GG). This further influenced the least gelation concentration, foam capacity, and foam stability. However, the critical strain (from 11.83% [UT] to 41% [230‐60]), cross‐over frequency (from 3.39 Hz [UT] to 15.3 Hz [230‐60]), and degradation activation energy (from 18.445 kJ/mol [UT] to 21.721 kJ/mol [230‐60]) of the PT‐GG were increased (from 18.445 kJ/mol [UT] to 21.721 kJ/mol [230‐60]) signifying the increased stability of gels by intramolecular and electrostatic forces. Thus, the cold plasma‐induced depolymerization and hydrophilic modification of galactomannan influence the gelation and functional attributes which widen the potential applications of the hydrocolloid.Practical ApplicationsDepolymerized guar gum is industrially known for its specific applications such as low‐viscosity source of dietary fiber, stabilizers, complex forming, and encapsulating agents. This study shows the potential of cold plasma processing as an eco‐friendly sustainable technology for producing depolymerized guar gum which can be applied as a source of fiber in enteral feed formulations, stabilizers in low viscous spreads and sauces, and also in thermo‐reversible gel networks due to its thermal gel transition attributes.

FORMULASI GEL HAND SANITIZER EKSTRAK DAUN PALIASA (Kleinhovia hospita Linn) DENGAN GELLING AGENT HPMC

Gel hand sanitizer is a novel product formula that can be utilized as a cost-effective and portable replacement for hand washing soap. One of the plants whose leaves can be used as a central component of hand sanitizer gel is the Paliasa plant (Kleinhovia hospita Linn). Staphylococcus and Escherichia coli resist the antimicrobial effects of alkaloids, tannins, and saponins. To create the hand sanitizer gel, three different concentrations of the HPMC gelling ingredient were used: 1%, 2%, and 3%. Variations in the amount of HPMC used in each formulation impact the gel's characteristics, particularly its viscosity, spreadability, and adherence. Following the cycle test, the three formulations' viscosity decreased, but their pH, spreadability, and stickiness increased. There was no significant difference between the stability test on day 0 and day 12 for pH, viscosity, spreadability, and gel adhesion, according to testing utilizing the paired sample T-test. &gt; 0.05.

Unraveling an Alternative Mechanism in Polymer Self-Assemblies: An Order-Order Transition with Unusual Molecular Interactions between Hydrophilic and Hydrophobic Polymer Blocks.

Polymer self-assembly leading to cooling-induced hydrogel formation is relatively rare for synthetic polymers and typically relies on H-bonding between repeat units. Here, we describe a non-H-bonding mechanism for a cooling-induced reversible order-order (sphere-to-worm) transition and related thermogelation of solutions of polymer self-assemblies. A multitude of complementary analytical tools allowed us to reveal that a significant fraction of the hydrophobic and hydrophilic repeat units of the underlying block copolymer is in close proximity in the gel state. This unusual interaction between hydrophilic and hydrophobic blocks reduces the mobility of the hydrophilic block significantly by condensing the hydrophilic block onto the hydrophobic micelle core, thereby affecting the micelle packing parameter. This triggers the order-order transition from well-defined spherical micelles to long worm-like micelles, which ultimately results in the inverse thermogelation. Molecular dynamics modeling indicates that this unexpected condensation of the hydrophilic corona onto the hydrophobic core is due to particular interactions between amide groups in the hydrophilic repeat units and phenyl rings in the hydrophobic ones. Consequently, changes in the structure of the hydrophilic blocks affecting the strength of the interaction could be used to control macromolecular self-assembly, thus allowing for the tuning of gel characteristics such as strength, persistence, and gelation kinetics. We believe that this mechanism might be a relevant interaction pattern for other polymeric materials as well as their interaction in and with biological environments. For example, controlling the gel characteristics could be considered important for applications in drug delivery or biofabrication.

Development of confectionery products based on edible oleogel

The article discusses the important issues of replacing saturated and trans fats in foodstuff s with edible oleogels — analogues of solid fats based on vegetable oils, which have a solid consistency. Formulations and technology of edible oleogels based on grape seed oil and a natural structure-former have been developed. The textural characteristics of hybrid gels have been studied. The technology of sugar-free confectionery based on oleogels has been developed.

The Effect of Protein Derivatives and Starch Addition on Some Quality Characteristics of Beef Emulsions and Gels

Starch and plant or animal proteins represent a rich source that can be used for fortifying meat products. The present study aimed to analyze how the different additives used (soy protein isolate, chickpea flour, lupine concentrate, sodium caseinate and starch, in 2% concentration) influence the rheological properties of beef emulsions and gels, cooking losses and the texture of the finished products. Rheological parameters G’ (storage modulus), G* (complex modulus) and Delta angle were determined by increasing the temperature from 5 to 70 °C, with a rate of 1 °C/min. The study highlighted that the addition of vegetable proteins (soy, chickpeas and lupine) improved strength of meat gels (G’ &gt; 1057.8 Pa), while the addition of sodium caseinate and starch reduced the consistency of the gel network structure (G’ &lt; 1057.8 Pa). All additions led to a decrease in heat treatment losses (a reduction of maximum 62% of cooking loss, from 11.89% for control to 4.54% in case of samples with added starch) and the hardness of heat-treated products. The maximum reduction of hardness was observed for samples with added starch, from 2.83 kgf to 1.08 kgf.

Status of TG enzyme modified fish gelatin

TG enzyme can catalyze the ligation reaction (glycosylation reaction), crosslinking reaction and deamination reaction between or within proteins, and has great application potential in the food field. TG enzyme was used as coagulant to modify fish gelatin, and the effects of crosslinking temperature, pH, TG enzyme dosage, gelatin concentration and crosslinking time on the characteristics of fish gelatin gel were discussed.

Properties of whey protein isolation/konjac glucomannan composite gels: Effects of deacetylation degrees

The effects of konjac glucomannan (KGM) with different deacetylation degrees (DDs) on the gel properties of whey protein isolate (WPI) were investigated. The appropriately deacetylated KGM (DDs in the range of 0–53.85 %) incorporated within WPI and formed relatively uniform compound gels, while excessive deacetylated KGM (DDs = 63.46 or 71.63 %) caused macroscopic precipitation and aggregation in WPI-KGM system. The water holding capacity of WPI-KGM gels decreased with the gradual increase of DDs, and the removal of acetyl groups reduced the whiteness of the composite gels. The hardness and chewiness of the composite gel tended to increase and subsequently decrease with the enhancement of DDs, and reached the maximum (244.15 and 148.88 g, respectively) at the DDs of 53.85 %. The rheological analysis indicated that rigid structured WPI-KGM gels could be formed when incorporated with moderately deacetylated KGM. The deacetylated KGM (DDs = 53.85 %) enhanced the hydrogen bond and disulfide bond within the mixed system, resulting in a more compact network structure of the composite gels. Moreover, deacetylated KGM particles might also reinforce the gel strength by the “filling effects”. Overall, the gelation characteristics of the WPI-KGM system can be regulated by controlling the DDs of KGM.

Electro‐Reconfigurable Adaptive Microlens with Simultaneous Multidirectional Focal Adjustment and Zooming

AbstractElectrically reconfigurable lenses capable of focal adjustment and zooming require deformable adaptive optical components. However, existing electroactive optical devices that perform these functions are limited by fluid leakage or require complex mechanical parts. Although polyvinyl chloride (PVC) gel‐based lenses with variable focal lengths and zooming have recently been developed, focal adjustment can only be made in the horizontal axis. Herein, a PVC gel‐based adaptive microlens capable of controlling the focal length and focal point simultaneously in the vertical, horizontal, and diagonal directions without mechanical gears or liquid leakage is presented. By optimizing the characteristics of PVC gels plasticized with three different structured plasticizers, a PVC gel‐based adaptive microlens is fabricated. The produced microlens demonstrates the properties of multidirectional focal adjustment, variable focal length (+33.7 to −15.1 mm) at low input voltages (&lt;300 V), excellent transparency (&gt;90%), fast response (0.10 s at 100 V), silent operation, low power consumption (0.39 mW), and excellent potential for further miniaturization.

The role of guar gum in improving the gel and structural characteristics of germinated highland barley starch

Germinated highland barley has been shown to have many health benefits, but the weakening of the starch gel properties during the germination limits its further application. In this study, germinated highland barley starch (GBS) was obtained after germination treatment. Guar gum (GG) was added to explore the effects of gelatinization on the rheology, gel and structural characteristics of GBS, and the potential of preparing gel-based products was also evaluated. The results showed that the addition of GG significantly increased the viscosity, gel strength and viscoelasticity of GBS, which was beneficial to the formation of gel, and promoted its formation of an ordered and compact gel network structure. The study provides a theoretical reference for the preparation of gel-based food with highland barley starch, and increases the application range of highland barley.

DEVELOPMENT OF A TOPICAL GEL CONTAINING A DIPEPTIDYL PEPTIDASE-4 INHIBITOR FOR WOUND HEALING APPLICATIONS

Chronic wounds are challenging for healthcare because they are difficult to treat and cannot heal by themselves. Active compounds that can accelerate wound healing are, therefore, necessary. Dipeptidyl peptidase (DPP)-4 inhibitors are antihyperglycemic drugs widely used in patients with type 2 diabetes that not only maintain the homeostasis of blood sugar levels but have also been shown to promote chronic wound healing. In this study, we formulated a topical gel containing, sitagliptin, a commonly used DPP-4 inhibitor drug to treat diabetes, using Carbopol 940 as a base due to its high viscosity and biocompatibility. The characteristics of the sitagliptin gel, including its physical appearance, viscoelastic properties, swelling and degradation, and stability, were investigated. The gel appeared to be transparent with a uniform distribution of drug molecules and was stable at 4 °C for more than 1 month. Moreover, the gel was shown to exhibit shear thinning pseudoplastic behavior, which is desirable for topical gels. The gel could absorb up to 250% of liquid within 2 days but later degraded in aqueous solution following zeroth-order kinetics. In the in vitro release study, the cumulative release data were best fitted with the first order kinetic model, in which the release rate depended on the concentration. To further demonstrate the use of the DPP-4 inhibitor gel, the gel was applied directly onto subcutaneous wounds on experimental pigs. The topical gel was shown to exhibit the desired spread ability without causing any inflammation around the wound area which was comparable to IntraSite® gel and commercial silver nanoparticle cream.

Development of a Topical Gel Containing a Dipeptidyl Peptidase-4 Inhibitor for Wound Healing Applications

Chronic wounds are challenging for healthcare because they are difficult to treat and cannot heal by themselves. Active compounds that can accelerate wound healing are, therefore, necessary. Dipeptidyl peptidase (DPP)-4 inhibitors are antihyperglycemic drugs widely used in patients with type 2 diabetes that not only maintain the homeostasis of blood sugar levels but have also been shown to promote chronic wound healing. In this study, we formulated a topical gel containing, sitagliptin, a commonly used DPP-4 inhibitor drug to treat diabetes, using Carbopol 940 as a base due to its high viscosity and biocompatibility. The characteristics of the sitagliptin gel, including its physical appearance, viscoelastic properties, swelling and degradation, and stability, were investigated. The gel appeared to be transparent with a uniform distribution of drug molecules and was stable at 4 °C for more than 1 month. Moreover, the gel was shown to exhibit shear thinning pseudoplastic behavior, which is desirable for topical gels. The gel could absorb up to 250% of liquid within 2 days but later degraded in aqueous solution following zeroth-order kinetics. In the in vitro release study, the cumulative release data were best fitted with the first order kinetic model, in which the release rate depended on the concentration. To further demonstrate the use of the DPP-4 inhibitor gel, the gel was applied directly onto subcutaneous wounds on experimental pigs. The topical gel was shown to exhibit the desired spread ability without causing any inflammation around the wound area which was comparable to IntraSite® gel and commercial silver nanoparticle cream.

Interaction of Pulsed Electric Modified Elephant Foot Yam (Amorphophallus paeoniifolius) Starch and Polyvinyl Alcohol to Enhance the Mechanical and Barrier Properties of Film

AbstractElephant foot yam starch (EFYS) is modified by the pulsed electric field (PEF, 4–16 kV cm−1) and used for the development of the biodegradable film. The increase in PEF intensity increases the oil (1.66–2.22 g g−1) and water absorption capacity (1.79–2.08 g g−1) and reduces the gelatinization temperature (Tg) and enthalpy (ΔΗ). Storage modulus (G') is found to be higher than loss modulus (G"), indicating strong gel characteristics of EFYS. Electrical intensity affects the degree of crystallinity and disrupts the granule's surface. Film prepared with PEF‐modified EFYS and different concentrations of polyvinyl alcohol (PVA, 25%, 50%, and 90%) shows that the increase in the concentration of PVA results in increased thickness, tensile strength, % elongation, water vapor permeability, water vapor transmission rate, seal strength, and solubility. PEF modification increases the film's mechanical and moisture barrier properties. The study proves that PEF changes the physico‐functional and structural characteristics of EFYS, making it suitable to be used in the biodegradable film.

Polyaspartic Acid-Stabilized CaCO3-Containing In Situ Hydrogel for Protection and Treatment of Gastric Ulcer.

The lack of effective oral drug delivery systems to treat gastric ulcer is an urgent challenge in clinical practice. Herein, a gastric acid pH-responsive hydrogel of curcumin/sodium alginate/polyaspartic acid@CaCO3 (Cur/SA/PC) was developed for sustained release of Cur, exerting effective protection and treatment of gastric ulcers. The in vitro gelatinization properties and the corresponding gel characteristics of the SA/PC delivery system demonstrated the successful construction of the in situ hydrogel with uniform strength. The cellular uptake illustrated the successful uptake and sustained release of Cur. Besides, Cur effectively inhibited NLRP3-mediated pyroptosis both in vitro and in vivo, exhibited an excellent pro-healing effect by regulating the PI3K/Akt signaling pathway, and alleviated acetic acid-induced chronic gastric injury in rats. Moreover, the relative bioavailability of Cur in the SA/PC hydrogel could effectively increase in the pharmacokinetic study. Importantly, the protective barrier formed by the SA/PC hydrogel could effectively protect against alcohol-induced acute gastric ulcers in rats. Overall, the designed SA/PC oral delivery system is a promising strategy to overcome gastric barriers for oral drug delivery.

Preparation of water-in-oil Pickering emulsion stabilized by Camellia oleifera seed cake protein and its application as EGCG delivery system

The use of plant proteins as stabilizers for Pickering emulsions is attracting attention in the food industry. Herein, a protein extract with a high hydrophobic content (extraction ratio up to 21.6%) was obtained from the byproduct generated by the extraction of oil from Camellia oleifera. The effects of different oil-towater ratios and protein concentrations on the stability and rheological properties of the Pickering emulsions were investigated. A stabile emulsion that exhibited gel characteristics was made using an oil:water ratio of 6.5:3.5 and a protein concentration of 3%. The EGCG encapsulation efficiency of the Pickering emulsion was 82.3%. The emulsion remained stable during different environmental pressures (pH, ionic strength, heat, UV) and long-term storage, effectively protecting EGCG from chemical degradation in extreme environments. In vitro digestion results showed that the Pickering emulsion significantly delayed the release of EGCG from 80.52% to 26.81% and that the bioaccessibility of the EGCG was increased by 30.8% in the intestine when incorporated into the Pickering emulsion compared to free EGCG. This research indicates that Camellia oleifera seed cake could be used in plant-based protein emulsions for improved nutrient delivery.

Effect of Black Tea Powder on Antioxidant Activity and Gel Characteristics of Silver Carp Fish Balls.

The effect of black tea powder on the antioxidant activity and gel characteristics of fish balls from silver carp were investigated after freezing storage for 7 days. The results show that black tea powder with different concentrations of 0.1%, 0.2% and 0.3% (w/w) could significantly increase the antioxidant activity of fish balls (p < 0.05). In particular, at the concentration of 0.3%, the antioxidant activity was the strongest among these samples, where the reducing power, DPPH, ABTS and OH free radical scavenging rate were up to 0.33, 57.93%, 89.24% and 50.64%, respectively. In addition, black tea powder at the level of 0.3% significantly increased the gel strength, hardness and chewiness while greatly reducing the whiteness of the fish balls (p < 0.05). ESEM observation found that the addition of black tea powder could promote the crosslinking of proteins and reduced the pore size of the gel network structure of the fish balls. The results suggest that black tea powder could be used as a natural antioxidant and gel texture enhancer in fish balls, which we found to be much related to the phenolic compounds of black tea powder.