Sweep Test Research Articles

Performance evaluation of rapeseed oil-based derivatives modified hard asphalt binders: Towards greener and more sustainable asphalt additives

Hard asphalt binder is regarded as a favorable option in comparison to polymer-modified asphalt for rutting due to the benefits of cost-effectiveness and extreme stiffness behavior. However, its inherent poor ability to withstand fatigue damage and thermal cracking restricts its applications as a pavement material. This study aimed at enhancing the low-temperature and fatigue performance of hard asphalt binders with newly-developed rapeseed oil (RO)-based derivatives. Two rapeseed oil -based derivatives of epoxidized rapeseed oil (ERO) and acrylated epoxidized rapeseed oil (AERO) were laboratory synthesized through oxidation and ring-opening grafting reactions, respectively. Fourier transform infrared spectroscopy (FTIR) and Hydrogen nuclear magnetic resonance (1were conducted to confirm the successful synthesis of derivatives. Mass loss, aging index, performance grading, temperature-frequency sweep, linear amplitude sweep and bending beam rheometer test were employed to assess the modified effects of rapeseed oil-based derivatives on two types of hard asphalt binders. To further explore the differences between RO and derivatives, the properties of modified hard asphalt binders using two derivatives were compared against the performance of RO-modified hard asphalt binders. With the additional RO, ERO, and AERO, the modified hard asphalt binders had significantly improved the resistance to thermal cracking and fatigue damage at low and intermediate temperatures, respectively. RO was found to have the most positive effect on the stress relaxation and the most adverse effect on the stiffness of hard asphalt binders. While, ERO- and AERO-modified hard asphalt binders had shown better antioxidative and anti-aging performance than that of RO-modified hard asphalt binders. Additionally, AERO-modified hard asphalt binders were noticed to have improved the elasticity of hard asphalt binders owing to the formation of a polymer elastic network. According to the study, two rapeseed oil-based derivatives had shown great potential as green and sustainable asphalt modifiers on the improvement of thermal and fatigue cracking resistance with the minimal adverse effect on anti-rutting performance of the hard asphalt binders. The test results revealed that the rapeseed oil-based derivatives modified hard asphalt binders could be employed in various pavement applications with great economic and sustainable benefits.

Vitamin E-fortified emulsion-templated oleogels structured with xanthan gum and soybean lecithin and their application in pound cakes

Vitamin E-fortified oleogels (E-OGs) were prepared by vitamin E-loaded emulsion template using xanthan gum (XG) and soybean lecithin (SL) as oleogelators. Optimum processing conditions of E-OGs were obtained with 0.3% XG and 2.0% SL, which exhibited a small particle diameter of 651.50 ± 23.84 nm and adequate zeta potential of −30.20 ± 2.95 mV. This zeta potential value indicates that E-OGs are very stable due to the electrostatic repulsion between particles. The oil binding capacity (OBC) of E-OGs maintained above 99.97% when the XG concentration was 0.30% or more, whereas the OBC containing 0.15% XG significantly decreased from 99.84% to 96.79% after 5 days of storage. The E-OGs prepared at 0.3% XG or higher exhibited solid-like behavior with higher G’ than G” in the results of the frequency sweep test. Solid-like behavior of E-OGs has some advantage such as ease of process, handling, and storage stability. E-OGs have been applied in pound cake manufacturing to replace commercially available butter. The rheological properties of the pound cake were analyzed using a texture profile analyzer. The hardness of the pound cake decreased significantly from 9.73 ± 1.33 N to 7.95 ± 0.58 N, and the porosity increased as butter was replaced with E-OGs, showing the potential of E-OGs to improve the quality of bakery products. E-OGs may also provide the benefits of vitamin E fortification. These results highlight the promising prospects of E-OGs in the food industry, particularly in the development of healthier and functional foods.

Metallurgical, mechanical and corrosion behavior of Interpulse and pulsed current TIG dissimilar welds of Monel 400 and AISI 316L

This research work explores the weldability, structural integrity, mechanical properties, and corrosion behavior of dissimilar welds of Monel 400 and AISI 316L developed by using Interpulse and pulse arc current modes in TIG welding process. ERNiCrMo-3 filler of 1.6 mm was used to fill the V-groove configuration of 5 mm thick plates in multiple passes. Metallurgical changes were observed in both Interpulse and pulsed current dissimilar weldments using optical and scanning electron microscope techniques. Mechanical properties of the joined structures were evaluated by performing tensile tests on UTM and hardness measurements on weld surfaces using Vickers hardness tester. The resistance against the corrosion especially at the weld area of both welded structures was measured using a cyclic sweep test. From the XRT and visual inspection analyses, the joined structures were free from defects and also seen the uniformity of the filler distribution toward the base metals. The grain structure with well-defined grain structures were identified in PC-TIG weldments whereas fine grains with clear distribution of filler alloying elements were seen in Interpulse-TIG weldments. Interpulse-TIG weldments exhibited with better mechanical and corrosion resistance properties than the PC-TIG weldments vowing to constricted arc mode during the welding process.

Characterization of novel alginate-Aloe Vera raft systems for treatment of gastroesophageal reflux disease

Raft-forming systems are designed to relieve reflux symptoms by forming a physical barrier on top of the stomach. The present study aimed to evaluate the physico-chemical properties of alginate-aloe vera raft-forming systems for the first time. To achieve this goal, aloe vera was used in the proportion of 1 and 1.5 % in raft suspensions containing 5 % alginate as the main component of gel structure. Rafts were characterized by their volume, floating behavior, thickness, swelling properties, strength, resilience, reflux resistance, and acid neutralization capacity (ANC). Results showed the effectiveness of aloe vera in forming rafts that were voluminous, buoyant with greater total floating time (TFT), and stronger than formulations with no aloe vera. Furthermore, data showed that the presence of aloe vera could improve resilience time, swelling proportions, resistance to reflux under simulant conditions of movement in the stomach, and ANC values of rafts. Rafts were further characterized by oscillatory strain sweep test, differential scanning calorimetry, and Fourier transform infrared spectroscopy. Evaluation of the mechanical properties of rafts displayed a viscoelastic behavior of gels corresponding to the internal cross-linked structure of rafts. This study demonstrated that designing of alginate-aloe vera rafts can be suitable for the treatment of gastro-esophageal reflux disorders.

Prediction of viscoelastic properties of peanut-based 3D printable food ink.

Viscoelastic properties of 3D printable peanut-based food ink were investigated using frequency sweep and relaxation test. The incorporation of xanthan gum (XG) improved the shear thinning behavior (n value ranging from 0.139 to 0.261) and lowered the η*, G', and G'' values, thus making food ink 3D printable. The addition of XG also caused a downward shift in the relaxation curve. This study evaluates the possibility of an artificial neural network (ANN) approach as a substitute for the Maxwell three-element and Peleg model for predicting the viscoelastic behavior of food ink. The results revealed that all three models accurately predicted the decay forces. The inclusion of XG decreased the hardness and enhanced the cohesiveness, so enabling the 3D printing of food ink. The hardness was highly positively correlated with Maxwell model parameters Fe , F1 , F2 , F3, and Peleg constant k2 (0.57) and negatively correlated with k1 (-0.76).

Hydrogel based on patch halloysite nanotubes: A rheological investigation

The rheological behaviour of Patch halloysite nanotubes (PT_Hal) was investigated here. Their peculiar morphology shows longer and thinner nanotubes and gives rise to the formation of gel-like systems that are not evidenced in halloysite from other natural sources. According to frequency sweep tests, PT_Hal possesses solid-like characteristics even at low concentrations, suggesting that the material is highly structured. Interestingly, flow ramp analysis evidenced two distinct behaviours based on the clay concentration: a yield stress was detected only from 0.75 wt%, indicating the sample's ability to resist deformation or breaking. Furthermore, the study investigated the influence of ionic strength, revealing that the addition of salt did not significantly affect the gel's properties of this clay. Accordingly, in this work we propose a new hydrogel system based on green nanoclays that can be suitable for industrial and biological applications as well as for cultural heritage.

Investigating the rheological behaviour of styrene–butadiene–styrene modified asphalt

The rheological properties of the styrene–butadiene–styrene modified asphalt (SBSMA) binder have not been thoroughly investigated yet. In this study, SBSMA binders with various SBS contents and base asphalt types were prepared and analysed. Fluorescence microscopy, temperature sweeping, and multiple stress creep recovery (MSCR) tests were conducted to analyse the phase structure and rheological behaviour of SBSMA. The results indicate that the special rheological behaviour of a decreasing phase angle value in SBSMA as the temperature increases is a result of the gradual dominance of the network structure over SBSMA’s rheological behaviour. Results from MSCR tests indicate that with the increase in stress levels, the elasticity of the network structure gradually diminishes, signifying a significant stress sensitivity in the network structure. Consequently, due to the stress sensitivity of the network structure, traditional rheological indicators measured at low stress levels (such as phase angle, elastic recovery rate) may overestimate the elasticity of SBSMA at high temperatures (40–80°C).

Effect on dynamic parameters of waste reinforced soil under vibrations generated through traffic loading: Experimental evaluation

The constructive use of agricultural and industrial waste is quite promising, currently, the research areas are highly focusing on agricultural waste and observing their effects on desired materials to enhance the durability properties of specific materials. This research focused on enhancing and observing dynamic characteristics of low plastic silty clay under the condition of traffic loading vibrations through resonant column equipment under sweep and free vibration decay test. The agricultural wastes considered for this study are wheat straw, bagasse, and coir fiber. These fibers were added in a proportion of 0.2%, 0.4%, 0.6%, 0.8%, and 1% of dry soil mass, and their effects were noted on two basic dynamic properties, (i) shear modulus (G) and (ii) damping ratio (D). In addition to that, the optimum content of agricultural waste was also checked under free vibration decay and amplification on the application of loading frequency and strain ranges. The results found bagasse to be the most effective one as it increased the shear modulus by 33% and enhanced the damping by 12.2%.

The effect of incorporating magnetic fly ash in asphalt binders with respect to permanent deformation and fatigue

The search for efficient and environmentally viable materials to improve the quality and durability of asphalt binders used in roadways has been growing in recent years. This is especially true giving the increase in the volume and magnitude of traffic loads, as well as the changes in the earth's temperature that cause frequent pavement distresses, such as permanent deformation and fatigue. In this context, the objective of this work is to evaluate the potential of magnetic particles from fly ash, as a residual resource with high added value and low-cost raw material for modifying asphalt binders. Magnetic particles were incorporated into the asphalt binder at 2%, 4%, 6% and 8%, content by weight. The materials were characterized by chemical, empirical and rheological tests, specifically the Multiple Stress Creep and Recovery and the Linear Amplitude Sweep test. X-ray Fluorescence data revealed silicon, aluminum and iron as the main elements present in the fly ash, as well as the increase in iron concentration after magnetic separation in the magnetic particle sample. A homogeneous dispersion of magnetic particles in the asphalt binder observed by Scanning Electron Microscopy and shifts in infrared bands characteristic of iron (ca. 450 cm-1) and of asphalt binder (ca. 1456 cm-1) clearly indicated a significative interaction between the magnetic particles and the asphalt binder. The rheological results indicated that the incorporation of particles provide better performance to the binder in terms of both permanent deformation and fatigue. The modified binders were less susceptible to permanent deformation than the neat binder, and this is reflected in the increase in adequate traffic levels, moving from standard traffic to heavy traffic at a temperature of 64 °C. This economical, easy, and sustainable approach to using magnetic particles in hot asphalt binders can contribute to producing asphalts that are more efficient with changes in temperature and traffic.

Chemical and rheological analysis of unaged and aged bio-extended binders containing lignin

The use of alternative renewable sources to totally or partially replace bitumen is one of the most current challenges in the road pavement sector. The growing energy cost and environmental concerns lead to the necessity to find alternative solutions, by supporting at the same time sustainability and circular economy principles. Within this framework, this paper presents the application of a powder lignin, a natural bio-polymer deriving from by-products of wood pulp and paper industry, to replace part of bitumen. The bituminous blend consisting in 70% of bitumen and 30% of powder lignin (by weight) was made in laboratory through the use of a high shear stirring mixer, and a reference plain bitumen characterized by a similar consistency (i.e., same penetration grade) was used as comparison. Then, an extensive investigation on chemical and rheological properties of the bio-binder is presented. Fourier transform infrared spectroscopy (FTIR), saturates, aromatics, resins and asphaltenes (SARA), bending beam rheometer (BBR), frequency sweep tests and multiple stress creep recovery tests (MSCR) with a dynamic shear rheometer (DSR) were performed. Moreover, unaged, short- and long-term aging conditions were considered. Results indicated that powder lignin dominates the rheological behavior of the bio-binder and, from chemical analysis, it seems that it partially acts as a filler and partially as a binder. This would result in improved performances at both low and high temperatures, leading to a wider temperature range of performance grade (PG). Moreover, despite a stiffening effect is recognized, lignin also offers an antioxidant potentiality, reducing the aging susceptibility of the investigated bio-binder.

Development of a “Green” Emulsion with a Milk Protein Hydrolysate: An Evaluation of Rheology, Texture, In Vitro Bioactivity, and Safety

Bioactive peptides are promising cosmetic active ingredients that can improve skin health and appearance. They exhibit a broad spectrum of activity, including anti-aging, antioxidant, antimicrobial, and anti-inflammatory effects. The aim of this study was to develop a safe, stable, and efficacious environmentally friendly (“green”) emulsion using a milk protein hydrolysate as a model active ingredient. Potential emulsions were formulated with biodegradable emollients, stabilized with naturally derived mixed emulsifier, and prepared by cold process. They were evaluated for rheological behavior (continuous rotation and oscillation tests), physical stability (dynamic mechanical thermal analysis—DMTA test), and texture profiles, as well as cytotoxic, antioxidant, and antimicrobial effects. Rheological characterization revealed shear-thinning flow behavior with yield point from continuous rotation tests and predominantly elastic character from oscillation (amplitude and frequency sweep) tests, with small structural change detected in the DMTA test. These results implied satisfactory rheological properties and good stability. Texture analysis revealed acceptable spreadability and substantivity of the emulsions. The protein hydrolysate showed antioxidant activity. The developed emulsions showed low antibacterial activity against selected microorganisms, but this was due to the action of preservatives, not peptides. All potential emulsions showed a desirable safety profile. The results obtained provide the basis for the next stage of formulation development, i.e., in vivo efficacy tests.

Controlled Degradation and Erosion of Polyrotaxane Solids via the Formation of Multivalent Hydrogen Bonding in Water

AbstractBiodegradable polyrotaxanes (PRXs) are important scaffolds for the development of biomaterials. However, the degradation behavior of PRXs constructed via physical crosslinking remains largely unexplored. Herein, a degradable PRX exhibiting physical hydrogen bonds as crosslinks between α‐cyclodextrins (α‐CDs) as the cyclic molecules is synthesized by introducing hyperbranched polyglycerol (HPG) containing numerous terminal 1,2‐diols into the α‐CDs with an incorporation ratio of HPG (HPG/PRX) varying from 2 to 19 via anion ring‐opening polymerization of glycidol. Rheological analysis by a frequency sweep test reveals that a typical HPG‐PRX forms hydrogels by physical crosslinking via hydrogen bonding, whereas a low branched degree of HPG in HPG‐PRX weakens the physical crosslinking. The obtained gels recover their original shape upon pulling and releasing, which is consistent with a pulley effect. Degradation and erosion tests in water show that increasing the molecular weight of the introduced HPG changes the degradation behavior from bulk degradation to surface erosion. Owing to its controllable degradation or erosion by tuning the rate of water ingress according to the number of hydrogen bonds and the branched degree, this HPG‐modified PRX paves the way for the development of new biodegradable/erodible gels.

Structure Strengthening Phenomena of Gluten Matrices under Different Stress Types.

To predict the achievable product volume with respect to the gas retention capacity of the gluten matrix in wheat flour doughs, strain hardening evaluation is crucial. But assessing these structure hardening phenomena in wheat flour dough systems is still a challenging task. In this work, a simple shear method applied to kneaded dough samples was tested and compared to biaxial extension tests performed with a lubricated squeezing flow method. The comparability of shear-induced structure hardening with biaxial extension tests was shown. Structure hardening and breakdown after overload were visualized using shear flow and a comparison of the obtained shear flow over Hencky strain curve peaks. To predict the behavior of the analyzed flours according to their composition, a correlation analysis of the flour and dough properties was performed. The influence of the HMW glutenin subunits on the sensitivity of the dough matrix according to the applied shear speed (0.1 and 1.0 mm/s) could be shown with a correlation coefficient of 0.94. The LMW glutenin subunits, on the other hand, showed a high correlation coefficient of 0.89 with the achievable network connectivity parameter z [-] gained from frequency sweep testing.

Cell-Laden 3D Printed GelMA/HAp and THA Hydrogel Bioinks: Development of Osteochondral Tissue-like Bioinks.

Osteochondral (OC) disorders such as osteoarthritis (OA) damage joint cartilage and subchondral bone tissue. To understand the disease, facilitate drug screening, and advance therapeutic development, in vitro models of OC tissue are essential. This study aims to create a bioprinted OC miniature construct that replicates the cartilage and bone compartments. For this purpose, two hydrogels were selected: one composed of gelatin methacrylate (GelMA) blended with nanosized hydroxyapatite (nHAp) and the other consisting of tyramine-modified hyaluronic acid (THA) to mimic bone and cartilage tissue, respectively. We characterized these hydrogels using rheological testing and assessed their cytotoxicity with live-dead assays. Subsequently, human osteoblasts (hOBs) were encapsulated in GelMA-nHAp, while micropellet chondrocytes were incorporated into THA hydrogels for bioprinting the osteochondral construct. After one week of culture, successful OC tissue generation was confirmed through RT-PCR and histology. Notably, GelMA/nHAp hydrogels exhibited a significantly higher storage modulus (G') compared to GelMA alone. Rheological temperature sweeps and printing tests determined an optimal printing temperature of 20 °C, which remained unaffected by the addition of nHAp. Cell encapsulation did not alter the storage modulus, as demonstrated by amplitude sweep tests, in either GelMA/nHAp or THA hydrogels. Cell viability assays using Ca-AM and EthD-1 staining revealed high cell viability in both GelMA/nHAp and THA hydrogels. Furthermore, RT-PCR and histological analysis confirmed the maintenance of osteogenic and chondrogenic properties in GelMA/nHAp and THA hydrogels, respectively. In conclusion, we have developed GelMA-nHAp and THA hydrogels to simulate bone and cartilage components, optimized 3D printing parameters, and ensured cell viability for bioprinting OC constructs.

Influence of Modified Stalk Fibers on the Fatigue Performance of Asphalt Binder

The type and content of modified stalk fibers significantly influence the fatigue properties of asphalt binder. In this study, different concentrations of NaOH solution were used to modify stalk fibers, and scanning electron microscopy (SEM) was used to observe the effect of the modified concentration on the fiber morphology. A dynamic shear rheology (DSR) test and a linear amplitude sweep (LAS) test were conducted to analyze the effects of the fiber type and content on various factors such as the complex shear modulus G*, phase angle δ, and fatigue parameters (A35 and B). Consequently, the fatigue life Nf of the fiber asphalt binder was calculated using a viscoelastic continuum damage model. The results show that stalk fibers modified using a 5% alkali solution exhibited the best oil absorption and heat resistance, the asphalt binder with a 1.5%–2% fiber content exhibited the best resistance to fatigue, and the fatigue performance of the asphalt binder with different types of fibers was superior when fiber doping was at 1.5%. Additionally, the fatigue parameter A35 of the modified cotton and corn stover fibers increased by 40.5% and 57.6%, respectively, and the fatigue parameter B decreased by 5.8% and 4.8%, respectively, compared with that of the unmodified stover fibers. Finally, the modified corn stalk fiber asphalt binder with a 1.5% fiber content demonstrated the best fatigue resistance.

Performance evaluation of styreneic methyl copolymer regenerated SBS-modified asphalt and its mixture with high content RAP

The aging degree of reclaimed asphalt pavement (RAP) is complex and diverse, and the current utilization rate of RAP is far from meeting the needs of green cycle development. To explore the effect of Styreneic Methyl Copolymer (SMC) rejuvenator of aging asphalt and the performance of SMC regenerated asphalt mixture containing 50% and 60% RAP, this study used SMC rejuvenator to regenerate SBS-modified asphalt with different aging degrees. The high and low-temperature rheological properties of regenerated asphalt were evaluated by temperature sweep test, multi stress creep recovery test, and bending beam rheometer test. Then, the recommended content of the SMC rejuvenator was obtained by using Matlab to establish the corresponding model. Finally, the road performance of the regenerated mixture with high-content RAP was verified. The test results showed that the recommended content range of the SMC rejuvenator for the aging asphalt with PAV (Pressurized Aging Vessel) 0 h, PAV5h, PAV10h, PAV15h, PAV20h were 1.56∼2.31%, 3.03∼3.36%, 4.269∼4.48%, 5.23∼5.66%, 5.95∼6.91%, respectively. The road performance of the SMC regenerated asphalt mixture with 50% and 60% RAP content met the specification requirements. SMC rejuvenator had no significant negative impact on high-temperature performance, significantly improving low-temperature cracking resistance. SMC regenerator had a positive significance in improving regeneration efficiency.

Shape stability control of a 3D-printed clay/biochar-based monolith to support Fe catalyst for continuous levofloxacin degradation with low metal leaching

Disposing of wet solid waste sludge has become a prominent issue because it has high environmental risks. Herein, a clay/biochar-based monolith (CBM) is prepared using a three-dimensional (3D) printing design method. The CBM is loaded with iron (Fe) and used as a catalyst (Fe/CBM) to activate peroxymonosulfate (PMS) for degrading levofloxacin (LVF) in an aqueous solution. The monolith preparation process is inexpensive, and the monolith has designable flow paths that facilitate improved mass transport and material recycling. ZnCl2, as a chemical activator, is added to the 3D-printed slurry to improve the catalytic performance of Fe/CBM. Oscillatory stress sweep and frequency sweep tests prove that incorporating ZnCl2-containing sludge in the slurry effectively increases the elastic modulus and critical stress, improving structural stability and constructability. The slurry containing 10% sludge (S10%-Zn with 1 M ZnCl2), exhibits 30% higher static yield stress than the slurry containing only clay and water (S0%). Fe/CBM is prepared by loading Fe active sites onto the surface of CBM via an impregnation method, and it leaches very low amounts of Fe (<0.2 mg/L) and other heavy metals (e.g., Cd, and Pd, etc). Fe/CBM-S10%-Zn/PMS with 10% mass fraction of sludge exhibits much higher (∼80% at 20 min) degradation efficiency than Fe/CBM-S0%/PMS (∼15% at 20 min) and Fe/CBM-S10%/PMS (∼43% at 20 min). Combining with XPS results, when ZnCl2 is added to the slurry, the content of Fe2+ in the catalytic material increases, improving the catalytic performance. The PMS activation mechanism of Fe/CBM-S10%-Zn for LVF degradation is also discussed, which is ascribed to the radical and nonradical pathways. This provides new insights on how to recycle solid waste and make high-performance clay/biochar-based monolith catalysts for the continuous wastewater treatment.

Rheology of cellulose nanocrystal and nanofibril suspensions

Nanocellulose is a sustainable nanomaterial and a versatile green platform that has attracted increasing attention. Although the wide applications of its aqueous suspensions are closely related to rheology, comprehensive studies of their rheological behavior, especially the yielding behavior, are still limited. Herein, to investigate the relationship between structure and rheological properties, the viscoelasticity, thixotropy and yielding behavior of two commonly used nanocelluloses, rod-shaped cellulose nanocrystals (CNCs) and filamentous cellulose nanofibrils (CNFs), were systematically investigated. The viscosity, viscoelasticity and thixotropic behavior of the suspensions were analyzed by steady-state shear, frequency sweep, creep-recovery, hysteresis loop, and three-interval thixotropic recovery tests. The yielding behaviors were evaluated through creep, steady-state shear, step shear rate, stress ramps, amplitude sweep, and large amplitude oscillatory shear tests. The rheological properties of the two typical suspensions showed a strong dependence on concentration and time. However, compared to CNC suspensions, CNF suspensions exhibited stronger thixotropy and higher yield stress due to the higher aspect ratio of CNF and the stronger structural skeleton of the suspensions as supported by Simha's equation and micromorphology analysis. This work provides a theoretical rheology basis for the practical applications of nanocellulose suspensions in various fields.

Rheological and thermal properties of an enteral nutrition formula for nutritional support patients using a combined mixture of gelatin and maltodextrin.

Enteral nutrition is a type of nutritional support that provides the necessary sources of energy and protein for patients who suffer from dysphagia, chronic disease, and loss of appetite. In this study, a gelatin-maltodextrin binary biopolymer system has been incorporated into a semi-solid formula. The I-optimal combination design approach was used to create 19 formulations, and the dynamic rheological properties, dynamic laser scattering, and zeta potential responses were evaluated over 30 days of storage at 5°C. Solid viscoelastic behavior has been approved since G' > G″ in the frequency sweep test with no cross-over point. Maltodextrin may interfere within the gelatin network, and increasing the maltodextrin to gelatin (from 0.14 to 1) may lead to a wider linear viscoelastic (LVE) strain range (2.16%), a lower storage modulus at LVE (52%), a lower yield stress (46%), and a lower glass transition temperature (34%). The presence of maltodextrin may reduce the temperature of the sol-to-solid transformation by 48% and enhance its flexibility. In contrast, increasing the gelatin-to-maltodextrin ratio following melting at 37°C led to an increase in the cumulant mean and polydispersity index, indicating a relatively unstable system. The range of zeta potential values between -4.4 and 1.7 mV confirmed a tendency toward coagulation. Microscopic images revealed instability because of irregular or compact chains formed in the gelatin matrix by using higher amounts of maltodextrin. Finally, the best formula had the best rheological stability and was suitable for tube-feeding patients, with a gelatin-to-maltodextrin ratio of 4.35:3.64% w/w on day 17.4.

Concentration-dependent rheological characteristics of chickpea (Cicer arietinum L.) flour dispersion in steady and dynamic shear

Chickpea (Cicer arietinum L.) flour (CF) is the basic raw material used in the form of dispersion in varied concentrations for making promising oriental sweets and snacks in the Asian subcontinent. The finished product quality of these fried food items thus mainly depends on the consistency of flour dispersions. Therefore, a concentration-dependent steady-state and dynamic rheological study, along with the pasting behaviour, was carried out. Steady shear rheology exhibited concentration-dependent pseudoplastic behaviour with significantly higher apparent viscosity for 40 - 45% CF dispersions, and a desirable consistency to be used in making fried sweets and snacks. The Herschel-Bulkley model described dispersions better at 5 - 20%, while Mizrahi-Berk at 25 - 50%. Hahn Ree-Erying's model described thixotropic behaviours for time-dependent flow; increasing CF concentration from 30 - 50% and increasing storage (G') and loss (G'') modulus in the linear viscoelastic region. However, G' values were dominant over G'' values in the small amplitude region, showing elastic behaviour, whereas viscous behaviour was exhibited in the higher amplitude region. During heating (30 - 80°C) in the temperature sweep test, concentrated samples (30 - 50%) showed a drastic increase in G' and complex viscosity (η*), while in cooling stages (95 - 25°C), a 25% concentration sample resulted in the highest values of G', G'', and η*.