Rheological Changes Research Articles

Carbon microspheres prepared from soluble starch hydrothermal carbonization for extending thermal stability of water-based drilling fluid

This study employed hydrothermal carbon microspheres (HCMs) as high-temperature stabilizers in drilling fluids. The HCMs were synthesized through a green hydrothermal carbonization method, using soluble starch as the precursor. The impact of HCMs on the thermal stability of xanthan, polyanionic cellulose and synthetic polymer solutions was assessed by comparing their rheological changes before and after thermal aging. The rheology and filtration properties of a polymer-based drilling fluid in the presence of HCMs were recorded before and after dynamic thermal aging at various temperatures for 16 h and static thermal aging at 200 °C for 96 h. The results demonstrated that HCMs effectively maintained stable rheology and low filtration loss following dynamic hot rolling at various temperatures and prolonged static thermal aging, surpassing the performance of conventional Na2SO3 and nano-SiO2 stabilizers. Mechanistic studies, including dissolved oxygen measurements, free radical detection, and cryo-scanning electron microscopy observations, revealed that HCMs can consume dissolved oxygen, scavenge free radicals, and physically crosslink polymers. This process prevents polymer thermo-oxidative degradation and ensures the stability of the drilling fluid. HCMs are novel, stable, sustainable, and highly effective high-temperature stabilizers for water-based drilling fluids. This study introduces a new application of biomass-derived hydrothermal carbonaceous materials for high-temperature drilling.

Spreading of graphene oxide suspensions droplets on smooth surfaces

Understanding and predicting the spreading of droplets on solid surfaces is crucial in many applications such as printed electronics and spray coating where the fluid is a suspension and in general non-Newtonian. However, many models that predict the maximum spreading diameter usually only apply to Newtonian fluids. Here, we study experimentally and theoretically the maximum spreading diameter of graphene oxide suspension droplets impacting on a smooth surface for a wide range of concentrations and impact velocities (5≤We≤700, 30≤Re≤2000). As the particle concentration increases the rheological behavior changes from a viscous fluid to a shear-thinning yield stress fluid and the maximum spreading diameter decreases. The rheology for all concentrations is well described by a Herschel–Bulkley model that allows us to determine the characteristic viscosity and corresponding Reynolds number Re during spreading. Analogous to Newtonian fluids, the spreading ratio follows the Re1/5 scaling in the viscous spreading regime. Furthermore, we use this characteristic viscosity to develop an energy balance model that takes into account the viscous dissipation and change in surface energies to find the maximum spread diameter for a given impact velocity. The model contains one non-dimensional parameter α that encodes both the dynamic contact angle during spreading and the droplet shape at maximum spread. Our model is in good agreement with our data at all concentrations and agrees well with literature data on Newtonian fluids. Furthermore, the model gives the correct limits in the viscous and capillary regime and can be solved analytically for Newtonian fluids.

Incorporation of Cyanobacteria and Microalgae in Yogurt: Formulation Challenges and Nutritional, Rheological, Sensory, and Functional Implications

This review presents an approach to the incorporation of cyanobacteria and microalgae in yogurts and explores their impact on the nutritional, rheological, sensory, and antioxidant qualities of these products. First, the yogurt market context and its relationship with nutritional quality are outlined, emphasizing the quest for functional foods that meet consumer demands for healthy and nutritious products. A discussion of the incorporation of cyanobacteria and microalgae, especially Spirulina platensis, in foods, particularly yogurt, is then presented, highlighting the nutritional and functional benefits that this type of biomass can provide to the final product. The fermentation process and the quantity of algae to be incorporated are discussed to understand their fundamental role in the characteristics of the final product. In addition, this article considers some challenges such as sensory and rheological changes in the product resulting from the interaction of milk, algal biomass, and the fermentation process. Addressing these challenges involves delineating how these interactions contribute to changes in the traditionally consumed product, while obtaining a pro- and prebiotic product is crucial for creating an innovative dairy product that diversifies the market for derived dairy products with increased functional properties.

Effects of ultraviolet and thermal oxygen ageing on the rheological properties of SEBS/MWCNTs composite-modified asphalt

To enhance the anti-ageing properties of asphalt binder, multiwalled carbon nanotubes (MWCNTs) and styrene-ethylene-butylene-styrene (SEBS) were used to create a composite-modified asphalt (CMA). The ageing resistance was assessed through rheological property changes, using a dynamic shear rheometer (DSR) for various tests. FTIR spectroscopy analyzed the ageing mechanism. The results showed that CMA exhibited significantly better rutting resistance than matrix and SBS asphalt. Although the fatigue life of CMA was lower than SBS asphalt, ist was still dramatically higher than matrix asphalt. MWCNTs reduced the low-temperature relaxation performance of unaged asphalt. Notably, CMA showed superior ageing resistance against both thermal oxygen and UV ageing, with decreases of about 30% and 28% in the UV ageing index and long-term ageing index, respectively, compared to matrix asphalt. The carbonyl and sulfoxide indices increased after ageing, with the composite containing 3% SEBS demonstrating optimal ageing resistance and road performance.

The Basic Rheological Properties of LDPE Modified Bitumen

Various polymers have widely known in its capability in enhancing rheological properties of bitumen for various pavement applications. Many polymer types have been used in studies, where the properties of the final product of the polymer modified bitumen (PMB) are different, depending on the used polymers. LDPE or Low-Density Polyethylene are one of widely studied polymers in bitumen modification that exhibit higher bitumen's viscosity, perform better in resisting deformation under heavy loads, and tend to show better integrity in high temperatures. LDPE-modified bitumen also believed to enhance elasticity, allowing a potentially better resistance to cracking due to ability to recover at low strain. Many studies also stated the improvement of LDPE-modified bitumen against thermal and mechanical stress, better adhesion to aggregates in asphalt mixtures, and various promising result for overall durability and longevity of pavement. This study explains basic rheological properties of LDPE-modified bitumen prepared by high shear mixing and specified preparing methodologies. Five variables of %modifications were used: 2%, 4%, 6%, 8% and 10% of bitumen weight. Ring and Ball softening point, Penetration test and rotating spindle viscometry were done to understand the rheological changes of the modified bitumen compared to unmodified bitumen control. For further understanding the behaviour, two types of LDPE were used: virgin LDPE and recycled LDPE. The study shows interesting noticeable differences between the two used LDPE polymers, allowing further proposed studies in this field.

The impact of calcined mud on the rheological properties of eco-friendly concretes using the equivalent mortar method (CEM)

In order to harmonise technical and environmental aspects, people today focus not only on concrete's technical characteristics but also on environmental imperatives. Thus, the emphasis is on the development of concrete and cements that offer ecological and sustainable advantages. Commonly, people use various natural materials as cement additives, demonstrating their effectiveness by replacing a significant portion of the cement in the hardened state of concrete. This substitution leads to a substantial and remarkable reduction in carbon dioxide emissions. However, when it comes to the physical properties of the material in its fresh state, challenges may arise. Indeed, the rheological changes induced by these additives may hinder the on-site use of this eco-concrete. The main purpose of this study is to find out how adding minerals to environmentally friendly concrete changes its rheological parameters (yield stress, plastic viscosity) and fresh properties (slump, flow time). We will approach this using the concept of mortar equivalent to concrete (CEM). We developed five formulations of CEM’s by substituting cement with calcined mud (CM) in binary mixing systems at a temperature of 20 °C. The results showed that adding binary cements with calcined mud had a negative effect on the fresh properties and rheological parameters. However, when substitution happens at a low rate, it behaves almost like control mortar (OPC).

Irregular Eccentric Wellbore Cementing: An Equivalent Circulation Density Calculation and Influencing Factors Analysis

In the field of cement, if the formation cannot be given sufficient pressure to maintain stability during construction, pressure control failure may occur, leading to the leakage of liquids and gasses from the formation to the wellbore. In addition, irregular wellbore diameter and casing eccentricity are important factors that are easily overlooked and affect the prediction of ECD (Equivalent Circulation Density) calculation. This results in major accidents and ecological disasters, further impacting the global environment. This study focuses on a well in the eastern oilfields of China, and based on a rheological experiment of high temperature and high pressure, an irregular eccentric wellbore model is established according to the measured wellbore diameter and eccentricity data to calculate the ECD of the whole cementing process. Then, a data set is constructed and analyzed using the random forest method to quantitatively evaluate influencing factors such as displacement, rheology, density, and eccentricity on the bottomhole and wellbore ECD. Results find that the density of cement slurry and drilling fluid has the most significant impact on the maximum ECD, with the impact reaching 0.3142 and 0.2902, respectively, and the main factors that affect the minimum ECD are the density and rheological changes in the drilling fluid, reaching 0.7014 and 0.2846. These research findings will contribute to the precise control of wellbore pressure during cementing operations, further ensuring the safety of cementing operations, and laying a technical foundation for the automation and intelligentization of subsequent cementing operations.

Using Rheology and Image Processing to Study the Effects of Cellulose Nanocrystal Sedimentation.

The effect of sedimentation on lyotropic liquid crystalline dispersions is both an interesting subject in colloidal science and is of practical importance for understanding changes that can occur during dispersion storage. This research explored how the seemingly subtle changes in average length resulting from a single sedimentation step affected the rheological properties and self-assembly of aqueous dispersions of sulfated cellulose nanocrystals. Sedimentation of a primarily isotropic aqueous cellulose nanocrystal dispersion for 1 month at ambient conditions resulted in an isotropic top phase and a biphasic bottom phase, which were separated for further study. Both atomic force microscopy measurements and intrinsic viscosities determined via Fedor's equation showed preferential fractionation of longer cellulose nanocrystals (CNCs) to the bottom phase. The effects of this fractionation on dispersion rheology and phase behavior were studied by preparing a range of concentrations from each phase. As expected, the concentration for the isotropic-biphasic phase transition was significantly lower for the bottom phase than for the top phase or parent dispersion. Rheological changes were generally subtle, but significant differences were seen in the storage modulus at concentrations approaching rheological gelation. Most notably, quantitative image processing showed that even this simple, single-step fractionation process had a significant impact on the relative proportion of tactoids and chiral helices with planar and homeotropic anchoring in self-assembled cellulose nanocrystal films. These results highlight the impact that changes in polydispersity due to sedimentation can have on the self-assembly of nanomaterial mesogens.

Influence of chemical admixtures on buildability and deformation of concrete for additive manufacturing

In this study, the buildability of three-dimensionally (3D) printed (3DP) concrete that uses coarse aggregate was evaluated in the fresh state according to the contents of three chemical admixtures (high-range water-reducing agent (HRWRA), viscosity-modifying agent (VMA), and setting-time modifying agent), and the correlation between fluidity changes and buildability was analyzed. Polycarboxylate HRWRA and VMA contents were varied to control the flowability and static yield stress, which affect the workability. In addition, the SMA content was varied, and slump tests and table flow tests were performed at 30-minute intervals up to 6.5 h after mixing to measure flowability. Simultaneously, static yield stress was measured to analyze rheological changes, and penetration resistance and green strength tests were performed to analyze the main factors influencing buildability over time. The highest buildability was observed when the VMA content was 1.5 %. The static yield stress of fresh concrete could be ≤3000 Pa to guarantee adequate 3DP concrete transport performance while that at 1 h after mixing could be ≥2000 Pa to secure buildability. When the penetration resistance of fresh concrete is ≥80 kPa, the deflection of concrete may be <10 %. Through this, buildability can be approximately judged based on penetration resistance.

Could oxygen gradient ektacytometry help to detect sickle cell trait carriers at risk for kidney disorders or exercise-related complications?

The study of Ellsworth etal. (Br J Haematol, 2024) demonstrated the usefulness of oxygen gradient ektacytometry technique to better identify the physiological parameters that could increase the risk of sickling of red blood cells (RBCs) from sickle cell trait (SCT) carriers. Oxygen gradient ektacytometry combined with pH and osmolality modulations could help in identifying SCT carriers at risk for kidney disorders or exercise-related complications. Other factors than the percentages of haemoglobin S are probably involved in the propensity of RBCs from SCT carriers to sickle during deoxygenation. Commentary on: Ellsworth etal. Hypertonicity and/or acidosis induce marked rheological changes under hypoxic conditions in sickle trait red blood cells. Br J Haematol 2024; 205:1565-1569.

Hypertonicity and/or acidosis induce marked rheological changes under hypoxic conditions in sickle trait red blood cells.

Deformability and sickling of red blood cells (RBCs) from individuals with sickle cell trait (SCT) was evaluated under harsh biophysical conditions that mimic certain vascular beds invivo. RBC deformability in osmotic-gradient ektacytometry was decreased in HbAS (SCT) compared to HbAA (wild-type) RBCs at supraphysiological osmolalities. RBC deformability was also measured by oxygen-gradient ektacytometry. Whereas RBC sickling was not observed under isotonic and neutral pH conditions, hypertonicity and acidosis alone or in combination induced reversible sickling of SCT RBC. These data suggest that hyperosmolality and/or acidosis enhance hypoxia-induced sickling of SCT RBC.

Conching of dark chocolate – Processing impacts on aroma-active volatiles and viscosity of plastic masses

The conching process plays a key role in determining the sensory and rheological properties of dark chocolate. To further understand this process, changes in the chocolate mass during plastic conching were investigated on a time-resolved basis with varying conching temperature, shear direction, and with or without the presence of residue from previous trials (pre-charge) on the conche vessel wall. Six selected odorants (acetic acid, benzaldehyde, linalool, 2,3,5,6-tetramethylpyrazine, 2-phenylethanol, 2-phenylethyl acetate) were quantified in fat and particle phases of chocolate masses. Particularly at elevated conching temperature, the odorant concentrations were found to decrease (up to 78.0% in the fat phase). The highest concentrations of desired odorants were determined mostly after conching without pre-charge. During conching, odorants were observed to accumulate increasingly in the fat phase (up to 91.7%) with decreasing odorant polarity. Similarly, it was found that conching temperature and the absence of pre-charge had the highest impact on the rheological properties of the chocolate mass, resulting in lowest and highest complex viscosity, respectively. In conclusion, some positive outcomes of conching, namely the retention of desired odorants and the reduction of viscosity, were inversely related at elevated temperature or in the absence of pre-charge, necessitating compromises to achieve optimal flow properties and flavor. Our results contribute to a deeper understanding of the influence of conching on the quality of dark chocolate by providing insights into the complexity of aroma migration and rheological changes during conching.

Interrogating an along-strike variation in the evolution and rheology of a large continental strike-slip fault zone

Along-strike variations in lithology, temperature, fluid activity, etc. can induce rheological changes in strike-slip faults that may be recorded by different fault rocks and fabrics. This article interrogates localized formation of granite-derived mylonite in a large strike-slip fault zone in which ultramylonite is the principle granite-derived fault rock to better understand this rock record of faulting. Microtextures show that rate-limiting deformation mechanisms in mylonite were dislocation creep in quartz and diffusion creep in very-fine-grained feldspar aggregates. Microtextures also show that mylonite formation is fully compatible with continuous viscous deformation whereas coeval ultramylonite along strike formed after whole-rock cataclasis at the brittle-viscous transition. Differential stresses determined from quartz aggregates in ultramylonites are 40–150% greater than stresses in mylonites. Hence, mylonites represent a local weak sector within this otherwise relatively strong fault zone. Mylonite formation is correlated with syndeformational chemical alteration as well as quartz microstructures and mineral assemblages indicating elevated deformation temperatures. Not all mylonite samples record significant chemical alteration. Therefore, mylonite formation likely records locally elevated temperatures. These results illustrate how a local shift in deformation conditions can affect the evolution and rheology of a large strike-slip fault zone, and how fault rocks record these processes.

Dilute Polymer Droplets Show Generalized Wetting Dynamics via an Average Viscosity.

Despite the prevalence of non-Newtonian fluids in various practical applications, comprehensive dynamic wetting models are lacking. Existing models often oversimplify complex rheological behavior, limiting our ability to predict wetting dynamics. This work introduces and experimentally validates a generalized model for the dynamic wetting of non-Newtonian shear-thinning fluids (dilute polymer solutions) on solid substrates. We experimentally analyzed 12 different shear-thinning fluids using both a power-law model and Carreau-Yasuda model. The data clearly show that the dynamic contact angle can be generalized using an average viscosity to capture rheological changes during droplet spreading. The average viscosity was defined using the fluid's constitutive model over shear rates relevant to the spreading process. Using a small droplet approximation, we propose and validate a semianalytical spreading model to predict the basal radius of non-Newtonian droplets. The model agrees well with the experimental data. Additionally, the average viscosity was used to define a spreading time scale, which is capable of collapsing the spreading of different non-Newtonian fluids onto a master spreading curve. This work offers significant potential for predicting the dynamic shape and spreading of non-Newtonian fluids with complex rheologies in a range of applications and industrial processes.

Self-assembly of mixed-linkage glucan hydrogels formed following EG16 digestion

Mixed-linkage glucans are major components of grassy cell-walls and cereal endosperm. Recently identified plant endo-β-glucanase from the EG16 family cleaves MLGs with strong specificity towards regions with at least four sequential β(1,4)-linked glucose residues. This activity yields a low molecular-weight MLG with a repeating structure of β(1,3)-linked cellotriose that gels rapidly at concentrations as low as 1.0 % w/v. To understand the gelation mechanism, we investigated the structure and behavior using rheology, microscopy, X-ray scattering, and molecular dynamics simulations. Upon digestion, the material's rheological behavior changes from typical polymeric material to a fibrillar network behavior seen for e.g. cellulose nanofibrils. Scanning electron microscopy and confocal microscopy verifies these changes in micro- and nanostructure. Small-angle X-ray scattering shows in-solution self-assembly of MLG through ~10 nm elemental structures. Wide-angle X-ray scattering data indicate that the polymer association is similar to cellulose II, with dominant scattering at d-spacing of 0.43 nm. Simulations of two interacting glucan chains show that β(1,3)-linkages prevent the formation of tight helices that form between β(1,4)-linked d-glucan chains, leading to weaker interactions and less ordered inter-chain assembly. Overall, these data indicate that digestion drives gelation not by enhancement of interactions driving self-assembly, but by elimination of unproductive interactions hindering self-assembly.

Antimicrobial adhesive self-healing hydrogels for efficient dental biofilm removal from periodontal tissue

ObjectivesOral biofilms, including pathogens such as Porphyromonas gingivalis, are involved in the initiation and progression of various periodontal diseases. However, the treatment of these diseases is hindered by the limited efficacy of many antimicrobial materials in removing biofilms under the harsh conditions of the oral cavity. Our objective is to develop a gel-type antimicrobial agent with optimal physicochemical properties, strong tissue adhesion, prolonged antimicrobial activity, and biocompatibility to serve as an adjunctive treatment for periodontal diseases. MethodsPhenylboronic acid-conjugated alginate (Alg–PBA) was synthesized using a carbodiimide coupling agent. Alg–PBA was then combined with tannic acid (TA) to create an Alg–PBA/TA hydrogel. The composition of the hydrogel was optimized to enhance its mechanical strength and tissue adhesiveness. Additionally, the hydrogel’s self-healing ability, erosion and release profile, biocompatibility, and antimicrobial activity against P. gingivalis were thoroughly characterized. ResultsThe Alg–PBA/TA hydrogels, with a final concentration of 5 wt% TA, exhibited both mechanical properties comparable to conventional Minocycline gel and strong tissue adhesiveness. In contrast, the Minocycline gel demonstrated negligible tissue adhesion. The Alg–PBA/TA hydrogel also retained its rheological properties under repeated 5 kPa stress owing to its self-healing capability, whereas the Minocycline gel showed irreversible changes in rheology after just one stress cycle. Additionally, Alg–PBA/TA hydrogels displayed a sustained erosion and TA release profile with minimal impact on the surrounding pH. Additionally, the hydrogels exhibited potent antimicrobial activity against P. gingivalis, effectively eliminating its biofilm without compromising the viability of MG-63 cells. SignificanceThe Alg–PBA/TA hydrogel demonstrates an optimal combination of mechanical strength, self-healing ability, tissue adhesiveness, excellent biocompatibility, and sustained antimicrobial activity against P. gingivalis. These attributes make it superior to conventional Minocycline gel. Thus, the Alg–PBA/TA hydrogel is a promising antiseptic candidate for adjunctive treatment of various periodontal diseases.

Fire resistance of phosphoric acid activated metakaolin geopolymer

Fire resistance is a key advantage of geopolymer (GP) materials. While most research focuses on alkali-activated GPs, this study examines the fire resistance of phosphoric acid-activated GPs with varying phosphorus-to-aluminum (P/Al) molar ratios. By activating metakaolin with different ortho-phosphoric acid (H3PO4) solutions, it was found that GPs with P/Al > 0.59 exhibited intumescence during fire tests, resulting in a 110 °C lower backside temperature (310 °C) compared to non-intumescent GPs (420 °C). Physico-chemical changes were analyzed before and after fire tests using DMA, TGA NMR, EPMA, and XRD. The study revealed dehydration, crystallization, and rheological changes, with NMR showing transitions from Al(VI) to Al(IV), full condensation of phosphorus species, and Si-O-Al to Si-O-Si bonds. Intumescence was linked to GP softening between 100 and 160 °C, achievable only with a P/Al ratio ≥ 0.74, with no additional benefits from excess phosphorus.

Lawsonite eclogite records subduction rheology and slab detachment, Faro, Yukon-Tanana Terrane, Yukon Territory, Canada

Lawsonite eclogites represent cold subduction in the rock record, and new localities provide rare natural field laboratories to investigate deep deformation processes. We present a new lawsonite eclogite locality near Faro, Yukon Territory, Canada, the first reported lawsonite eclogite locality of the Yukon-Tanana Terrane. The discovery indicates that mid- to Late Permian subduction in the Yukon-Tanana Terrane subducted cold material in an oceanic subduction zone, in contrast to most previous models. We define a pressure-temperature-deformation (P-T-d) pathway for the lawsonite eclogites using a combination of microstructures, mineral compositional mapping, crystal orientation mapping, and phase equilibrium modeling. Metamorphism in the Faro eclogites followed a clockwise pathway through the lawsonite eclogite facies, reaching peak pressures of 22−24 MPa at 525−550 °C. Rocks then exhumed to 14.5−16 MPa during heating to 630−655 °C. Crystallographic preferred orientations (CPOs) in omphacite developed dominantly by dissolution-precipitation creep and oriented grain growth concurrently with CPOs developed in glaucophane by a combination of dislocation- and dissolution-precipitation creep with oriented grain growth. We link this fabric and CPO development in omphacite and amphibole to lawsonite dehydration, slab decoupling, and initiation of exhumation of the eclogites, providing evidence that lawsonite dehydration plays a significant role in changes in subduction zone rheology.

Rheological behavior during thermoplastic deformation of metallic glasses: A molecular dynamic simulation

Nanoimprint is a low-cost and effective method to manufacture nanostructures for metallic glasses with a precision replication of the mould shape and control of size. However, the atomic structure of the materials changes during the processing, which affects the practical application and the performance of the nanostructures. This crucial issue has not been addressed as thoroughly as it deserves. Here, we investigate the rheological behaviors of metallic glasses under the deformation with different temperatures and strain rates via molecular dynamic simulation. We find an abnormal rheological mode change in the non-Newtonian region, which is attributed to the evolution of short- and medium-range ordered structures. Mechanical deformation leads to the destruction and regeneration of atomic short-range ordered structures at all strain rate ranges. Their total amount and distribution remain at a similar level when the strain rate is low. When the strain rate exceeds a critical value, the deformation accelerates the relaxation by shortening the β-relaxation, resulting in the decrease of the total amount of short-range ordered structure and reorganization in the medium-range ordered structure. Furthermore, the results show a significant inheritability from the sample during deformation to the cooled-down sample, demonstrating the influence of deformation history on the properties of materials manufactured with the nanoimprint. The deformation during the nanoimprinting could reduce the ultimate strength and increase the plasticity of the materials, which provides a potential method to precisely turn the properties of metallic glasses by controlling the rheological process in the nanoimprint possessing.

Use of optical absorption and scattering properties to monitor the change of chemical characteristics, particle structure and viscoelasticity during apple puree processing

This work explored the optical absorption (μa) and reduced scattering (μs') properties at 400–1050 nm (Vis-NIR) and 900–1650 nm (SWIR) of apple puree at different heating times to evaluate their changes in composition and structure. The optical absorption and scattering coefficients of μa and μs' decreased with increasing heating time. The specific μs' coefficients at 432 nm, 455 nm, 1183 nm and 1304 nm were related to particle structural changes. The partial least squares regression (PLSR) models based on μs' coefficients in the combined Vis-NIR and SWIR regions provided satisfactory estimations of puree particle area (Rp2 = 0.90) and particle perimeter (Rp2 = 0.85), whereas the μs' coefficients in the Vis-NIR region predicted puree viscosity (Rp2 = 0.83), elasticity modulus (Rp2 = 0.81) and viscous modulus (Rp2 = 0.78). Consequently, optical properties can be a potential tool to determine structural and rheological changes of apple puree.