Apparent Viscosity Research Articles

Ultrasound-assisted fabrication of chitosan-hydroxypropyl methylcellulose nanoemulsions loaded with thymol and cinnamaldehyde: Physicochemical properties, stability, and antifungal activity

This study investigated the influence of chitosan (CH) and hydroxypropyl methylcellulose (H), along with ultrasound power, on the physicochemical properties, antifungal activity, and stability of oil-in-water (O/W) nanoemulsions containing thymol and cinnamaldehyde in a 7:3 (v/v) ratio. Eight O/W formulations were prepared using CH, H, and a 1:1 (v/v) blend of CH and H, both with and without ultrasonication (U). Compared to untreated samples, U-treated nanoemulsions had lower droplet sizes (433–301 nm), polydispersity index (0.42–0.47), and zeta potential (−0.42–0.77 mV). The U treatment decreased L* and b* values, increased a* color attribute values, and increased apparent viscosity (0.26–2.17) at the same shear rate. After 28 days, microbiological testing of nanoemulsions treated with U showed counts below the detection limits (< 2 log CFU mL−1). The U-treated nanoemulsions exhibited stronger antifungal effects against R. stolonifer, with the NE/CH-U and NE/CH-H-U formulations demonstrating the lowest minimum inhibitory and fungicidal concentrations, measured at 0.12 and 0.24 μL/mL, respectively. On day 28, U-treated nanoemulsions demonstrated higher ionic, thermal, and physical stability than untreated samples. These findings suggest that the stability and antifungal efficacy of polysaccharide-based nanoemulsions may be improved by ultrasonic treatment. This study paves the way for innovative, highly stable nanoemulsions.

Electrospun zein fibers loaded with pomegranate flower extract: Characterization and release behavior

In the present study electro-spinning technique was used to encapsulate pomegranate flower extract (PFE) in zein fibers. The effect of PFE concentrations (0%, 5%, 10%, and 15% (v/v)) on the electrospun solution properties, such as surface tension, apparent viscosity, and electrical conductivity were investigated. These effects on various fibers properties including morphology, thermal properties, structural characteristics, morphology, antioxidant and antimicrobial activity, encapsulation efficiency (EE), and release behavior was also evaluated. The results revealed that, increasing the PFE concentration (0–15%) led to increased surface tension and electrical conductivity and decreased the apparent viscosity of the electrospinning solution. This caused an increase in the fiber diameter from 217.1 to 722.2 nm with considerable EE (92.21–96.1%) and loading capacity (LC) (12.3–36.1%). Increasing the PFE concentration increased the surface hydrophilicity (contact angle of 93.21° and 57.82° respectively for 0 and 15% PFE loaded electrospun). Field emission scanning electron microscope (FESEM) results showed that all the fibers were uniform and free of beads. Also, molecular interaction between the PFE and zein has been confirmed with Fourier transform infrared (FTIR). DSC results indicated that the thermal stability were increased with increasing PEF concentration. The study also showed that the release of the PFE was slowest in a fatty food simulant. The primary release mechanism in simulated environments was Fickian diffusion. This research demonstrated that PFE loaded zein fibers can be used successfully in drug delivery, active packaging, and cosmetic products.

Cold plasma processing of kiwifruit juice: Effect on physicochemical, nutritional, microstructure, rheological properties and sensory attributes.

This study aimed to compare the untreated, cold plasma (CP)-optimized (30 kV/5 mm/6.7 min), CP-extreme (30 kV/2 mm/10 min), and thermally treated (TT) (90 ℃/5 min) kiwifruit juices based on the physicochemical (pH, total soluble solids (TSS), titratable acidity (TA), total color change (ΔE)), physical (particle size and rheology), microstructure (optical microscope), bioactive compounds (polyphenol, ascorbic acid, and sugar compounds), and sensory characteristics of kiwifruit juice. The pH, TSS, and TA were not significantly affected in CP and TT juice, whereas the ΔE (6.52) of TT juice lies in the range of "greatly visible." The microstructure characteristics of juice significantly changed after CP and thermal treatment. The cell and tissue disruption in CP-extreme and thermally treated juice was more than CP-optimized. The particle size of juice decreased irrespective of treatment, but the span value of CP-optimized juice was the lowest. Further, the CP treatment showed a lower consistency index, apparent viscosity, and pseudoplasticity of juice than the thermal treatment. The CP-treated juice retained bioactive and nutritional attributes more than thermally treated juice. The CP-optimized, CP-extreme, and thermal treatment reduced the sucrose content by 54, 55, and 23%, while the fructose and glucose content were increased by 17, 12, & 93%, and 17, 11 & 99%, respectively. Among the CP-treated juice, CP-optimized (71.36 mg/100g) contained a higher amount of ascorbic acid than the CP-extreme (64.36 mg/100g). Based on the similarity values in the fuzzy logic analysis, the sensory attributes of CP-optimized treated juice were superior to CP-extreme and thermal treated. PRACTICAL APPLICATION: In this era, non-thermal processing techniques are trending for retaining the nutrition and stability of juice. The old plasma (CP)-treated kiwifruit juice had better nutritional, bioactive compounds, and sensory attributes than the thermally treated juice. Further, the CP-treated juice had higher flowability and lower viscosity, making it ideal for juice processing. The conclusions drawn suggest that CP processing is a better alternative for processing kiwifruit juice than thermal processing.

Dynamics of non-Newtonian droplets eccentrically impacting hydrophobic spherical surfaces

In this study, the dynamic behaviors of non-Newtonian fluid droplets with shear-thinning properties eccentrically impacting hydrophobic particle surfaces are investigated through a combination of numerical simulations and experiments. The simulation integrates the dynamic contact angle and a non-Newtonian fluid power-law model within the volume of fluid model framework. The effects of apparent viscosity (η), impact velocity (v0), and dimensionless eccentricity parameter (B) on the dynamic behaviors of non-Newtonian droplets are analyzed. Furthermore, the study offers insight into the progression of pressure distribution, kinetic energy, and liquid viscosity across droplets during the entire impact process. An energy balance analysis, which includes kinetic energy, surface energy, potential energy, and viscous dissipation, is employed to elucidate the fundamental physical mechanisms that govern the dynamics of eccentric impacts of non-Newtonian droplets. Finally, a model (Recr D* = −95.7 + 11 450.6e−B/0.18) is proposed to predict the adhesion or detachment of shear-thinning droplets eccentrically impacting hydrophobic particle surfaces.

Preparation and properties of new green polyacrylamide hydrogels

Abstract The pursuit of low-toxicity hydrogels represents a focal point and frontier in contemporary research endeavors. Partially hydrolyzed polyacrylamide emerges as the most prevalent polymer employed in the formulation of priority flow control gels, owing to its favorable cost-efficiency and heightened receptivity to crosslinking agents. A noteworthy discovery pertains to the utilization of a green crosslinking agent derived from TiSO4, which induces the gelation of polyacrylamide, resulting in an elevation of apparent viscosity from 1159 mPa·s to 100, 000 mPa·s. Extensive investigations into the primary factors influencing the performance of crosslinked polymer gels and their underlying principles have been conducted. The advent of such gel plugging agents holds promise in addressing challenges encountered in select reservoir scenarios, thereby furnishing reliable technical underpinnings for the efficacious stimulation of oil fields.

Chemometric approaches for polysaccharide viscosity profiling

Traditional viscosity measurements for carrageenan are laborious, present practical and environmental challenges, and fail to provide structure-property understanding for application and manufacturing development. We hypothesize that integrating Size Exclusion Chromatography (SEC) with Multi-Angle Light Scattering (MALS) and online viscometry, combined with chemometric techniques, can develop a more efficient and environmentally friendly method for determining the apparent viscosity of carrageenan solutions.To test this hypothesis, predictive chemometric models were developed using SEC-MALS data for carrageenan extracted from four different seaweed species. By integrating SEC-MALS with Partial Least Squares (PLS) regression, key molecular parameters such as hydrodynamic radius, intrinsic viscosity, and molecular mass were identified as significant influencers of viscosity. The model for carrageenan from Eucheuma denticulatum yielded the lowest prediction error (RMSEP 8.4), while those for carrageenan extracted from Kappaphycus alvarezii or from several species of the Chondrus genus showed higher errors due to κ-carrageenan sensitivity. For carrageenan extracted from seaweed of the Gigartina genus, incorporating the root mean square radius resulted in a low prediction error of 10.This study concludes that integrating SEC-MALS with PLS regression effectively identifies key molecular parameters influencing carrageenan viscosity, enhancing structure-property understanding and providing a reliable analytical method for optimizing quality control and application in various industries.

Calibration modeling of drilling fluid rheological parameters in variable temperature environment based on support vector machine.

Traditional measurement of drilling fluid rheological parameters suffers from significant lag due to the inability of the instruments to promptly capture real-time parameters of the drilling fluid. These measurement models are typically constructed based on fixed temperature conditions and empirical formulas, rendering them inadequate for complex temperature gradient environments. Consequently, this limitation results in increased prediction errors, severely compromising the precise monitoring of drilling fluid performance. Aiming at the problems of low accuracy and poor stability of drilling fluid measurements under variable temperature conditions, a support vector machine-based calibration model for drilling fluid rheological parameters in a variable temperature environment is proposed in this paper. First, the measurement principle of the double-tube differential pressure rheology real-time measurement device is analyzed. The relationship between shear stress and shear rate is then established using differential pressure sensor and flow rate data. Utilizing the gray wolf optimization algorithm to optimize the kernel function weights and parameters, an SVM-based calibration model for predicting drilling fluid rheology correction parameters is constructed. Finally, a real-time monitoring platform for drilling fluid is developed. Experimental results show that the maximum relative errors for the predictions of apparent viscosity, plastic viscosity, and yield point are within ±5%, with coefficients of determination (R2) all greater than 0.95. These results validate the effectiveness of the proposed method in accurately monitoring the rheological performance of drilling fluids.

Effect of the membrane processing on tannin removal from soluble fraction of Persian gum

SummaryTannins, which are known as anti‐nutrient compounds with capability of limiting proteins and minerals bioavailability, are present in Persian gum. Ultrafiltration (UF, polysulfone membrane, 30 and 90 kDa, 1, 2 and 5 bar) and nanofiltration (NF, polysulfone, 400 Da, 2.5 and 5 bar) were used to remove tannin from the soluble fraction of Persian gum. The results revealed that the highest amount of tannin removal was achieved in UF (5 bar) and NF (5 bar). However, the use of the membrane process significantly decreased the apparent viscosity of the permeate, which might have an undesirable effect on the functionality of the gum. The effects of membrane molecular weight cut‐off, feed temperature, ultrasound pre‐treatment, feed concentration and pH, on the amount of tannic acid reduction, and changes in permeate flux, volume concentration factor difference, tannin reduction efficiency, and permeate apparent viscosity were evaluated. The results showed that total tannin removal efficiency was increased by ultrasound pre‐treatment, reduction of feed pH, and higher membrane molecular weight cut‐off. Increasing the feed temperature and concentration enhanced the apparent viscosity of permeate, although its value was lower than the control sample.

Hydration and solution properties of fluorescently labeled wheat arabinoxylans following enzymatic hydrolysis

Wheat arabinoxylan (AX) exhibits characteristics of high molecular weight (Mw), strong water absorption and water holding capacity, which significantly influence the hydration and solubility properties of wheat flour. However, challenges existed in visualizing the distribution of AX and quantifying water content accurately. This study investigated the effect of fluorescent labeling on the physicochemical properties of AX with different Mw. AX was initially degraded using xylanase, which resulted in the formation of AX fragments with different Mw. As the xylanase concentration increased, the Mw, degree of aggregation and apparent viscosity of AX decreased, whereas the water binding capacity, solubility and hydrophilicity increased. Enzymatically hydrolyzed AX was covalently linked to fluorescein isothiocyanate (FITC) through reductive amination modification, yielding AX-tyramine-FITC. Compared to AX, AXTF exhibited a slightly higher Mw, with a slight increase in water binding capacity and hydrophilicity, a significant increase in solubility. The degree of aggregation and apparent AX viscosity also increased slightly. The fluorescent labeling had a minor effect on AX properties, and the trend in AXTF properties with respect to Mw was consistent with that of AX. This study established a basis for the effect of AX with different Mw on the water migration pattern in the flour system, and provided a theoretical basis for the application of AX fluorescent labeling for visualization purposes.

Effect of micro-vessel stenosis severity and hematocrit level on red blood cell dynamics and platelet margination: A numerical study

Understanding many micro-vascular diseases is aided by examining the dynamical behavior of blood cells. For instance, micro-vascular stenosis significantly influences the dynamics of red blood cells and hence causes several micro-vascular disorders. Thus, the objective of the current study is to numerically simulate cellular blood flow in stenosed micro-vessels with different stenosis severities and hematocrits to examine hemodynamic features which have important clinical implications. Red blood cells’ migration, velocity, and deformation are predicted. Furthermore, platelets’ margination and cell-free layer formation are examined. Accordingly, a three-dimensional numerical simulation of blood cells and their interaction with the surrounding plasma is considered. The simulation is performed using a validated code developed for cellular blood flows. Red blood cells’ migration and platelets’ margination are confirmed, which enhances the validity of the code. The obtained results report a high dependence of red blood cells’ migration and platelets’ margination on the hematocrit level, which agrees with other published studies. An asymmetrical cell-free layer thickness is exhibited along the stenosed vessel, with a maximum value at the throat of the stenosis, which greatly affects blood apparent viscosity and induces plasma skimming in this region. In addition, it is found that the cell-free layer thickness is strongly linked to stenosis severity and the hematocrit level. Due to its role in the endothelial cells’ function and structure, the wall shear stress is estimated. A reduction more than 75 % in the wall shear stress is obtained due to stenosis, with maximum values at the throat compared with the healthy case. The Fahraeus effect is examined, and the obtained results are compared with published experimental and computational works with an acceptable degree of agreement.

Exploring the impact of poly(sodium styrene sulfonate) dispersants’ architecture on their performance in coal water slurry preparation

In this work, the architecture of poly(sodium styrene sulfonate) (PSSNa) dispersants were flexibly tailored by various strategies. Three categories of PSSNa dispersants with different topologies were obtained, namely, linear structured PSSNa (1-A-PSSNa), three-arm star PSSNa (3-AS-PSSNa) and six-arm star PSSNa (6-AS-PSSNa). The molecular weights (Mn) of these dispersants were adjusted in the range of 3200–26,200 g/mol by varying the feeding ratio of monomer to initiator. In addition, the polydispersity index (PDI) of resultant dispersants were also varied by using different polymerization technologies, such as atom transfer radical polymerization (ATRP) and conventional free radical polymerization technique (RP). Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography (GPC) verified these architecture parameters of resultant PSSNa dispersants. Afterwards, the impact of these architectural factors on the performance of PSSNa dispersants in coal water slurry (CWS) preparation were evaluated. The results revealed that with the Mn of dispersants increased from 9800 to 26,200 g/mol, the apparent viscosity of CWS increased by around 11 %. The comparison between dispersants with approximate Mn (26,200 and 26,900 g/mol) and very different PDI (1.27 and 2.25) indicated that wide PDI are favourable for the performance. This work also confirmed that the topology of dispersants has a significant impact on their performance. The maximum coal loaded can increase from 63.9 % to 64.3 % when 1-A-PSSNa dispersant was replaced by 6-AS-PSSNa. Meanwhile, these architectural factors have a limited impact on the fluid type of CWSs, as all CWSs obtained in this work were pseudoplastic fluids regardless of the used dispersants. The potential mechanism was investigated using various technologies, such as the measurements of zeta potentials, contact angles, and low-field nuclear magnetic resonance spectra. The results revealed that topologizing did not alter the interaction between dispersant and coal surface. However, due to the special features of topological polymers, they can grant adsorbed coal particles with enhanced electrostatic repulsion and steric hindrance, which facilitated the dispersion of coal particles.

Fabrication and characterization of Zanthoxylum schinifolium essential oil Pickering emulsion stabilized by bacterial cellulose nanofibrils/whey protein isolate complexes and fortified with cinnamaldehyde

The inherent hydrophobicity, high volatility, instability and pungent flavor of Zanthoxylum schinifolium essential oil (ZSEO) are important issues to restrict its preservation and practical applications. To overcome these drawbacks, the ZSEO-loaded Pickering emulsions stabilized by bacterial cellulose nanofibrils/whey protein isolate (BCNFs/WPI) complexes and fortified with cinnamaldehyde (CA) were fabricated, and their physical property and functionality were characterized. When the concentration of BCNFs/WPI complexes was 0.7 wt%, the emulsions had the smallest and uniform droplet size (<150 nm) and showed good stability over 30 d storage. Moreover, the emulsions with different CA contents (0–1.0 wt%) maintained a long-term stability with no significant droplet size change during 30 d storage. All Pickering emulsions showed a shear-thinning behavior, and their apparent viscosity and viscoelastic moduli gradually increased with the increase of BCNFs/WPI complexes contents. The presence of CA enhanced the physical stability of emulsions against environmental stresses such as acid, heat and salinity. Compared to free ZSEO, the ZSEO-loaded Pickering emulsions fortified with CA not only improved the stability of ZSEO, but also maintained or even enhanced its antioxidant and antimicrobial activity. This study would provide a promising strategy for ZSEO encapsulation and improve its stability and functionality in food applications.

Influence of different genotype combinations of β-lactoglobulin and β-casein in cow milk on physicochemical and sensory properties of stirred yoghurt

In this study, stirred yoghurts were produced from Turkish Holstein cow milk with different genotype combinations of β-lactoglobulin and β-casein. The distribution of AA, AB, and BB genotypes of β-lactoglobulin and A1A1, A1A2, and A2A2 genotypes of β-casein was determined in a total of 135 cow milk samples. Raw cow milk samples containing AA genotype of β-LG exhibited higher non-fat total solids, protein, and fat contents in comparison to milk containing AB and BB genotypes of β-LG. Compared to the samples made from milk with other β-LG genotypes, the stirred yoghurt made from milk with β-LG AA genotype showed lower degree of syneresis and higher for hardness, apparent viscosity, and consistency coefficient. The lowest number of grains, the perimeter of grains, and the visual roughness values were obtained in the stirred yoghurts made from milk with BB genotype of β-LG and A2A2 genotype of β-CN. The sensory analysis revealed that β-CN genotypes of milk significantly influenced the overall acceptability scores of the stirred yoghurts, while β-LG genotypes did not significantly influence these scores except for the visual grainy score. The findings of this study showed that the selection of specific milk protein genotypes resulted in substantial differences in the physicochemical and sensory properties of stirred yoghurt.

Rheological Properties and Sensory Profile of Yoghurt Produced with Novel Combination of Probiotic Cultures

Novel probiotic yoghurt was produced using the combination of bacterial cultures Lactobacillus plantarum HA119 and Bifidobacterium animalis subsp. lactis B94 and yoghurt bacteria Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. Its basic nutritional composition, colour, texture, rheological properties, and sensory profile were compared with yoghurt produced using the same technological process and standard yoghurt cultures (control sample), as well as other commercially available yoghurts with different milk fat contents. Despite the fat content of the yoghurt made with the new probiotic cultures being 1.44%, its apparent viscosity was similar to that of high-fat yoghurt (2.99%). Other results from rheological measurements indicate that the new yoghurt had a stronger protein network, presumably due to the higher number of exopolysaccharides compared to both control and commercial yoghurts. Sensory analysis revealed that there were no statistically significant differences between the novel probiotic yoghurt and high-fat yoghurt as perceived by panellists. In conclusion, this combination of probiotic cultures can be used to produce yoghurt with rheological and sensory properties similar to high-fat yoghurts, without the need for hydrocolloids or changes in the production process.

On Mapping Local Foam Mobility in Porous Media from Computed Tomography Data

Summary Recovering apparent viscosity and foam texture fields from coreflooding experiments is challenging, even with modern computed tomography (CT) scan equipment. In this work, we present an explicit expression for efficiently calculating effective foam viscosity and propose an improved procedure for processing CT scan images to obtain accurate water saturation profiles. Using these techniques, we processed data from a CT scan of a coreflooding experiment, showing that the increase in effective foam viscosity due to foam generation occurs early during injection and before breakthrough. The fast increment in apparent viscosity is due to foam generation before breakthrough. After breakthrough, foam texture reaches its maximum, and effective foam viscosity grows logarithmically over time as the foamed gas sweeps out the water phase. The pressure drop obtained by using the effective foam viscosity showed good agreement with the experimentally obtained values before breakthrough. The workflow proposed here could be readily adapted to other foam models, provided reasonable estimates for these new quantities can be determined from experiments.

Aerodynamic breakup of emulsion droplets in airflow

AbstractAerodynamic breakup refers to the process where large droplets are fragmented into small droplets by the aerodynamic force in airflow, which plays a vital role in fluid atomization and spray applications. Previous research has primarily concentrated on the aerodynamic breakup of single‐component droplets, but investigations into the breakup of emulsion droplets are limited. This study experimentally investigated the aerodynamic breakup of water‐in‐oil emulsions in airflow, utilizing high‐speed photography to observe the breakup process and digital in‐line holography to measure fragment sizes. Comparative analyses between emulsion droplets and single‐component droplets are conducted to examine the breakup morphology, breakup regime, deformation characteristics, and fragment size distributions. The emulsion droplets exhibit higher apparent viscosity and shorter stretching lengths of the bag film and peripheral rim due to the presence of a dispersed phase. The breakup regime transitions of emulsions are modeled by integrating the viscosity model of emulsions and the transition model of the pure fluid. The fragment sizes of emulsion droplets are larger due to the shorter lengths of the bag film and peripheral rim.

Assessing the Rheological and Filtration Loss Control Potential of Selected Plant-Based Additives in Oil-Based Mud

In drilling operations, chemical additives pose environmental concerns during mud disposal. This study evaluated three plant-based additives, namely rice husk (RH), &amp;lt;i&amp;gt;Detarium microcarpum&amp;lt;/i&amp;gt; (DM), and &amp;lt;i&amp;gt;Brachystegia eurycoma&amp;lt;/i&amp;gt; (BE), in oil-based mud at low-pressure, low-temperature conditions. The mud’s rheological profile followed Herschel Bulkley’s model. With 8 g additive content, RH increased the mud&amp;apos;s apparent viscosity (AV), plastic viscosity (PV), and yield point (YP) by 62.5%, 51.25%, and 34.38%, respectively. DM showed higher increases of 200.0%, 195.0%, and 162.5%, while BE exhibited the most significant improvements of 287.5%, 272.5%, and 250.0%. The filtration tests indicated that RH reduced spurt loss and fluid loss volumes by 83.33% and 62.35%, while DM decreased by 82.41% and 47.94%, as BE had the highest reduction of 94.44% and 51.18%. Again, the filter cake thickness of RH, DM, and BE muds increased by 210.29%, 273.53%, and 79.41%, respectively, with permeabilities of 8.90×10&amp;lt;sup&amp;gt;-3&amp;lt;/sup&amp;gt; mD, 11.87×10&amp;lt;sup&amp;gt;-3&amp;lt;/sup&amp;gt; mD, and 7.35×10&amp;lt;sup&amp;gt;-3&amp;lt;/sup&amp;gt; mD. Furthermore, the mud susceptibility to NaCl showed that AV decreased for RH, DM, and BE, while YP decreased significantly. The filter cake thickness and permeability increased by 62.38 and 359.55% for RH, as the DM decreased by 93.80% and 84.37% and the BE by 96.68% and 96.62%, which indicates that RH is more susceptible to NaCl than DM and BE in the mud. Also, these plant-based additives in mud exhibited fragile gel strength and commendable cake characteristics: firm, smooth, and soft/slippery, which make them potentially suitable for oil well drilling.

Improvement on gel properties of chicken myofibrillar protein with electron beam irradiation: Based on protein structure, gel quality, water state

This study aimed to investigate the effects of electron beam (E-beam) irradiation at different doses (0–15 kGy) on the solubility, rheological properties, emulsification characteristics, and moisture distribution of chicken myofibrillar proteins (MPs). Irradiation treatment notably increased the solubility, surface hydrophobicity, emulsification properties, and apparent viscosity of MPs, based on conformational changes caused by irradiation-induced oxidative denaturation of proteins. However, high doses of irradiation (15 kGy) induced in excessive cross-linking and aggregation of proteins, reducing the solubility, emulsification properties, and shear stress. Degradation of myosin heavy and light chains in irradiated MPs increased the content of β-turns and random coils. Additionally, the initial relaxation times of T21 and T22 in irradiated protein gels were reduced, and the peak value of P21 was increased, which improved the water-capturing ability of protein gels. Altogether, these results findings suggest that electron beam irradiation can be applied as a potential technique for modifying muscle proteins.

Effect of H2O2/ascorbic acid degradation and gradient ethanol precipitation on the physicochemical properties and biological activities of pectin polysaccharides from Satsuma Mandarin

In this work, three degraded polysaccharides (DMPP-40, DMPP-60, DMPP-80) were successfully obtained by H2O2/ascorbic acid degradation and gradient ethanol precipitation from Satsuma mandarin peel pectin (MPP), and their physicochemical properties, antioxidant and prebiotic activities were investigated. The molecular weight of MPP, DMPP-40, DMPP-60, DMPP-80 were determined to be 336.83 ± 10.57, 18.93 ± 0.54, 26.07 ± 0.83 and 8.71 ± 0.27 kDa, respectively. The ethanol concentration significantly affected the physicochemical properties of DMPPs. DMPP-60 showed the highest yield (69.07 %) and uronic acid content (64.85 %), DMPP-80 showed the lowest molecular weight (8.71 kDa), and the composition and proportion of monosaccharides of DMPPs were significantly different. Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (1H NMR) confirmed that DMPPs exhibited similar functional groups, while X-ray diffraction (XRD) indicated that DMPP-40 possessed some crystallographic sequences. Scanning electron microscopy (SEM) images directly verified the fragmented structure and reduced surface area of DMPPs. Besides, the H2O2/ascorbic acid treatment could obviously reduce the apparent viscosity and thermal stability of MPP. Meanwhile, the results of bioactivity assay showed that DMPPs possessed better antioxidant activity and probiotics pro-proliferative effects compared with MPP. DMPP-80 could significantly inhibit lipopolysaccharides (LPS)-stimulated production of inflammatory factors (including nitric oxide (NO), interleukin (IL)-6, tumor necrosis factor (TNF)-α and interleukin (IL)-1β) in RAW264.7 cells. Results suggest that the H2O2/ascorbic acid combined with gradient ethanol precipitation has potential applications in degradation and separation of MPP to improve its biological activities.

Computerized Penetrometry Methodology Assisted by Advanced Algorithms Applied in the Multi-Dimensional Analysis of the Rheology of Mold-Ripened Cheeses

The main objective of this study is to understand the rheological behavior of various types of cheeses with mold subjected to multiple stresses during processing/handling, transport, or storage, aiming to maintain or even improve product quality, using computer-assisted penetration methods and advanced regression algorithms. Uniaxial penetration tests with a cone at a constant speed were conducted using a universal Hounsfield testing equipment connected to a computer to analyze the texture behavior (tangential stress, flow index, apparent viscosity) of four of the most common types of cheese with mold depending on the cone’s tip angle (9, 19, and 90 degrees) and penetration speed (12, 30, and 60 mm/min). From the results obtained for the four categories of mold cheeses (Brie, Camembert, Dorblue, and Roquefort), the amplitude of the speed and angle of penetration were considered as the main influencing factors for the shear deformation (τc), flow index (Kf), and apparent viscosity (ηa). The moisture and firmness of mold cheeses are closely linked and depend on the type of mold, the maturation process, or storage conditions. Careful control of these factors is essential to achieve the desired texture and taste characteristics in cheeses with mold.