Maximum Viscosity Research Articles

Role of Ta and Nb alloying elements on the viscosity of Fe-B-Si melts

Alloying of Fe – B – Si alloys is a key issue in the preparation of promising bulk amorphous materials. In the present study, we examine temperature and concentration dependences of the kinematic viscosity of (Fe0.75B0.15Si0.10)100-xMx (M = Ta, Nb, x = 0–4) melts. Detailed structural analysis is performed. The results demonstrate importance of sedimentation processes for understanding temperature dependences of the viscosity with a concentration of alloying elements of more than 1 at.% Ta and 1.5 at.% Nb. The sedimentation processes are associated with the presence of the refractory compounds, FeTaB and NbB2, in the (Fe0.75B0.15Si0.10)100-xTax and (Fe0.75B0.15Si0.10)100-xNbx (x = 0–4) alloys, respectively. Alloying elements, Ta and Nb, even at low concentrations, have different effect on the viscosity of Fe–B–Si melts. Small Ta additions slightly affect the viscosity, while the Nb additions increase its value. The concentration dependences show the local maxima of viscosity at 1 at.% Ta and 3 at.% Nb. Ab initio calculations show the difference in the chemical interaction of Ta and Nb atoms in the melts. The alloying preserves the main features of the melt local structure and increases the dispersion of component interaction radii which improves the amorphization ability.

Phytate-mediated phosphorylation of maize, rice, and potato starches at different pH conditions

Maize, rice, and potato starches were dispersed with phytate at pH 7, 9, and 11, and were subjected to dry-heating at 130 °C for 12 h. The residual phosphorus content and structural characteristics revealed that the treatment resulted in starch phosphorylation. Further, pasting viscosity, clarity, solubility, and swelling power were analyzed to determine the physicochemical properties of the phosphorylated starch. These heat-treated starches retained phosphorus mainly in the form of monostarch monophosphate. Phosphorylation increased the peak viscosity and decreased the pasting temperature in maize and rice starches, but not in potato starch. Paste clarity, solubility, and swelling power were also increased in phosphorylated maize and rice starches. Phosphorus content, paste clarity, solubility, and swelling power were the highest at pH 7, but the maximum paste viscosity was at pH 9. These results indicate that phytate can be used for starch phosphorylation, with the reaction efficiency based on the botanical source of the starch and the reaction pH.

Physiochemical mechanisms involved in the improvement of grain-filling, rice quality mediated by related enzyme activities in the ratoon cultivation system

Abstract The grain quality of rice in the ratoon cultivation system is often higher than in the main crop (late season). To investigate the reason for that difference, a study of physiochemical factors, particularly relevant enzyme activities and their relationships with grain-filling and rice quality, was conducted with two hybrid rice cultivars, indica type Taifengyou 3301″ and indica-japonica type Yongyou 2640″. The results showed that the head rice yield of the superior and inferior grains in ratoon rice were significantly higher than those of their counterpart main crops (late season) to which rice heading time was synchronized. The degree of grain chalkiness and chalky grain percentage of both superior and inferior grains in ratoon rice were much lower than those of the late season main crop of both cultivars over two years of study. The starch RVA (Rapid Viscosity Analyzer) profile parameter analysis indicated that the maximum viscosity and setback viscosity of the superior and inferior grains of ratoon rice were higher than the late season main crop counterparts in both cultivars. We also found that the grain-filling of ratoon rice, especially for inferior grains, initiated earlier and continued longer and steadier than that of the late season main crop at the early and middle stages, which was driven by better translocation of photosynthate and the coordinated activity of enzymes including starch synthase and starch branching enzyme. These findings suggest that lower grain sink capacity and higher photosynthate remobilization ability result in fast and steady grain-filling in ratoon crops. Furthermore, coordinated enzyme activity appears to be involved in the process of starchsynthesis and dry matter translocation that drives the improvement of grain-filling and the grain quality of ratoon rice.

Numerical Investigation of Effect of Temperature Profile Imposed on the Crucible Surface on Oxygen Incorporated at the Crystal Melt Interface for 450 mm Diameter Silicon Single Crystal Growth in Presence of CUSP Magnetic Field Using Czochralski Technique

Numerical investigation has been carried out to study the effect of thermal boundary condition on turbulent melt flow and oxygen transfer inside a crucible used to grow 450 mm diameter silicon single crystal using Czochralski method. Two types of thermal boundary conditions, namely, isothermal crucible surface and experimentally measured temperatures on the crucible surface have been imposed on the crucible wall and crucible bottom. Melt motion owing to buoyancy, surface tension variation at the free melt surface as well as crystal and crucible rotation has been considered. Effect of CUSP magnetic field has also been investigated. Melt having aspect ratio of 1 and 0.5, representing high and moderate level of melt inside the crucible have been considered. K-epsilon turbulent model with low Reynolds number formulation has been used for turbulence modelling. Melt motion governed by natural convection, Marangoni convection and crystal as well as crucible rotation shows higher oxygen concentration at melt crystal interface for aspect ratio of 1, when experimental temperature profile is imposed at the crucible wall. For melt aspect ratio of 0.5, natural convection and Marangoni convection dependent melt show higher oxygen concentration for isothermal crucible wall boundary condition. Marangoni convection in absence of rotation of crystal and crucible leads to low oxygen concentration zone near the crystal outer surface, the size of which is larger for melt aspect ratio of 0.5. Maximum turbulent viscosity values for aspect ratio of 1, in case of experimental temperature at the crucible are higher compared to isothermal case, which is just the opposite of the trend for aspect ratio of 0.5. Imposing a CUSP magnetic field leads to similar distribution of turbulent viscosity for both types of thermal boundary conditions, irrespective of the type of thermal boundary condition. Oxygen concentration at the melt crystal interface is found to be higher in presence of CUSP magnetic field. Value of maximum turbulent viscosity for the two boundary condition are similar for melt aspect ratio of 1.0. Crucible surface temperature profile for aspect ratio of 1, on actual melt aspect ratio of 0.5 predicts lower oxygen concentration at melt crystal interface. Values and distribution of turbulent viscosity is however the same for both temperature profiles.

Rheology and 3D Printability of Percolated Graphene-Polyamide-6 Composites.

Graphene–polyamide-6 (PA6) composites with up to 17.0%·w/w graphene content were prepared via melt mixing. Oscillatory rheometry revealed that the dynamic viscoelastic properties of PA6 decreased with the addition of 0.1%·w/w graphene but increased when the graphene content was increased to 6.0%·w/w and higher. Further analysis indicated that the rheological percolation threshold was between 6.0 and 10.0%·w/w graphene. The Carreau–Yasuda model was used to describe the complex viscosity of the materials. Capillary rheometry was applied to assess the steady shear rheology of neat PA6 and the 17.0%·w/w graphene–PA6 composite. High material viscosity at low shear rates coupled with intense shear-thinning in the composite highlighted the importance of selecting the appropriate rheological characterisation methods, shear rates and rheological models when assessing the 3D printability of percolated graphene–polymer composites for material extrusion (ME). A method to predict the printability of an ME filament feedstock, based on fundamental equations describing material flow through the printer nozzle, in the form of a printing envelope, was developed and verified experimentally. It was found that designing filaments with steady shear viscosities of approximately 15% of the maximum printable viscosity for the desired printing conditions will be advantageous for easy ME processing.

Efficiency analysis of thermosyphon solar flat plate collector with low mass concentrations of ND–Co3O4 hybrid nanofluids: an experimental study

In the present study, the thermal efficiency, convective heat transfer and friction factor analysis are investigated for a flat plate solar collector with thermosyphon (natural circulation) system using water and nanodiamond–cobalt oxide hybrid nanofluids as the working fluids. The nanodiamond–cobalt oxide hybrid nanoparticles were synthesized using in situ growth and chemical co-precipitation method and characterized using X-ray diffraction, transmission electron microscope and vibrating sample magnetometer. The investigations were performed at different volume flow rates 0.56–1.35 L min−1 and various mass concentrations of 0.05–0.15%. The thermal conductivity and viscosity of nanofluids were measured experimentally at various mass concentrations and temperatures. Due to the augmented thermo-physical properties of hybrid nanofluids, the collector reached higher coefficient of heat transfer as well as improved thermal efficiency than the water data. Maximum thermal conductivity and viscosity enhancements are found to be 15.71% and 45.83% at particle loadings of 0.15% mass concentration and at a temperature of 60 °C. Results show the Nusselt number enhancement of 0.15% mass concentration of hybrid nanofluid is 21.23% with maximum friction factor penalty of 1.13 times against water data. The collector thermal efficiency is found to 59% for the case of 0.15% mass concentration of hybrid nanofluid, where the thermal efficiency of water is 48%. The empirical correlations were developed for Nusselt number and friction factor for collector with hybrid nanofluids within the deviation of ± 3%.

Experimental determination of thermophysical properties of Indonesian fly-ash nanofluid for heat transfer applications

The heat transfer fluid's thermal properties are a significant topic of current research. In this study, coal fly ash nanoparticles of 14 nm average diameter were dispersed in water to prepare stable nanofluid in the concentration range of 0.1–0.5% volume concentration. The nanofluid was stabilized and uniformly dispersed using an ultrasonic homogenizer with the addition of Triton–X 100 surfactant. The thermophysical properties, viz., thermal conductivity, viscosity, density, and specific heat of the nanofluid were measured in the temperature range of 30–60 °C. The maximum thermal conductivity and viscosity augmentation of 14 and 6.38% are observed for 60 and 30 °C, respectively, at 0.5% volume concentration compared to water at the same temperatures. The experiment results revealed that thermal conductivity, viscosity, and density increased while specific heat decreased with an increase in nanofluid concentration. Also, the thermal conductivity and specific heat increase, while viscosity and density decrease with an increase in temperature. The thermal conductivity of fly ash nanofluid is observed to be superior by 3.9% compared to SiO2 nanofluid which can be due to its chemical constituents. Hence, fly ash particles are useful in heat transfer applications.

Microstructure characterizations, thermal properties, yield stress, plastic viscosity and compression strength of cement paste modified with nanosilica

In this study, the effect of nano-silica (NS) as an additive to Ordinary Portland Cement was evaluated and quantified. Scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy analysis was used to identify the cement and NS contents. Experimental tests and modeling were conducted to quantify and predict the rheological properties of the cement in the liquid phase such as yield stress, maximum shear strength, plastic viscosity, and mechanical behavior such as compressive strength of cement after hardening. The cement modified with NS was tested at water-to-cement ratios (w/c) of 0.35 and 0.45 and temperatures ranging from 25 to 75°C. X-ray diffraction (XRD) and TGA were used to analyze the cement, nano-silica, and cement modified with nano-silica. The behavior of cement paste in the liquid phase (slurry) and hardened phase modified with different percentages of nano-silica up to 1% (by dry weight of cement) was investigated. The compressive strength of cement paste modified with nano-silica was tested from a young age up to 28 days of curing. Non-linear regression (NLR) based model was used to assess the effect of nano-silica on the rheological properties and compressive strength of cement. Replacing the cement with nano-silica substantially reduced the volume of Ca(OH)2. TGA tests showed that the 1% nano-silica additive leads to low cement weight loss up to 800°C due to the de-carbonation of CaCO3 in the hydrated compound and due to interacting the NS with the cement. The addition of NS increased the ultimate shear strength (τmax) and the yield stress (τo) by 15% to 53% and 23% to 186%, respectively based on the NS content, w/c, and temperature. An additional 1% of NS the compressive strength increased of the cement hardened by 15.1% to 72% based on the curing period, and w/c. Based on the model parameters and the experimental performance, the nano-silica is the most effective parameter in improving the properties of cement in both liquid and hardened phases.

Analysis of viscosity function models used in friction stir welding

Friction stir welding (FSW) is a solid-state process, where a tool that consists of a shoulder and a pin rotates between the plates to be welded by plastic deformation. This process involves several physical phenomena. To better understand this complex phenomenon, simulations have been performed for a range of maximum viscosity values. The viscosity model used in friction stir welding simulations depends on two variables, the temperature and strain rate; however, the viscosity goes toward infinity for low values of temperature and strain rates. This study analyzed two different friction stir welding simulation, by observing how the viscosity functions behave for low values of temperature and strain rates. The maximum viscosity value was shown to be restricted to values, where the velocity field tends to zero. Furthermore, when the viscosity value exceeds the maximum value, the temperature and viscosity field is significantly impaired. In the correct results, the change in viscosity is restricted to stir zone.

Investigation of the Effect of Nanoparticle-Stabilized Foam on EOR: Nitrogen Foam and Methane Foam.

In recent years, studies conducted on foam stabilization have focused on nanoparticles by generating strong adsorption at the interface to stabilize the foam under harsh reservoir conditions. Meanwhile, the selection of a gas source is also of great importance for foam performance. In this study, a mixed system of surfactants was selected, and the foamability and foam stability of nitrogen and methane were evaluated according to the improved jet method. After adding modified SiO2 nanoparticles, the foam-related parameters were analyzed. The plugging abilities of the different foams were compared through core-flooding experiments, and the oil displacement effects of the different foams were compared through microfluidic experiments. The results show that the amphoteric surfactant betaine has an excellent synergistic effect on the anionic surfactant SDS. The methane foam produced using the jet method has a larger initial volume than the nitrogen foam, but its stability is poor. The half-life of the nitrogen foam is about two times that of the methane foam. After adding 1.0 wt % SiO2 nanoparticles to the surfactant solution, the viscosity and stability of the formed foam improve. However, the maximum viscosity of the surfactant nanoparticle foam (surfactant-NP foam) is 53 mPa·s higher than that of the surfactant foam. In the core-flooding experiment, the plugging performance of the methane foam was worse than that of the nitrogen foam, and in the microfluidic experiment, the oil displacement abilities of the methane foam and the nitrogen foam were similar. The plugging performance and the oil displacement effect of the foam are greatly improved by adding nanoparticles. The surfactant-NP foam flooding has a better oil displacement effect and can enhance the recovery factor by more than 30%. Under actual high-pressure reservoir conditions, although the stability of the methane foam is weaker than that of the nitrogen foam, some methane may be dissolved in the crude oil to decrease the viscosity after the foam collapses, which leads to the methane foam being the preferred method in oilfields.

Synergistic interactions in dilute aqueous solutions between alginate and tropical vegetal hydrocolloids

Encapsulation in alginate beads has always been limited by the leakage due to the too wide distribution of pore sizes. Mixing alginate with other polymers have sometimes reduced the problem. Hydrocolloids from seven tropical vegetal species (barks of Triumfetta cordifolia and Bridelia thermifolia, seeds of Irvingia gabonensis and Beilschmiedia obscura, and leaves of Ceratotheca sesamoides, Adansonia digitata and Corchorus olitorius) were screened for synergistic interactions with alginate in dilute aqueous solution. Mixtures with alginate were made at different volume proportions and deviations from the initial viscosity set at 1 were evaluated. In distilled water, the gums from T. cordifolia, B. obscura, C. sesamoides and C. olitorius presented synergies with alginate. In 2 mM calcium chloride, the seven gums showed positive synergy. Interactions are favored by gum flexibility and the presence of charges, although high charges reduced the interactions. Alginate fraction of maximum viscosity enhancement depends on the ability to conformational order of the gum. The measure by laser diffraction of alginate-gum particles sizes at different fractions showed that the cooperative interactions did not always involve the largest complexes formed in gums associations. The occurrence of these interactions predicts the formation of homogeneous mixed gels at higher polymer and calcium concentrations.

INVESTIGATION OF THE TECHNOLOGICAL PROPERTIES OF EMMER FLOUR

The article presents the results of studying the technological properties of emmer flour obtained from the grain of the variety Golikovska, in comparison with commercial patent wheat flour. It has been found that emmer flour contains 1.4 times as much crude gluten and 1.3 times as much dry gluten as wheat flour does. It has been shown that gluten of emmer flour is 1.2 times less strong and 1.3 times more elastic than gluten of wheat flour, and can be included in the 2nd group of quality. According to the results of farinographic tests, it has been established that the experimental emmer dough sample is formed 2 minutes earlier and is 3 times less stable than wheat dough. The results of the alveographic tests have shown that, compared to wheat dough, the tenacity of emmer dough is lower by 25.9%, the extensibility is higher by 26.3%, its alveogram configuration ratio is lower by 36.4%, and its baking strength is lower by 28.2%. It has been established that the starch of emmer flour starts being gelatinised (turning into paste) a little later and at a slightly higher temperature than wheat flour starch does. The maximum viscosity of wheat starch paste is by 58.3% higher than that of emmer starch paste. It has been established that the falling number of emmer flour is by 9.6% smaller in comparison with that of wheat flour. The dough-raising capacity of model yeast dough systems prepared from emmer flour is by 25.0% better than it is in model systems made from wheat flour. It has been found that in emmer yeast dough, fermentation processes are more intensive than in wheat yeast dough: at the end of fermentation, the emmer dough had by 13.3% higher titrated acidity and had formed by 12.5% more carbon dioxide. The volume of emmer dough was by 16.7% higher than that of wheat dough. The sensory evaluation of unleavened and yeasted puff pastries made from emmer flour has shown that they are not inferior in quality to baked products made from wheat flour, have a regular shape and a bright crust colour, and are large in volume.

Dendrimer Dynamics: A Review of Analytical Theories and Molecular Simulation Methods.

The theoretical study of dendrimers is reviewed, considering both analytical approaches and molecular simulation methods. We discuss the effect of molecular symmetry on the degeneracy of the relaxation times, and then the calculation of observable quantities, in particular the intrinsic viscosity, and then the viscoelastic complex modulus and the dynamic structure factor, in comparison with the available experimental data. In particular, the maximum intrinsic viscosity with increasing molar mass is analyzed in some detail. The approximations and/or assumptions of the adopted methods are also described in connection with analogous results for polymer of a different topology, in particular linear and star polymers.

Changes and quantitative characterization of hyper-viscoelastic biomechanical properties for young corneal stroma after standard corneal cross-linking treatment with different ultraviolet-A energies

Corneal collagen cross-linking (CXL) treatment can restore vision in patients suffering from keratoconus and corneal injury, by improving the mechanical properties of the cornea. The correlation between ultraviolet-A (UVA) irradiant energies of standard CXL (SCXL) and corneal visco-hyperelastic mechanical behavior remains unknown. In this study, SCXL with four different UVA irradiant energy doses (0–5.4 J/cm2) were administered as part of quantitative treatments of corneal stromal lenticules extracted from young myopic patients via small incision lenticule extraction (SMILE) corneal refractive surgery. Double-strip samples with symmetric geometries were cut simultaneously for SCXL treatment and non-treated control. First, 40 pairs of strips were loaded to failure to assess the mechanical parameters of the material. Then, another 40 pairs were tested using a special uniaxial tensile test including quasi-static loading–unloading, instantaneous loading, and stress relaxation, to determine the visco-hyperelastic mechanical behavior. Upon combining the collagen fibril crimping constitutive model with the quasi-linear viscoelastic model, it was observed that with increasing UVA energy dose, the corneal strength and hyperelastic stiffness were significantly enhanced, while the maximum stretch and viscosity of the cornea were significantly reduced. Considering the quantitative analysis of SCXL and the rehabilitation prediction of keratoconus treatment, the results clarify the biomechanical behavior of human corneal stroma in SCXL clinical surgery. Statement of SignificanceThis study quantitatively analyzes the improvement in the biomechanical properties of young central corneal stroma, due to SCXL treatment with different energies. Furthermore, the correlation between the hyper-viscoelastic mechanical parameters and UVA irradiant energy doses of SCXL are clarified. The contribution of this study fills the knowledge gap of the CXL on corneal biomechanics. It can not only clarify this mechanism better but also assist with guiding SCXL surgery for individualized patient corneas.

The influence of fumed silica content, dispersion energy, and humidity on the stability of shear thickening fluids

Shear thickening fluids (STFs) are smart materials that change from liquid to solid reversibly when undergoing critical stresses. These materials are good alternatives to improve applications where energy dissipation is important, for example, in the fabrication of liquid body armor and shock absorbing protective gear. However, as much as it is known about the effect of several variables on their properties, such as particle concentration and medium viscosity, the stability of these colloidal dispersions over time and over shearing is not yet well understood. The development and design of new applications depend on predicting for how long the material will keep its properties. In this project, we studied the influence of fumed silica content, ultrasonication energy used during dispersion of the silica particles, and humidity during storage to analyze the changes in properties of STFs. The influence of shearing magnitude on their properties was also studied. STFs with higher amounts of silica and produced using less dispersion energy showed the highest viscosity peak on initial tests, but they were also the least stable over time, due to flocculation of the particles. In stable samples, water absorption led to a large loss of maximum viscosity. The presence of humidity on samples diminished the overall viscosity, but did not prevent the sample from becoming a gel if the parameters used resulted in an unstable STF. Shearing the STF reduced its maximum viscosity, being more evident in samples with higher viscosity.

Preparation of auxetic warp-knitted spacer fabric impregnated with shear thickening fluid for low-velocity impact resistance

This paper reports the preparation of auxetic warp-knitted spacer fabric impregnated with shear thickening fluid and studied its impact behavior under low-velocity impact loading. The shear thickening fluids have been prepared by mechanically dispersing 12 nm silica particles with weight fraction of 10, 15, 20, and 25% in various carriers (PEG200, PEG400, and PEG600). Rheological results indicate that shear thickening fluid experiences shear thickening transition at a specific shear rate. The critical shear rate reduces, and initial viscosity and maximum viscosity increase with the increase of silica weight fraction. The higher molecular weight of polyethylene glycols can lead to lower critical shear rate. The impact process of composite under impact loading can be divided into three stages. The warp-knitted spacer fabric with different negative Poisson’s ratio has a significant effect on the impact behavior. The warp-knitted spacer fabric with better auxetic performance endows composite better impact resistance, the specific performance is the deformation depth, and energy absorption and peak load increase with the increase of auxetic effect of fabric. The silica weight fraction of shear thickening fluid can increase the energy absorption of composite due to the shear thickening transition of shear thickening fluid. Shear thickening fluid has a synergistic effect with the auxetic warp-knitted spacer fabric on impact resistance of composite. The various carriers have no obvious influence on the overall energy absorption and impact load of composites.

Characterization and modeling the flow behavior and compression strength of the cement paste modified with silica nano-size at different temperature conditions

In this study, the effect of nano-silica (NS) as an additive to the Ordinary Portland Cement was evaluated and quantified. Scanning Electronic Microscope (SEM), X-ray diffraction (XRD), Thermogravimetric Analysis (TGA), Fourier-Transform Infrared Spectroscopy (FTIR), and Raman Spectroscopy analysis were used to identify the cement and NS content. Experimental tests and modeling were conducted to quantify and predict the rheological properties of the modified cement in the liquid phase such as yield stress, maximum shear strength, plastic viscosity, and mechanical properties such as compressive strength of cement after hardening. The cement modified with NS was tested at water-to-cement ratios (w/c) of 0.35 and 0.45 and temperatures ranging from 25 °C to 75 °C. Non-linear regression (NLR) based model was used to evaluate the effect of nano-silica on the rheological properties and compressive strength of cement. Modifying the cement with nano-silica substantially reduced the volume of Ca (OH)₂. TGA tests showed that the 1% nano-silica additive leads to a decrease in the total weight loss of the cement at 800 °C by 82% due to the de-carbonation of CaCO3 in the hydrated compound and due to interacting the NS with the cement. The addition of NS increased the ultimate shear stress (τmax) and the yield stress (τo) by 15% to 53% and 23% to 186% respectively based on the NS content, w/c, and temperature. An additional 1% of NS to the cement paste the compressive strength increased by 14%–66% based on the curing time, and w/c. The unprecedented conclusions can be drawn in this study, which is the effect of the nano-silica content, water-cement-ratio and temperature effect on the plastic viscosity, yield stress and shear stress limit in the fresh stage (slurry) of the cement paste and also, the impact of the nano-silica content, water-cement-ratio and curing time on the compressive strength in the hardened stages of the cement modified with nano-silica were modeled. The experimental and the modeling results illustrated that the SiO2 nanostructure, which was mixed with the cement paste was highly beneficial in improving the rheological properties of cement paste and compressive strength after hardening.

Fabrication of films with tailored properties by regulating the swelling of collagen fiber through pH adjustment

Acid swelling collagen fibers have been commonly used to prepare casing or film, but how the swelling degree regulates the properties of collagen fiber dispersions (CFD) and their related films are still unclear. Herein, variant swelling degrees of collagen fiber were obtained by controlling the pH of CFD. The swelling ratio of collagen fiber increased and then decreased with the decrease of pH from 4.0 to 1.5. The maximum viscosity, modulus and denaturation temperature appeared at pH 3, where the fibers interconnected to form a dense network structure. This sufficient swelling enabled excellent mechanical and thermodynamic properties of films, whereas insufficient swelling of CFD led to inferior properties. Films from collagen fiber swelled at pH 3 further showed a more ordered layer structure, but cross-sectional microstructures with disintegrated tiny fibers along with the reduction of triple helix content for those at low pH were observed. This study provided a better understanding and guidance of pH regulation in actual production of collagen films using bovine dermis.

Improvement of zefir production by addition of the developed blended fruit and vegetable pasteinto its recipe

A method has been developed for the production of a fruit and vegetable paste-like semi-finished product based on an Antonovka apple, Muscat pearl pumpkin and Bona beet. The method is characterized by concentration in gentle temperature conditions (50...55 °C) in a rotary film apparatus to content of 45 % dry matters lasting 1.25...2.0 min. The structural and mechanical characteristics of the mashed potatoes of the components of raw materials and blended concentrated pastes by the developed method are determined. The structure of the developed fruit and vegetable paste was confirmed to be strengthened, since its maximum dynamic viscosity is 283 Pa∙s, which is 1.9 times more compared to the control (apple paste). Thus, a rational composition is selected for further research with the following components in the paste: apple – 60 %; pumpkin – 20 %, beets – 20 % (composition 1). This paste in comparison with the control has a high content of functional physiological ingredients and has good organoleptic properties. The feasibility of using the developed fruit and vegetable paste in composition of zefirs (composition 1) in the amount of 75 % replacement of apple puree is confirmed. The selected zefir sample differs in its original organoleptic properties. This ensures an increase in the effective viscosity (η ef , Pa∙s) of zefirs with the replacement of 75 % of apple puree with blended paste, compared to control (zefirs without additives) from 391 to 782. The plastic strength (P k ) also increases depending on the duration: 75 % – 54.2 kPa (control sample – 47 kPa), which is generally a positive phenomenon from a technological point of view. Such a solution will provide consumers with food products with physiologically functional ingredients of natural origin, subject to the partial or complete replacement of individual raw materials with blended fruit and vegetable compositions, providing an increase in their functional value

IMPROVEMENT OF ZEFIR PRODUCTION BY ADDITION OF THE DEVELOPED BLENDED FRUIT AND VEGETABLE PASTEINTO ITS RECIPE

A method has been developed for the production of a fruit and vegetable paste-like semi-finished product based on an Antonovka apple, Muscat pearl pumpkin and Bona beet. The method is characterized by concentration in gentle temperature conditions (50...55 °C) in a rotary film apparatus to content of 45 % dry matters lasting 1.25...2.0 min. The structural and mechanical characteristics of the mashed potatoes of the components of raw materials and blended concentrated pastes by the developed method are determined. The structure of the developed fruit and vegetable paste was confirmed to be strengthened, since its maximum dynamic viscosity is 283 Pa∙s, which is 1.9 times more compared to the control (apple paste). Thus, a rational composition is selected for further research with the following components in the paste: apple – 60 %; pumpkin – 20 %, beets – 20 % (composition 1). This paste in comparison with the control has a high content of functional physiological ingredients and has good organoleptic properties. The feasibility of using the developed fruit and vegetable paste in composition of zefirs (composition 1) in the amount of 75 % replacement of apple puree is confirmed. The selected zefir sample differs in its original organoleptic properties. This ensures an increase in the effective viscosity (ηef, Pa∙s) of zefirs with the replacement of 75 % of apple puree with blended paste, compared to control (zefirs without additives) from 391 to 782. The plastic strength (Pk) also increases depending on the duration: 75 % – 54.2 kPa (control sample – 47 kPa), which is generally a positive phenomenon from a technological point of view. Such a solution will provide consumers with food products with physiologically functional ingredients of natural origin, subject to the partial or complete replacement of individual raw materials with blended fruit and vegetable compositions, providing an increase in their functional value.