scholarly journals Dependence of surface tension of fruit puree on temperature exposure

2021 ◽  
Vol 22 (6) ◽  
pp. 907-917
Author(s):  
L. K. Patsyuk ◽  
V. V. Kondratenko ◽  
M V. Lukyanenko
Keyword(s):  
Surface Tension ◽  
Surface Tension Coefficient ◽  
Effect Of Temperature ◽  
Technological Processing ◽  
Temperature Exposure ◽  
Food Media ◽  
Increasing Temperature ◽  
Apple Puree ◽  
Fruit Purée ◽  
Apple Purée

When developing food products with new properties using innovative technologies, it is important to obtain data on the physicochemical, thermal-physical and structural-mechanical properties of the processed food media. So, one of the key components in the selection of the mode of collapsing ultrasonic cavitation is the surface tension of vegetable purees. The paper presents research data (2020) on the effect of temperature on the surface tension coefficient of fruit puree of different viscosity. The objects of research are cherry plum, pear and apple puree, combined in a row by viscosity. The surface tension coefficient was determined by the stalagmometric method, for which the puree was preliminarily centrifuged. The measurements were carried out at temperatures of 25 and 35 °С. It was found that, under equal conditions of centrifugation of puree, the proportion of supernatant in pear puree is noticeably higher – 77.37 % to the weight of puree in comparison with cherry plum puree (67.20 %) and apple puree (52.75 %). This fact can be explained by the presence of stony cells in the former which form an incompressible sediment, which allows a greater separation of the dispersed phase (sediment) and the dispersion medium (supernatant). It was found that the coefficient of surface tension of fruit purees, despite the slight difference, decreases with increasing temperature. Analysis of the steepness of the slope of the curve characterizing the effect of temperature on the surface tension coefficient showed that temperature stabilization during technological processing is more required for pear puree.

Experimental Study of Surface Tension Coefficient for Magnetic Fluid

2011 ◽  
Vol 492 ◽  
pp. 277-282
Author(s):  
Qing Lei Wang ◽  
De Cai Li ◽  
Fan Wang
Keyword(s):  
Surface Tension ◽  
Magnetic Fluid ◽  
Liquid Surface ◽  
Surface Tension Coefficient ◽  
Fluid Surface ◽  
Liquid Surface Tension ◽  
Experimental Apparatus ◽  
Different Temperatures ◽  
Increasing Temperature ◽  
The Relationship

The author measured surface tension coefficient for liquid with a new experimental apparatus, measured magnetic fluid surface tension coefficient at different temperatures and with different volume of surfactant. By the analysis of experimental data, we obtained that magnetic fluid surface tension coefficient decreases with the increasing temperature and increases with the addition of surfactant volume and reaches a certain stability value. We also obtained the expression of magnetic fluid surface tension coefficient and the temperature or surfactant. This paper discussed the relationship between the liquid surface tension coefficient and the temperature and surfactant from the view of thermodynamics.

EFFECT OF TEMPERATURE ON THE CHANGE IN THE SURFACE TENSION COEFFICIENT OF VEGETABLE PUREES

2021 ◽  
Author(s):  
Т.В. ФЕДОСЕНКО ◽  
Л.К. ПАЦЮК ◽  
В.В. КОНДРАТЕНКО ◽  
Ю.Ю. УСАНОВА
Keyword(s):  
Surface Tension ◽  
Surface Tension Coefficient ◽  
Raw Material ◽  
Effect Of Temperature ◽  
Influence Of Temperature ◽  
Dispersion Surface ◽  
Temperature Dependences ◽  
Influence Of Temperature On ◽  
Taxonomic Affiliation ◽  
Carrot Puree

При применении инновационных способов производства пищевых продуктов, например ультразвуковой кавитационной обработки, для управления параметрами ультразвукового воздействия необходима предварительная информация об исходных свойствах обрабатываемой среды – теплопроводности, плотности, вязкости, дисперсности, поверхностном натяжении, которой, особенно для пищевых продуктов, пока еще недостаточно. Цель настоящей работы – экспериментально установить влияние температуры на величину коэффициента поверхностного натяжения образцов овощных пюре из моркови, тыквы и кабачков, изготовленных на оборудовании технологического стенда по классической технологии. Из образцов предварительно удаляли дисперсную фазу центрифугированием с фактором разделения 8000 g. Супернатант фильтровали через складчатый бумажный обеззоленный фильтр и для образцов фильтрата определяли коэффициент поверхностного натяжения сталагмометрическим методом по ГОСТ 33276–2015 в сравнении с водой. Плотность пюре устанавливали пикнометрическим методом. Для определения влияния температуры на величину поверхностного натяжения образцы овощного пюре нагревали на водяной бане до 25 и 35°С. Установлено, что для всех исследованных образцов овощных пюре величина коэффициента поверхностного натяжения практически в два раза превышает значение аналогичного показателя для воды. Для математического описания зависимости коэффициента поверхностного натяжения от температуры в образцах овощных пюре использовали эмпирическую формулу Катаямы–Гуггенгейма. Установлено, что изменение коэффициента поверхностного натяжения овощных пюре под влиянием температуры практически не зависит от таксономической принадлежности исходного сырья и начальной текучести продукта. Поэтому при практическом использовании установленную зависимость необходимо исследовать отдельно для каждого вида овощного пюре. Зависимости коэффициентов поверхностного натяжения образцов кабачкового и морковного пюре от температуры практически идентичны. Наиболее выражено влияние температуры на коэффициент поверхностного натяжения тыквенного пюре, что указывает на очевидную необходимость стабилизации температуры технологического процесса для сохранения условий, не выходящих за границы оптимума его реализации. When using innovative methods of food production, for example ultrasonic cavitation treatment, to control the parameters of ultrasonic exposure, preliminary information about the initial properties of the treated medium – thermal conductivity, density, viscosity, dispersion, surface tension is necessary. The purpose of this work is to experimentally establish the effect of temperature on the value of the surface tension coefficient of samples of vegetable purees from carrots, pumpkins and zucchini made on the equipment of the technological stand. The dispersed phase was previously removed from the samples by centrifugation with a separation factor of 8000 g. The supernatant was filtered through a folded paper decontaminated filter and the surface tension coefficient was determined for the filtrate samples by the stalagmometric method according to GOST 33276–2015 in comparison with water. The density of the puree was set pycnometrically. To determine the effect of temperature on the value of surface tension, samples of vegetable puree were heated in a water bath to 25 and 35°C. It was found that for all the studied samples of vegetable purees, the value of the surface tension coefficient is almost twice the value of the same indicator for water. The Katayama–Guggenheim empirical formula was used to mathematically describe the dependence of the surface tension coefficient on the temperature in the samples of vegetable purees. It is established that the change in the surface tension coefficient of vegetable purees under the influence of temperature practically does not depend on the taxonomic affiliation of the raw material and the initial fluidity of the product. Therefore, in practical use, the established dependence should be investigated separately for each type of vegetable puree. The temperature dependences of the surface tension coefficients of zucchini and carrot puree are almost identical. The influence of temperature on the surface tension coefficient is most pronounced in pumpkin puree, which indicates the obvious need to stabilize the temperature of the technological process in order to maintain conditions that do not exceed the optimal limits of its implementation.

scholarly journals The behaviour of crystals and lenses of fats on the surface of water.—Part II. The effect of temperature on the equilibrium pressure

1925 ◽  
Vol 109 (750) ◽  
pp. 318-330 ◽  
Keyword(s):  
Surface Tension ◽  
Pure Water ◽  
Hydrocarbon Chain ◽  
Effect Of Temperature ◽  
Two Dimensional ◽  
Equilibrium Pressure ◽  
Equilibrium Surface Tension ◽  
Rate Of Spread ◽  
Definite Interval ◽  
Increasing Temperature

In Part I a study was made of the rate of spread and unimolecular nature of films of fatty substances, containing a long hydrocarbon chain and a polar “head,” over a surface of pure water or of N/100 HC1. It was shown that after a definite interval of time, the surface became saturated with a unimolecular film in equilibrium with either a crystal or a lens of the substance in question, and that the time taken to attain equilibrium as well as the equilibrium surface tension was a function of the temperature. In the present paper the effect of increasing temperature on the two-dimensional equilibrium pressure is considered in detail.

scholarly journals Theoretical Effect of Temperature on Threshold in the Hodgkin-Huxley Nerve Model

1966 ◽  
Vol 49 (5) ◽  
pp. 989-1005 ◽  
Author(s):  
Richard Fitzhugh
Keyword(s):  
Relaxation Time ◽  
Relaxation Times ◽  
Giant Axon ◽  
Temperature Curve ◽  
Effect Of Temperature ◽  
Threshold Temperature ◽  
Ionic Conductances ◽  
And Shifts ◽  
The Right ◽  
Increasing Temperature

In the squid giant axon, Sjodin and Mullins (1958), using 1 msec duration pulses, found a decrease of threshold with increasing temperature, while Guttman (1962), using 100 msec pulses, found an increase. Both results are qualitatively predicted by the Hodgkin-Huxley model. The threshold vs. temperature curve varies so much with the assumptions made regarding the temperature-dependence of the membrane ionic conductances that quantitative comparison between theory and experiment is not yet possible. For very short pulses, increasing temperature has two effects. (1) At lower temperatures the decrease of relaxation time of Na activation (m) relative to the electrical (RC) relaxation time favors excitation and decreases threshold. (2) For higher temperatures, effect (1) saturates, but the decreasing relaxation times of Na inactivation (h) and K activation (n) factor accommodation and increased threshold. The result is a U-shaped threshold temperature curve. R. Guttman has obtained such U-shaped curves for 50 µsec pulses. Assuming higher ionic conductances decreases the electrical relaxation time and shifts the curve to the right along the temperature axis. Making the conductances increase with temperature flattens the curve. Using very long pulses favors effect (2) over (1) and makes threshold increase monotonically with temperature.

scholarly journals DFT calculation for the electronic properties and quantum capacitance of pure and doped Zr2CO2 as electrode of supercapacitors

2021 ◽  
Author(s):  
Shuo Xu ◽  
Shi-Jie Wang ◽  
Li Xiao-Hong ◽  
Hong-Ling Cui
Keyword(s):  
Electronic Properties ◽  
Electrode Materials ◽  
Chemical Properties ◽  
Effect Of Temperature ◽  
Quantum Capacitance ◽  
Substitutional Site ◽  
Level Shifts ◽  
Dirac Distribution ◽  
Increasing Temperature ◽  
Physical And Chemical

Defect and doping are effective methods to modulate the physical and chemical properties of materials. In this report, we investigated the structural stability, electronic properties and quantum capacitance (Cdiff) of Zr2CO2 by changing the dopants of Si, Ge, Sn, N, B, S and F in the substitutional site. The doping of F, N, and S atoms makes the system undergo the semiconductor-to-conductor transition, while the doping of Si, Ge, and Sn maintains the semiconductor characteristics. The Cdiff of the doped systems are further explored. The B-doped system can be used as cathode materials, while the systems doped by S, F, N, Sn atoms are promising anode materials of asymmetric supercapacitors, especially for the S-doped system. The improved Cdiff mainly originates from Fermi-level shifts and Fermi-Dirac distribution by the introduction of the dopant. The effect of temperature on Cdiff is further explored. The result indicates that the maximum Cdiff of the studied systems gradually decreases with the increasing temperature. Our investigation can provide useful theoretical basis for designing and developing the ideal electrode materials for supercapacitors.

scholarly journals Effects of the Temperature and the pH on the Main Protease of SARS-CoV-2: A Molecular Dynamics Simulation Study

2021 ◽  
Vol 12 (6) ◽  
pp. 7239-7248
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Root Mean Square ◽  
Dynamics Simulation ◽  
Effect Of Temperature ◽  
Water Molecules ◽  
Mean Square ◽  
Main Protease ◽  
Decreasing Ph ◽  
Increasing Temperature

The novel coronavirus, recognized as COVID-19, is the cause of an infection outbreak in December 2019. The effect of temperature and pH changes on the main protease of SARS-CoV-2 were investigated using all-atom molecular dynamics simulation. The obtained results from the root mean square deviation (RMSD) and root mean square fluctuations (RMSF) analyses showed that at a constant temperature of 25℃ and pH=5, the conformational change of the main protease is more significant than that of pH=6 and 7. Also, by increasing temperature from 25℃ to 55℃ at constant pH=7, a remarkable change in protein structure was observed. The radial probability of water molecules around the main protease was decreased by increasing temperature and decreasing pH. The weakening of the binding energy between the main protease and water molecules due to the increasing temperature and decreasing pH has reduced the number of hydrogen bonds between the main protease and water molecules. Finding conditions that alter the conformation of the main protease could be fundamental because this change could affect the virus’s functionality and its ability to impose illness.

scholarly journals Using naturalistic incubation temperatures to demonstrate how variation in the timing and continuity of heat wave exposure influences phenotype

2020 ◽  
Vol 287 (1932) ◽  
pp. 20200992 ◽  
Author(s):  
Anthony T. Breitenbach ◽  
Amanda W. Carter ◽  
Ryan T. Paitz ◽  
Rachel M. Bowden
Keyword(s):  
Heat Wave ◽  
Time Course ◽  
Heat Waves ◽  
Heat Exposure ◽  
Effect Of Temperature ◽  
Similar Time ◽  
Expression Of Genes ◽  
Short Period ◽  
The Face ◽  
Temperature Exposure

Most organisms are exposed to bouts of warm temperatures during development, yet we know little about how variation in the timing and continuity of heat exposure influences biological processes. If heat waves increase in frequency and duration as predicted, it is necessary to understand how these bouts could affect thermally sensitive species, including reptiles with temperature-dependent sex determination (TSD). In a multi-year study using fluctuating temperatures, we exposed Trachemys scripta embryos to cooler, male-producing temperatures interspersed with warmer, female-producing temperatures (heat waves) that varied in either timing during development or continuity and then analysed resulting sex ratios. We also quantified the expression of genes involved in testis differentiation ( Dmrt1 ) and ovary differentiation ( Cyp19A1 ) to determine how heat wave continuity affects the expression of genes involved in sexual differentiation. Heat waves applied during the middle of development produced significantly more females compared to heat waves that occurred just 7 days before or after this window, and even short gaps in the continuity of a heat wave decreased the production of females. Continuous heat exposure resulted in increased Cyp19A1 expression while discontinuous heat exposure failed to increase expression in either gene over a similar time course. We report that even small differences in the timing and continuity of heat waves can result in drastically different phenotypic outcomes. This strong effect of temperature occurred despite the fact that embryos were exposed to the same number of warm days during a short period of time, which highlights the need to study temperature effects under more ecologically relevant conditions where temperatures may be elevated for only a few days at a time. In the face of a changing climate, the finding that subtle shifts in temperature exposure result in substantial effects on embryonic development becomes even more critical.

Sign in / Sign up

Export Citation Format

Share Document