Linear and non-linear viscoelasticity of low-in-cholesterol mayonnaise / Viscoelasticidad lineal y no lineal de mayonesas con bajo contenido en colesterol

2000 ◽  
Vol 6 (2) ◽  
pp. 165-172 ◽  
Author(s):  
A. Guerrero ◽  
P. Partal ◽  
C. Gallegos
Keyword(s):  
Transient Flow ◽  
Relaxation Modulus ◽  
Wall Slip ◽  
Egg Yolk ◽  
Shift Factor ◽  
Linear Relaxation ◽  
Constant Composition ◽  
Shear Rates ◽  
Non Linear ◽  
Whole Egg

Five different mayonnaise products were prepared with constant composition except for the type of egg product used. The linear viscoelastic functions were superposed using a time-temperature su perposition method and the shift-factor showed an Arrhenius-like temperature dependence. The ther mal susceptibility was found to be higher for processed-egg-containing mayonnaise and when egg yolk was used instead of whole egg as the emulsifier. Transient flow curves always showed a stress overshoot, but a stress undershoot was found for whole-egg-containing emulsions at high shear rates. Processed yolk gave rise to higher storage modulus values than did native yolk. This effect lost sig nificance when yolk was diluted by native egg white. Mayonnaise made from egg yolk was always more viscous and did not show a stress undershoot in transient flow. The non-linear relaxation modulus was factorized as the product of the linear relaxation modulus and the damping function. Hence, the Wagner model was able to predict the transient flow of these emulsions fairly well. However, this model failed at low shear rates. This fact may be explained on the basis of wall-slip phenomena.

scholarly journals STUDY OF CARBON DIOXIDE ADSORPTION ON CHROMIUM OXIDE AND GALLIUM OXIDE CATALYSTS ON BASIS OF NON-LINEAR RELAXATION TIMES

2018 ◽  
Vol 61 (2) ◽  
pp. 46 ◽  
Author(s):  
Nikolay I. Kol'tsov
Keyword(s):  
Carbon Dioxide ◽  
Relaxation Time ◽  
Chromium Oxide ◽  
Rate Constants ◽  
Gallium Oxide ◽  
Relaxation Times ◽  
Oxide Catalysts ◽  
Linear Relaxation ◽  
Adsorption And Desorption ◽  
Non Linear

Recently the analysis of transient regimes of chemical reactions is paid much attention. This is due to the fact that the time-dependent relaxation modes prior to achieving steady states contain important information about the features of the reactions. During unsteady mode the changes in reactant concentrations and rate of the reaction in time are observed. These changes are due to their own relaxation processes, depending on the structure of the reaction mechanism. A complete study of the reaction mechanism involves the study of the relaxation characteristics both near and away from the stationary state. Linear relaxation time describes the local transient modes near the steady state and it is calculated as the time decrease deviations of reactant concentrations from steady-state values in the e-times. Non-linear relaxation time describes the overall behavior reactions and it can be evaluated through the reaction time from the initial state to a stationary. Depending on the structural features of reactions ratio to determine the non-linear relaxation time through of reactions parameters (rate constants stages and reactant concentrations) differ significantly. The establishment of such ratio for a particular reaction allows getting more information to identify the mechanism and the constituent rate constants of its stages. The mechanism of any catalytic reaction involves stages adsorption of one or more of the starting materials on the catalyst surface. As a rule these stages are initial remaining stages of chemical transformation of reactants adsorbed forms follow them. Therefore, it is necessary to have the data on these stages and rate constants of adsorption of reagents on the catalyst surface. Earlier by author the method for estimating the values of the rate constants of adsorption and desorption by linear relaxation times was described. This method was used for determine of mechanism and kinetic parameters of process of adsorption of carbon dioxide on the chromium oxide and gallium oxide catalysts. In this article the method for estimating the values of the rate constants of adsorption and desorption by non-linear relaxation times for this process is described. The previously found CO2 dissociative adsorption mechanism was proved by the obtained results. The intervals of values changes of the rate constants of adsorption and desorption of carbon dioxide on the gallium oxide and chromium oxide catalysts were defined.Forcitation:Kol’tsov N.I. Study of carbon dioxide adsorption on chromium oxide and gallium oxide catalysts on basis of non-linear relaxation times. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 2. P. 46-52

scholarly journals HOW DOES CRYOGENIC FREEZING AFFECT THE CALORIMETRIC PROPERTIES OF LIQUID EGG PRODUCTS?

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Hidas Karina Ilona ◽  
Ildikó Csilla Nyulas-Zeke ◽  
László Friedrich ◽  
Anna Visy ◽  
Judit Csonka ◽  
...  
Keyword(s):  
Liquid Nitrogen ◽  
Frozen Storage ◽  
Colour Change ◽  
Egg Yolk ◽  
Egg White ◽  
Dry Matter Content ◽  
Scanning Calorimetry ◽  
Egg Products ◽  
Liquid Whole Egg ◽  
Whole Egg

Eggs are widely utilized because of their high nutrient value, coagulating, foaming, emulsifying and sometimes even colouring or flavouring facilities in food manufacturing. Production of processed egg products shows an increasing trend. Frozen products belong to first processing, their shelf life can increase up to 1 year. By freezing, a large reduction in microbial loss can be achieved. But different undesirable processes can occur. The effect of freezing on animal cells is highly dependent on freezing parameters. It has a different effect on egg subtituents. Egg yolk undergoes a gelation process while proteins can denaturate. In our study pasteurized liquid egg products (liquid egg white, liquid egg yolk and liquid whole egg) were frozen by dripping into liquid nitrogen. After that, a 14-day frozen storage experiment was carried out at -18°C. Before freezing and on the 1th, 7th and 14th days of storage experiment pH, dry matter content, colour and calorimetric properties (denaturation temperatures and enthalpy of denaturation) with differential scanning calorimetry were tested. For statistical analysis, one-way ANOVA (α = 0.05) was employed. In our experiment, we found no significant change in calorimetric properties of liquid egg white after freezing, but significant decreasing of enthalpy and denaturation temperatures of liquid egg yolk and liquid whole egg was identified. In contrast, frozen storage had a decreasing effect in all these products. Freezing caused a clearly visible colour change in LEW, a visible change in colour of LWE and a very clearly visible change in colour of LEY. In case of LEW and LEY changes increased to clearly visible 14 days. In conclusion, our results show that frozen storage had a greater effect on liquid egg products properties than freezing in liquid nitrogen.

Volatile compounds formed from cooked whole egg, egg yolk, and egg white

1990 ◽  
Vol 38 (2) ◽  
pp. 461-464 ◽  
Author(s):  
Katsumi Umano ◽  
Yukio Hagi ◽  
Akihiro Shoji ◽  
Takayuki Shibamoto
Keyword(s):  
Volatile Compounds ◽  
Egg Yolk ◽  
Egg White ◽  
Whole Egg

Temperature Correction of Backcalculated Moduli and Deflections Using Linear Viscoelasticity and Time-Temperature Superposition

1997 ◽  
Vol 1570 (1) ◽  
pp. 108-117 ◽  
Author(s):  
Sun Woo Park ◽  
Y. Richard Kim
Keyword(s):  
Linear Viscoelasticity ◽  
Superposition Principle ◽  
Asphalt Mixture ◽  
Temperature Shift ◽  
Relaxation Modulus ◽  
Analytical Description ◽  
Shift Factor ◽  
Temperature Correction ◽  
Temperature Superposition ◽  
Time Temperature Superposition

New analytical procedures for temperature correction of backcalculated asphalt concrete moduli and surface deflections were developed based on the theory of linear viscoelasticity and the time-temperature superposition principle and verified using falling weight deflectometer data and field temperature measurements. The new correction procedures explicitly utilize the thermorheological properties of the asphalt mixture. The resulting temperature-modulus correction factors depend only on the relaxation modulus and time-temperature shift factor of the mixture. The temperature-deflection correction factor depends on both the material properties and the layer thicknesses of the pavement section. Emphasis has been placed on the analytical description of the mixture’s thermoviscoelasticity responsible for temperature effects on mixture modulus and pavement deflection. A mechanistic framework for dealing with temperature correction problems for asphalt pavement has been introduced.

Behavior of Psychrotropic Pathogens Listeria monocytogenes, Yersinia enterocolitica, and Aeromonas hydrophila in Commercially Pasteurized Eggs Held at 2, 6.7 and 12.8° C.

1992 ◽  
Vol 55 (1) ◽  
pp. 8-12 ◽  
Author(s):  
JOHN P. ERICKSON ◽  
PHYLLIS JENKINS
Keyword(s):  
Listeria Monocytogenes ◽  
Yersinia Enterocolitica ◽  
Aeromonas Hydrophila ◽  
Egg Yolk ◽  
Egg White ◽  
Competitive Growth ◽  
Growth Responses ◽  
Egg Products ◽  
Spoilage Microflora ◽  
Whole Egg

Four commercially pasteurized liquid egg products were individually inoculated with Listeria monocytogenes, Yersinia enterocolitica, and Aeromonas hydrophila. They were unsalted whole egg blend, unsalted egg white, 5% NaCl whole egg blend, and 10% NaCl egg yolk. The inoculated samples and uninoculated controls were held at 2, 6.7, and 12.8°C (temperature abuse) for 14 d. Psychrotropic pathogen growth or survival risks in the unsalted and NaCl supplemented eggs were Y. enterocolitica > A. hydrophila > L. monocytogenes, and L. monocytogenes > Y. enterocolitica > A. hydrophila, respectively. Y. enterocolitica produced delayed (≥4 d) growth responses in unsalted eggs held at ≤6.7°C but was inhibited by ≥5% NaCl at all three holding temperatures. L. monocytogenes growth was prevented at ≤6.7°C in the unsalted and NaCl supplemented eggs. The organism rapidly increased in the temperature abused 5% NaCl whole egg blend. L. monocytogenes and A. hydrophila were inactivated in the unsalted egg white and NaCl supplemented eggs, respectively. Psychrotropic pathogen behavior was unaffected by the competitive growth of indigenous spoilage microflora including pseudomonads, Serratia spp., and NaCl tolerant micrococci. Properly refrigerated and hygienically handled pasteurized liquid eggs are microbiologically safe against a broad range of psychrotropic pathogen strains.

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