Influence of storing time and temperature on the viscosity of an egg yolk

Severa, Libor; Nedomová, Šárka; Buchar, J.

doi:10.1016/j.jfoodeng.2009.07.020

Cited by 39 publications

(26 citation statements)

References 15 publications

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“…Egg yolks were stored at 4-16 °C for 8 weeks. Analyses of egg yolks revealed elements of shear thinning behaviour and the presence of the shear stress limit (Severa et al 2010). We prevented these effects to occur in our experiment by storing egg yolks only for 3 days.…”

Section: Discussionmentioning

confidence: 99%

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Colour and viscosity of egg yolk after addition of beetroot to feed for laying hens

Kopřiva

Suchý

Straková³

et al. 2014

Acta Vet. Brno

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The colour and viscosity of egg yolk are among major indicators assessed by consumers and food technology. This study attempts to evaluate the colour and viscosity of yolk in laying hens' eggs after the addition of dried beetroot (Beta vulgaris L. ssp. esculenta var. rubra) at the amount of 1% and 2% per feeding dose (in July and August 2012). The experiment was performed on 24 hens that were divided into three groups of 8 laying hens. The preparatory phase lasted one week (standard diet), followed by four weeks during which experimental layers received a diet enriched with beetroot. Then, all layers were fed a mixture without beetroot for the following four weeks. Eggs were collected during the whole period of 8 weeks. In total, 30 eggs from each group were subjected to analysis. The colour of eggs was determined using spectrophotometry, by the Colour-guide sphere spex portable colorimeter. The results showed a significant (P < 0.05) increase in value L* of yolk colour in experimental groups whereas values a* and b* (indicators of the international colorimetric scale CIELAB) did not vary significantly. Similarly, specific purity C* ab did not show a significant difference (P < 0.05) between the control and experimental groups. The egg yolk viscosity was lower in experimental groups compared to the control group but the difference was not significant. The addition of dried beetroot at the amount of 1 and 2% per feeding dose had no effect on colour and viscosity. This paper supported the null hypothesis that the addition of dried beetroot to the feeding dose at the amount of 1% and 2% has no effect on the colour and viscosity of egg yolk.

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Section: Discussionmentioning

confidence: 99%

“…Variation in egg yolk viscosity with the temperature and duration of storage was studied by Severa et al (2010). Egg yolks were stored at 4-16 °C for 8 weeks.…”

Section: Discussionmentioning

confidence: 99%

Colour and viscosity of egg yolk after addition of beetroot to feed for laying hens

Kopřiva

Suchý

Straková³

et al. 2014

Acta Vet. Brno

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“…2 and Fig. 3 Table V. Above mentioned type of mathematical models is rather popular and it was successfully used for description of rheological behavior of diff erent fl uids, even those of biological nature Severa et al, 2010a;Severa et al, 2010b, Vítěz and.…”

Section: Resultsmentioning

confidence: 99%

Differences in rheological profile of regular diesel and bio-diesel fuel

Čupera

Sedlák

Karafiát

2014

Acta Univ. Agric. Silvic. Mendelianae Brun.

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AbstractČUPERA, J., SEDLÁK, P., KARAFIÁT, P.: Diff erences in rheological profi le of regular diesel and bio-diesel fuel. Acta univ. agric. et silvic. Mendel. Brun., 2010, LVIII, No. 5, pp. 67-74 Biodiesel represents a promising alternative to regular fossil diesel. Fuel viscosity markedly infl uences injection, spraying and combustion, viscosity is thus critical factor to be evaluated and monitored. This work is focused on quantifying the diff erences in temperature dependent kinematic viscosity regular diesel fuel and B30 biodiesel fuel. The samples were assumed to be Newtonian fl uids. Vis cosi ty was measured on a digital rotary viscometer in a range of 0 to 80 °C. More signifi cant diff erence between minimum and maximum values was found in case of diesel fuel in comparison with biodiesel fuel. Temperature dependence of both fuels was modeled using several mathematical modelspolynomial, power and Gaussian equation. The Gaussian fi t off ers the best match between experimental and computed data. Description of viscosity behavior of fuels is critically important, e.g. when considering or calculating running effi ciency and performance of combustion engines. The models proposed in this work may be used as a tool for precise prediction of rheological behavior of dieseltype fuels. diesel fuel, biodiesel, kinematic viscosity, modeling Diesel fuel viscosity has a signifi cant impact on how well fuel (either regular or biodiesel) burns. As viscosity increases, fuel molecules cluster together. The molecules on the outside of the cluster mix well with oxygen during combustion and burn well. The molecules on the inside of the cluster do not mix as well and do not burn completely. Knowledge of fuel viscosity is important for several reasons, as it determines the temperature for handling, the size of the centrifuges and the temperature at which the fuel is injected into the engine. It is well known that as the temperature of the fuel is increased, the viscosity is reduced, but diff erences between individual blends or e.g. regular and biodiesel can be expected. Some fuel suppliers publish temperature/viscosity charts which are based on the average data of a large number of samples. However, estimations from the charts cannot be regarded as precise since the exact relationship depends on the source and composition of the fuel. The viscosity usually quoted is the kinematic viscosity expressed in centiStokes (cSt) at some reference temperature. Although ISO 8217 has a reference temperature of 100 °C, it is anticipated that this will be changed to 50 °C at the next revision. This is a value widely used throughout the industry. A few extra degrees of preheating can o en make a fuel suitable for injection equipment. Because of the viscosity/temperature relationship, a few degrees change could make a big diff erence to the injection viscosity. In practical terms, this means that if the actual fuel viscosity is greater than that ordered, it is likely that the fuel heater can accommodate this.Biodiesel refers to a vegetable o...

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“…Although the issue of storage time and viscosity changes have been examined in the food and beverage industry, 34,35 this has not been addressed in relation to HES fluids. Given the fortuitous result concerning HES 130/0.4, it is possible that storage life may affect the viscous behaviour of these fluids, and this has presented us with the opportunity to conduct a long-term study to examine viscous changes in multiple batches from date of receipt to expiration date.…”

Section: Limitationsmentioning

confidence: 99%