| Titles |
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English :
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Study of the Non-Newtonian Properties of fruit concentrates
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Arabic :
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دراسة الخـواص اللانيـوتـونية لمركزات الفاكهة
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| Abstract |
Summary
The Rheological properties of Fig Jam puree were studied over the range: 20-¬90°C, concentrations 40-65% and the speed of spindle 10-50 rpm. Shear stress- Shear rate data indicate that the puree behaves as a non-Newtonian Bingham plastic fluid with yield stress.
The yield stress decreases with increasing temperature except for the samples that have solid concentrations from 60-65% wt. due to pectin formation. Also, the yield stress increases with an increase in solid concentrations (at all temperatures investigated). Fig jam puree exhibits a thixotropic behavior in which, the apparent viscosity of the material decreases with time of shearing at constant shear rate.
Three models were applied to simulate thixotropic behavior. Dependence of apparent viscosity on temperature was related through the Arrhenius law and the plot of ln(µ) versus (1/T) exhibits three regions with different temperature dependencies. Also, this study includes the dependence of the apparent viscosity of Fig jam puree on solid concentration, that follows the power law relationship.
The generalized friction factor-Reynolds number was constructed taking in consideration the results at different shear rates and concentrations.
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| URL |
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| Publication year |
2005
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| Organization Name |
Food Technology Research Institute (FTRI)
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| Country |
Egypt
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| Author(s) from ARC |
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| Agris Categories |
Food science and technology
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| Proposed Agrovoc |
flow behavior;
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| Publication Type |
PhD Thesis
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