Rheological characteristics of tamarind (Tamarindus indica L.) juice concentrates

被引:43
作者
Ahmed, Jasim [1 ]
Ramaswamy, H. S. [1 ]
Sashidhar, K. C. [1 ]
机构
[1] McGill Univ, Dept Food Sci & Agr Chem, Ste Anne De Bellevue, PQ H9X 3V9, Canada
关键词
tamarind juice concentrate; Herschel-Bulkley model; Casson model; Carreau model; apparent viscosity; complex viscosity; Cox-Merz rule;
D O I
10.1016/j.lwt.2005.11.002
中图分类号
TS2 [食品工业];
学科分类号
0832 ;
摘要
The steady-shear and small-amplitude oscillatory rheological properties of tamarind (Tamarindus indica L.) juice concentrate (TJC) were studied in the temperature range of 10-90 degrees C using a con trolled-stress rheometer. Under steady-shear deformation tests, shear stress-shear rate data were adequately fitted to the Herschel-Bulkley and Casson model at lower (10-30 degrees C) and higher (50-90 degrees C) temperature range, respectively. The Carreau model was applied to describe the shear-thinning behaviour of the concentrate, and the model parameters estimated empirically showed temperature dependence. Oscillatory shear data of TJC revealed predominating viscous behaviour (G" > G') at lower frequency range while the elastic modulus predominating over the viscous one (G' > G') at higher frequency range. The Cox-Merz rule that relates steady shear and dynamic material functions was tested and not followed by most of the temperatures. The specific heat of TJC increased with temperature and the glass transition temperature of the product was found to be -70.74 degrees C. (c) 2005 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.
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页码:225 / 231
页数:7
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