Rheological Properties of Carboxymethylcellulose and Whey Model Solutions before and after Freezing

Vesna Hegedušić*, Zoran Herceg and Suzana Rimac

Department of Food Engineering, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, HR – 10000 Zagreb, Croatia

Article history:

Received June 11, 1999
Accepted November 17, 1999

Key words:

rheological properties, carboxymethylcelluloses, whey proteins, freezing


Hydrocolloids, macromolecular carbohydrates are added to many foodstuffs with the aim to achieve the appropriate rheological properties, to prevent syneresis or to increase the viscosity and stability of foodstuffs. In this work, the influence of the type and concentration of commercial hydrocolloids (carboxymethylcelluloses) on the rheological properties of model solutions of whey, whey proteins, sucrose, sorbitol and lactose was examined. The influence of freezing on rheological properties of model solutions was also checked. Measurements were done using a Brookfield DV-III rotational viscometer at temperature of 20 °C. The results have shown that all examined systems are non-Newtonian. Depending on the chemical composition and on the mass fraction of hydrocolloids, they exhibited pseudoplastic or dilatant properties. All CMC effected a significant increase of the model solutions viscosity. The freezing process had no significant effect on the viscosity of the model solution prepared with water. However, whey based solutions had a greater viscosity after freezing. The results of variance analysis showed that all examined sources of variation (composition of model solution, type of CMC and freezing process) had a significant influence on the rheological parameters. 

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