Rheological Behavior of Processed Fluid and Semisolid Foods

Rheological Behavior of Processed Fluid and Semisolid Foods 

In this chapter, the rheological properties of processed fluid and semisolid foods will be discussed. Where data are available, the role of the composition of the foods on their rheological behavior will be emphasized. In addition, literature values of data on several foods, many of which are discussed here and some that are not discussed, are given at the end of this chapter. 

BecaiKe depectinized and filtered apple and grape Juices are Newtonian fluids, equations were derived by Bayindirli (1992,1993) that can be used to estimate their viscosities as a function of concentration and temperature. The equation for viscosity of both apple and grape Juices is of the form  

For grape juice in the concentration range 19-35°Brix and temperature 293-353 K (20-80°C), the constants A and B are  

Rao et al. (1984) studied the role of concentration and temperature on the viscosity of concentrated depectinized and filtered apple and grape juices. At a constant temperature, the effect of concentration could be well described by an exponential relationship. For example, at 20°C, the effect of concentration ( 41-68 °Brix) on the viscosity of apple concentrates was described by the equation (7 = 0.947)  

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Rao, M.A. (1999). Rheological behavior of processed fluid and semisolid foods, in Rheology of Fluid and Semisolid Foods Principles and Applications, M.A. Rao (ed.). Chapman Hall, Gaithersburgh, Maryland USA. 

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