FOOD RHEOLOGICAL STUDIES USING COAXIAL ROTATIONAL AND CAPILLARY EXTRUSION RHEOMETERS

摘要

The rheological constants of commercial sweetened condensed milk, mayonnaise, peanut butter, and tomato paste were obtained using the Hershel-Bulkley and Casson models. Data using a coaxial rotational rheometer showed that the shear history(shear rate range 0 to 650 s-1)affected observed shear stress ,and rheological constants. For the shear rate range 0 to 80 s-1, the rheological constants, using capillary extrusion rheometer, were much lower than or simlar to those obtained using the coaxial rotational rheometer. Both the Hershel-Bulkley and the Casson models were equally suitable in predicting the relationships between shear stress and shear rate.