2.4.3. Rheological measurements
The rheological behavior of molten chocolates was characterized
using a rotational viscometer (DINViscometer VT 550 Digital Rheometer,
Thermo Haake, Karlsruhe, Germany). Samples were incubated at 46–
48 °C for 75 min for melting and transferred, pre-sheared at 5 s−1 rate
for 15 min at 40 °C, before measurement cycles. The measurements
were performed at 40 °C as function of increasing the rotation number
from 1 to 100 rpm within 120 s. Temperature of the chocolate
samples was controlled during the experiment using Haake K20
Thermo-regulator (Thermo Electron Corp., Karlsruhe, Germany). Mean
value and standard deviation of triplicate readings were recorded. The
NCA-CMA modified Casson model tailored specifically for testing of
chocolate behaviorwas used to calculate Casson plastic viscosity frominterpolation
data. The Casson model equation is denoted by: