Rheological properties of cake batter The effect of
shortening replacement using pectin gel on the flow
behavior of cake batter was investigated under steady-shear
conditions. Stress versus strain rate plots of cake batter
samples are shown in Fig. 1. Since viscosity is a ratio of
stress to strain, the control batter had the lowest viscosity
while the batter viscosity increased with more pectin gel
replacement of shortening. Flow behavior was characterized
using the Power law model ( , where η=viscosity
and =shear rate). The Power-law parameters of cake
batter samples are shown in Table 1. The consistency index
(K) is a measure of the viscosity at a shear rate of 1/s (14).
Overall, higher K values were observed in cake batters
containing more pectin gel. The replaced percentages of
shortening were highly correlated with the flow behavior
index (R2=0.99). All batter samples had flow behavior
index (n) values of less than 1, clearly showing shear-thinning
features, in agreement with results observed in previous
studies (15). Also, shortening replacement using pectin gel
η K γ · ( )
n–1
=
γ