Quality of cake batter with and without tapioca
starch
The flow curves of the cake batters
containing different mixing ratios of WF and TS
(100:0, 75:25, 50:50) were determined from steady
shear measurements at 25 °C. All batters with and
without TS exhibited a pseudoplastic behavior. The
apparent viscosity of the batters decreased with
increasing shear rate and TS substitution for WF
(Figure 1a). The results obtained were in good
agreement with the results obtained from batters
containing WF and TS mixtures for fried products
(Ketjarut et al., 2010). Therefore, the WF content
in the cake batter played a predominant role in
increasing the batter viscosity due to the wheat
protein being the main cause of batter viscosity
development during mixing (Loewe, 1993).
Since the shear-thinning behavior was
exhibited in the middle region, the apparent
viscosity decreased with increasing shear rate for
the shear thinning fluid. Thus, the power law
equation (Equation 1) described the flow behaviors
of all cake batter formulations with different
mixing ratios of WF and TS (R2 = 0.998–1.000;
Table 2; Figure 1b). The consistency index (K) of
all batters decreased with increasing TS
substitution from 15.4 to 8.0 for batters without
TS and with 50% TS substitution for WF (Table
2), respectively. The addition of TS in the batters
significantly altered the flow behavior index of
the batters from 0.64 to 0.71 for the samples
without and with TS, respectively (Table 2)
suggesting that the batters containing TS had more
pronounced Newtonian behavior due to the value
of n approaching close to one.