Both swelling power and solubility properties of cassava, sweet potatoes, and commercial flour are shown in
Figure 1. These properties represent an evidence of interaction between the amorphous and crystalline areas [9,10].
Furthermore, it is influenced by amylose and amylopectin characteristics (Chan, et al., 2009). Figure 1 shows the
swelling power of tropical tubers flours having pattern that tend to decrease in contrast to its solubility. According to
Kumoro, et al [13] greater swelling power shows harmonious with higher solubility [12]. However, there is no direct
correlation between swelling and solubility that could be observed [13]. Cassava flour have high swelling power due
to their higher amylopectin in comparing with potatoes flour. Moorthy (2002) also reported that the swelling power
of cassava starch was vary from 42-71 (g/g) [8]. It shows that cassava flour and cassava starch have a different value
of swelling power.
The swelling power and solubility of sweet potatoes from various varieties are not significantly different,
ranged from 3.40 to 3.67 (g/g) and 8.61 to 9.57 (%). The lower swelling power of sweet potato starch has been
attributed to a higher degree of intermolecular association and higher amylose content compared to cassava flour.
Factors that may influence solubility of starches are source, swelling power, inter-associative forces within the
amorphous and crystalline domains, and presence of other components (phosphorous, etc) [13].