Rheological behavior of waxy rice starch gels is summarized in
Table 2. Storage modulus (G’) increased first to a maximum value
corresponding to completion of starch gelatinization and water
absorption. Starches exhibited G’max in the range between 41 and
815 Pa. Mutant genotype WR6 recorded the lowest G’max at
a temperature of 71.2 C and mutant genotype WR9 exhibited the
highest G’max at a temperature of 62.0 C.
Difference between temperatures at which G’ started increasing
(TG’) and temperatures at which G’ reached a maximum ðTG0
max
Þ was
within 4 C. Gelatinization of starches, including loss of birefringence,
is usually complete within a temperature interval of 10 C for
each type of starch (Salvador et al., 2006). The increase in G’ during
the heating phase also corresponds to starch granules getting
closely packed due to swelling (Eliasson, 1985).