Table 1 compares the melting and setting parameters
obtained from calorimetry and rheological measurement for
kappa carrageenan at a range of concentrations and for the
0.6% mixed gel (1:1) at pH 6.0. Under these conditions
deacetylation would not be expected to occur (see results in
Table 2). For kappa carrageenan alone both techniques
reveal a slight increase in melting (Tm) and setting
temperatures (Tgel) with polysaccharide concentration. The
melting temperature is approximately 178 higher than the
setting temperature. Tgel and Tm for the kappa carrageenan
and konjac glucomannan mixture (0.3%/0.3%) is higher
than found for 0.3% kappa carrageenan. The temperature
increase is greater for the melting transition. The enthalpy of
the transition, when expressed per g of kappa carrageenan,
is consistent with the value of w36 J/g reported by Williams
et al. (1993) for this polysaccharide in the concentration
range 0.3–0.6% prepared in 50 mM KCl. In contrast to these
previously reported results we observed only a small
decrease in enthalpy or increase in setting temperature for
the kappa carrageenan and konjac glucomannan mixture
(1:1) compared with 0.6% kappa carrageenan alone. These
differences between kappa carrageenan alone and the
mixture were more noticeable in the heating response