3.3.3. Cake crumb structure
One of the largest differences in perceived gluten-free cake
quality relates to the visual appearance of the crumb (Gambus et al.,
2009). Digital imaging data for cakes made from heat-treated sorghum
are listed in Table 4. Significant differences (p < 0.05) were
found for cells per slice area. The control sorghum flour had the
lowest cells per slice area, while the heat treated sorghum flour at
125 C for 30 min had the highest. Cook (2002) reported the quality
of cake crumb is linked to the number and size of air bubbles
incorporated into the batter during mixing. Thomasson et al. (1995)
reported that lower batter viscosity allows large gas cells to migrate
to the surface and be lost, resulting in a fine, uniform crumb grain.
This crumb grain is reflected in the high grain score of the cakes
baked with heat-treated flour. The higher viscosity of the batter
made with untreated flour would reduce the migration of the gas
cells. Coalescence of gas cells results in larger cells that are retained
by the viscous batter, producing cakes with an open crumb grain.
Since heat-treating the sorghum flour increased viscosity and
decreased specific gravity, it can be hypothesized that more air
bubbles were entrapped during mixing. Nakamura et al. (2008)
concluded dry-heating flour stabilized the foam of the cake
batter, and this stability of the foamwas maintained during baking.
This stability translated into reducing gas cell coalescence and
increasing cake volume. In the present study, the increase in overall
volume is related to the increase in gas cells per slice.