Bread surface colour profiles
Experimental studies were carried out to investigate the
effect of oven surface on bread colour development during
baking process. Two types of oven surface were used which
black and shiny surfaces. Bread surface colour was measured
using Minolta chromameter (CR-400). The colour was defined
by three coordinates, L* (lightness), the vertical coordinate
from L* = 0 (black) to L* = 100 (white), a* (redness), the
horizontal coordinate from +a* (red) to –a* (green) and b*
(yellowness), another horizontal coordinate from +b* (yellow)
to –b* (blue). Figure 5 shows the a* and b* parameter values
of the bread surface obtained from the experimental results.
Changes in the L*, a* and b* values of during baking are
shown in Figure 6 to 8. From the figures, it can be seen that
the value of lightness (L*) for black oven surface featured
lower values than shiny oven surface. L* for black surface
oven is ranged from 80 (dough surface colour) to 25 while
shiny surface oven is ranged from 80 to 60 over 30 min of
baking process. This indicates the differences between the
surfaces used in this experiment. Lower L* value means more
brownish of bread. Therefore, usage of black surface oven will
achieved the desired browning as well as producing the perfect
texture of the bread in a short period of time compared to
shiny surface oven. The values of a* for black and shiny oven
surfaces are ranged from -0.5 to 15 and -0.5 to 10,
respectively. The same situation goes to the values of b*
which show no significant effect since it has similar values, 18
to 30 for both oven surfaces.
Figure 5.