3.2. Texture of mantou
Texture is an important mantou quality. Gluten protein is a
main contributor to the strength of Chinese steamed bread [2].
Fig. 1 shows the effect of PCF on the texture and specific volume
of mantou. The hardness and gumminess of mantou
significantly increased with increasing the PCF substitution,
but the cohesiveness, springiness and specific volume significantly
decreased with the substitution.
Similar to the increase in the R value of the dough (Table 1),
the PCF-enriched steamed bread had higher hardness and
gumminess that resulted from the competition of water absorption
between PCF and wheat flour components or from
the rigid nature of the fiber. Because insoluble DF is the major
type of DF in PCF, incorporating PCF into the dough system
may interfere with the formation of the gluten network. This
lowers cohesiveness, springiness, and specific volume of the
PCF-enriched steamed bread.
Wuet al [3] report that hardness and springiness of 20e30%
bran fiber-enriched steamed breads had higher hardness than
breads with 0e10% wheat bran. Sangnark and Noomhorm[28]
found that bread containing 5% fiber from rice straw had
higher firmness and lower springiness, compared to the control
bread. Kaack et al [11] found that the hardness of bread
increased with the quantity (0e12%) of potato fiber containing
a high content of insoluble DF. However, date flesh fiber
concentrate added at 0e3% insignificantly decreased the
bread volume. [25].