32.7–34.7 and 54.5–58.7, respectively, for the blanched
sample and 31.8–33.8 and 57.8–62.2, respectively, for the
unblanched sample. This is due to the fact that higher puffing
temperature provides a higher product temperature,
which accelerates nonenzymatic browning reactions.[5,15]
To achieve less brown color, the banana should be puffed
at a temperature of 160C.
CONCLUSIONS
The effects of puffing temperature, thickness, chemical
pretreatment, and blanching on quality of puffed banana
slices were investigated. A higher puffing temperature provided
a shorter total drying time and caused a lower degree
of shrinkage and a correspondingly lower hardness but did
not affect the crispiness as characterized by initial slope
and number of peaks. Blanching could lengthen the total
drying time and provided a lower effective moisture diffusivity,
higher degree of shrinkage, and subsequently higher
hardness and less crispiness for 3.5-mm-thick samples.
However, the was no difference in texture for both
blanched and unblanched 2.5-mm-thick samples. The
blanched product appeared glossy with a golden yellow
color compared to the unblanched product, because the
starch in the banana was gelatinized during the blanching
step. From these results, it is recommended that banana
be puffed at a temperature of 160C.