Healthy snacks have received more attention because of their low
fat content. Color and texture are important to snack quality.
Effects of chemical pretreatment, thickness, blanching, and puffing
temperature on quality of banana slices were therefore investigated.
Banana slices (2.5 and 3.5 mm thickness) were chemically treated by
citric acid and sodium metabisulfite, blanched, and dried at a
temperature of 90C to an intermediate moisture content of 25%
db. They were then puffed in a fluidized bed dryer at 160 and
180C for 2 min and dried again at the same drying temperature
as the first drying step. Blanching, puffing temperature, and thickness
strongly affected the degree of shrinkage, effective moisture
diffusivity, morphology, textural properties such as hardness and
crispiness, and color, but the chemical treatment did not affect those
qualities. Blanching can improve the product appearance; the color
was uniform and shiny throughout the surface and golden yellow.
However, the textural attributes of the blanched sample had higher
hardness and less crispiness than those of unblanched sample.