After the harvest cassava is
processed for obtaining starch through various machines and processes.
To get better result cassava is processed in a shortest possible time.
The first step for obtaining cassava starch is peeling and washing.
Peeling is done by using peeler. After peeling cassava is rasped or
grated. The rasper machine is applied to grate the cassava into fine
pieces.
Rasper machine
Rasper machine is used for rupturing cell wall in order to release the
starch granules. On the basis of their sizes and operations raspers are
of different types :
- Mechanical rasper
Mechanical raspers is made up of sheet of galvanized iron with a
nail and then clamping it around a wheel with the sharp protruding
rims of the nail. The wheel is either hand driven or is driven by
pedals. The crushed pulp is collected in a basket.
- Hydraulic raspers
Hydraulic raspers are water powered. The waterwheel is rotated by
a flywheel and driving belts. The drum is either attached to a
primitive wooden construction or fitted into a rasping table. The
grated mass is forced through a narrow slit and later it is carried
to the sieves.
- Engine-driven raspers
Engine driven rasper has rotor of either hardwood or steel tube. It
also consists of rasping blades with saw teeth. The roots are
pressed onto the rasping surface, which moves downward in the hopper
and the mass is propelled through a slit in the bottom of the
hopper.
