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| Milss in Sungai Tohor Village |
In Indonesia,
the hub of commercial sago production is Selat Panjang, Riau Island. About 7000–8000
mt of dried sago is produced monthly. Processing is mostly done in the 50–60
small factories with capacities ranging from 50 to 200 mt/month (Jong 2000a). Sago-processing
technology varies from the very traditional sago pith chopping using
metal-capped wooden implement in Eastern Indonesia to modernized processing
technology in large factories in Riau. Debarking is very much manually done
using a heavy-duty knife. The screw mill, described
earlier, is becoming popular in several factories in Selat Panjang. When the screw
mill is used, the resulting pith is fed into a hammer mill for further
pulverizing.
In factories
not using a screw mill, debarked pith batons are rasped using nail-studded
wooden drum raspers. No hammer milling is carried out. Usually, a considerable
amount of starch is lost because of coarse rasping which is relatively inefficient
in breaking down the pith tissue. In the small factories, starch extraction is
almost totally carried out using wood-framed rotary barrel sieves. Normally
this is a one-step operation, two sieves in parallel for removing coarse fibers
and one or two sieves for removing fine fibers (Fig. 6.3a). Starch is
recovered by sedimentation in concrete tanks (Fig. 6.4a).
Normally in a
factory, several concrete sedimentation tanks are built, and filtered starch
slurry is channeled into these tanks. Heavier starch granules sink to the bottom,
and most of the lighter fibrous wastes are discharged in the overflow. When all
the tanks are filled (a few days to a week), the water is drained out. The starch
cake can either be dug out manually or pumped to another tank after water is added
to make concentrated slurry. The starch cake or slurry is then refined, again using
sedimentation, in wooden or concrete troughs with slurry flow controlled manually
by a skilled operator. The refined crude starch that settles in the trough is dug
out, crushed into finer particle sizes, and mostly sun-dried.
Some
factories use a centrifuge de-watering device to remove water from refined
crude slurry before sun-drying. Crushed starch is spread out on a rainproof
sheet measuring about 3 m × 3 m. When rain is approaching, the starch is gathered
at the center, and the sides of the sheet are folded over the starch to keep
off the rainwater (Fig. 6.4b).
In 2010, a 3000 mt/month modern
sago factory was built at Selat Panjang and is currently in operation. In the
late 1980s, medium-sized factories were also established in Halmahera (Maluku)
and Arandai (West Papua) but were subsequently closed. A new sago factory (3000
mt/month) is currently being built in West Papua.
