Sago starch grater machine for faster starch extraction

The traditional method in extracting starch from sago palm involves 20-25 steps from harvesting. The method is time consuming and requires a lot of energy. One whole sago log requires 10-12 laborers and 5-6 days to complete starch extraction. Generally, the process involves stripping debarked logs by knife, drying, series of hand pounding, and subsequent sieving until the size is further reduced. To improve the method, Loreto et al. (LSU and TUAT) fabricated a village-level sago starch grater machine and evaluated its performance in Barangay [village] Hilusig, Mahaplag, Leyte [Philippines], through a project, which began in 2003. The major bottlenecks identified in the traditional process that need mechanization were: (a) sun drying of the pith slabs, which was dependent on weather conditions; and (b) size reduction of dried slabs wherein pounding and sieving was repeated at least five times to obtain starch. The machine was evaluated using two different blade speeds (730 rpm and 875 rpm) and two types of blade perforation distance (10 mm and 20 mm). The capacity of the developed grater with 10 mm blade was 39.08 kg and 32.91 kg of sago pith per hour at 730 rpm and 875 rpm, respectively. On the other hand, the capacity of the developed grater with 20-mm blade was 153.09 kg/hour and 180.37 kg/hour at 730 rpm and 875 rpm, respectively. This showed that at higher speed and shorter blade perforation distance, grating was not accomplished because of the centrifugal force. The fineness modulus of the grated sago pith ranged from 2.12 micrometer to 2.87 micrometer. With the grater machine, crude fiber analysis showed that percentage of crude fiber in the extracted starch was lesser (0.7-3.2 for the 10 mm blade and 0.04-1.10 for the 20 mm blade) than in the traditional method (3.2-4.8). The grater machine could help in improving the traditional process of sago starch extraction, however, it could be further improved by determining the optimum operating conditions to recover a high percentage of starch. Sago generates 24 t/ha of starch per year higher than rice (6 t/ha), corn (5.5 t/ha), wheat (5 t/ha), and potato (2.5 t/ha). The starch has several food and industrial uses.