Effect of grater position on the size of grated sago (Metroxylon spp.)

The natural arrangement of sago palm’s fiber orientation is parallel to the vertical axis of the trunk. Extraction of the sago starch requires breaking of the trunk into fine sizes. The sago size is affected by the grater position which affects the of starch recovery. This study was conducted to evaluate grating efficiency through sago size produced at the different direction of grating (0° and 90° to roller teeth rotation). Sago palm trunks without outer layer were cut into square blocks of 100 mm3. Each trunk block was placed on roller grater platform at a different position where the cutting spike was parallel to the vertical axis of sago trunk fiber orientation (grating at 0° direction) and perpendicular (grating at 90° direction). 100 g of dry grated sago was sifted to determine the size distribution with different sieve sizes i.e. 2.80 mm, 2.00 mm, 1.00 mm, 0.85 mm and 0.425 mm. A total weight of 1 kg of grated sago was mixed with water and squeezed to be extracted. The starch recovery produced by the grating process at 0° directions was 10.30% higher than 90 0 directions. The present study showed that the direction of grating at 0° was able to produce finer grated sago with maximum starch recovery

Design and development of a grating machine for wet sago starch production

This thesis describes a study on the design, fabrication and testing of a prototype grating machine for wet sago starch production. In order to extract the starch, the mechanical method is required to break the trunk and producing fine grated sago. The more refined the grated sago produce, the more sago starch can be dissolved in water during the extraction process. In this case, it was reported that 65.7% of sago starch remained inside the residue. A new technology has been developed to overcome the issue. The determination of physical and mechanical properties of sago trunk was conducted as a prerequisite for designing process. A primarily study was conducted on Handheld Chainsaw, Roller Grater, Coconut Husk Decorticator and Coconut Grinder to determine the grating speed, grated sago size distribution and grating contact area. The result shown that the hand chainsaw produced the highest percentage of finer grated sago (56.80%: X≤0.85 mm) and the lowest teeth contact surface area of 4 mm2. However, it has the lowest capacity. A further study was conducted to determine the effect of grated sago sizes on starch recovery at different steeping periods and. As a result, a substantial amount of starch could be recovered from grated sago by reducing the grated size at X<0.30 mm which was up to 58% of the extraction efficiency. The increment of the steeping period from 5 min up to 24 hours increased the starch recovery. However, a longer steeping period showed an insignificant difference (P>0.05). A new concept of sago grater was designed and developed. Initially, an assessment of sago grating machine design requirement was conducted using surveys. All the needs and goals were divided into several sub-objectives. The sub-objective was converted into functions modeling to generate sub-functions and then select the appropriate technology. A Morphological Chart was used to produce 6 complete system concepts. The selection of complete system concepts was based on matrix assessment and detail design of concept was generated for the fabrication process. The newness of sago grating machine has the advantages over the existing machines. It does not require conducting a debarking process (20 minutes per log). The machine has the capability to adjust the feeding height (0 cm to 5 cm) according to the sago trunk diameter size which is minimizing the losses during the grating process. The design novelty, the grater disc has ability of adjusting the disc diameter size (40 cm to 48 cm), which is no need to be made in various of sizes and each single part of grater teeth can be replaced to reduce the maintenance costs. The grating capacity was 45.9 kg/min with a total starch recovery percentage was 19.86±0.14% and at 47.97%.of extraction efficiency

Sifat fizikal dan mekanikal batang pokok sagu (metroxylon spp.)

Pokok sagu rumbia (metroxylon spp.) mempunyai batang yang tegak, lurus, berkulit keras dan berteras lembut yang terbina daripada serat berorentasi selari dengan arah batang pokok. Kanji yang dihasilkan oleh pokok disimpan di bahagian terasnya sebagai makanan simpanan. Dalam proses- pengekstrakan sagu, teras batang sagu perlu dipecahkan kepada saiz yang lebih halus/kecil melibatkan penggunaan sistem mekanikal yang bergantung kepada sifat fizikal dan mekanikal pokok. Oleh itu, satu kajian ke atas batang pokok sagu dijalankan untuk mengenal pasti sifat fizikal dan mekanikalnya. Tiga sampel bagi setiap empat pokok sagu berukuran 50 cm panjang telah diukur sifat fizikal dari segi diameter (45.41±2.81 cm), ketebalan kulit (1.43±0.19 cm) dan nisbah berat kepada panjang keratan (1.12±0.21 kg/cm). 12 sampel blok teras batang pokok sagu berukuran 4cm x 4cm x 4cm disediakan dan ditentukan kandungan lembapan (MC%). Sampel blok diletak pada kedudukan orentasi serat berselari dengan arah pergerakan jarum penguji (P/5: 5mm Dia Cylinder Stainless Steel) yang dipasang pada Texture Analyzer untuk mengukur daya kerapuhan, dan proses ini diulang dengan kedudukan orentasi serat blok sampel secara berserenjang. Berdasarkan keputusan ujikaji, daya kerapuhan pada arah selari dengan orentari serat (529.15±19.14 N/cm2) lebih tinggi berbanding arah serenjang (317.91±22.08 N/cm2) di mana nilai P<0.05. Ini menunjukkan kehadiran orentasi serat dalam teras mempengaruhi daya kerapuhan

Study of machines performance in producing different sizes of grated sago

Sago starch is a product from sago palm. In order to extract the sago starch, certain process is needed to break the bonding of the pith either mechanically or manually by grating the pith into small sizes. Water is widely used as a solvent medium in the extraction process of sago starch. The more refined that grated sago, the more sago starch can be dissolved from the grated sago. Different machines were used to produce grated sago for machine capability test. The machines are handheld chainsaw, coconut husk decorticator, commercial coconut grater and in-house roller grating prototype. Sago palm trunk was cut into three parts with length of 50 cm long each. The outer layer of each sago palm trunks was peeled off and split into 8 pieces. All sago trunks were grated using four different machines as stated above. Each 100 gram of the grated sago trunk produced by each machine were sifted according to the grading size of 2.80 mm, 2.00 mm, 1.00 mm, 0.85 mm and 0.425 mm. The weights of sago starch from the sieving process were recorded according to their respected grading size. Based on results of the sieve experiments, the most finest grated sago trunk was produced from the handheld chainsaw with a weight percentage ratio of 13.028% (X < 0.3 mm), 10.682% (0.3 ≤ X < 0.425 mm), 28.361% (0.425 ≤ X <0.85 mm), 28.821% (0.85 ≤ X <1.0 mm), 4.728% (1.0 ≤ X <2.0 mm), 7.877% (2.0 ≤ X <2.8 mm), and 4.868% (X ≥2.8 mm) where X value refer to sieve mesh size