Development of Sago Starch Processing Equipment

application/pdfSago starch, produced from sago palm (Metroxylon spp.) has long been an importantsource of nutrition throughout the South East Asian archipelago and in some parts ofMelanesia, certain islands of Micronesia, and various areas of tropical South America. Thestarch has a multitude of uses. It has wide utilization in numerous industries both for foodindustries and non-food industries. Among those sago producer countries, Indonesia hasthe largest sago potential with the total area of sago palm stands about 1,398,000 ha.However, unfortunately, the sago starch production and utilization is very small comparingwith its potential. Millions of tons of the starch is not harvested and disappear every year.This is because of farmers in this area still use traditional method to process sago starchwhich are inefficient and ineffective. Up to the present time, there has been no significantincrease in sago starch production in Indonesia especially in West Papua where about 95%of the Indonesia’s sago potential existed. In contrary, in Serawak, Malaysia, even thoughthe sago potential was small, it was the world biggest exporter of sago starch. The sagostarch industry in Malaysia is well established and has become one of the importantindustries contributing to export revenue. In order to increase sago starch production,farmers should change the traditional method with mechanical one. With regard to themechanical processing, it is necessary to provide mechanical equipment which is suitableand easy to use by common farmers. The objective of this study was to develop sagostarch processing equipments in order to improve their performance.The equipments to be developed were intended for small scale (household)processing of sago starch because it was considered suitable to be applied in most sagoproducing area such as in Papua and Papua New Guinea. It consists of two separatelyoperation unit namely cylinder type sago rasper and stirrer blade type sago starch extractor.Overall, this study consists of five consecutive experiments; each was discussed indifferent chapter. In addition, there was another chapter, introduction (chapter 1) whichcontains an overview of knowledge with respect to the background and significance of thisstudy, importance and distribution areas of sago palm in the world, main production areasof sago starch, utilization of sago starch, processing of sago starch, the objective and thescope of this study.Development of cylinder type sago rasper for improving rasping performance(chapter 2). The objective of this experiment was to develop cylinder type sago rasper inviorder to improve its rasping performance. In this experiment, three densities of teethdistribution on the cylinder surface (2.2 cm × 4 cm distant, 2.2 cm × 3 cm distant and2.2 cm × 2 cm distant) and five level of cylinder rotation speed (745 rpm, 1490 rpm, 2235rpm, 2980 rpm, and 3725 rpm) were examined. Rasper’s performance test was carried outby measuring the parameter of rasping torque requirement, rasping efficiency, starchpercentage, starch yield, power requirement and starch yield efficiency. The experimentalresults showed that the higher the cylinder rotation speed, the lower the rasping torquerequirement, while the higher the density of cylinder’s teeth, the larger the rasping torquerequirement. The highest rasping efficiency (378.53 kg/hour) was resulted underexperimental condition of teeth density 2.2 cm × 4 cm distant at cylinder rotation speed of2235 rpm; The highest starch percentage (26.44%) was obtained at experimental conditionat teeth density 2.2 cm × 4 cm distant with cylinder rotation speed of 1490 rpm; Thehighest starch yield was 84.94 kg/hour resulted under experimental condition at teethdensity of 2.2 cm × 4 cm distant with cylinder rotation speed of 2235 rpm; The higheststarch yield efficiency (92 kg/kWh) was obtained at the condition of teeth density 2.2 cm ×3 cm distant with cylinder rotation speed of 1490 rpm. Therefore, teeth density 2.2 cm × 4cm distant with cylinder rotation speed of 2235 rpm was the optimum condition forrasping operation in which resulted the highest performance of the rasper.Improvement of cylinder type sago rasper using pointed teeth (chapter 3). Basedon previous experiment results (chapter 2) revealed that developed cylinder type sagorasper works properly and has high performance compared with existing prototype whichusing blunt teeth. Therefore it was able to be used as a basic form to develop further inactual size. This experiment purposes to develop further the sago rasper that has beendeveloped in previous experiment. Principally, this experiment was similar to previousexperiment, but differs only in the power source which is used and the frame was simplerbecause not equipped with torque meter device. Unlike with previous experiment which isdriven by 2 hp electric motor, in this experiment it is driven by 6.5 HP gasoline engine.Moreover, there were only three level of cylinder rotation speed to be examined (1500 rpm,2250 rpm and 3000 rpm), while teeth density was identical with previous experiment(chapter 2). The results revealed that the best experimental condition to produce highestrasping efficiency as well as starch yield was teeth density 2.2 cm x 4 cm distant withcylinder rotation speed of 2250 rpm. In the condition the rasping efficiency and the starchviiyield were 1009 kg/hour and 476 kg/hour respectively. In conclusion the improved sagorasper resulted in this study works properly and has high performance.Variant -2 of improved cylinder type sago rasper (chapter 4). At present time,the existing sago rasper that is widely used for household operation in West PapuaProvince, Indonesia is cylinder type with blunt teeth. The process system of this rasper washard wooden cylinder 15 cm in diameter and 20 cm long. The teeth were made of stainlesssteel rod 4 mm in diameter and 2 cm height. The rasper was driven at 3000 rpm by 5.5 hpgasoline engine. This experiment aims to investigate the rasping performance of threedifferent teeth density as mentioned previously in chapter 2 and chapter 3 when they drivenwith 5.5 hp gasoline engine at 3000 rpm. In general, this experiment was similar to theprevious experiment (chapter 3), except for the power source which was used. In addition,there was only one speed of cylinder rotation that was tested namely 3000 rpm. Theresults revealed that lower density of cylinder’s teeth resulted higher rasping efficiency aswell as starch yield. The highest rasping performance was resulted from teeth density of2.2 cm x 4 cm distant. The rasper’s performance at the condition were rasping efficiency635 kg/hour, starch percentage 22.40 % and starch yield 142 kg/hour. This performancewas higher compared to the performance of existing sago rasper.Development of sago starch extractor with stirrer rotary blade for improvingextraction performance (chapter 5). Extraction process is aimed to remove maximumamount of fibre possible from the starch and to obtain the maximum amount of starch. Theefficiency of the extraction depends on how carefully the operation is managed. Theprinciples of starch extraction are to suspend or to dissolve the starch into water and thenstirred rigorously to release the starch. The suspended starch or starch slurry is thenseparated from the fibre using a screen/sieve. The objective of this study was to developstirrer blade sago starch extractor in order to improve its extraction performance with thefocus on the effect of rotating speed of stirrer rotary blades and number of stationaryblades. In the experiment, three levels of rotating speed of stirrer blades (100 rpm, 150rpm and 200 rpm) and four levels of stationary blade numbers (no blade, 4 blades, 8 blades,and 12 blades) were examined. The extractor’s performance test was carried out bymeasuring extraction efficiency, starch percentage, starch yield, and starch left in sago pithwaste (hampas). Results showed that the higher the rotating speed, the higher theextraction efficiency, starch percentage, and starch yield. Meanwhile, the higher therotating speed the lower the starch left in hampas. Likewise, the greater the number ofviiistationary blade the higher the extraction efficiency, starch percentage, and starch yieldwhile the starch left in hampas was lower. The highest extraction efficiency of 491 kg/hour,starch percentage of 20.54 %, and starch yield of 101 kg/hour and not at all starch left inhampas was resulted at the experimental condition of 12 stationary blades and rotatingspeed of 200 rpm. Therefore, the optimum condition to achieve highest extractionperformance was 12 stationary blades with rotating speed of 200 rpm.Variant -2 of improved stirrer blade type sago starch extractor (chapter 6).Previous research (chapter 5) has shown that extraction performance was influenced byboth stirrer blades rotating speed and the number of stationary blades. However, it isnecessary to be investigated further the effect of stirrer rotating speed as well as number ofstationary blades on extraction performance when using screener with smaller holes. Itmay be expected that smaller holes of screener will give higher performance. In general,this experiment was similar to previous experiment (chapter 5), except for the screenerhave been used. Furthermore, the diameter of extraction cylinder was larger but shorter inheight. This was aimed to increase the cylinder capacity as well as to make it easier tofeed the repos into the extraction cylinder. The dimension of second stage screen was madelarger so that it will not full in one process of extraction. By doing so, it was easier tohandle the fine hampas, thus less time was needed to discard them. Experimentalconditions as well as parameters to be measured were same as previous one (chapter 5).Results revealed that the higher the rotating speed of stirrer blade, the higher the extractionefficiency, starch percentage, and starch yield. Meanwhile, the higher the rotating speedthe lower the starch left in hampas. Similarly, the greater the number of stationary bladethe higher the extraction efficiency, starch percentage, and starch yield while the starch leftin hampas was lower. Based on the results of this study suggests that the optimumcondition of extracting sago starch was 12 blades of stationary blades with rotation speedof stirrer blade 200 rpm. This condition resulted highest extraction efficiency, starchpercentage, starch yield, and resulted the lowest starch left in hampas. Compared to theprevious results (chapter 5), this result was doubled higher. In conclusion, the extractionperformance of Variant -2 was higher than previously.本文 / Graduate School of Bioresources Mie University, Japan127