Abstract:
This research aims to study the influence of varieties and harvesting ages of cassava root onthe water usage in the extractor unit. It is also purpose to determine the optimum water consumptionfor starch extraction from cassava root. Three varieties of cassava root, Kasetsart-50, Rayong-90and Rayong-5, at different harvesting ages of 8, 10, 12 and 15 months were used to carry out in thiswork. Cassava root of Kasetsart-50, Rayong-90 and Rayong-5 had starch content of 22.25, 22.69and 20.54 %, respectively. The fiber content in these three cassava root varieties were 3.53, 3.22 and3.54, respectively. Not only the cassava root varieties and harvesting ages were used to study but theamount of water usage to extract starch from root was also varied to study the efficiency in starchextraction. The volume of water per weight of cassava root on dry basis (L/S ratios) were varied at2, 4, 6, 8, 10, 12 and 16 for starch extraction.The results showed that the efficiency of starch extraction increased with the increase ofwater volume in extractor unit. The results suggested that efficiency of starch extraction was notdepended on harvesting ages of cassava root but variety of cassava root show the effect on starchextraction. The efficiency of starch extraction from Rayong-90 root was slightly higher thanKasetsart-50 and Rayong-5 root about 1-3%. The optimum L/S ratio for starch extraction was at 6and this ratio is suitable for all varieties and harvesting ages of cassava root. The efficiency of starch extraction of 50-55% was obtained. It was noticed that Rayong-90 root at harvesting age of 8months was the appropriate raw materials in tapioca starch factories. Moreover, the relationshipbetween efficiency of starch extraction (y) and water usage (L/S ratio; x) show the equation ofy = ax0.3 and this equation can be used as a guideline for starch extraction in the factory.