SMALL SCALE PRODUCTION OF CRUDE STARCH FROM POTATOES
ABSTRACT A small scale device for producing crude starch from cull potatoes was designed, built, and tested. The device uses a wire brush to grind the tubers and a screen centrifuge to separate the tuber pieces into fibre and non-fibre (starch) components. At a rotating speed of 2450 rpm, the machine produced a crude starch that contained a high average of 53.7% recovered starch at 96.4% purity. After removing 75.2% of the original water from the starch fraction in the best test average, the moisture content was reduced to 47.8%. Three separate drying felts were evaluated for their ability to extract liquid from the slurry. The slurry was spread on the different felts and a roller passed over the slurry on the felt. The roller was passed over the felt as many as three times. The process proved not to be sensitive to the felt type used nor to the number of passes of the roller. The drying felts performed adequately by removing 75.2% of the original liquid from the starch fraction and 54.4% from the fiber fractions.