Detailed Explanation of Coarse Potato Starch Processing Technology

Process flow

Potatoes → washing → grinding → potato residue separation → sedimentation → drying → coarse starch

Key operating points

(1) Grinding into slurry: Select potatoes with high starch content, pick out rotten and diseased potatoes, place them in a washing tank, add clean water and stir with a stick to wash the potato pieces clean. Put the washed potato pieces into a grinder, add water while grinding, grind into starch slurry, and let it flow into a receiving tank.

(2) Separation: Use coarse and fine flat screens twice respectively to screen out the potato residue from the starch slurry, or put the starch slurry into a cloth bag, tie the bag opening securely, place it in a tank, and tread it with feet so that the starch overflows from the bag holes; add water to the potato residue and tread again.

(3) Sedimentation: Put the starch milk into a sedimentation tank, stir thoroughly, and let it stand for more than 5h, then the starch settles to the bottom layer. Remove the upper clear liquid to separate out the starch. The starch separated in one pass contains more impurities, so it can be placed in a washing tank, stirred with added water, left to stand for several hours, and then the upper clear liquid is removed again. Repeat this washing 3 to 4 times, and after the final standing, the upper layer is the outer skin, the middle layer is starch, and the lower layer is sand and mud. Scrape off the upper impure matter and take out the middle starch layer, which is wet starch.

(4) Drying: Cut the wet starch blocks into small pieces, then spread them on bamboo sieves or shallow wooden trays, and sun-dry them in the sunlight until the starch pieces break as soon as they are touched; artificial drying may also be used.