What is the process of extraction of starch from cassava roots?
Cassava root has high starch content, but contains little protein, oil and ash. The fresh cassava root starch content accounts for 25% to 32% which is a high quality starch processing raw material. But what is the process of extraction of starch from cassava roots. Then we will explain this question for you.
The process for extraction of starch from cassava roots includes the following steps:
Choosing and weighting-cleaning and washing-cutting and rasping-slurry and residue separation-desanding-concentration and refining- dewatering-drying and packing
Cassava starch extraction process
1. Raw material choosing and weighting process
The first step for extraction of starch from cassava roots is choosing and weighting raw material. The quality of starch has a great relationship with the selected raw materials. The cassava yield is low if cassava roots is less than 10 months. While the cassava roots more than 24 months are lignified and cause difficult for rasping. Therefore it will be better to choosing cassava roots within 10 to 12 month without damage or moth. Then the chosen cassava roots is weight by weighbridge and put into the warehouse.
2. Cassava cleaning and washing process
The purpose of cleaning is to remove sand, stones peels and other debris which also facilitate next process for extraction of starch from cassava roots. The cleaning process is carried out at the same time of conveying. And then the cassava roots are conveyed to paddle washing machine for further removing the attached dirt, soil and so on.
Cassava cleaning machine
3. Cassava cutting and rasping process
Due to the cassava roots are long and the part near the main pole are already lignified, it is difficult to rasping them without cutting. The purpose of the cutting process for extraction of starch from cassava roots is to ensure the normal operation of the rasper and to improve the yield and quality of the starch. The diameter of the cassava pieces are generally 1 cm. Then the cut cassava is transported into rasper so that the cassava roots are crushed into slurry. The rasping is the most important procedure which determines the starch yield. DOING rasper breaking rate can reach up to 95%.
4. slurry and residue separation process
The slurry and residue separation machine for extraction of starch from cassava roots includes centrifuge sieve and fine fiber sieve. They are mainly used for separating starch and fibers. The centrifuge sieve is combined with four groups so as to achieve better separation effect. Then the starch slurry enters into fine fiber sieve for further separating small fiber out of slurry.
5. Concentration and refining process
After the desanding process for extraction of starch from cassava roots, the starch still contains a small amount of insoluble protein, soluble protein and other minerals which seriously affects the quality of the starch. The hydrocyclone station is used in series with 14 units for removing these substance. It consists mainly of three working chambers and dozens to hundreds of swirl tubes and pumps. The starch milk enters from the inlet, while the washing water is added from the last stage which forms a countercurrent washing. Thus the impurities are thoroughly removed.
cassava starch dewatering machine
6. Cassava starch dewatering process
The dewatering process for extraction of starch from cassava roots is mainly for reduce the water content of cassava starch so that it meet the standard for drying. Peeler centrifuge is the widely used cassava starch dewatering machine which can achieve the automatic control and auto scraper-unloaded.
7. Cassava starch drying and packing process
Then it comes to the last step for the process of extraction of starch from cassava roots. The dewatered starch enters into flash dryer for drying. The drying tower adopts negative pressure drying method, which can effectively dry the starch within 2-3 seconds. Then the dried cassava starch is packed by automatic semi-packing machine for storage.