Starch content of cassava:
The vast majority of cassava is starch. Starch contains about 25% to 30% in fresh potatoes and about 80% in dried potatoes.
Cassava is native to tropical America and is widely cultivated in tropical regions of the world. There are succulent long cylindrical roots. The roots are rich in starch, which can be eaten or used as a paste. They can grind tapioca flour, make bread, provide tapioca starch and starch for washing and even alcoholic beverages. However, cyanoglycosides are contained in the roots, stems, and leaves, which are not suitable for raw consumption. They must be soaked in water for a long time and cooked to relieve toxicity.
Cassava starch is a powder made from cassava starch after dehydration and drying. There are two types of cassava starch: raw starch and various modified starches. They are widely used in food industry and non-food industry.
Cassava raw starch is widely used in food formulations, such as baked goods, but also used to make extruded snacks and tapioca beads. Modified starch or starch derivatives have been used as thickeners, binders, bulking agents and stabilizers, and are also the best extenders, sweeteners, flavoring carriers and fat substitutes. Foods using Thai tapioca starch include canned foods, frozen foods, dry mixes, baked goods, snacks, condiments, soups, sausages, dairy products, meat and fish products, and baby food.
Modified starch is used as a colloidal stabilizer in beverages containing solid ingredients. In beverages, cassava starch sweetener is better than sucrose, because the former improves the processing process and strengthens product characteristics. When combined with other sweeteners, it can fully meet consumer demand. Highly hydrolyzed syrup formed from the hydrolysis of cassava starch is an ideal source of easily fermentable sugar in beer brewing.
Wet processing technology of cassava starch, including drum cleaning, secondary disintegration, thick pulp screening, countercurrent washing, redox bleaching, cyclone sand removal, thick pulp separation, overflow dewatering, first stage negative pressure pulse air flow dry. 5. Process flow
The main process of preparing raw materials is the material basis of production. The quality of raw materials is directly related to the quality of the product. The raw materials of cassava starch factory are fresh cassava and dried cassava chips.
After the fresh cassava is harvested, the soil, roots, whiskers and wooden parts should be removed in a timely manner and stacked on clean ground to avoid mixing with iron debris, nails, stones, wood and other sundries. It is required to be harvested on the same day, entered the factory on the same day and processed In order to ensure the freshness of raw materials, thereby improving the extraction rate and product quality.
The dried cassava chips should be dry, mildew-free, non-degradable, and free of worms to ensure product quality.
The raw material is conveyed by a belt conveyor to transport the cassava from the storage yard to the washing machine. It is required to ensure the normal supply of raw materials in the process. During transportation, special care should be taken to prevent the inclusion of iron, iron nails, stones, wood and other debris. If debris is found, it should be picked out in a timely manner. The cleaning adopts hsgx-850 drum type washing machine and hsxs-850 paddle potato washing machine. The machine is divided into rough washing area, bathing area and clean washing area. The cassava raw material rotates and rolls along with the wall of the garden cylinder, and sprays, rinses, bathes, grinds, cleans, and peels with water as the medium. It is required to remove the sediment by washing, and the peeling rate is above 80%.
Feed the clean cassava into the cutter and then into the filer for the disintegration process. The function of disintegration is to destroy the tissue structure of cassava, so that tiny starch particles can be disintegrated and separated from cassava roots. Using hscm-600 stainless steel file grinder, this machine relies on high-speed operation, so that the saw blade on the rotating drum, sieve plate, etc. can file and crush the continuously fed cassava in the machine, so that the cassava is broken up and the starch particles are constantly Separate it and use water as a medium to process the crushed cassava into starch puree. The crushed starch stock passed through a 1.2-1.4 mm sieve. The crushed and stirred thin starch puree needs to be sieved to separate the starch milk from the fiber. At the same time, starch milk needs to be screened to remove fine residue, and the fiber needs to be washed with starch to recover the starch.
Through screening, the purpose of separating and purifying starch is achieved. At present, the 4-level hslxs-850 vertical centrifugal sieve is mainly used to remove fine residue. Multiple screening or countercurrent washing processes are commonly used. It is required to be sieved and washed through the original pulp. The potato residue contains less than 35% starch, which contains less than 5% free starch; the fiber impurity content of the milk slurry is less than 0.05%; and the milk slurry concentration reaches 5 to 6 Baume degrees.
Bleaching is an important part of ensuring the quality of dried cassava starch. Its role is to adjust the pH value of the slurry to control microbial activity and fermentation and saccharification; accelerate the separation of starch from other impurities; bleach the gelatin on the outer layer of starch granules, and make starch granules white and durable.
According to the principle of specific gravity separation, the starch slurry is pumped into a swirling flow with a pressure pump, and the bottom flow removes sand, and the top flow passes through the slurry to achieve the purpose of sand removal. After removing the sand, not only the impurities such as fine sand can be removed, but also the disc separator can be protected.
The function of separation is to separate insoluble proteins, residual soluble proteins and other impurities from starch milk slurry, so as to achieve the purpose of washing, refining and concentrating starch milk.
Our company uses a 12-stage hsxlq-360 washing cyclone unit to wash, refine and concentrate the starch emulsion. It separates according to different specific gravity of water, starch and yellow plasma protein. Generally, the 12-stage hsxlq-360 washing cyclone is used in series, and the slurry concentration is required to be 20-22 degrees.
After the separation process, the concentrated slurry still contains a lot of water, so it must be dehydrated to facilitate drying.
Our company uses vacuum suction filter for dehydration. It is required that the moisture content of the wet starch after dehydration is lower than 38%.
The wet starch dehydrated by the vacuum suction filter is sent to an air dryer for drying. The steam pressure is controlled at 0.8mpa. It is required that the moisture content of the finished starch product be about 13.5% by drying.
Packing and storage
It is required to have enough bags, sewn the bags firmly, and store them in time.