The Production Process Of Sweet Potato Starch
The sweet potato starch production process is as follows:
(1) raw material pretreatment: fresh sweet potato after harvest, it is usually cut into flakes or filaments, after sun or fire dry, made of sweet potatoes dry. This sweet potato stem in the processing and transportation process is inevitably mixed with a variety of impurities, it must be pretreated. Pretreatment is dry and wet. Dry method is the use of screening equipment and wind selection equipment. Wet treatment is done with a washing machine or a washing tub.
(2) soaking: In order to improve the rate of starch can be used alkaline water immersion. Generally add saturated lime milk or 1% dilute alkali solution soaked water, so that the value of ph is 10-11. Soaking time of about 12 hours, the temperature control at 35-40 degrees Celsius. After soaking, the water content of sweet potato chips is 60%.
(3) broken and ground: soaked sweet potato chips with water into the hammer mill crushing, to a certain degree of fineness, through the sieve outside the machine. The instantaneous temperature of the potato stem is increased during the pulverization process, and some of the starch is susceptible to hot gelatinization, so that the separation of starch and potato residue is affected at the time of sieving. It is not easy to precipitate when the tank is separated, Out of rate. In order to prevent a crushing treatment easy to starch gelatinization, you can use two crushed, split the process of sieving. That is, dried by the first potato crushed, sieved, and then by the second crushing treatment, and then screened. In the crushing process, in order to low instantaneous temperature rise, according to the different crushing particle size, adjust the slurry concentration, the first road for the 3-3.5 Baume degree, two for the 2-2.5 Baume degree. At the same time using the equalizer control sweet potato dry into the amount of balanced slurry, to avoid the phenomenon of crusher overload, but also conducive to the trough separation.
(4) screen: sweet potato stem after crushing the red wine paste also known as liquid, must be sieved, separated from the slag, that is, fiber. Usually using a flat sieve, the material into the sieve surface, requiring uniform sieving, constantly pouring water, starch with the water through the sieve into the pulp pool, and slag retained on the screen surface from the sieve tail discharge. Screen cloth for 120 mesh nylon cloth. In the process of sieving, as the liquid containing pectin and other viscous substances remain on the screen surface, affecting the separation of the sieve effect, therefore, the screen cloth should always wash to ensure smooth sieve.
(5) flow tank separation: after fine sieve treatment of starch, the general use of trough separation of protein. Its advantages are easy to build, less steel, save kinetic energy, operation is also more stable. Disadvantages are large area, intermittent operation, separation efficiency is low, starch loss, poor working conditions.
(6) centrifugal separation and drying: After washing the starch contains high moisture content, must be dehydrated by centrifugal separator, so that the starch moisture content dropped to below 45%. Some plants are sold directly or as wet starch. In order to facilitate storage and transportation, dehydrated wet starch needs to be dried to achieve the required starch moisture content. Usually sweet potato starch water content of 12% -13%. Starch drying can be air-dried, because it has the advantages of fast drying speed, high efficiency, high equipment production capacity and low equipment cost.
(1) raw material pretreatment: fresh sweet potato after harvest, it is usually cut into flakes or filaments, after sun or fire dry, made of sweet potatoes dry. This sweet potato stem in the processing and transportation process is inevitably mixed with a variety of impurities, it must be pretreated. Pretreatment is dry and wet. Dry method is the use of screening equipment and wind selection equipment. Wet treatment is done with a washing machine or a washing tub.(2) soaking: In order to improve the rate of starch can be used alkaline water immersion. Generally add saturated lime milk or 1% dilute alkali solution soaked water, so that the value of ph is 10-11. Soaking time of about 12 hours, the temperature control at 35-40 degrees Celsius. After soaking, the water content of sweet potato chips is 60%.
(3) broken and ground: soaked sweet potato chips with water into the hammer mill crushing, to a certain degree of fineness, through the sieve outside the machine. The instantaneous temperature of the potato stem is increased during the pulverization process, and some of the starch is susceptible to hot gelatinization, so that the separation of starch and potato residue is affected at the time of sieving. It is not easy to precipitate when the tank is separated, Out of rate. In order to prevent a crushing treatment easy to starch gelatinization, you can use two crushed, split the process of sieving. That is, dried by the first potato crushed, sieved, and then by the second crushing treatment, and then screened. In the crushing process, in order to low instantaneous temperature rise, according to the different crushing particle size, adjust the slurry concentration, the first road for the 3-3.5 Baume degree, two for the 2-2.5 Baume degree. At the same time using the equalizer control sweet potato dry into the amount of balanced slurry, to avoid the phenomenon of crusher overload, but also conducive to the trough separation.
(4) screen: sweet potato stem after crushing the red wine paste also known as liquid, must be sieved, separated from the slag, that is, fiber. Usually using a flat sieve, the material into the sieve surface, requiring uniform sieving, constantly pouring water, starch with the water through the sieve into the pulp pool, and slag retained on the screen surface from the sieve tail discharge. Screen cloth for 120 mesh nylon cloth. In the process of sieving, as the liquid containing pectin and other viscous substances remain on the screen surface, affecting the separation of the sieve effect, therefore, the screen cloth should always wash to ensure smooth sieve.
(5) flow tank separation: after fine sieve treatment of starch, the general use of trough separation of protein. Its advantages are easy to build, less steel, save kinetic energy, operation is also more stable. Disadvantages are large area, intermittent operation, separation efficiency is low, starch loss, poor working conditions.
(6) centrifugal separation and drying: After washing the starch contains high moisture content, must be dehydrated by centrifugal separator, so that the starch moisture content dropped to below 45%. Some plants are sold directly or as wet starch. In order to facilitate storage and transportation, dehydrated wet starch needs to be dried to achieve the required starch moisture content. Usually sweet potato starch water content of 12% -13%. Starch drying can be air-dried, because it has the advantages of fast drying speed, high efficiency, high equipment production capacity and low equipment cost.