The traditional production process is as follows: raw material selection - water washing - crushing - grinding filter - pulping - crucible and cylinder - pulp - powder - drying. (1) Selection of raw materials: Because of the different varieties of sweet potatoes, their quality and starch content are also different. Even in the same variety, the quality of the same variety varies greatly. To choose a good variety of processed starch, high starch content is required. The sweet potato with disease is not only suitable for starch processing raw materials, but also will be transmitted to other potato pieces during storage, which is prone to rot and loss. Therefore, the diseased potatoes should be removed. . (2) Washing: Add fresh water to the human tank and add water. Rinse it by hand. After washing, take it out and drain off the remaining water. (3) Crushing: The fresh potato after draining is broken into pieces with a crusher, and the size of the block is 2 cm or less to facilitate the grinding. (4) Grinding filtration: This is the main link in the production of sweet potato starch, which affects product quality and starch yield. The fresh potato pieces are sent to a stone mill or a diamond sand mill and water milled into a potato paste. The ratio of the weight of fresh potatoes to the amount of water added is 1:3-3.5. The potato paste was poured into a sieve having a pore size of 60 mesh for filtration. (5) For the pulp: the starch milk obtained by filtration is placed in a large tank, and then the acidity and concentration of the starch milk are adjusted by adding the acid slurry and water in proportion. The acidity and concentration of starch milk are closely related to the precipitation of starch and protein. If the starch lactic acid is too large, starch and protein precipitate at the same time, so that the starch is not clearly separated. If the acidity is too small, both protein and starch will not precipitate well, and it will be an emulsion and cannot be separated. According to production experience, the pH value of physalis is 3.6-4.0. The concentration of starch milk in the large tank is 3.5-4.0 Baume, the amount of acid slurry added is 2% of starch milk, and the pH of starch milk after adding acid slurry is 5.6. If the temperature is high, the fermentation is fast, and the amount of acid slurry can be reduced. (6) Cylinder and sitting cylinder: After the slurry is allowed to stand for about 20-30 minutes, the sedimentation is completed, and the crucible can be carried out. The upper layer of clear water and a mixture of protein, fiber and a small amount of starch are taken out, and the starch remaining on the bottom layer. The bottom starch after the crucible is mixed with water to adjust the starch milk to reprecipitate the starch. In the precipitation process, the syrup is fermented, and it is called a cylinder. Temperature and time should be controlled when sitting in the tank. The cylinder temperature is around 20 degrees Celsius. Hot water must be used when it is cold or when it is mixed with water. The fermentation in the tank must be permeable and properly stirred during the fermentation to promote the fermentation. Generally, the tank time is 24 hours, and the daily heat can be shortened accordingly. After the fermentation is completed, the starch precipitates. (7) Slurry filtration: The acid slurry produced by the cylinder is called the second and the slurry, that is, the acid slurry mainly used in the acid slurry method. The normal physalis of the fermentation has a clear fragrance, and the color is white as milk. If the physalis is insufficiently fermented or over-fermented, the color and the aroma are poor, and the effect is not good when used for the pulp. The mash is used to extract the upper syrup as a slurry. The starch after mashing was sieved with a fine sieve having a mesh opening of 120. The sieve top is fine slag and can be used as feed. The sieved material is starch and transferred to a small cylinder. After the starch is transferred to the small tank, the starch is rinsed with water and placed for about 24 hours to prevent fermentation. (8) Starting powder: After the starch is precipitated in a small tank, the upper liquid is a small slurry, which can be used together with the acid slurry or as a grinding water. After removing the syrup, a layer of gray oil powder is left on the surface of the starch, which is an impure starch containing protein. The oil powder can be washed away from the surface of the starch with water. The washing liquid can be used as a nutrient material for culturing the acid syrup. The bottom starch is removed with a shovel, and the bottom of the starch may have fine sand adhered, which should be brushed off. (9) Drying: After the above procedure, wet starch was obtained. Drying is necessary to facilitate storage and transportation. It is usually dried in the sun or dried in a drying room. Mechanized production process: conveying - cleaning - disintegration - screening - sand removal - sedimentation (or concentration) - dehydration - drying - air-cooled packaging. First, the basic principle of cleaning The role of cleaning: Mainly to remove the sediment from the outer skin layer of sweet potato, and wash away the epidermis of the roots of sweet potato. Cleaning the fresh sweet potato or sweet potato chips as raw materials for the production of starch is the basis for ensuring the quality of the starch. The cleaner the cleaning, the better the quality of the starch. Second, the basic principle of fragmentation The role of disintegration: Sweet potato starch is mainly stored in the fleshy part of the roots, only a small amount stored in the endothelium. The purpose of the disintegration is to destroy the structure of the sweet potato, so that the tiny starch granules can be smoothly separated from the roots. The starch released from the cells is called free starch; it is called bound starch in the cells inside the dregs. Crushing is one of the important processes in the processing of fresh potatoes. It is related to the flour extraction rate of fresh potatoes and the quality of starch. The requirements for crushing are: 1. Burst the cells of fresh potatoes as much as possible to release more free starch granules; 2. Easy to separate. It is not desirable that the skin residue is too fine, and the skin residue is too fine to separate the starch from other components, which increases the difficulty of separating the fine residue. Third, the basic principle of screening Sweet potato slag is a slender fiber with a larger volume than starch granules. The Pengsheng coefficient is also larger than that of starch granules. The specific gravity is lighter than that of starch granules. The raw pulp that will be disintegrated is treated with water as the medium to further melt the starch slurry contained in the potato slag. Filter out. Fourth, the basic principles of purification and precipitation The specific gravity of mud and sand is greater than that of water, and is greater than the specific gravity of starch granules. According to the principle of separation of specific gravity, the use of cyclone to remove sand, or the use of the trough sedimentation method, can achieve better results. The specific gravity of the yellow pulp is close to water, and is lighter than the specific gravity of the starch granules. The shape is palm shape. The longer the processing cycle is, the greater the rubber properties are. The sifting screen sticks to the starch granules and is extremely difficult to separate. Therefore, the raw materials are required to be fresh. The process is short and separated in time. Fifth, the basic principle of dehydration The concentrated starch slurry still contains more water and can be dried after further dehydration. Sixth, the basic principle of drying The whole process time of the airflow drying (also called rapid drying) generally used in the starch plant is completed in an instant. Therefore, the moisture inside the starch granules is not dried and the gelatinization has been dried, so that gelatinization or degradation does not occur. Airflow drying is a cocurrent drying process, that is, the cocurrent process of the wet powder material and the hot gas flow, which consists of two processes of heat transfer and mass transfer. When the wet starch is in contact with the hot air, the hot air transfers the heat energy to the surface of the wet starch and then from the surface to the inside. This process is the heat transfer process; at the same time, the moisture in the wet starch is from the inside of the material to the liquid or gaseous state. It spreads to the surface of the starch and diffuses from the surface of the starch through the gas film into the hot air. This is a mass transfer process. That is, the high-temperature airflow and the wet starch are uniformly exchanged in the drying tube to make the dried starch powdery, and after cooling, it can be packed into the storage. Chengdu JRT is a world leader in the design and manufacture of highly accurate, precise and digital and analogue laser measurement sensors, including serial laser distance transducer,usb laser distance module,distance module ttl laser sensor rs232/RS485/Bluetooth. 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