Characteristics of potato starch: Starch can be divided into corn starch, bean starch, potato starch and grain starch according to different extraction objects. Potato starch is a kind of potato starch, which is especially favored because of its special quality. Potato starch is a kind of high-quality starch with a series of unique properties. It has unique qualities and functions that cannot be replaced by other starches.
1. Because potato starch granules are larger and have higher viscosity than other starch granules, it can prepare high-consistency paste, which makes its quality and grade in industrial application far higher than other starches.
2. The molecular weight of amylopectin of potato starch is higher than that of most other starches, which can produce excellent flexible films. It is the best raw material for preparing cationic starch, because its viscosity and film-forming property decrease the least in the production process.
3. Potato starch contains natural phosphate groups. Although the potato starch also contains amylose, the potato starch paste rarely appears gel or denaturation because of its large branched molecular weight and the substitution of phosphate groups. Therefore, it can prolong the shelf life of products with it, and is widely used as a stabilizer in food, daily chemical and other industries.
4. Potato starch is mild in taste and non-irritating. It doesn't have the typical cereal flavor like corn and wheat starch. Therefore, it is the best choice for food additives. At present, no famous brand food in the world will choose other starches as additives.
Production technology of potato starch. Traditional production technology:
Wash the new potato (potato), remove the bud eyes, remove the epidermis, weigh it, take 200g of potato, shred it, put it in 1000 ml water15min to 30min, let it cool slightly, then filter it with four layers of gauze, and take the filtrate to replenish water to 1000 ml! This method of using potato starch should be made as needed and used for seed production.
Beat peeled potatoes into fine pulp, put them into a container, add water, mix them evenly, filter them with four layers of gauze for 2-3 times, naturally precipitate the filtrate, remove the supernatant after precipitation, and then spread the obtained starch thinly on a glass plate to dry. Finally, the fully dried starch is sealed in a container so that it can be taken at any time when seed production is needed in the future. During seed production, weigh 20g of starch and add 1000 ml of water. The nutritional components of potato starch prepared by this method are hardly destroyed.
Second, the small-scale production process:
1. Washing and grinding: The washing process of potatoes is carried out in the washing machine. Remove impurities such as mud, stones, stems and leaves, mud and sand attached to the potato surface. The water consumption is about 5 times that of raw materials. After washing, send it to the crusher for treatment. There are two kinds of grinding machines used: toothed plate type and hammer type.
2. Screening: the ground mashed potatoes are screened. The traditional method is to use a flat vibrating screen, and the modern potato starch factory uses a centrifugal screen. In the screening process, water should be added for washing, the undersized material is starch milk, and the oversize material is screened for the second time to recover some starch, and the washed starch residue can be used as feed.
3. Separation and cleaning of the launder: The starch milk from the screening section is first separated from impurities such as protein in the launder, and then cleaned in the cleaning tank. Yellow slurry water containing starch is separated from the launder, sent to the launder to recover starch, and then secondary starch is obtained by cleaning the launder.
4. Dehydration and drying: After washing the starch, the water content is very high, so it must be dehydrated by centrifuge to obtain wet starch with water content of 45 {BF}, and then dried by air dryer to obtain dry starch with balanced water content of 20 {BF}.
Third, the mass production process:
The production process of large-scale potato starch is basically similar to that of small-scale production, and its process flow is potato-hydraulic transportation-cleaning transportation-secondary cleaning-cleaning, stone removal and lifting-crushing, separation-sand removal-concentration and refining-vacuum dehydration-airflow drying-finished product packaging.
1, cleaning technology and equipment: mainly to remove the sediment from the outer skin of the material and wash off the skin at the root of the material. The stone-removing cleaning machine is used to remove hard impurities from materials. Cleaning the raw materials used to produce starch is the basis to ensure the quality of starch. The cleaner the cleaning, the better the starch quality. Conveying is to transfer materials to the next working procedure, which often has cleaning function at the same time. Commonly used conveying, cleaning and stone removal equipment include: hydraulic launder, spiral pulp washer, inclined squirrel cage pulp washer, paddle pulp washer, stone removal feed pulp washer, (flat) squirrel cage pulp washer, drum pulp washer, scraper conveyor, etc. According to the characteristics of soil and materials, some of them can be combined to meet the requirements of high cleanliness and convenient transportation.
2. Raw material crushing and equipment: the purpose of crushing is to destroy the organizational structure of materials, so that tiny starch particles can be disintegrated and separated from root tuber smoothly.
The requirements for crushing are:
(1) try to break the cells of the material and release more free starch particles;
(2) easy separation. We don't want the skin residue to be too fine, which is not conducive to the separation of starch from other ingredients and increases the difficulty of separating fine residue.
3. Screening technology and equipment: Starch extraction, also known as pulp residue separation or separation, is a key link in starch processing, which directly affects starch extraction rate and starch quality. The crushed material is fine fiber, with larger volume, larger expansion coefficient and lighter specific gravity than starch particles.
4. Washing technology and equipment: The washing and concentration of starch are completed by starch cyclones, which are divided into concentration cyclones and washing and refining cyclones. After screening, the starch slurry first passes through the concentration cyclone, and the underflow enters the washing and refining cyclone, finally reaching the product quality requirements. The equipment is equipped with a complete set of automatic control system, adopts high-quality cyclone tube and optimized exhaust scheme, which can make the concentration of starch milk discharged from the last cyclone separator reach 23Be', making it an ideal choice for starch washing equipment.
5, starch dehydration: potato starch is commonly used vacuum suction filter dehydrator. Automatic feeding, automatic dehydration and automatic cleaning can be realized.
6. Starch drying: The air dryer suspends and dries wet starch by using high-speed hot air during air flow. It has the characteristics of high heat transfer coefficient, large heat transfer area and short drying time.
7. Cooling, sieving and packaging the starch: the temperature of the dried starch is high. In order to ensure the viscosity of starch, it is necessary to quickly cool the starch after drying. The cooled starch enters the finished product screen and enters the final packaging process on the premise of ensuring the fineness and output of the product.
Starch residue produced by small factories is directly used as feed without drying, while starch residue produced by large factories is mostly dried. In order to save heat energy consumption, you can use a press to dehydrate and then use an air dryer to dry.
New uses of potato starch: first, the first choice for meat products;
After adding starch to meat emulsion products, it has obvious effect on improving water retention and microstructure of products. This process is caused by the gelatinization of starch during heating. [1] Fresh meat contains 72 {BF}-80 {BF} of water, and most of the other solids are protein. When meat products are heated, protein promotes the ability to bind water due to denaturation, and starch can absorb this part of water, gelatinize and form a stable structure. Compared with other starches, the gelatinization temperature of potato modified starch is lower, protein denaturation and starch gelatinization in the product are almost simultaneous, and no small "water sugar" is formed inside.
Modified potato starch has high swelling degree and strong water absorption capacity. During the heating process, the meat protein is denatured by heat, forming a network structure. Because some water in the grid is not tightly combined, it is absorbed and fixed by starch particles, which makes starch particles soft and elastic, and plays a dual role of adhesion and water retention. The meat products added with potato modified starch have uniform and delicate texture, compact structure, elasticity, smooth section, fresh and palatable taste and strong water retention when stored for a long time and refrigerated at low temperature.
Second, the excellent thickener of sauce:
As a good thickener, modified starch is widely used in sauces, which can reduce the production cost. At the same time, because the quality of the sauce is stable, it can be stored for a long time without delamination, which makes the product look shiny and taste delicate.
Most sauce products have high salt content, so the PH value changes greatly, which generally requires high-temperature disinfection, accompanied by moderate to strong stirring or homogenization; In view of the different requirements of various sauces in texture, acidity and emulsifying effect, the selection and use of modified starch is particularly important.
The gelatinization temperature of potato modified starch is low, which can reduce the loss of nutrition and flavor caused by high temperature, and the smell is mild, which will not affect the original flavor of the product; High transparency, which can give the sauce a good appearance; Sieved small particle products can provide a very smooth surface. At the same time, potato modified starch has good aging resistance, shear resistance, high temperature resistance and low PH value, which can effectively prevent the coagulation and dehydration of sauce products and increase the emulsification effect to some extent. In sauce products, potato modified starch can not only be used as thickener, but also give the product a specific texture and taste. Special potato modified starch can also be used to improve the rheology of soy sauce, thus enhancing the adhesion and wall-hanging feeling of sauce.