With the continuous improvement of people's living standards, people have a new understanding of the extruded puffed food, and the demand has gradually increased. Its crispy and delicious taste, sweet taste and convenient consumption are very popular among people, especially Loved by children. Extrusion technology is increasingly used in the food industry, and a wide variety of snack foods, baby foods, breakfast foods, and functional foods are available. The advantage of extrusion technology is that it offers many unique processing methods that produce unexpected results. Although the application time of food extrusion processing technology in China is not long, it has been rapidly promoted and applied. The equipment manufacturer represented by Jinan Daxie Machinery has successfully developed a product that meets China's national conditions on the basis of introducing advanced foreign technology, digestion and absorption and bold innovation after more than ten years of unremitting efforts by researchers and engineers. Type food extrusion processing equipment and its ancillary products are well received by food manufacturers. This chapter will focus on the processing and application practices of five typical extruded foods as a reference for people engaged in the production of extruded food.
1. Full-expansion snack food technology and equipment
Fully puffed snack foods are a very wide range of foods that are widely consumed. This type of food is named for its direct expansion from the extruder die and does not require further processing other than drying. Typical examples of direct puffed snack foods are corn rings, crispy fruit, onion balls, potato strips, and recently popular three-dimensional snack foods.
The expanded product has five processing sections: mixing → conveying → extrusion → drying → coating.
1. Mixing - Its function is to mix the water with the water to achieve the effect of pre-wetting, and provide some time for the hydration of the starch. This process has a great influence on the final puffing effect. The total water content required for the general expanded material is 13-20%, which is completed by the powder mixer.
2. The transport-mixed material is conveyed from the mixer to the feed hopper. Long bucket elevators, screw conveyors or vacuum conveyors are used.
3. Extrusion - This is the key to extrusion processing. The extruder cooks the materials and converts them into plastic melt under a certain pressure. The cooked materials form a certain shape under the action of a small die hole under pressure, and then the extruded holes are extruded to form a final shape. shape. The cutting device cuts the continuous discharge into products of the desired size. The operating unit of the extruder can be used to control the density and texture of the directly expanded product. The processing parameters that can be separately controlled are water content, feed rate, barrel temperature and screw speed (if the speed is variable). The stencil resistance is also a parameter that can be independently controlled, but will not change during the stabilization process after assembly by the extruder.
4. Dry-direct puffed foods are generally dried after extrusion processing. The water content of the expanded raw material is 13%-16%. After being squeezed, the moisture is reduced to 8%-12% due to steam flashing, and then dried to reduce the moisture to below 2-5% to form a crisp texture. And the environment required for a stable price of goods, because the product density is small, so the drying time is very short can achieve the effect.
5. Coatings - Puffed and dried products are finally sprayed with oil and flavoring agents. There is a better taste to the product, the flavoring gives the product a different flavor, and the oil and flavor coatings typically account for about 20-35% of the weight of the finished product.
Taking the production line of twin-screw puffing snack food of Shandong Daxie Company as an example to introduce the production process of onion rings
Process route: batching→mixing→transporting→expansion→baking→packaging
Second, full-expansion sandwich roll (cake) production process and equipment
Puffed sandwich roll (cake) production technology (also known as double extrusion technology) room using advanced extrusion technology to use rice, corn or other grains as raw material on single-screw or twin-screw equipment, using pure cream as medium, and egg yolk The powder, milk powder, sugar, sesame paste, chocolate powder and other raw materials are diluted to form a sandwich material, and the sandwich material is injected into the puffed cereal food while being extruded, and processed into a sandwich small food. The food has a crisp taste and unique flavor, and can be processed into various nutritious foods, therapeutic foods, functional foods, etc. according to different processes and different non-releases, and the application of puffing technology in food provides a new way.
1. Crushing - use fresh raw material (corn peeled) powder to 20 mesh (double screw material needs to be powdered to more than 60 mesh).
2. Mixing - Mix different raw materials in proportion and keep the moisture of the mixed raw materials at 15-16% (the moisture of the twin-screw extruder is adjusted to 18-20%). The experiment proves that rice and Corn is best mixed at 5:1.
3, the preparation of fillings - because the cream has good stability and lubricity, and can give the product a better flavor, so the carrier used as a sandwich material is ideal. The cream is warmed and melted, then cooled to about 40 °C, and various fillings are added in proportion (the various raw materials to be added need to be powdered to 60 mesh or more) and stirred evenly. To ensure the quality of the product, the cream should be added in an appropriate amount to ensure the material is diluted. Uniform and good fluidity. (Cream is pure cream, not right water).
4, grain puffing and stuffing - this is the key process of the process, the material puffing directly affects the final texture and taste, the material in the extrusion through high temperature (130 ° C -170 ° C or so), high pressure (5 -10 atmospheres) becomes a fluid gel state, which is uniformly and stably injected into the touch roll through a specially designed sandwich mold, and is extruded together with the expanded material, and the material moisture is reduced to 9-10% during extrusion.
5. Plastic cutting--The strip-shaped sandwich material is towed to the entrance of the special roll-shaped shaping machine. The shaping machine pulls the material, automatically completes and cuts, and the material is cut into a rod-shaped sandwich roll with uniform length and uniform thickness. At this time, the material is cooled. Water is reduced to 6-8%.
6. Baking-baking purpose room In order to improve the taste and shelf life of the product, some of the fillings can be cooked and cooked by baking to produce a pleasant fragrance. After baking, the moisture content of the raw materials is reduced to below 2-5%.
7. The mixing-mixing chamber is carried out in the drum, including oiling the surface of the embryo and spraying the seasoning. The oil is applied to prevent the product from absorbing moisture, giving the product a certain stability, prolonging the shelf life, and spraying the seasoning for improvement. Taste and flavor. As the drum rotates, the material rolls up and down, from one end to the other, and the advantage is made when the material enters the drum. By tumbling and stirring, the oil is evenly applied to the surface of the material. When the material passes through the middle of the drum, the seasoning is added to continue mixing. The product that comes out of the drum is the finished product. The product should have the same color, the surface presents a pleasant golden yellow, and the seal is beautiful and smooth.
Main equipment preparation:
According to the process requirements of the production line, the following equipment needs to be prepared.
1. Mixing machine:
A. Rotary leaf type mixing machine is suitable for mixing and humidifying 60-mesh raw materials, rotating blade speed is 368 rpm, and the first mixing capacity is 10kg (with single screw).
B. Drum type powder mixing machine is suitable for mixing and humidifying 20-mesh raw materials, with a rotation speed of 35 rpm and a half-length capacity of 10kg (with single screw).
2. Conveyor: The mixed material is raised to the main material silo (also can be manually added), the conveying capacity is 0.5 tons/hour, and the working of the machine is intermittent.
3. Puffing machine: At present, the main machine used for domestic production of sandwich food is mainlytwin-screw extruder , which is divided into two types according to the structure.
SLG65-III full-expansion twin-screw main machine: This machine is composed of two pairs of screws that mesh with each other and rotate in the same direction. They together play the role of conveying, friction, extrusion and heating, and the two screws push the material. During the process, the screw is stirred, mixed, sheared and extruded, and externally heated, gelatinizes, gelatinizes, and heats up the starch. The puff is finished through the die, and the uniformity of the material can be adjusted by adjusting the screw. The speed is realized, the drive motor adopts foreign advanced frequency conversion speed regulation technology to ensure the reliability and economy in the operation of the equipment. The equipment is easy to operate, easy to clean, easy to change varieties, large output, screw, screw life than single screw Long, but the processing cost is large.
Screw, barrel is the heart part of the extruder. Its quality directly affects the quality of the product. It should ensure that the screw and barrel work under good conditions. Because the screw and barrel rotate at high speed, the surface of the chrome steel material is unblocked. Hardened to improve its wear resistance and heat resistance.
4. Stuffing machine: the function is to mix the filled stuffing into the mold by the screw pump, and the stuffing of the stuffed material is extruded at the same time. The stuffing machine has the functions of heat preservation, stirring and extrusion. The filling material is continuously stirred in the holding tank to maintain good fluidity of the filling material, and the amount of the filling material can be controlled by adjusting the screw pump speed.
5, multi-function shaping machine: multi-function shaping machine is composed of traction roller, shaping roller cutter, speed synchronization adjustable size, strips from the main machine puffed out, or strip-shaped puffing can be cut into regulations through multi-functional shaping machine The length dimension of the sandwich roll is completed in this process.
6. Hoist and dryer: The cut-off blanks are cut into the hopper of the hoist and directly sent to the dryer (tunnel oven). The drying temperature is set at about 170 °C, the material is run in the dryer for 30 seconds, the water can be reduced to below 2-5%, the dryer is heated by far infrared, and the speed of the mesh belt is adjustable (frequency control) .
7. Lifting machine and rotating drum: The material coming out of the dryer falls directly into the hopper of the hoist, and the hoisting machine is turned into the rotating drum. The front half of the drum is welded with the wing in the circumferential direction, so that the material can be tumbling here to ensure the oil energy. Evenly coated on the surface of the embryo, the second half is a smooth inner wall, and the inner wall of the sandwich roll is rolled, so that the seasoning is evenly hike on the surface of the embryo, the drum is inclined (the slope is adjustable), and the rotation speed of the drum can be controlled to control the material. Residence time in the drum.
8. Fuel injection machine, seasoning machine and conveyor: According to the process requirements, the fuel injection quantity of the fuel injection machine is adjustable. The oil is composed of a gear pump flow valve and a throttle valve. The seasoning machine adopts screw conveying to realize long-distance spraying, and the conveying amount is adjustable. The mixing chamber has a stirrer to continuously stir to prevent arching. The function of the conveyor is to transport the finished product out of the drum and enter the packaging machine.
9. Packaging machine: According to the output of the production line, the packaging capacity of the packaging machine is designed.
Third, nutritious rice flour (rice) food technology and equipment
Cereal porridge fast food is a typical example of the application of extrusion technology, which successfully revolutionized the manufacturing process of traditional fast food. The use of extrusion technology to process cereal porridge foods avoids many of the limitations of the old process, requires no expensive equipment investment, does not require boilers, has a continuous production process, and is free of waste water and waste. The multi-functional convenient rice porridge production line developed by the company has reasonable design, stable and reliable performance, high degree of automation and convenient operation and maintenance. The main feature of the production line is that it greatly simplifies the production process of traditional rice porridge. The cereal porridge equipment designed by extrusion technology can accept different materials and produce cereal flakes with different shapes. For example: corn flakes, rice flakes, millet flakes, oat flakes, and flakes made by mixing two or more ingredients. The process can produce instant foods such as instant nutritious cereals, corn, eight-treasure porridge, instant rice, nutritional granules and the like which are popular among marketers. The use of the product, long-time foaming, smooth taste, is a family breakfast, tourist snack Ideal food.
Raw material crushing→mixing→extruding→granulation→cooling→tableting→drying→direct packaging→mixing with auxiliary materials
Crushing machine→mixing machine→extruding extruder→winding machine→tableting machine→three-layer oven→mixer packing machine
Fourth, one-time squeeze fried food process and equipment
As consumers' demands for new and specialty foods continue to increase, puffed food is a rapidly growing market. In order to meet the needs of the market, on the basis of requiring the production style to change and the convenience of processing, our company has successfully developed a new process of potato deep processing (also known as cold extrusion) based on the absorption of foreign advanced equipment technology and China's national conditions. Pressure technology), this is the third generation of puffed food.
The third generation of puffed food is another snack food after the second generation of puffed food. The production line adopts a unique extrusion process to achieve the best sensory effect. The product shape is natural and realistic, the texture is exquisite, the precise parameter control and the perfect process flow ensure the stable quality of the processed products, the taste is loose, and it is not scattered, which is the perfect combination of traditional crafts and modern technology. The technology is based on high-quality potato starch and potato whole powder as the main raw materials, and mixed into a mixture according to a certain formula ratio. This kind of raw material is rich in starch, and after puffing, it forms a network structure and becomes a structural skeleton of the expanded product. In a certain shape, the raw materials are added to the extruder for mixing, cooking and aging under a certain temperature and pressure condition, and finally the raw materials are pressed into a desired shape through a special mold, and then pressed out by a rotary cutter capable of speed regulation. The continuous shaped blank is cut into the required length, and different shapes of the mold, composite, and three-dimensional shapes can be processed by replacing different molds or matching different cutting equipment. This is followed by a drying process in which the billet is dried to a moisture content of about 10% at a specific temperature and moderate conditions. This moisture content ensures that the billet is optimally puffed when fried. In fact, the dried material is convenient to transport and store and can last for about 2 years. Frying is to fry the batch in vegetable oil at a temperature of about 200 ° C for a few seconds, then season the warm product to achieve the best taste. Keeping the product brittle as long as possible must immediately package the product in a bag that is only highly moisture resistant.
Puffed foods that are processed by cooling extrusion are better in chewing and mouthfeel than direct-expanded products, and the fat content is much lower than that of fried potato chips, which meets the requirements of today's consumers for healthy foods.
Mixing→Extrusion→One Drying→Second Drying→Frying→Deoiling→Flavouring→Packaging
Mixing machine→Extrusion extruder→Cooling wind bed→Drying machine→Frying machine→Seasoning machine→Packing machine