Multi-field application of extrusion technology

1) Application in snack food processing

Extruded food is a successful product of applying extrusion technology to food processing. With rice, corn and other grains and potatoes as the main raw materials, through extrusion, cooking, puffed into loose porous products. After roasting, dehydrating or frying, the surface is sprayed with a delicious seasoning. Puffed shrimp belong to this category.

The other is puffed stuffed snacks, which are extruded through co-extrusion, that is, granular materials are extruded into empty tubes, and various ingredients such as egg yolk powder, powdered sugar, milk powder, seasonings, and spices are pressed together. After adding a certain proportion, fully stir and mix to form a filling material with good fluidity. Through a sandwich pump and co-extrusion die head, the filler is injected into the middle of the tube while the puff is extruded. With the change of the filling, the taste is crisp and the flavor is diverse. By changing the formula of the filling material, various nutrient-fortified foods and functional foods can be processed.

2) Application in oil leaching

For oil crops with high oil content, it is an ideal new technology to first extrude the oil after husking (skin), and then extrude some oil in advance to form particles with certain structure before leaching. Currently in the United States, Brazil, India, Switzerland and other countries have extruder manufacturers. Among them, ANDERSON Intrntionl Corp’s pre-pressed extruders for processing high oil content are particularly eye-catching.

In addition, the invention of the extruder and its application in the solvent leaching process of the oil sheet have greatly improved the efficiency of the solvent leaching process. The sheet in the extruder is squeezed by a series of intermittent spirals and rubbed against the retaining bolt protruding from the barrel, which causes more oil cells to break.

When the flakes are mashed, steam is injected into the bucket containing the flakes, and the flakes are boiled in the bucket for 15-20 seconds. Cooking changes the protein properties of the flakes, making them softer.

At the same time, when the steam enters the barrel and mixes with the sheet, the pressure in the barrel causes the steam to change from the gas phase to the liquid phase, releasing a lot of heat and producing an effective cooking effect in the extruder. The liquid permeates the sheet and fully permeates the blank.

In addition, after the oil billet is fully cooked, it is discharged from the outlet of the extruder. Due to the sudden drop in pressure, the water in the blank will immediately change from the liquid phase to the gas phase.

As the liquid turns into a gas, it absorbs heat from its surroundings, which cools the protein and forms a rigid, porous protein structure that expands.

3) Application of extrusion technology in the preparation of resistant starch

The application of extrusion technology in the preparation of resistant starch preparation is because extrusion plays a pre-gelatinization role in the preparation process of resistant starch, and improves the gelatinization degree of starch.

It has been reported that the gelatinization degree of starch after extrusion can reach more than 90%, while the gelatinization rate of traditional process is only 80-90%.

Only when starch is gelatinized completely, amylase and puralanase can fully act on it to generate amylose molecules of a certain length. The yield of resistant starch can be improved by adjusting the condition of enzyme.

4) Application in the production of organic plant protein

The production of plant protein takes plant protein as raw material, such as soybean protein isolate, wheat protein, etc., after extrusion and shearing, the tertiary structure of protein molecules is destroyed, forming a relatively linear protein molecular chain. At a certain temperature and humidity, due to the high shear force and the directional flow of the screw, the protein molecule becomes fibrous when it is extruded through the mold outlet. The structure.

After the plant protein is constructed, it improves the taste and elasticity, expands the range of use, and improves the nutritional value. Compared with animal protein, it has the advantages of low price, no cholesterol, long shelf life, easy coloring, easy to increase flavor and so on. It can be made into all kinds of different foods.

It can be added to meat raw materials, used as meat stuffing, or made into imitation meat food instead of meat, fish, poultry, etc. Such meat supplements have been added to hamburger steaks, patties and sandwiches in the United States, and up to 30 percent of hamburger steaks are meat substitutes.

5) Application of extrusion technology in the development of health mix powder

Black rice, barley, buckwheat flour as raw materials. These materials have high nutritional value and health function. However, due to their hard texture, they are difficult to gelatinize and digest during normal cooking. Therefore, they must undergo special treatment. Extrusion technology is the ideal method.

In addition, due to the uneven distribution of various nutrients in various raw materials, people’s needs for various nutrients are often not met.

Development prospect of extrusion technology

One of the purposes of food processing is to make full use of existing food resources, develop new sources of raw materials, and develop a variety of popular foods.

The emergence of bulking technology can be said to open up a new way for the application of raw materials such as grain and starch, which we call coarse grains, in the food industry.

And puffed food generally need seasoning, so the development of puffed food processing industry will inevitably drive the development of the condiment industry, but also will drive the development of packaging technology such as film.

In addition, with the development of the food industry, the emergence of new technologies, new processes, and the improvement of people’s living standards, extrusion technology and its equipment are also developing in a better direction, producing more popular low-oil, health care and natural food.

Such as low temperature, ultra-low temperature bulking technology, chemical bulking technology, ultrasonic bulking technology may be applied in practice in the near future; As a new type of extruding technology, microwave extruding technology and baking extruding technology have attracted people’s attention, and have been gradually applied in production.

According to reports, with starch as the main raw material, with 9% corn protein isolate, 1.5% palm oil, under the condition of 50% water content, 500W, 2450MHz microwave radiation for two minutes to obtain high-quality raw material puffed food.

Vacuum frying extruding technology is of great significance for improving food quality and reducing oil deterioration. If deep-fried at a vacuum of 20mmHg and a temperature of 100°C, water vapor will be produced at 60°C; If fried at 80-120°C, the water in the raw material can be fully evaporated, and the volume will be reduced after the evaporation of water. Significant expansion.

In addition to the obvious swelling effect of the products prepared by vacuum frying, the frying time is also relatively short.

In short, with the improvement of people’s living standards, extrusion technology to produce puffed food and extrusion technology in other fields of application in our country has a very broad prospect.

Extruding technology, microwave extruding technology, baking extruding technology will be the development direction of extruding technology; Vacuum frying bulking technology is an effective improvement method to keep the vitality of frying bulking technology.

Research on swelling theory and technology, the development of new raw material sources, the development of new extrusion equipment, the organic combination of extrusion technology and other food processing technology will be the focus and hot spot of the development of extrusion technology.

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