What happens to food after extrusion processing?

The process of food extrusion and puffing is a process in which the food raw materials are suddenly released to normal temperature and pressure under the condition of high temperature and high pressure, so that the internal structure and properties of the raw materials are changed. So what changes after the food is squeezed? Darin Machinery tells you today.

Food ingredients can reach quite high temperatures during extrusion, but at such high temperatures the dwell (residence) time is extremely short (5-10 seconds), thus making the beneficial effects of food heating (improved digestibility) more likely. To maximize, while the harmful effects (browning, the destruction of various vitamins and essential amino acids, the production of bad flavor, etc.) tend to be minimized. In detail it is:

1. The loss of nutrients is small, which is conducive to digestion and absorption:

Since extrusion is a high temperature and short time processing process, the nutrients in the food are hardly destroyed. However, the appearance of the food has changed, and the internal molecular structure and properties have also been changed. A part of the starch is converted into dextrin and maltose, which is convenient for the human body to absorb. And because the texture of the food after extrusion and puffing is porous, the gaps between the molecules are conducive to the entry of human digestive enzymes.

For example, unexpanded coarse rice has a protein digestibility of 75%, which can be increased to 83% after extrusion and puffing.

2. The taste becomes better:

(1) Grains contain more starch, vitamins, calcium, phosphorus, etc., which are extremely beneficial to the human body, but have a poor taste. After the grain is extruded and puffed, these components are completely micronized and partially granulated due to the high temperature, high pressure, shearing, friction in the press, and instantaneous puffing at the extrusion die mouth of the extruder. Molecular degradation + structural change enhances water solubility and improves taste.

(2) After the puffing treatment, the "rice bread" produced from the light and crisp wheat flour has a unique fragrance due to a series of texture changes.

(3) The beany smell of soybean products is the result of oxidation reaction catalyzed by lipoxygenase inside soybean. The instantaneous high temperature during the extrusion process has destroyed the enzyme, thus avoiding the production of odors. In addition, some naturally occurring toxic substances, such as trypsin inhibitor in soybeans, are also destroyed.

3. Convenience to eat:

The product after extrusion and puffing has a porous sponge-like structure, strong water absorption and easy rehydration, so it is more convenient to eat directly or to prepare it.

4. Easier to regenerate

Usually the staple food is processed by steaming. For example, the freshly cooked rice is soft and delicious, but it becomes hard and unpalatable after being placed for a period of time, which is called "rejuvenation".

Using extrusion technology to process, due to high-strength extrusion, shearing, friction, and heating during processing, starch granules are fully swollen, gelatinized and partially degraded under the condition of low moisture content. , the material changes from the high temperature and high pressure state to the normal pressure state, and an instant "flash evaporation" occurs, because the α starch after gelatinization is not easy to restore its starch granule structure, but still maintains its β starch molecular structure, so it is not easy to produce "flash". Rebirth" phenomenon.

5. More convenient for storage

The process time of extruded food processing is short, and the moisture content of raw materials is generally low, which is not conducive to the growth and reproduction of microorganisms; from raw materials to products, the production process is simple and the assembly line is short, so there is basically no chance of pollution, and the water content of the puffed product is also low. This state is also not conducive to the reproduction of microorganisms, so as long as the preservation method is proper, the extruded product can be preserved for a long time.

6. Manufacture of new products:

Food extruders can modify some vegetable proteins, starches and other food raw materials to make new products.

Darin Machinery has a variety of food extrusion production lines, such as pasta, soy protein, bread crumb production lines, etc., including Cheetos/Kurkure production lines, if you are interested, please contact us.