The difference between wet and dry extruded food machinery
Extruded food machinery has the characteristics of wide use of raw materials, low maintenance costs, and energy conservation. The extrusion processing method is to use the driving force of the extruder screw to push the material forward. The material is mixed, stirred, and frictional, as well as subjected to high shear effects, causing the starch particles to disintegrate. At the same time, the temperature and pressure of the machine cavity increase, and then the material is instantly extruded with a certain shape of mold hole.
The principle of extruded food is to use instantaneous pressure changes at high temperatures to make food raw materials texture fluffy and crispy, increasing the surface area for easy grinding into powder or adsorption. The advantages of puffed food are obvious, especially for grains and grains, which have undergone a high-temperature gelatinization process and can be more easily digested and absorbed; Moreover, it is easier to absorb water after drying, and it is better to make paste than to cook Congee directly before.
But the drawbacks are also obvious. Due to its large surface area, it has strong adsorption capacity. If you fry it in oil, it will absorb a lot of oil (fat is prone to exceeding the standard); If you use seasoning, you will absorb a lot of seasoning (sugar and salt can easily exceed the standard); If you put it in the air, it is easier to oxidize. So, puffed food is not harmful. If you can eat puffed food without seasoning, it is actually very healthy.
It is incorrect to believe that adding water during the puffing process of food machinery is wet puffing, and not adding water is dry puffing. The wet puffing machine is an additional conditioner on top of the dry puffing machine, with the aim of increasing the material temperature, softening and maturing the material, and supplementing a certain amount of water.
Wet expansion has higher efficiency and longer service life of spiral and expansion cavity vulnerable parts compared to dry expansion. The reason is that if the material expansion temperature is 130 ℃, the dry expansion needs to be heated by 110 ℃ to increase from room temperature (20 ℃) to 130 ℃; If wet production is adopted, the temperature after quenching and tempering is 80 ℃, and only a material temperature of 50 ℃ needs to be increased. Therefore, wet expansion requires less mechanical energy than dry expansion, and more energy can be used to increase production; Due to the softening of the material, the wear of vulnerable parts such as screws and expansion cavities is reduced, and their service life is improved.
