1.Selection of extrusion methods Extrusion methods mainly include dry extrusion and wet extrusion. Which one to choose depends on the actual situation. First of all, it depends on the function of the extruder you use. At present, we are using the DGP135 dry extruder of Henan Sunshine Industrial High-efficiency Extruder. The latter can be used for dry and wet extrusion. It should be determined according to the moisture content of soybeans. When the moisture of soybean is high, it is better to use dry puffing, which is conducive to the evaporation of water and reduces the moisture of soybean flour. Wet puffing is mainly through the steam in the conditioner, and the clinker enters the puffing cavity, but the product after pressure puffing has a high moisture content and must be dried and cooled. When the moisture content of soybeans is low, the wet puffing method can be used, because adding steam is easy to temper, which can increase the yield per unit time, and has a strong destructive effect on some anti-nutritional factors, which can further improve and improve soybean flour. nutritional value.

2. Adjustment of temperature and time The adjustment of puffing temperature and time is mainly adjusted according to the moisture content of soybean. When the moisture content of soybeans is high, the quality of soybean meal meets the requirements. The method of curing is to increase the curing speed without adding steam. temperature, slow down processing and extend post-cure time. We explore in practice that when the soybean moisture is 14%-16%, the processing temperature is gradually increased to 150-160°C for 6-7 minutes; if the soybean moisture is below 13.5%, the temperature can be lowered to 120- 130 ℃, the time is 5-6 minutes, will get better marinating effect.

3. Maturity detection The purpose of ripening raw soybeans is to effectively destroy some anti-nutritional factors, improve their utilization rate, and obtain better production performance after raising livestock and poultry. However, if it is overripe, it will cause some amino acid damage. Excessive heating causes greater damage to lysine, arginine and cystine, and also leads to reduced digestibility of methionine, isoleucine and lysine, and reduced food intake. If the maturity is not enough, some anti-nutritional factors in soybean, such as trypsin inhibitor, lipoxygenase, urease, etc., cannot be effectively destroyed, which seriously affects its utilization rate, so the maturity must be tested. Generally, urease activity in soybean meal is measured to determine maturity. At present, there are many detection methods, the more commonly used are the pH value increase method and the phenol red method. my country's feed standard stipulates that the pH value of urease activity should not exceed 0.4. Many studies have shown that the urease activity is only in the range of 0.03 to 0.4, and the feeding effect is the best. But it is better to use urea phenol red qualitative method to detect the activity of urease in the feed factory. Therefore, the method is simple and quick, has a low technical level, is easy to master, can also achieve the purpose of detection in production, and is suitable for popularization and use. The more commonly used methods are the pH increase method and the phenol red method. my country's feed standard stipulates that the pH value of urease activity should not exceed 0.4. Many studies have shown that the urease activity is only in the range of 0.03 to 0.4, and the feeding effect is the best. But it is better to use urea phenol red qualitative method to detect the activity of urease in the feed factory. Therefore, the method is simple and quick, has a low technical level, is easy to master, can also achieve the purpose of detection in production, and is suitable for popularization and use. The more commonly used methods are the pH increase method and the phenol red method. my country's feed standard stipulates that the pH value of urease activity should not exceed 0.4. Many studies have shown that the urease activity is only in the range of 0.03 to 0.4, and the feeding effect is the best. But it is better to use urea phenol red qualitative method to detect the activity of urease in the feed factory. Therefore, the method is simple and quick, has a low technical level, is easy to master, can also achieve the purpose of detection in production, and is suitable for popularization and use. 03～0.4, the feeding effect is the best. But it is better to use urea phenol red qualitative method to detect the activity of urease in the feed factory. Therefore, the method is simple and quick, has a low technical level, is easy to master, can also achieve the purpose of detection in production, and is suitable for popularization and use. 03～0.4, the feeding effect is the best. But it is better to use urea phenol red qualitative method to detect the activity of urease in the feed factory. Therefore, the method is simple and quick, has a low technical level, is easy to master, can also achieve the purpose of detection in production, and is suitable for popularization and use.

4. The effect of puffing on the conventional nutritional components of full-fat soybeans As can be seen from Table 1, the soybeans we use have higher moisture content. Generally, according to the national standard, the moisture content of soybean should be below 13.5%. Because it is a new soybean, the moisture content of the soybean flour to be processed is also higher. It can be seen from the data that the moisture of raw soybeans is reduced by 34% and the crude fiber is reduced by 36% after dry puffing. Because at the moment of puffing, the moisture in the feed loses its bond at high temperature, the crude fiber is hydrolyzed, and the intermolecular connection is destroyed, resulting in a significant reduction in the content of moisture and crude fiber, which is also the reason why the raw soybean can improve the nutritional value after puffing. important reasons. one. There was a slight increase in protein, mainly due to lower moisture content, but little change in fat content.

Table 1 Determination % of some items of soybean and soybean meal

Items Raw Soybeans Soybean Flour

Moisture 14.23 9.38

Crude protein 36.65 37.21

Crude fat 17.02 17.11

Crude fiber 6.72 4.35

Loss rate 5.67

5. Treatment after curing. After the soybean meal is pickled, it should be noted that the soybean meal cannot be packaged immediately after it comes out, because the temperature of the soybean meal is relatively high at this time, generally 85-95 °C. Immediately encapsulated, the heat is difficult to dissipate and it takes a long time. The soybean flour in the middle of the high temperature bag will coke, causing overcooking and protein denaturation, affecting its utilization and palatability. Soy flour should be cooled before packaging after puffing. Special attention should be paid to the fact that the moisture content of the wet-expanded product is high, and it must be fully dried and cooled to achieve safe storage of moisture.