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28
Sep

The problems in the processing of extruded floating feed

1.Selection of extrusion methods There are mainly two kinds of extrusion methods: dry extrusion and wet extrusion. Which one to choose depends on the actual situation. First of all, it depends on the function of the puffing machine you use. At present, we are using the PHG135 dry extruder from high-efficiency extrusion extruder from Henan Lima machinery. The latter can be used for both dry and wet extrusion. It should be determined according to the moisture of soybeans. When the moisture of soybeans is high, it is best to use dry puffing, which is conducive to the evaporation of water and the reduction of the moisture content of soybean flour. Wet puffing is mainly to pass steam in the conditioner, and the cooked material enters the puffing cavity, but the moisture content of the product after pressure puffing is high, and it must be dried and cooled. When the moisture content of soybeans is low, wet puffing can be used, because it is easy to temper by adding steam, which can increase the yield per unit time, and has a stronger 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 based on the moisture content of soybeans. When the moisture content of soybeans is high, the quality of soybean flour meets the requirements. The method of curing is to increase the curing rate without adding steam. temperature, slow down the processing speed, and extend the post-curing time. We have explored in practice that when the moisture of soybeans is 14% to 16%, the processing temperature is gradually increased to 150 to 160 °C for 6 to 7 minutes; if the moisture of soybeans is below 13.5%, the temperature can be lowered to 120-130 ℃, the time is 5-6 min, will get better curing effect.
3.Inspection of ripening degree The purpose of ripening raw soybean is to effectively destroy some anti-nutritional factors, improve their utilization rate, and enable livestock and poultry to obtain better production performance after feeding. However, if it is over-ripened, it will cause the destruction of some amino acids. Such as excessive heating, the damage to lysine, arginine and cystine is greater, and it will also cause the digestibility of methionine, isoleucine and lysine to decrease, and food intake to decrease. If the degree of ripening 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 degree of ripening must be tested. Generally, the urease activity in soybean flour is determined to determine the degree of ripening. There are many detection methods at present, the more commonly used are pH value-added method and 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. However, it is best to use the urea-phenol red qualitative method to detect the activity of urease on the feed factory site. Therefore, the method is simple and fast, the technical level is not high, and it is easy to master, and it can also achieve the purpose of detection in production, which is suitable for popularization and use.
4.The influence of puffing processing on the conventional nutrients of full-fat soybeans It can be seen from Table 1 that the moisture content of the soybeans we use is relatively high. Generally, according to the national standard requirements, the moisture of soybeans should be below 13.5%. Because it is new soybeans, it is necessary to process The moisture content of the finished soybean flour was also somewhat high. 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 water in the feed loses its restraint at high temperature, the crude fiber is hydrolyzed, and the intermolecular connection is broken, resulting in a substantial reduction in the content of water and crude fiber, which is also an important reason why raw soybeans can improve their nutritional value after puffing. one. There was a slight increase in protein, mainly due to reduced 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 curing soybean meal, it should be noted that the soybean meal should not be packaged immediately after it comes out, because the temperature of soybean meal is relatively high at this time, generally 85-95°C. Immediately package, the heat is difficult to dissipate, and it will take a long time. The soybean flour in the middle of the high-temperature bag will be coke, which will cause over-cooking and protein denaturation, which will affect its utilization and palatability. Soybean flour should be cooled after puffing before packaging. Special attention should be paid to the fact that the moisture content of the product after wet puffing is high, and it must be fully dried and cooled to achieve safe storage moisture.