Extrusion technology in pet food production line

The application of extrusion technology to pet food originated in the 1950s.

Dry puffed pet food is usually extruded puffed food produced. The material is crushed in two stages and mixed twice before entering the puffing bin. After being fully tempered, it enters the extruder for extrusion puffing. At the same time, oil, pigment, meat pulp, etc. can be added to the conditioner to avoid the problem of congealing of high-fat or high-moisture materials after being added to the mixer. After extrusion, the moisture content of the material is 20% ~ 30%, and it is conveyed to the dryer by air force for drying. The dried material enters the intermittent spraying machine, which can be sprayed with grease, food attractant and flavor powder. The temperature of the feed pellets just after drying is high, which is conducive to the uniform distribution of oil. After the feed is added with oil, the internal moisture is not easy to volatilize, and the moisture content of the food attractant is also high. Before spraying, the drying intensity of the dryer should be increased accordingly. After spraying, the material enters the cooler for cooling, the moisture drops below 9%, and the temperature drops to close to room temperature.

After the pellet feed leaves the finished product warehouse, a sieve is carried out to control the broken grains and powder in the product within an ideal range, and finally it is packed by a packing scale. Pet food pellets are generally conveyed by pneumatic conveying or inclined belts to reduce residues during processing.

Pet food can be extruded by single-screw extruder or twin-screw extruder. Single-screw extruder is suitable for some low-end pet food with low oil content in the formula. The moisture during extrusion is generally at 22% ~ 28%. However, when the fresh meat content in the formula reaches 20%, the strong mixing and shearing required in the extrusion process is difficult to provide by single-screw extruders. At this time, the advantages of twin-screw extruders will be highlighted. Compared with the extruder, the twin-screw extruder can add almost twice the amount of fat to pet food, and the feed formula can contain 12% fat.