Temperature control techniques for foam resistance in aquatic fish and shrimp feed

The effect of temperature on the soaking resistance of fish and shrimp feed is mainly achieved through the starch gelatinization rate. The starch in fish and shrimp feed needs to be fully gelatinized to form a dense network structure that encapsulates nutrients such as protein, thus extending soaking resistance. When the temperature of the manual fish food making machine is controlled at 120-135℃, the starch gelatinization rate can reach over 90%. A protective film forms on the surface of the feed after it enters the water, effectively delaying water penetration. If the temperature is below 110℃, the starch gelatinization rate is less than 60%, resulting in a loose feed structure that disintegrates within 10-15 minutes after entering the water. Temperatures above 140℃ lead to excessive starch gelatinization, causing the feed surface to become sticky and easily clump together, also affecting feeding efficiency.

Different fish and shrimp species require different feed temperature controls. Feeds for benthic crustaceans such as shrimp and crabs require higher resistance to soaking. The temperature of the extrusion section should be controlled at 130-135℃, while the temperature of the discharge section should be lowered to 125-130℃ to prevent scorching of the feed surface. Feeds for freshwater fish such as grass carp and crucian carp have slightly lower requirements for soaking resistance; the temperature of the extrusion section can be set at 120-125℃, balancing soaking resistance and digestibility. Feeds for carnivorous fish such as perch and grouper have high animal protein content, and the temperature needs to be controlled at 110-120℃ to prevent high temperatures from damaging the active ingredients in the fishmeal, such as EPA and DHA. These components will show significant degradation above 130℃, with a loss rate of over 25%.

In practice, a "segmented precise temperature control + real-time monitoring" model should be adopted. The feeding section operates at 80-90℃ to preheat the raw materials and remove some moisture. The compression section gradually heats up to 100-110℃, initially plasticizing the materials. The extrusion section is set to a target temperature of 110-135℃ based on the fish and shrimp species, with precise temperature compensation via electromagnetic heating coils. The discharge section temperature is 5-10℃ lower than the extrusion section to ensure stable feed formation. Simultaneously, an infrared thermometer is installed at the extruder outlet to monitor the feed temperature in real time. Starch gelatinization rate is sampled every 10 minutes; if the gelatinization rate is below the standard, the extrusion section temperature is promptly increased by 3-5℃.

Furthermore, temperature control requires coordinating with raw material pretreatment. Fish and shrimp feed ingredients need to be pre-dried to a moisture content of 12%-14% to avoid temperature fluctuations within the barrel due to excessive moisture. For shrimp and crab feeds with high crude fiber content, 1%-2% oil can be added to the raw materials to reduce mechanical shear resistance, minimize additional heat generation, and facilitate temperature control.

About Us

Customer visit

Certificate of Honor