회사 소식 What Is the Cooking Degree of a Single-Screw dog food pellet maker machine?

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The degree of cooking in a Single-Screw dog food pellet extruder machine typically ranges from 70% to 95%, depending on:

1. Raw material formulation (starch and protein content)
2. Moisture level (usually 20%–30%)
3. Extrusion temperature (120°C–160°C)
4. Screw configuration and speed
5. Residence time inside the barrel

A higher degree of cooking improves digestibility, expansion, and product quality, making it essential for pet food and aquatic feed production.

Understanding “Cooking Degree” in Extrusion

In extrusion processing, “cooking” does not mean traditional heating. It is a controlled transformation where heat, pressure, moisture, and mechanical shear work together to modify raw materials. The degree of cooking determines whether the final product is digestible, well-expanded, and nutritionally effective.

For manufacturers, mastering this parameter is like controlling the “doneness” of every pellet produced.

What Is the Degree of Cooking in a Single-Screw dog food pellet making machine?

The degree of cooking refers to how completely raw materials, especially starch and protein, are gelatinized and denatured during extrusion.

Key transformations include:

• Starch gelatinization
• Protein denaturation
• Destruction of anti-nutritional factors

In most applications, a single screw extruder achieves 70%–95% cooking, depending on process conditions.

Why the Degree of Cooking Is Critical for Feed Quality

A proper cooking degree directly impacts:

• Digestibility: Higher cooking improves nutrient absorption
• Expansion: Well-cooked starch creates better puffing
• Texture: Determines whether pellets are crispy or dense
• Water stability: Important for aquatic feed

Too low or too high cooking can both reduce product quality.

Key Factors Affecting the Degree of Cooking

1. Raw Material Composition

The formula acts as the “chemical foundation.”

• High starch → easier gelatinization
• High protein → requires more energy to cook

Balanced formulations improve overall cooking efficiency.

2. Moisture Content

Moisture is essential for heat transfer and gelatinization.

• Too low → incomplete cooking
• Too high → reduced expansion

Recommended range: 20%–30%

3. Extrusion Temperature

Temperature drives the cooking reaction.

• Low temperature → undercooked material
• High temperature → over-processing or nutrient loss

Optimal range: 120°C–160°C

4. Screw Design and Speed

The screw controls shear force and residence time.

• Higher speed → more shear, shorter time
• Lower speed → longer cooking time

Proper balance ensures uniform cooking.

5. Residence Time

Residence time is how long material stays inside the barrel.

• Short time → insufficient cooking
• Long time → possible degradation

Optimal residence time ensures full but controlled cooking.

How to Measure the Degree of Cooking

In industrial practice, cooking degree is evaluated through:

• Starch gelatinization tests
• Water absorption index (WAI)
• Product expansion ratio
• Digestibility tests

These indicators help verify whether the extrusion process is optimized.

Single-Screw Pet Food Extruder Machine vs. Twin-Screw Dog Food Maker Machine: Cooking Performance Comparison

• Single Screw Extruder:
  Cooking degree: 70%–95%
  Suitable for standard feed production

• Twin Screw Extruder:
  Cooking degree: up to 100%
  Better for complex formulations and premium products

Single-Screw dog food pellet machines offer a balance between cost and performance.

Common Problems Related to Cooking Degree

Undercooked Product

• Dense texture
• Poor digestibility
• Low expansion

Solution: Increase temperature, moisture, or residence time

Overcooked Product

• Burnt smell
• Nutrient degradation
• Dark color

Solution: Reduce temperature and adjust screw speed

How to Optimize Cooking Degree in Production

To achieve ideal cooking performance:

• Adjust formulation (increase starch content)
• Control moisture precisely
• Maintain stable temperature zones
• Optimize screw configuration
• Monitor product quality continuously

Fine-tuning these factors ensures consistent results.

Application Scenarios: Why Cooking Degree Matters

• Pet food production: improves palatability and digestibility
• Fish feed: enhances floating performance and water stability
• Livestock feed: increases nutrient utilization

Cooking degree directly influences product competitiveness in the market.

FAQ: Degree of Cooking in Extrusion

Q1: Is higher cooking degree always better?
No, excessive cooking can damage nutrients and reduce quality.

Q2: Can single screw extruders achieve full cooking?
They can reach high levels, but typically not as complete as twin screw systems.

Q3: What is the ideal cooking degree?
Generally between 80%–90% for most feed applications.

Q4: How to quickly judge cooking quality?
Check expansion, texture, and internal structure of pellets.

Conclusion: Controlling Cooking Degree for Better Product Quality

The degree of cooking in a Single-Screw floating fish food extruder machine is a critical parameter that defines the success of feed production. By carefully balancing raw materials, moisture, temperature, and mechanical settings, manufacturers can achieve optimal cooking levels that enhance digestibility, texture, and overall product value.

In extrusion, perfection is not accidental. It is engineered through precise control.