Introduction: From Traditional Crushing to Superfine Pulverization Technology
Peanuts are one of the most important oilseed and economic crops worldwide. With the rapid development of deep-processing technologies, the peanut industry is experiencing a significant transformation from traditional coarse processing to high-precision, high-value manufacturing.
Among various emerging technologies, the superfine pulverization system has become a key breakthrough in physical processing. By reducing peanut materials to micron or even sub-micron levels, this technology fundamentally improves product functionality, application scope, and economic value. It enables the production of high-value products such as superfine peanut protein powder, nano-scale peanut butter, whole-peanut functional powders, and special medical nutrition ingredients.
This article provides a systematic overview of superfine pulverization systems in peanut processing, covering technical principles, system configuration, industrial applications, economic benefits, and future development trends, offering practical guidance for peanut processors and food manufacturers.
1. Technical Principles and System Composition of Superfine Pulverization
1.1 Basic Principles of Superfine Pulverization
Superfine pulverization is a physical process that overcomes the internal cohesive forces of materials through high-energy mechanical action, reducing particle size to 1–100 μm, or even below 1 μm.
Unlike traditional crushing methods that rely on single mechanical forces, superfine pulverization systems typically combine multiple forces, including:
High-Energy Impact Pulverization
High-speed rotors generate strong centrifugal forces, causing intense collisions between particles and equipment walls. This is essential for breaking down peanut cell walls composed of cellulose, hemicellulose, and lignin.
Airflow Vortex Grinding
Particles are accelerated by high-velocity airflow to form vortex motion, achieving refinement through particle-to-particle collision and friction. This method is particularly suitable for high-oil materials such as peanuts, as it minimizes temperature rise and prevents oil oxidation or protein denaturation.
Medium Grinding
Grinding media such as ceramic or zirconia beads are used inside closed chambers. Parameters like media size, filling ratio, and grinding time directly determine final particle size distribution and uniformity.
Integrated Classification and Separation
Dynamic classifiers are integrated into superfine systems to separate qualified particles in real time, preventing over-grinding and ensuring narrow particle size distribution. For peanut protein powder, this significantly enhances solubility and emulsification performance.
1.2 Main Components of a Superfine Pulverization System
A modern peanut superfine pulverization system typically consists of the following modules:
Pretreatment Module
Includes low-temperature drying, pre-crushing, and homogenized feeding. Peanut moisture content is adjusted to 4–6%, pre-crushed to 20–40 mesh, and fed uniformly to ensure stable system operation.
Core Pulverization Module
Different equipment types are selected based on product requirements:
- Air jet mills for peanut protein, ensuring minimal temperature rise (≤10 °C)
- Vibration mills or stirred media mills for whole peanut powder, enabling complete cell wall disruption
Classification Module
High-precision classifiers enable particle size control down to 1 μm, ensuring consistent product quality (e.g., D90 ≤15 μm for peanut protein powder).
2. Application of Superfine Pulverization in Peanut Protein Processing
2.1 Enhancing Functional Properties of Peanut Protein
Traditional peanut protein powders usually have particle sizes above 50 μm, resulting in limited solubility and emulsification performance.
After superfine pulverization:
- Particle size is reduced to 10–20 μm
- Specific surface area increases 5–8 times
- Hydrophilic groups are more exposed
Performance improvements include:
- Solubility at pH 7.0 increases from ~65% to ~89%
- Emulsification Activity Index (EAI) improves by 40–60%
- Emulsification Stability Index (ESI) increases 2–3 times
These improvements allow superfine peanut protein to be used in liquid protein beverages, plant-based dairy alternatives, and functional foods.
2.2 Improving Protein Extraction Rate and Purity
Superfine pulverization significantly enhances protein extraction efficiency from peanut meal:
Improved Cell Wall Disruption
Cell disruption rates exceed 95%, compared with 70–80% for traditional crushing.
Higher Protein Yield
Protein extraction rates increase from 75% to over 92%, while extraction time is reduced by one-third.
Reduction of Anti-Nutritional Factors
Mechanical action disrupts protein–phytate complexes:
- Phytic acid residues reduced by ~60%
- PDCAAS value improves from 0.65 to 0.82
3. Application in Peanut Butter and Peanut-Based Products
3.1 Improving Texture and Stability of Peanut Butter
Superfine pulverization fundamentally solves common peanut butter quality issues:
- Particle size reduced to 15–25 μm
- Narrow particle size distribution (span <1.5)
- Smooth, creamy texture without grittiness
Stability performance:
- Oil separation after 6 months at 25 °C < 2%
- Traditional peanut butter: 8–12%
3.2 Development of Innovative Peanut Products
Superfine pulverization enables new product categories:
Instant Whole Peanut Powder
- Cold-water solubility > 85%
- Suitable for infant food, elderly nutrition, and sports supplements
- Fast reconstitution with no sedimentation
Peanut-Based Texture Modifiers
- Used as fat substitutes in bakery applications
- 15% addition can reduce butter usage by 20%
- Maintains flavor and sensory quality
4. Economic Benefits and Nutritional Preservation Advantages
4.1 Economic Benefit Analysis
Although initial investment is relatively high, overall ROI is attractive:
- Typical system investment: RMB 2–5 million
- Payback period: 2–3 years
Value Creation Examples
- Protein yield increase: +30–40 kg per ton of peanut meal
- Added value: RMB 600–800 per ton
- Annual revenue increase (10,000 t/year): > RMB 6 million
Superfine products also command significantly higher market prices.
4.2 Preservation of Nutritional Components
Superfine pulverization operates under low-temperature conditions (<40 °C), offering clear advantages:
- Peroxide value reduced by ~70%
- Shelf life extended 2–3 times
- Protein digestibility improves by 8–12%
- Essential amino acid absorption increases by 10–15%
5. Technical Challenges and Development Trends
5.1 Current Technical Challenges
- High equipment and operating costs
- Energy consumption, especially for air jet systems
- Temperature control for high-oil peanut materials
5.2 Future Development Trends
Intelligent and Automated Control
AI-based monitoring systems will enable real-time particle size adjustment and process optimization based on raw material characteristics.
Low-Temperature and Cryogenic Pulverization
Liquid nitrogen and deep-cryogenic technologies will further protect heat-sensitive nutrients and flavors, supporting premium functional food development.
Conclusion
The superfine pulverization system represents a major shift in peanut processing—from coarse grinding to precision manufacturing. It unlocks the full value potential of peanuts by improving functionality, nutritional quality, and economic returns.
For peanut processors and food manufacturers, adopting superfine pulverization technology is not only a pathway to product differentiation but also a strategic step toward high-value, technology-driven, and sustainable development.
As equipment technology matures and costs decrease, superfine pulverization will become a core processing solution across the global peanut industry.
