Fine Grinding of Peanut Butter and Sesame Paste: the Birth of Colloid Mill
Introduction: The Importance of Sauce Grinding Technology
As popular condiments, the delicate taste and rich flavor of peanut butter and sesame paste largely depend on the fine grinding process. Although traditional stone mills can achieve a certain degree of fineness, the modern food industry generally uses colloid mill technology, which can crush solid particles to micron level and form a stable emulsified system. This article will deeply analyze the key role of colloid mill in the production of nut butters, from equipment structure, working principle to systematic optimization of process parameters.
Working Vedio of Seasame Peanuts Butter Maker
Section 1: Basic structure and core components of colloid mill
Colloid mill is a high shear force crushing and emulsification equipment, mainly composed of the following core components:
Grinding head system: It consists of a stator and a rotor, usually made of special alloy or tungsten carbide, and the surface is precisely machined to form a serrated structure. The gap between the stator and the rotor can be precisely adjusted (usually 50-200μm), which is the key parameter for controlling the fineness of the grinding.
Power system: A high-power motor (usually 7.5-45kW) drives the rotor at a high speed of 3000-15000rpm through a belt or direct drive, generating a strong centrifugal force.
Cooling system: To prevent high-speed friction from causing temperature rise and affecting product quality, a circulating water cooling jacket is designed around the grinding chamber to keep the working temperature in the ideal range of 40-60℃.
Feeding and discharging system: Continuous feeding by screw or pumping, the discharge port is equipped with a pressure regulating device to control the residence time of the material in the grinding chamber.
Section 2: How colloid mills work in nut butter production?
When the pre-treated peanuts or sesame seeds (after roasting and peeling) enter the colloid mill, they undergo a three-stage crushing and emulsification process:
Primary crushing stage: The high-speed rotating rotor forcefully sucks the material into the grinding tooth gap, and the coarse particles are initially crushed under mechanical extrusion and shearing. Experimental data show that this stage can reduce the average particle size from the initial 500-1000μm to 100-200μm.
Fine grinding stage: The material experiences violent turbulence and cavitation effect in the narrow grinding gap, and the particles are further crushed to 10-50μm. At this time, the nut cell structure is completely destroyed and the oil begins to release.
Homogenization and emulsification stage: The released oil and solid particles form an O/W emulsion under the action of surfactants (such as natural phospholipids in nuts). The high-frequency vibration (up to 20kHz) generated by the colloid mill promotes emulsification stability, giving the sauce a delicate and dense taste.
Section 3: The influence of process parameters on product quality
Particle size control: By adjusting the gap between the stator and rotor and grinding in multiple cycles, the peanut butter D90 particle size can be ≤25μm. Studies have shown that when the particle size is <30μm, more than 90% of consumers cannot perceive the particle texture.
Temperature management: The optimal grinding temperature should be controlled at 50±5℃. Too low temperature (<40℃) will increase viscosity and affect fluidity; too high temperature (>65℃) may cause protein denaturation and oil oxidation.
Viscosity adjustment: Adding an appropriate amount of vegetable oil (1-3% of the total amount) can reduce the viscosity of the system and improve grinding efficiency. However, excessive addition will make the product too thin and affect the taste.
Oxidation control: Nitrogen filling in the grinding chamber can control the peroxide value (POV) of the sauce below 0.5meq/kg, significantly extending the shelf life.
Section 4: Technological innovation of modern colloid mill
Compared with stone mill (average particle size about 80-100μm) and ball milling process, colloid mill has significant advantages:
Improved efficiency: The required fineness can be achieved in a single pass, and the processing capacity can reach 500-2000kg/h, which is 10-15 times that of a stone mill.
Stable quality: CV value (particle size variation coefficient) <5%, much lower than the 15-20% of traditional methods.
Nutritional retention: Low-temperature and short-time processing can retain vitamin E >95%, while the stone grinding process is about 85%.
Automation degree: CIP online cleaning can be realized to reduce the risk of microbial contamination.
Conclusion and Outlook
Through its unique structure and precise parameter control, colloid milling technology achieves the texture transformation of nut butter from macroscopic particles to microscopic emulsion. In the future, with the development of nano-grinding technology and intelligent sensing, high-quality products with more uniform particle size (D90≤10μm) and better oxidation stability may appear. At the same time, energy saving and clean production will also become the focus of equipment research and development, promoting the development of nut butter processing technology in a more efficient and precise direction.