Pine pollen consists of the dried pollen from Pinaceae plants (such as Masson's pine and Chinese pine) and is rich in proteins, amino acids, vitamins, minerals, and various bioactive components. It has a wide range of applications in health products, functional foods, and animal feed additives. To enhance its processing characteristics and application efficacy, it is often processed into granular form. Wet granulation is one of the most commonly used and efficient techniques to achieve this goal.

I. Working Principle of a Pine Pollen Wet Granulator

Wet granulation is a process in which a liquid binder is added to medicinal substances or raw powder materials; utilizing the bridging and adhesive effects of the binder, fine powder particles are agglomerated to form uniform granules. This method encompasses various specific techniques, mainly including extrusion granulation, rotary granulation, fluidized bed granulation, and high-shear granulation. Compared to dry granulation, granules produced via wet granulation possess unique characteristics—such as rounded surfaces, uniform particle size, high mechanical strength, excellent abrasion resistance, and superior compressibility—making this method the most widely used in the pharmaceutical, food, and health product industries.

II. Core Objectives of Pine Pollen Granulation

Granulating pine pollen primarily aims to achieve the following key objectives:

1. Improvement of Physical Properties: Significantly enhance the flowability of the material, minimize dust generation (reduce dispersibility), and reduce the adhesion of the material to equipment surfaces, thereby ensuring precise metering in subsequent packaging, filling, or tableting operations.

2. Optimization of Production Processes: Since granules serve as intermediates in tablet manufacturing, good flowability is crucial to ensure that the weight variation of the final tablets meets quality standards. Furthermore, the granulation process improves the compressibility of the material, helping to produce tablets with an appealing appearance and appropriate hardness.

3. Enhancement of Product Quality: The resulting granules are required to have a regular shape, uniform particle size, and attractive appearance, thereby meeting the visual quality standards set for the final product.

4. Protection of the Production Environment: Effectively reduce airborne dust and powder particles, thereby creating a cleaner and safer operating environment, in compliance with modern manufacturing regulations and standards.

III. Detailed Steps and Requirements of the Pine Pollen Wet Granulation Process

To ensure granulation quality, the following rigorous process flow must be strictly adhered to:

1. Pre-treatment Stage:

• Pass the pine pollen raw material through an 80–100 mesh sieve to effectively remove potential impurities and coarse particles, thereby ensuring a uniform and consistent fineness of the base powder.

• Depending on the performance requirements of the final product (e.g., hardness, disintegration rate), appropriate excipients—such as microcrystalline cellulose (MCC) or soluble starch—may be added in suitable amounts to enhance the formability, stability, and functionality of the granules.

2. Wet Mass Preparation (Mixing and Wetting) Stage:

• In a mixer, thoroughly blend the pre-treated pine pollen with the excipients until uniform.

• Add the wetting agent—such as purified water, a specific concentration of ethanol-water solution, or other suitable binders—to the powder mixture in batches and slowly.

• During stirring, ensure the wetting agent is evenly distributed until the material reaches the ideal "wet mass" state—characterized by the ability to form a lump when squeezed by hand, yet easily crumbles upon light touch. This is a critical step determining the quality of the subsequent granules.

3. Granulation Stage:

• Load the prepared wet mass into an oscillating granulator or a high-speed rotary granulator.

• Extrude the material through a 12–20 mesh sieve to form wet granules. The sieve mesh size can be adjusted according to the target granule size.

4. Drying and Sizing Stage:

• Spread the wet granules evenly on trays and place them in a hot air circulation oven for drying; alternatively, a more efficient fluidized bed dryer may be used.

• The drying temperature is typically controlled between 40–60°C to prevent degradation of heat-sensitive components. Drying is considered complete when the moisture content of the material is reduced to ≤8% (or meets specific standard requirements).

• After drying, the granules may contain a small amount of agglomerates or fine powder; therefore, a sizing step using a 14–18 mesh sieve is necessary to obtain finished granules with uniform particle size, while collecting the undersized fine powder for subsequent rework.

IV. Core Features of an Efficient Pine Pollen Wet Granulator

Designed to meet stringent processing requirements