Particle Size, Solubility and Blend Compatibility in Powdered Ingredients
Quick Summary
- Particle size affects blend uniformity, solubility rate, mouthfeel, and flow in capsule-filling equipment — it is not a cosmetic specification
- Solubility depends not just on the ingredient's inherent chemistry but on the conditions of your specific formulation matrix: pH, temperature, ionic strength, and presence of other dissolved solutes
- Blend compatibility concerns physical behaviour (particle size segregation, hygroscopicity, electrostatic charge) and chemical behaviour (reactivity between ingredients under storage or processing conditions)
- Specifying particle size on your purchase order protects against batch-to-batch variation that would affect your product's performance
Particle Size — Why It Matters and How It's Measured
Particle size describes the average physical dimensions of powder particles. For bulk powdered ingredients, it is typically expressed as:
- Mesh size (Tyler or US Standard): A coarser measure — e.g. "100 mesh" means particles pass through a sieve with 100 openings per linear inch (~150 μm). Larger mesh numbers = smaller particles.
- D50 / D90 (volume-weighted median diameter): D50 is the median particle diameter (half of particles are smaller, half are larger); D90 means 90% of particles are below this diameter. Both expressed in microns (μm). More precise than mesh for functional specification.
Effect on blend uniformity: In a multi-component supplement powder, large particle size differences between ingredients cause segregation — heavy, coarse particles settle while fine particles remain suspended, creating non-uniform dose distribution. Best practice is to minimise particle size differences across blend components, or to granulate fine/coarse ingredients together before final blending.
Effect on solubility rate: Smaller particles dissolve faster than larger particles of the same composition because surface area relative to volume is greater. Micronised Creatine Monohydrate dissolves more readily in a shake than standard Creatine Monohydrate for this reason — same molecule, different dissolving behaviour.
Effect on flow in capsule filling: Very fine powders (<10 μm) often have poor flowability due to interparticle adhesion and electrostatic charge. Silicon Dioxide (0.5–2%) reduces this by coating particles and reducing adhesion. Standard Creatine Monohydrate flows well; highly micronised amino acids may need a flow agent.
Key YNP Ingredients by Typical Particle Size Profile
| Ingredient | Typical form | Relevant particle concern |
|---|---|---|
| Creatine Monohydrate | Standard and micronised grades | Standard: coarser, lower solubility; micronised: finer, better dispersion |
| Beta-Alanine | Fine powder | Good flow for capsule filling; fine enough for rapid beverage dispersion |
| BCAA 2:1:1 | Powder | L-Leucine in the blend has poor flow; silicon dioxide recommended |
| Whey Protein Concentrate | Spray-dried powder | Particle size affects dispersibility — instant grades use lecithin for better wetting |
| Pea Protein | Spray-dried powder | Larger particle size than whey; may settle faster in beverages — stabiliser required |
| Silicon Dioxide | Ultrafine amorphous powder | Acts as flow agent by coating larger particles |
| Citric Acid | Granule or fine powder | Granule flows better; fine powder can cake at humidity — confirm grade |
| Maltodextrin | Spray-dried | Particle size determines dispersibility and carrier properties |
*(Table is horizontally scrollable on mobile)*
Solubility — What "Freely Soluble" Means in Practice
Published solubility values (e.g. "freely soluble in water") are measured in pure water at a defined temperature, typically 25°C. Your formulation matrix is almost certainly not pure water:
- pH: Ascorbic Acid is more stable and fully soluble at acidic pH; its solubility decreases and stability collapses at alkaline pH. L-Tyrosine is sparingly soluble at neutral pH but more soluble at acidic pH.
- Temperature: Most ingredients dissolve faster and more completely at higher temperatures. Confirm that your mixing temperature allows adequate hydration.
- Ionic strength: Dissolved salts in a formulation matrix can either increase or decrease solubility of other compounds via salting-in or salting-out effects.
- Other dissolved solutes: A high-protein matrix may reduce effective solubility of minerals through protein-mineral binding.
Practical rule: Always test solubility in your actual formulation matrix at your actual processing conditions — do not rely solely on published single-ingredient values.
Blend Compatibility — Physical and Chemical Considerations
Physical incompatibility: Highly hygroscopic ingredients (L-Carnitine Base, taurine) can accelerate caking of adjacent particles in a blend. Store hygroscopic ingredients separately until immediately before blending, or consider encapsulated forms where available.
Chemical incompatibility: Ascorbic Acid (a reducing agent) can accelerate oxidation-reduction reactions with certain mineral ingredients or reactive amines under storage conditions. Amine-containing ingredients (amino acids) and reducing sugars (fructose, maltodextrin) can undergo Maillard reaction under warm, humid storage — browning of powder blends on shelf is a documented commercial problem.
Buyer Checklist
- Particle size (D50 or mesh range) specified in purchase order for any ingredient where blend uniformity is critical
- Solubility tested in your actual formulation matrix at your actual processing temperature — not assumed from published values
- Hygroscopic ingredients identified and separated in storage until immediately before blending
- Silicon Dioxide (0.5–2% w/w) included in blends containing poor-flow amino acids (leucine, some vitamins)
- Maillard-reactive combination (reducing sugars + amino acids in warm, humid storage) evaluated for colour stability
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Related Glossary Terms
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References
Industry Information
- Rowe RC, Sheskey PJ, Cook WG, Fenton ME (eds). *Handbook of Pharmaceutical Excipients.* 7th ed. Pharmaceutical Press — standard reference for particle size, flow, and blend compatibility of excipients.
- Langford N, Boor BE. *Nutraceutical Powder Blending and Content Uniformity.* Nutraceutical World — industry reference for blend uniformity challenges in dietary supplement manufacturing.