Flaxseed Powder — Process & Workflow Document¶

Document ID: PROD-PROC-001
Version: 1.0
Effective Date: 2026-07-20
Product: Flaxseed Powder (Full-Fat & Defatted)

1. Process Overview¶

The flaxseed powder manufacturing line converts cleaned flaxseed kernels (or whole seed) into a shelf-stable, finely milled powder. Two distinct process lines exist: Full-Fat and Defatted. The core flow is shared but key parameter differences are noted in each section below.

Process Flow Diagram¶

Kernel / Whole Seed
       ↓
  Metal Detection (CCP-5)
       ↓
  Milling (Hammer / Pin / Cryo)
       ↓
     Sifting
       ↓
  N₂ Flush & Blending
       ↓
  Metal Check (CCP-5)
       ↓
    Packaging

2. Detailed Process Steps¶

2.1 Kernel / Whole Seed Receiving & Pre-Cleaning¶

Parameter	Full-Fat Line	Defatted Line
Seed source	Brown/golden flaxseed kernels	Defatted flaxseed meal from oil press
Moisture spec	≤8.0%	≤6.0%
Foreign matter	≤0.5%	≤1.0%
Pre-cleaning	Air classifier + magnet	Vibrating screen + magnet

Quality Gate: Visual inspection per batch — no mold, insect damage, or off-odor.
Defatted: Meal is received from the screw press (see oil-process.md), typically with 8–12% residual oil.

2.2 Metal Detection — CCP-5¶

Parameter	Value
Detection threshold	Fe ≥1.0 mm, Non-Fe ≥1.5 mm, SS ≥2.0 mm
Reject mechanism	Pneumatic diverter gate
Calibration frequency	Every 2 hours (with test wands)
Deviation limit	≤1 reject per 1000 kg

CCP-5: Metal detection is the controlling critical control point for physical hazards.
Corrective action: Reject contaminated batch; recalibrate detector; record in CCP log.
Monitoring: Continuous with auto-reject; verified every 30 min by operator.

2.3 Milling¶

Three mill types are available depending on target particle size and product specification.

2.3.1 Hammer Mill (Standard, Full-Fat & Defatted)¶

Parameter	Range / Typical
Rotor speed	2,800 – 3,600 RPM
Screen aperture	0.8 – 3.0 mm
Tip speed	80 – 120 m/s
Throughput	300 – 800 kg/hr (depends on screen size)
Motor power	30 – 55 kW

Particle size control: Smaller screen aperture → finer powder. A 0.8 mm screen produces ~200 mesh; 1.5 mm → ~100 mesh; 3.0 mm → ~60 mesh.
Full-Fat line: Pre-chill kernels to 4–10°C to prevent heat buildup and oil smear.

2.3.2 Pin Mill (Ultra-Fine, Full-Fat)¶

Parameter	Range / Typical
Rotor speed	6,000 – 12,000 RPM
Pin disc diameter	300 – 600 mm
Airflow	500 – 1,500 m³/hr (pneumatic conveying)
Throughput	100 – 400 kg/hr
Product temperature at outlet	≤45°C

Particle size control: Higher RPM → finer particles. At 10,000+ RPM, D50 reaches 30–50 µm (~300 mesh).
Note: Suitable for full-fat only when combined with cooling air. Not recommended for defatted (high fines → dust explosion risk).

2.3.3 Cryogenic Mill (Premium, Full-Fat)¶

Parameter	Range / Typical
Grinding temperature	−150°C (liquid N₂ injection)
N₂ consumption	1.5 – 2.5 kg N₂ per kg product
Mill type	Impact mill (pin or hammer) enclosed in cryogenic shroud
Throughput	80 – 200 kg/hr
Product temperature at outlet	≤−20°C

Particle size: D50 = 20–40 µm (~400 mesh) achievable without thermal degradation.
Advantages: Preserves omega-3 fatty acids; prevents oil smear and screen clogging; extends shelf life by 30–50%.
Cost factor: Cryogenic milling adds $0.30–0.60/kg to production cost.
Quality Gate: Verify mill chamber temperature via thermocouple every 15 min.

2.4 Sifting¶

Parameter	Value
Sieve mesh	60 – 200 mesh (depending on target)
Sieve type	Gyratory or tumbler sifter
Oversize recycle	Returns to mill hopper
Throughput	Matches mill output

Quality Gate: Sieve analysis every 30 min — 95% passing target mesh.
Target mesh table:

Powder Grade	Target Mesh	Typical D50	Application
Coarse	60 mesh	250 µm	Baking, bulk blends
Standard	80 mesh	180 µm	General food ingredient
Fine	100 mesh	150 µm	Smoothies, beverages
Ultra-fine	200 mesh	75 µm	Nutritional supplements

2.5 N₂ Flush & Blending¶

Parameter	Full-Fat Line	Defatted Line
Residual O₂ in headspace	≤2.0%	≤3.0%
N₂ purity	≥99.9%	≥99.5%
Blending time	5 – 10 min (ribbon blender)	3 – 5 min
Temperature after blending	≤35°C	≤30°C

Purpose: Displace oxygen to prevent lipid oxidation (full-fat is more susceptible).

2.6 Metal Check — CCP-5 (Final)¶

Parameter	Value
Detection threshold	Fe ≥0.8 mm, Non-Fe ≥1.2 mm, SS ≥1.5 mm
Reject mechanism	Pneumatic pusher on conveyor
Verification	Test wand every 2 hours

Critical limit: Any ferrous metal >0.8 mm triggers rejection.
Record keeping: All reject events logged with batch ID, time, and corrective action.

2.7 Packaging¶

Parameter	Full-Fat Line	Defatted Line
Pack sizes	0.5 – 25 kg (multiwall kraft + PE liner)	10 – 25 kg
Gas flushing	N₂ (optional for retail pouches)	Not required
Seal integrity	Vacuum decay test every 100 packs	Visual check
Shelf life (declared)	12 months (ambient)	18 months

3. Quality Gates (In-Process Checks)¶

Check	Frequency	Method	Acceptable Limit	Action if Out of Spec
Mill outlet temperature	Every 30 min	Infrared thermometer	≤45°C (≤30°C for defatted)	Reduce feed rate, check cooling
Particle size (sieve)	Every 30 min	Ro-tap sieve shaker	95% passing target mesh	Adjust screen/RPM, re-mill oversize
Peroxide Value (PV)	Every 30 min (full-fat)	AOCS Cd 8-53	≤2.0 meq O₂/kg	Divert to defatted line, check N₂ supply
Moisture content	Every 30 min	Halogen moisture analyzer	≤6.0% (full-fat), ≤5.0% (defatted)	Adjust drying parameters
Metal detector test	Every 2 hours	Test wands (Fe, Non-Fe, SS)	All detected and rejected	Recalibrate, hold product since last OK test
Color (visual)	Every hour	Visual standard (Lab* optional)	Consistent with reference	Check for scorching, adjust mill speed

4. CCP Integration Summary¶

CCP Code	Hazard Type	Control Point	Critical Limit	Monitoring
CCP-4	Biological (moisture)	Pre-mill drying / moisture control	Moisture ≤8.0%	In-line moisture meter every 30 min
CCP-5	Physical (metal)	Inlet metal detector + final metal check	Fe ≥1.0 mm / ≥0.8 mm	Continuous + test wand every 2 hr

5. Troubleshooting¶

5.1 Overheating During Milling¶

Possible Cause	Check	Solution
Feed rate too high	Mill amperage draw	Reduce feed rate by 10–20%
Screen clogged	Pressure drop across screen	Replace or clean screen
Insufficient cooling air	Airflow meter	Increase airflow or check ducting
Blunt hammers/pins	Visual wear pattern	Replace wear parts
High ambient temp	Room thermometer	Pre-cool feedstock to ≤10°C

5.2 Poor Grind (Inconsistent Particle Size)¶

Possible Cause	Check	Solution
Worn screen / pin disc	Visual inspection	Replace worn parts
Wrong screen aperture	Screen spec tag	Install correct screen
Variable feed rate	Feed hopper level	Ensure consistent feed (vibratory feeder)
Moisture > 8%	Moisture analyzer	Pre-dry seed to ≤8%
RPM too low	Tachometer reading	Increase to target RPM range

5.3 High Peroxide Value (PV > 2.0 meq/kg)¶

Possible Cause	Check	Solution
Mill temperature too high	Product outlet temp	Reduce mill speed, increase cooling
High O₂ in headspace	Headspace O₂ analyzer	Increase N₂ flow rate
Old feedstock	Raw material age	Use fresher seed (≤6 months old)
Metal contamination (pro-oxidant)	Metal detector	Check for wear metal in product
Cryo mill — insufficient N₂	N₂ flow meter	Increase N₂:product ratio to ≥1.5:1

5.4 Clogging / Screen Blinding¶

Possible Cause	Check	Solution
Oil smear (full-fat, temp > 40°C)	Mill outlet temp	Pre-chill seed, reduce RPM
High moisture (> 8%)	Moisture analyzer	Dry seed before milling
Screen aperture too small	Screen spec	Use larger aperture (e.g., 1.5 mm)
Feed rate too high	Mill load amps	Reduce feed rate
Fine recirculation buildup	Oversize return line	Clean recirculation path

5.5 High Fines / Dust (Defatted Line)¶

Possible Cause	Check	Solution
Hammer mill speed too high	RPM reading	Reduce to 2,800–3,000 RPM
Screen too fine	Screen size	Increase to ≥1.5 mm
Meal too dry	Moisture analyzer	Target 5–6% moisture
Inadequate dust collection	Baghouse differential pressure	Clean or replace filter bags

6. Line-Specific Differences — Full-Fat vs. Defatted¶

Aspect	Full-Fat Line	Defatted Line
Feedstock	Whole flaxseed or kernel	Press cake (8–12% residual oil)
Pre-milling cooling	Required (chill to 4–10°C)	Not required
Mill type	Hammer, pin, or cryo	Hammer mill only
Temperature sensitivity	High (oil oxidation risk)	Moderate
N₂ flushing	Required	Optional
Target particle size	100–200 mesh	60–100 mesh
Shelf life	12 months	18 months
PV monitoring	Every 30 min	Every 60 min
Dust explosion risk	Low (oil suppresses dust)	Higher (dry, fine particles)

7. Equipment List¶

Equipment	Specification	Supplier Options
Hammer mill	30–55 kW, 2800–3600 RPM	Fitzpatrick, Hosokawa
Pin mill	15–30 kW, 6000–12000 RPM	Alpine, Kemutec
Cryogenic mill	LN₂ injection, −150°C	Air Products, Messer
Sifter / screener	Gyratory, 60–200 mesh	Sweco, Russell
Ribbon blender	500–2000 kg capacity	Munson, ASCO
N₂ generator	≥99.9% purity, 50–200 Nm³/hr	Atlas Copco, Parker
Metal detector (inlet)	Pipeline, Fe ≥1.0 mm	Eriez, Loma
Metal detector (final)	Conveyor, Fe ≥0.8 mm	Mettler-Toledo, Loma
Packaging machine	VFFS or pre-made bags	Bosch, Ishida

8. References¶

AOCS Cd 8-53 — Peroxide Value, Acetic Acid-Chloroform Method
ISO 2070 — Determination of particle size by sieving
CCP-4 & CCP-5 Standard Operating Procedures (see QMS-SOP-004/005)
Flaxseed Powder Product Specification — PROD-SPEC-001

End of Document — Flaxseed Powder Process Flow