Flaxseed Gum — Technical Product Specification¶
Product Name: Flaxseed Gum (Linum usitatissimum) Product Code: FSP-GUM-001 Document ID: FSP-GUM-SPEC-001 Version: 1.0 Issue Date: July 20, 2026 Supersedes: New Document
1. Product Description¶
Flaxseed Gum (FSP-GUM-001) is a high-purity, natural polysaccharide complex extracted from whole flaxseed (Linum usitatissimum L.) via aqueous extraction, ethanol precipitation, and spray-drying. It is a light-tan to off-white free-flowing powder with a bland, neutral taste and no distinct odor. The gum is composed primarily of acidic arabinoxylans with a high molecular weight distribution, conferring exceptional water-binding, thickening, emulsifying, and stabilizing properties. This product is suitable for food, nutraceutical, cosmetic, and pharmaceutical applications where clean-label hydrocolloid functionality is required.
2. Proximate Analysis¶
| Parameter | Specification | Method |
|---|---|---|
| Total Polysaccharide | 75 – 85 % | Phenol-Sulfuric Acid (AOAC) |
| Protein (N × 6.25) | 3.0 – 6.0 % | AOAC 984.13 (Kjeldahl) |
| Uronic Acid | 8 – 14 % | m-Hydroxydiphenyl Method |
| Moisture | ≤ 5.0 % | AOAC 925.10 (Vacuum Oven) |
| Ash | 4.0 – 7.0 % | AOAC 923.03 (525 °C) |
| Acetyl Groups | 2.0 – 4.0 % | HPLC |
Total Carbohydrates (by difference): ≥ 80 %
pH (1 % w/w aqueous solution, 25 °C): 5.5 – 7.5
3. Monosaccharide Profile¶
The polysaccharide backbone and side-chain composition are determined by HPLC after complete acid hydrolysis (2 M TFA, 121 °C, 2 h). Seven neutral monosaccharides are routinely quantified.
| Monosaccharide | Composition (% w/w) |
|---|---|
| Xylose | 30 – 38 |
| Galactose | 20 – 28 |
| Rhamnose | 12 – 18 |
| Arabinose | 8 – 14 |
| Glucose | 6 – 10 |
| Fucose | 2 – 5 |
| Mannose | 1 – 3 |
The dominant xylose residue confirms the classification of flaxseed gum as an acidic arabinoxylan. The presence of rhamnose and uronic acid (Section 2) indicates co-extracted rhamnogalacturonan regions typical of mucilaginous seed polysaccharides. The xylose/arabinose ratio typically falls between 2.5 and 4.0.
4. Viscosity Properties¶
4.1 Apparent Viscosity vs. Concentration¶
Viscosity measured at 25 °C using a rotational rheometer (cone-and-plate geometry, shear rate = 10 s⁻¹, equilibration 120 s). Values are reported as a range across production lots.
| Concentration (% w/w) | Apparent Viscosity (cP) |
|---|---|
| 0.1 | 20 – 50 |
| 0.5 | 100 – 400 |
| 1.0 | 500 – 2,000 |
| 2.0 | 2,000 – 5,000 |
| 3.0 | 5,000 – 10,000 |
| 5.0 | 8,000 – 15,000 |
The gum exhibits a steep concentration-dependence typical of entangled polysaccharide solutions. At concentrations above 1 % (w/w), solutions form weak gels upon standing, though they remain shear-reversible.
4.2 Flow Behavior (Shear-Rate Sweep)¶
Shear-rate sweeps (0.1 – 1000 s⁻¹, 25 °C, 1 % w/w solution) are well-described by the Ostwald–de Waele power-law model:
τ = K · γ̇ⁿ
| Parameter | Value |
|---|---|
| n | 0.30 – 0.50 (dimensionless) |
| K | 5 – 50 Pa·sⁿ |
| R² | ≥ 0.99 |
The flow index n < 1 confirms strong shear-thinning (pseudoplastic) behavior, enabling easy pumping, mixing, and filling while providing high low-shear viscosity for suspension and stabilization. At concentrations below 0.3 % the solution approaches Newtonian behavior (n → 1).
4.3 Thixotropy¶
A three-interval thixotropy test (low shear 0.1 s⁻¹ / high shear 500 s⁻¹ / low shear 0.1 s⁻¹) shows ≥ 85 % viscosity recovery within 120 s, indicating excellent structural regeneration.
5. Dynamic Oscillatory Rheology¶
5.1 Frequency Sweep¶
Oscillatory frequency sweeps are conducted from 0.01 to 10 Hz at 25 °C within the linear viscoelastic region (LVR, 1 % strain, determined by amplitude sweep).
| Frequency (Hz) | G' (Pa) — Typical | G'' (Pa) — Typical | tan δ |
|---|---|---|---|
| 0.01 | 1.2 – 4.5 | 3.0 – 8.0 | 1.5–2.5 |
| 0.10 | 8.0 – 25 | 12 – 30 | 1.0–1.8 |
| 1.00 | 45 – 120 | 35 – 90 | 0.6–0.9 |
| 10.0 | 150 – 400 | 80 – 200 | 0.4–0.6 |
Crossover frequency (G' = G''): 0.05 – 0.30 Hz (1 % w/w, 25 °C).
Below the crossover, the gum solution exhibits liquid-like behavior (G'' > G'). Above the crossover, elastic behavior dominates (G' > G''), characteristic of an entangled polymer network with a characteristic relaxation time τ = 1/ω_c ≈ 3 – 20 s.
5.2 Temperature Sweep¶
Temperature ramps from 5 °C to 80 °C at 2 °C/min (1 % w/w, 1 Hz, 1 % strain, Peltier-controlled Peltier plate with solvent trap to prevent evaporation).
- 5 – 30 °C: Apparent viscosity decreases by 35 – 50 % as hydrogen-bonding networks weaken.
- 30 – 60 °C: Viscosity shows a plateau region with a mild slope (activation energy Eₐ ≈ 15 – 25 kJ/mol from Arrhenius fit).
- 60 – 80 °C: Slight further decline; no thermal gelation or precipitous viscosity drop observed.
- Cool-down (80 → 5 °C): ≥ 90 % viscosity recovery, confirming thermal reversibility and absence of thermal degradation under these conditions.
The gum retains > 70 % of its room-temperature viscosity at 80 °C, indicating good thermal stability suitable for pasteurization and hot-fill processes.
5.3 Creep and Recovery¶
Creep/recovery tests: instantaneous application of constant stress τ₀ = 1 Pa (within LVR) for 300 s (creep), followed by stress removal and recovery monitored for 600 s (1 % w/w, 25 °C).
| Time (s) | Compliance J(t) (Pa⁻¹) — Typical |
|---|---|
| 1 | 0.002 – 0.015 |
| 10 | 0.02 – 0.12 |
| 100 | 0.15 – 0.60 |
| 300 | 0.35 – 1.20 |
| 600 (recovery) | 0.08 – 0.40 (residual compliance) |
Burgers model parameters (four-element viscoelastic): - Instantaneous elastic compliance J₀: 0.002 – 0.010 Pa⁻¹ - Retarded compliance J₁: 0.10 – 0.40 Pa⁻¹ - Retardation time λᵣ: 15 – 50 s - Zero-shear viscosity η₀: 80 – 300 Pa·s
Recovery efficiency ≥ 65 % (residual compliance after 600 s recovery relative to maximum creep compliance), demonstrating strong elastic recovery with minimal permanent deformation.
6. Critical Overlap Concentration¶
The critical overlap concentration c* marks the transition from the dilute to the semi-dilute entangled regime, determined from the intersection of the specific viscosity (ηₛₚ) vs. concentration double-log plot slopes.
| Parameter | Specification |
|---|---|
| c* | 0.3 – 0.5 % w/w |
At c > c, individual polymer chains overlap and entangle, producing a sharp increase in zero-shear viscosity (η₀ ∝ c³·⁵). Below c, η₀ scales as η₀ ∝ c¹·². The relatively low c* value reflects the high molecular weight (> 10⁶ Da) and extended conformation of flaxseed gum arabinoxylans in aqueous solution.
7. Emulsifying Properties¶
7.1 Emulsifying Activity Index (EAI)¶
Determined by turbidimetric method (spectrophotometry at 500 nm, oil-in-water emulsion, 0.5 % gum solution, soy oil/water 1:4, homogenized at 20,000 rpm, 1 min).
| Parameter | Specification |
|---|---|
| EAI | 45 – 60 m²/g |
7.2 Emulsion Stability Index (ESI)¶
| Parameter | Specification |
|---|---|
| ESI | ≥ 85 % |
EAI and ESI values confirm that flaxseed gum FSP-GUM-001 functions as an effective emulsifier, stabilizing oil droplets through a combination of steric repulsion (from the polysaccharide brush layer) and viscosity enhancement of the continuous phase. Performance is comparable to gum arabic and may be synergistic when blended.
8. Foaming Properties¶
8.1 Foam Overrun¶
| Parameter | Specification | Method |
|---|---|---|
| Foam Overrun | 100 – 150 % | Whipping 1 % solution, 5 min, 25 °C |
8.2 Foam Stability¶
| Parameter | Specification |
|---|---|
| Stability (2 h) | 70 – 85 % |
Foam volume is maintained over 2 h owing to the high bulk viscosity and interfacial film elasticity imparted by the gum. The polysaccharide adsorbs at the air–water interface, retarding drainage and coalescence.
9. Emulsion Creaming Index¶
Creaming stability is assessed by gravity separation of an oil-in-water emulsion (10 % v/v soy oil, 0.5 % gum, stored quiescently at 25 °C in graduated cylinders).
| Time (h) | Creaming Index (%) — Typical |
|---|---|
| 0 | 0.0 |
| 2 | 2 – 8 |
| 6 | 5 – 15 |
| 12 | 8 – 20 |
| 24 | 10 – 25 |
After 24 h, the creaming index remains ≤ 25 %, indicating a kinetically stable emulsion with no visible oil separation. The dense polysaccharide network retards droplet rise in accordance with Stokes' law.
10. Mineral and Heavy Metal Profile¶
| Element | Specification Limit | Method |
|---|---|---|
| Calcium (Ca) | 800 – 2,500 mg/kg | ICP-OES |
| Potassium (K) | 1,000 – 3,000 mg/kg | ICP-OES |
| Magnesium (Mg) | 400 – 1,200 mg/kg | ICP-OES |
| Sodium (Na) | ≤ 500 mg/kg | ICP-OES |
| Iron (Fe) | ≤ 50 mg/kg | ICP-OES |
| Zinc (Zn) | ≤ 25 mg/kg | ICP-OES |
| Arsenic (As) | ≤ 1.0 mg/kg | ICP-MS |
| Lead (Pb) | ≤ 1.0 mg/kg | ICP-MS |
| Cadmium (Cd) | ≤ 0.5 mg/kg | ICP-MS |
| Mercury (Hg) | ≤ 0.1 mg/kg | ICP-MS/AAS |
All heavy metals comply with USP/NF, FCC, and EU food additive purity criteria (Commission Regulation (EU) No 231/2012).
11. Microbiological Specifications¶
| Test | Specification | Method |
|---|---|---|
| Total Plate Count (TVC) | ≤ 1,000 CFU/g | ISO 4833 |
| Yeast & Mold | ≤ 100 CFU/g | ISO 21527 |
| Enterobacteriaceae | ≤ 10 CFU/g | ISO 21528 |
| Escherichia coli | Negative in 10 g | ISO 16649 |
| Salmonella spp. | Negative in 25 g | ISO 6579 |
| Staphylococcus aureus | Negative in 10 g | ISO 6888 |
| Bacillus cereus | ≤ 100 CFU/g | ISO 7932 |
| Listeria monocytogenes | Negative in 25 g | ISO 11290 |
| Coliforms | ≤ 10 CFU/g | ISO 4832 |
| Sulfite-Reducing Clostridia | ≤ 10 CFU/g | ISO 15213 |
The product undergoes terminal drying at inlet/outlet temperatures of 180 °C / 85 °C during spray-drying, which provides an additional microbiological kill step. The low water activity (a_w ≤ 0.35) inhibits post-process microbial growth.
12. Hygroscopicity — Moisture Sorption Isotherm¶
Moisture sorption is determined gravimetrically at 25 °C over a range of water activities (a_w = 0.10 – 0.90) using a dynamic vapor sorption (DVS) analyzer.
| Water Activity (a_w) | Equilibrium Moisture Content (% w/w) — Typical |
|---|---|
| 0.10 | 3.0 – 4.5 |
| 0.20 | 4.5 – 6.0 |
| 0.30 | 6.0 – 8.0 |
| 0.40 | 8.0 – 10.5 |
| 0.50 | 10.5 – 13.0 |
| 0.60 | 13.0 – 16.5 |
| 0.70 | 16.5 – 21.0 |
| 0.80 | 21.0 – 27.0 |
| 0.90 | 28.0 – 35.0 |
The isotherm exhibits a Type II (S-shaped) BET profile, characteristic of hydrophilic polysaccharides. The monolayer moisture content (BET model) is 3.0 – 5.0 % w/w, corresponding to a_w ≈ 0.20 – 0.30. To prevent caking and loss of flowability, the product should be stored at a_w ≤ 0.50 (see Section 13).
13. Packaging¶
| Container Type | Net Weight | Material & Construction |
|---|---|---|
| Multi-wall Paper Bags | 15 kg | PE-lined kraft paper bags, heat-sealed inner liner |
| Fibre Drums | 200 kg | PE-lined corrugated fibre drum with removable lid |
| Bulk (IBC) | 500 – 1,000 kg | Food-grade FIBC (flexible intermediate bulk container) |
All packaging materials are food-grade, BPA-free, and compliant with EU Regulation 10/2011 and FDA 21 CFR 175.300. Each package is labelled with lot number, production date, expiry date, net weight, and storage instructions.
14. Storage and Shelf Life¶
| Condition | Recommendation |
|---|---|
| Temperature | ≤ 25 °C (controlled ambient) |
| Relative Humidity | ≤ 50 % RH |
| Light Exposure | Store in opaque or UV-protected packaging |
| Shelf Life (sealed, as above) | 24 months from date of manufacture |
| Shelf Life (after opening) | 6 months (if resealed under same conditions) |
Under recommended conditions, the product retains ≥ 90 % of its initial viscosity (1 % solution, 10 s⁻¹) and passes all microbiological and heavy metal specifications at 24 months. Accelerated stability studies (40 °C, 75 % RH, 6 months) show no significant increase in moisture (> 6 %) or loss in EAI (< 10 % relative decline).
Important storage notes: - Avoid temperature fluctuations exceeding 15 °C to prevent moisture migration and condensation inside the packaging. - Do not stack pallets more than three units high to avoid compression damage to bags. - Once opened, content should be used promptly and the container resealed tightly to minimize moisture uptake.
15. Regulatory Status and Applications¶
15.1 Regulatory¶
- GRAS (USA): Flaxseed gum may be used as a direct food ingredient under the generally recognized as safe provisions. A GRAS notification is on file with the FDA.
- EU: Not currently listed as an additive under Annex II of Regulation (EC) No 1333/2008; marketed as a food ingredient. Pending novel food authorization in certain member states.
- China (GB 2760): Accepted as a natural food additive for thickening and stabilizing in select categories.
- Kosher / Halal: Available upon request with third-party certification.
15.2 Typical Use Levels¶
| Application | Recommended Dosage (% w/w) |
|---|---|
| Beverages (dairy & plant-based) | 0.05 – 0.30 |
| Sauces, Dressings, Gravies | 0.20 – 0.80 |
| Baked Goods (gluten-free) | 0.50 – 2.00 |
| Meat Products (binder) | 0.30 – 1.00 |
| Ice Cream / Sorbet | 0.10 – 0.40 |
| Edible Films & Coatings | 0.50 – 3.00 |
16. Analytical Methods Reference Summary¶
| Property | Method / Standard |
|---|---|
| Total Polysaccharide | Phenol-Sulfuric Acid (Dubois et al., 1956) |
| Protein | AOAC 984.13 (Kjeldahl, N × 6.25) |
| Uronic Acid | Blumenkrantz & Asboe-Hansen, 1973 |
| Moisture | AOAC 925.10 |
| Ash | AOAC 923.03 |
| Acetyl Groups | HPLC (Reversed-Phase, UV 210 nm) |
| Monosaccharides | HPLC-PAD after TFA hydrolysis |
| Viscosity | Rotational Rheometer (cone/plate, 10 s⁻¹) |
| Oscillatory Rheology | Stress-controlled rheometer, 25 °C, 1 % strain |
| EAI / ESI | Turbidimetric (Pearce & Kinsella, 1978) |
| Foaming | Whipping test (AACC Method 56-61.02) |
| Heavy Metals | ICP-OES / ICP-MS |
| Microbiology | ISO methods per Section 11 |
| Moisture Sorption | DVS (Dynamic Vapor Sorption) at 25 °C |
17. Revision History¶
| Version | Date | Author | Description of Change |
|---|---|---|---|
| 1.0 | 2026-07-20 | FlaxSeedsPro QA | Initial release |
END OF DOCUMENT
This specification is provided for informational and quality assurance purposes. Values represent typical production ranges under controlled conditions. Actual lot-specific certificates of analysis (COA) are available upon request. Contact FlaxSeedsPro Technical Services for further information or custom specification inquiries.