Powder and Dry Extract Stability Testing Service

Spray-Dried Extract, Freeze-Dried Extract, Granulated Extract, Maltodextrin Carrier Extract, and Encapsulated Powder are five powder and dry extract formats produced from natural plant material for use in dietary supplements, functional foods, nutraceuticals, and cosmetic active ingredient applications. These formats are downstream intermediates used in the manufacture of Tablets, Capsules, Sachets, and Bars, and are also sold as finished consumer products in sachet or jar format. The inherent challenges of powder and dry extract products in the tropical ASEAN Zone IVb environment include rapid moisture absorption causing Hygroscopicity and Caking, color change from Maillard reaction, degradation of thermolabile active compounds including Curcuminoids, Anthocyanins, and Catechins, encapsulation system failure under elevated temperature and humidity, and reduction in Probiotic CFU viability during storage.

TIBD’s Powder and Dry Extract Stability Testing service covers Moisture Content by Karl Fischer Titration and Loss on Drying, Water Activity, Particle Size Distribution by Laser Diffraction, Bulk Density and Tapped Density with Carr’s Index and Hausner Ratio, Hygroscopicity by Dynamic Vapor Sorption (DVS) Sorption Isotherm, Caking Assessment, Color by CIE Lab* Colorimeter, Active Compound Assay by High Performance Liquid Chromatography (HPLC), and Probiotic Viability (CFU/g), under ASEAN Zone IVb conditions per ICH Q1A(R2), in partnership with VISBIO as an Independent Quality Assurance Verifier (IQAV) using Validated Methods per ICH Q2(R1).

Five powder and dry extract formats are tested under TIBD’s service.

• Spray-Dried Extract is produced by atomizing a liquid herbal extract through a nozzle into a heated drying chamber, producing hollow microspheres of 10 to 100 µm diameter. Spray-dried extracts have high specific surface area and are highly hygroscopic. Representative products include Spray-Dried Green Tea Extract (Catechin-rich), Spray-Dried Turmeric Extract (Curcuminoids), Spray-Dried Centella asiatica Extract (Asiaticoside), and Spray-Dried Andrographis paniculata Extract (Andrographolide). The stability challenge for spray-dried extracts is moisture absorption and the resulting Caking, Maillard browning, and accelerated active compound degradation when the Critical Relative Humidity threshold is exceeded.
• Freeze-Dried Extract (Lyophilized Extract) is produced by freezing the liquid extract and sublimating the ice under vacuum at temperatures below 0°C. Freeze-drying preserves thermolabile compounds better than spray-drying, making it the preferred process for Probiotic cultures, enzyme preparations, peptide extracts, and heat-sensitive polyphenols. Freeze-dried extracts are very porous, brittle, and highly hygroscopic; they must be packaged with an efficient moisture barrier and desiccant to maintain viability and active compound content throughout the declared shelf life.
• Granulated Extract is produced by Wet Granulation or Dry Granulation (roller compaction) of the spray-dried or freeze-dried extract with binders and excipients to form granules of 200 to 800 µm. Wet Granulation uses aqueous PVP or HPMC binder solution and produces denser, more flowable granules. Dry Granulation avoids moisture contact and is preferred for moisture-sensitive actives. Granulated extracts are the most common intermediate for Plain Tablet and Capsule manufacture. Stability testing of granulated extracts includes all powder parameters plus Granule Strength and Compressibility assessment for tablet and capsule production inputs.
• Maltodextrin Carrier Extract is produced by spray-drying the liquid herbal extract with Maltodextrin (DE 10 to 20) as the primary carrier. Maltodextrin provides low hygroscopicity and fast dissolution compared to the pure extract alone. This format is widely used for hygroscopic herbal actives including polyphenol-rich extracts (Rosemary, Grape Seed, Pomegranate) where Maltodextrin reduces moisture uptake from the ASEAN Zone IVb humid environment and extends the effective shelf life.
• Encapsulated Powder produced by Microencapsulation or Fluid Bed Coating technology protects sensitive actives from moisture, oxygen, and light during storage and controls the release profile. Microencapsulation techniques applied to dry extracts include Spray Drying with wall material (Gum Arabic, Modified Starch, WPI), Coacervation (gelatin-gum arabic), and Spray Chilling (hydrogenated vegetable fat). The stability testing protocol for encapsulated powders must confirm both the integrity of the encapsulation system over time (Encapsulation Efficiency, Leakage Rate) and the protection it provides to the core active compound.

Six stability challenges are specific to powders and dry extracts in the ASEAN Zone IVb environment.

1. The first challenge is Hygroscopicity and Critical Relative Humidity exceedance. Spray-dried and freeze-dried extracts with high Polyphenol, Polysaccharide, or Sugar content absorb moisture rapidly from humid ambient air. When the ambient relative humidity exceeds the Critical Relative Humidity (CRH) of the product, moisture absorption accelerates sharply, increasing Water Activity above the safe threshold of 0.60 and triggering Caking, chemical degradation, and microbial growth. The CRH is unique to each product formulation and must be determined experimentally from the DVS Sorption Isotherm before packaging specifications can be finalized.
2. The second challenge is Caking. Caking occurs when individual powder particles absorb sufficient moisture to become tacky, then stick together into hardened agglomerates upon drying. Caked powder cannot flow freely through filling equipment and cannot be reconstituted to a uniform solution. Caking is assessed visually and by measuring Bulk Density at each Pull Point, with a significant increase in Bulk Density indicating the onset of agglomeration.
3. The third challenge is color change from Maillard reaction and Polyphenol oxidation. Maillard reaction between reducing sugars and amino acids in the extract matrix produces brown melanoidin pigments, causing darkening detectable by CIE Lab* Colorimetry. Polyphenol oxidation under elevated temperature and humidity also generates dark quinone derivatives. A Delta E (color difference from T0) of more than 3 units is considered a visually significant change.
4. The fourth challenge is active compound degradation. Curcuminoids in turmeric extract, Anthocyanins in berry and purple sweet potato extracts, and Catechins in green tea extract are all sensitive to heat, humidity, and oxidation. The degradation kinetics are faster in dried powder form than in bulk liquid extract because the surface area to volume ratio is much higher and oxygen contact is greater. Stability Indicating HPLC methods must be applied to resolve the parent compound from degradation products.
5. The fifth challenge is encapsulation system failure under elevated temperature and humidity. For microencapsulated powders, the wall material (Gum Arabic, Maltodextrin, Modified Starch, or gelatin) can absorb moisture and become permeable, or can flow and fuse at elevated temperatures above the glass transition temperature (Tg), releasing the encapsulated core and exposing the active to degradative conditions. Encapsulation Efficiency is measured by the surface-to-total active ratio; an increase in surface content indicates wall material failure.
6. The sixth challenge is Probiotic viability reduction. Probiotic dry powders must maintain the labeled CFU/g (Colony Forming Units per gram) throughout the declared shelf life. Probiotic viability is sensitive to moisture, temperature, and oxygen. The typical accepted minimum at end of shelf life is the labeled CFU count (overage is specified at manufacture to account for decline during storage). Probiotic stability testing requires an additional storage condition at 25°C / 60% RH for products labeled for cool storage, and at 5°C ± 3°C for refrigerated Probiotic products.

TIBD’s stability testing protocol for powders and dry extracts covers the full set of physical, chemical, and flow property parameters.

• Moisture Content is measured by Karl Fischer Titration (primary method for extracts containing ethanol or other organic solvents) or Loss on Drying at 105°C for 2 hours. The acceptance criterion for most spray-dried and freeze-dried herbal extract powders is 3 to 5%. Moisture Content above 5% is associated with Caking, Maillard browning, and Probiotic viability loss.
• Water Activity (aw) is measured by Water Activity Meter at each Pull Point. The acceptance criterion is Not More Than 0.60 to prevent microbial growth and to maintain chemical stability. Water Activity is more informative than Moisture Content alone because it reflects the thermodynamic availability of water for chemical reactions and microbial metabolism, not just total water mass.
• Particle Size Distribution is measured by Laser Diffraction Particle Size Analyzer (Wet or Dry Dispersion depending on product solubility). The D50 (median particle size) and D90 (90th percentile) values are reported. Caking is detected by an upward shift in D50 and D90 over time, indicating agglomerate formation. The Span value (D90 minus D10, divided by D50) indicates the breadth of the particle size distribution.
• Bulk Density and Tapped Density are measured by graduated cylinder and mechanical tapper per Ph.Eur. 2.9.34. These values are used to calculate Carr’s Index: (Tapped Density minus Bulk Density) divided by Tapped Density, expressed as percentage; and the Hausner Ratio: Tapped Density divided by Bulk Density. Carr’s Index below 15% and Hausner Ratio below 1.18 indicate good flow. Increasing Carr’s Index over the shelf life indicates progressive loss of flowability due to moisture uptake and incipient Caking.
• Caking Assessment by visual examination classifies the physical state of the powder at each Pull Point using a defined scale (Free-flowing, Slightly cohesive, Moderately caked, Hard cake). Any transition to Moderately caked or worse is recorded as a significant change.
• Solubility and Dispersibility testing confirms that the powder reconstitutes completely in the specified volume of water within the specified time (typically 2 minutes with gentle stirring) at each Pull Point. Loss of dispersibility indicates Caking or active compound aggregation.
• Color assessment by CIE Lab* Colorimeter provides quantitative measurement of Lightness (L*), Red-Green axis (a*), and Yellow-Blue axis (b*) at each Pull Point. Delta E greater than 3 units from T0 is considered a visually significant color change.
• Sensory evaluation (aroma and visual) by trained panel is conducted at T0 and at each Pull Point for food-grade extracts where aroma is a quality attribute. Development of off-aroma or color change visible to the naked eye triggers additional investigation.

TIBD and VISBIO apply compound-specific HPLC methods validated as Stability Indicating methods per ICH Q2(R1) for each active compound class.

• Curcuminoids (Curcumin, Demethoxycurcumin, Bisdemethoxycurcumin) by HPLC with UV detection at 425 nm, resolving all three curcuminoid fractions individually. Curcuminoids are the primary Marker Compounds for Curcuma longa (turmeric) dry extract. The method must resolve parent curcuminoids from oxidative degradation products. Acceptance criterion: Not Less Than 90% of labeled value.
• Catechins in Green Tea Extract by HPLC with UV detection at 280 nm, resolving EGCG (Epigallocatechin Gallate), EGC (Epigallocatechin), ECG (Epicatechin Gallate), and EC (Epicatechin) as individual fractions. EGCG is the primary active compound in green tea extract with the highest antioxidant activity and the fastest degradation rate under heat and moisture. The method quantifies all four catechin fractions simultaneously.
• Resveratrol (Trans-Resveratrol and Cis-Resveratrol) by HPLC with UV detection at 306 nm for grape extract dry powder. The Trans isomer is the biologically active form; isomerization to the Cis form under UV light or heat is a stability indicator. The method resolves both isomers.
• Anthocyanins by pH Differential Method per AOAC 2005.02, expressed as total Anthocyanin content in Cyanidin-3-Glucoside Equivalents. Applied to dry extracts from blueberry, Roselle, Elderberry, and purple sweet potato. Anthocyanins are among the most unstable active compounds in dry extract products and degrade rapidly above 40°C or under elevated humidity. Monitoring both total Anthocyanin content and the HPLC profile (Cyanidin, Delphinidin, Petunidin, Peonidin, Malvidin glycosides) at each Pull Point tracks both quantity and profile stability.
• Withanolide by HPLC with UV detection at 220 nm for Ashwagandha (Withania somnifera) dry extract. Primary Marker Compound for adaptogenic supplement applications.
• Andrographolide by HPLC with UV detection at 225 nm for Andrographis paniculata dry extract. Primary Marker Compound for immune support applications.
• Asiaticoside by HPLC with ELSD or UV detection at 200 nm for Centella asiatica (Gotu Kola) dry extract.
• Probiotic Viability (CFU/g) measured by plate count on selective media at 37°C and at 42°C for thermophilic strains. The measurement must be conducted on the intact product matrix (not isolated cultures) to reflect the viability of cells in the actual product environment. Acceptance criterion: Not Less Than the labeled CFU/g value (considering specified overage at manufacture). For products labeled per gram or per serving, viability is reported per gram and per serving unit.

All active compound content values are held at Not Less Than 90% of the labeled value throughout the declared shelf life.

Long-term Stability testing uses 30°C / 75% RH conditions per ASEAN Zone IVb for a minimum of 24 months. Accelerated Stability testing uses 40°C / 75% RH for 6 months.

For Probiotic Powder products, an additional storage condition at 25°C / 60% RH is included to simulate products labeled for storage below 25°C, and at 5°C ± 3°C for products labeled for refrigerated storage. Probiotic viability results from the 25°C condition are used as the primary shelf life prediction data for ambient-stable Probiotic products.

Standard Pull Points for Long-term testing are months 0, 3, 6, 9, 12, 18, and 24. Standard Pull Points for Accelerated testing are months 0, 1, 2, 3, and 6. For Probiotic products, Pull Points at 1, 3, 6, 9, 12, 18, and 24 months are used for the primary storage condition to generate a detailed CFU decline curve.

DVS Sorption Isotherm is conducted at T0 to generate the complete moisture absorption isotherm from 0% to 95% RH, identifying the Critical Relative Humidity (CRH) above which moisture absorption accelerates. The CRH data directly informs the specification for packaging materials (required WVTR in g/m²/day), desiccant quantity, and storage condition labeling.

TIBD provides consultation on carrier selection and packaging design before the stability study commences to maximize the probability of a stable product.

• Maltodextrin DE 10 to 20 is the most widely used spray-drying carrier for herbal extracts. Lower DE grades (DE 10 to 12) provide lower hygroscopicity and higher glass transition temperature than higher DE grades, and are preferred for moisture-sensitive extracts.
• Gum Arabic (Acacia) is the standard carrier for oil-containing and lipid-soluble extracts in spray drying because of its unique emulsification and film-forming properties at high solid concentrations. It is used for spray-dried Essential Oil powders, Oleoresin powders (Turmeric, Paprika), and Omega-3 powder products.
• Beta-Cyclodextrin Inclusion Complex is formed by mixing the liquid extract with Beta-Cyclodextrin in water, allowing the hydrophobic active molecule to insert into the cyclodextrin cavity, then drying. Beta-Cyclodextrin complexation is used for poorly water-soluble actives (Curcuminoids, Quercetin, Resveratrol) and for volatile compound stabilization in aromatic herbal extracts.
• Whey Protein Isolate (WPI) and Sodium Caseinate are used as encapsulation wall materials for Probiotic bacteria in spray-drying, providing protein matrix protection from heat, moisture, and acid. Inulin and Fructooligosaccharides (FOS) are incorporated as Prebiotic substrates in Probiotic Synbiotic powder products.
• Packaging selection is critical for all powder and dry extract products. Aluminum Foil Laminate Sachets (Alu-Alu or Metallized PET/PE) provide maximum moisture barrier (WVTR less than 1 g/m²/day) for highly hygroscopic extracts. Amber Glass Jar with induction-sealed liner protects light-sensitive actives (Curcuminoids, Anthocyanins, Catechins) from photodegradation. Single-use sachet packaging eliminates repeated air and moisture exposure from multiple-use containers. Nitrogen Flushing during sachet sealing reduces headspace oxygen to below 2%, protecting oxidation-sensitive actives. Silica Gel or Molecular Sieve Desiccant inside the primary package reduces ambient humidity to well below the product’s CRH, particularly important for hygroscopic and Probiotic powders.

VISBIO, acting as Independent Quality Assurance Verifier (IQAV), conducts Moisture Content, Water Activity, Particle Size Distribution, Bulk Density, Tapped Density, Caking Assessment, Color by CIE Lab*, Active Compound Assay by HPLC, and Probiotic Viability (CFU/g) on samples collected at each Pull Point, using Validated Methods per ICH Q2(R1) with full Traceability documentation at every step and operations conducted under ISO/IEC 17025 standards.

The Powder and Dry Extract Stability Testing service is conducted in partnership with Dr. Wuttipong Panitsettakorn, Advisor and Co-Founder, who specializes in commercial technology management for the health and beauty industry, and Ms. Mandhamon Uttamo, Advanced Formulator, who has extensive experience in the development of extract powder products for dietary supplement and functional food applications. Our team includes researchers specializing in Powder Technology, Spray Drying Process, Freeze Drying, Encapsulation Technology, Food Microbiology, and Stability Indicating HPLC method development for thermolabile polyphenol and probiotic actives.

Is your Powder or Dry Extract product ready for Thai FDA registration or ASEAN export? Contact TIBD for a customized stability protocol and starting price from ฿15,000.