Phosphatidylserine Acetone-Insoluble Matter Review for US and EU Buyers

When a quality team receives a phosphatidylserine (PS) specification or certificate of analysis, the acetone-insoluble row is easy to skip. It is also one of the most informative purity checks on the page for a lecithin-derived powder. The direct answer: acetone-insoluble matter measures the phospholipid-rich fraction of a lecithin-based ingredient; for a PS powder the buyer should confirm the test method, the limit in the product specification, the batch result on the COA, and the raw-material context, because a PS-grade limit of around 95% or higher is not the same as the 50-60% acetone-insoluble benchmark used for food-grade lecithin.

This review is written for importers, distributors, supplement manufacturers, and quality teams in North America and Europe. It explains what the test measures, how laboratories perform it, which lecithin benchmarks exist in the EU and the US, why a PS product should show a much higher result, and how to review the row on a COA. This is a specification and quality-control discussion, not a medical discussion.

Where Nutranexa is mentioned, only verified public facts are used. Nutranexa identifies itself as Shandong Baianrui Biopharmaceutical Co., Ltd., founded in 2013, operating a 110,000+ m2 campus, cooperating with East China University of Science and Technology, and primarily serving export markets in Europe and North America. Its public PS specification matrix shows an acetone-insoluble row of 95.0 g/100g or higher for the PS 20% sunflower and PS 50% grades, sample COA evidence with a QB/T 5821-2023 test basis is shown on the Quality & R&D page, and its published minimum order is 25 kg with 25 kg net per drum.

The Direct Answer Buyers Need First

Run this five-point map before approving a PS specification or accepting a batch:

What Acetone-Insoluble Matter Measures

Acetone-insoluble matter is a classical purity parameter for lecithin and lecithin-derived ingredients. Lecithin is a complex mixture of phospholipids combined with other substances such as triglycerides, fatty acids, and carbohydrates. When the material is mixed with cold acetone, most neutral lipids and fatty components dissolve, while the phospholipid-rich fraction does not. The residue left after washing and drying is the acetone-insoluble matter, usually reported as a percentage or as grams per 100 grams.

In practical terms, the result estimates the phospholipid content of the material. A higher acetone-insoluble value means a larger share of the ingredient is phospholipids rather than neutral oil and fatty components. That is why the test appears in lecithin monographs and in PS specifications: it is a fast, well-established measure of how "concentrated" the phosphatide fraction is.

For phosphatidylserine, the relationship is direct. PS is produced from lecithin, so the phospholipid fraction of the finished powder is expected to be high. A PS product that shows a low acetone-insoluble result would signal that the powder carries more non-phospholipid material than the specification allows, which can affect assay consistency, blend behavior, and sensory quality in finished products.

Why the Row Appears on a PS Specification

Buyers sometimes assume the acetone-insoluble row on a PS COA is a leftover from lecithin testing. It is not a leftover; it is a meaningful purity control for two reasons:

• Phospholipid concentration. The test confirms that the material is dominated by the phospholipid fraction, which is the foundation the PS assay is built on.
• Process and raw-material control. The result responds to the quality of the lecithin base and the efficiency of purification, so a stable value across batches supports supplier consistency.

The row becomes especially relevant when a buyer compares suppliers. Two grades can show the same nominal PS assay while differing in total phospholipid balance, and the acetone-insoluble result is one of the visible signals of that difference. It belongs in the same review file as assay-to-batch calculation, moisture, and peroxide value rather than being read in isolation.

How the Test Is Performed

The classic procedure is AOCS official method Ja 4-46, "Acetone-Insoluble Matter in Vegetable Lecithins," which is recommended for lecithin and lecithin-type products. In outline, the laboratory:

1. Weighs a representative sample of the material.
2. Disperses it in cold acetone, which dissolves neutral lipids and fatty acids.
3. Separates the insoluble residue, typically by centrifugation or filtration.
4. Washes the residue with chilled acetone to remove dissolved material.
5. Dries and weighs the remaining residue.
6. Reports the residue as a percentage or as grams per 100 grams.

Pharmacopeia lecithin monographs describe the same principle. The USP-NF Lecithin monograph, for example, uses chilled acetone with centrifugation and reports the dried residue as the content of acetone-insoluble matter. The key practical point for buyers is that the method details matter: solvent temperature, washing steps, and drying conditions all affect the result. When a COA shows an acetone-insoluble value, the buyer should be able to see which method produced it.

Benchmarks for Lecithin: EU, JECFA, and USP

Public specifications for food-grade lecithin give the closest regulatory benchmarks for the raw material. The table below summarizes the published floors:

These numbers describe lecithin as a food additive or excipient. They are not limits for phosphatidylserine. Their value for a PS buyer is contextual: they show what a baseline lecithin is expected to contain, and they make the much higher PS-grade requirement easier to understand. If a supplier's lecithin base barely clears 60%, the finished PS powder cannot plausibly report 95% or higher without substantial purification and concentration during processing.

PS Grades Are Not Lecithin: Read the Right Limit

The most common mistake in acetone-insoluble review is comparing a PS COA result against the lecithin benchmark. A finished PS powder is a concentrated phospholipid product, so its specification should be much higher.

Nutranexa's public PS specification matrix is a practical example. The PS 20% sunflower and PS 50% rows show an acetone-insoluble limit of 95.0 g/100g, while the soy PS row asks buyers to confirm the current specification with sales. The published sample COAs on the Quality & R&D page report batch results above that limit on a QB/T 5821-2023 test basis:

Three points follow for buyers. First, the relevant limit is the one in the quoted product specification, not a lecithin monograph. Second, a healthy PS result sits well above 95%, with published examples around 98%, because the phospholipid fraction has been concentrated during processing. Third, the soy grade and any special assay should be confirmed directly, because published specifications can differ by source and target assay. The general workflow for reading a PS certificate is covered in the COA and specification review.

US Regulatory Context: GRAS Lecithin and Supplement GMP

In the United States, lecithin is a GRAS substance under 21 CFR 184.1400, which incorporates the specifications of the Food Chemicals Codex by reference. This is the regulatory anchor for lecithin as an ingredient and explains why lecithin-derived PS powders are common in the US supplement market.

For the finished PS ingredient, the acetone-insoluble row is a quality attribute controlled under dietary supplement GMP:

• Specifications. Under 21 CFR 111.70, manufacturers must establish specifications for identity, purity, strength, and composition of components and finished products, and verify that they are met.
• Verification. The COA and batch testing are the evidence trail for that verification.
• Contract review. A US brand or contract manufacturer should confirm the acetone-insoluble limit in the supplier quality agreement and tie it to incoming release.

The practical US review is document-based: confirm the PS specification states the limit, the batch COA shows the method and result, and the incoming inspection procedure checks the row against the acceptance criterion.

EU Regulatory Context: Ingredient Purity and the E 322 Benchmark

In the European Union, phosphatidylserine is an ingredient used in food supplements rather than a food additive with its own harmonized specification. Regulation (EU) No 231/2012 sets the specification for E 322 lecithins, which is the nearest additive benchmark for the raw lecithin base, including the 60.0% acetone-insoluble assay. That benchmark describes the starting material, not the finished PS product.

For supplement ingredients without an EU specification, Directive 2002/46/EC states the general principle that, where purity criteria are not specified by Community legislation, generally acceptable purity criteria recommended by international bodies apply. In practice, EU buyers should:

• Confirm the PS specification and the named test basis for the quoted grade.
• Treat internationally recognized methods, such as AOCS Ja 4-46 or the QB/T 5821-2023 basis used on published Nutranexa sample COAs, as acceptable evidence.
• Ask whether the supplier can supply current batch COA data and method statements when the destination market requires them.

The EU review is therefore a specification and document review. The acetone-insoluble row on a PS COA should be read against the PS product limit, while the E 322 60% floor remains a useful raw-material context. Buyers who want independent confirmation can route the batch to a third-party laboratory.

How to Review the Acetone-Insoluble Row on a COA

When a PS COA arrives, check these fields in order:

• Parameter name. Acetone-insoluble matter or acetone insoluble, in the expected units.
• Limit. The specification limit, typically 95.0 g/100g or higher for concentrated PS grades.
• Result. The batch value, which for a healthy PS powder should sit clearly above the limit.
• Method or test basis. AOCS Ja 4-46, a pharmacopeia method, or the QB/T 5821-2023 basis seen on published examples.
• Batch linkage. Lot number, manufacture or test date, and report date should match the shipment.
• Consistency. Compare the value with previous batches; a steady result supports process control, while a large swing is a change-control signal.
• Cross-checks. Confirm the row agrees with the assay story: high phospholipid purity and high PS assay should move together.

If any field is missing, request the complete current batch COA before release. The documents for PS ingredients checklist shows the full document set to hold, and the sample evaluation and bulk approval workflow covers when a sample-level check becomes a batch-level commitment.

Supplier Questions for Acetone-Insoluble Control

Add these questions to the supplier questionnaire:

1. Does the quoted grade have a written acetone-insoluble limit in its specification? What is it?
2. Which method or test basis generates the COA result: AOCS Ja 4-46, a pharmacopeia method, or the QB/T 5821-2023 basis?
3. Can you provide current batch COA data, and does the result include the method and batch linkage?
4. How does the lecithin raw material and its purification affect the finished PS acetone-insoluble value?
5. What routine control keeps the result consistent across batches, and what triggers a recheck?
6. Will the specification and COA be committed in the supplier quality agreement?

For acceptance criteria, agree on the exact limit in the product specification, the named method, and the response when a result falls between the specification and the historical range. The supplier onboarding workflow is the right place to record these decisions in writing.

Need current PS specifications, COA samples, and method statements for your acetone-insoluble review? Request the specification and document evidence with your source preference, target assay, application, and destination market.

Conclusion

Acetone-insoluble matter is a simple-sounding row with a specific meaning: it measures the phospholipid-rich fraction of a lecithin-derived ingredient and confirms that a PS powder is genuinely concentrated rather than diluted with neutral lipid material. The correct review reads the PS product limit, not the 50-60% lecithin benchmark; confirms the method or test basis; ties the result to a named batch; and watches consistency across orders. In both the US and the EU, the parameter sits inside the specification-and-COA framework, supported by GRAS lecithin status and supplement GMP verification in the US and by the ingredient-purity and document-review framework in the EU. A well-documented acetone-insoluble row turns one line on a certificate into solid evidence of phospholipid purity.

FAQ

What is acetone-insoluble matter in phosphatidylserine?

Acetone-insoluble matter is the phospholipid-rich fraction of a lecithin-derived ingredient that does not dissolve in cold acetone. A higher value means a larger share of the powder is phospholipids rather than neutral oil and fatty components, which is why it appears as a purity row on PS specifications and COAs.

What acetone-insoluble limit should a phosphatidylserine powder meet?

A concentrated PS powder should meet the limit in its quoted product specification, typically 95.0 g/100g or higher. Nutranexa's public PS 20% sunflower and PS 50% specification rows show 95.0 g/100g, and published sample COAs report about 98 g/100g on a QB/T 5821-2023 test basis.

Why is acetone insoluble on a lecithin certificate of analysis?

Lecithin is a mixture of phospholipids with triglycerides, fatty acids, and carbohydrates, and the acetone-insoluble test separates the phospholipid-rich fraction from the dissolved neutral lipids. It is a classical purity check for lecithin and lecithin-derived ingredients such as PS.

What is the acetone-insoluble requirement for lecithin in the EU and the US?

Regulation (EU) No 231/2012 requires E 322 lecithins to contain not less than 60.0% of substances insoluble in acetone, JECFA's lecithin monograph requires not less than 60% acetone-insoluble matter, and the USP-NF Lecithin monograph requires not less than 50.0%. These are lecithin benchmarks, not PS limits.

How is acetone-insoluble matter measured?

The laboratory disperses the sample in cold acetone, separates the insoluble residue, washes and dries it, and reports the residue as a percentage or grams per 100 grams. AOCS method Ja 4-46 is the classical method for vegetable lecithins, and pharmacopeia monographs use the same principle.

What should I request from a PS supplier for an acetone-insoluble review?

Request the grade-specific specification with the written limit, the current batch COA with method or test basis and batch linkage, data for the sample and first bulk lot, and a statement on routine control. Record the agreed limit and method in the supplier quality agreement.

Sources

• legislation.gov.uk: Commission Regulation (EU) No 231/2012, Annex - E 322 Lecithins specification
• FAO/WHO JECFA: Lecithin monograph (INS 322(i)), Combined Compendium of Food Additive Specifications
• USP-NF: Lecithin monograph (USP29-NF24), content of acetone-insoluble matter
• AOCS: Official Method Ja 4-46, Acetone-Insoluble Matter in Vegetable Lecithins
• eCFR: 21 CFR 184.1400 - Lecithin (GRAS, FCC specifications incorporated by reference)
• eCFR: 21 CFR 111.70 - Requirements for Establishing and Maintaining Specifications
• legislation.gov.uk: Directive 2002/46/EC on Food Supplements (purity criteria)
• EFSA: Re-evaluation of Lecithins (E 322) as a Food Additive (EFSA Journal 2017;15(8):4742)
• National Standards of the PRC: QB/T 5821-2023 record (industry standard for phosphatidylserine)

Étapes suivantes recommandées

• Passez en revue le Phosphatidylserine page produit.
• Comparer Soy PS et Sunflower PS.
• Vérifier preuve de fabrication et Qualité & R&D.