In short: the grape range is split by plant part, and that is the whole buying decision. Seed gives you OPC (oligomeric proanthocyanidins), assayed by UV. Skin gives you grape-source resveratrol, assayed by HPLC. The two are different materials with different markers and different assay methods — a quotation for “grape extract 95%” tells you nothing until it names both the part and the marker.
Botanical identity and general specification
| Botanical identity | Vitis vinifera L. |
|---|---|
| Plant parts used | Seed and skin — the plant part determines which marker applies |
| Marker families | OPC (seed, by UV) and grape-source resveratrol (skin, by HPLC) |
| Shelf life | Two years when stored properly |
Compare Available Grades
4 commercial grades are listed below with their declared marker or ratio, the assay method, a representative batch and the routine physical parameters.
| Grade | Plant part | Specification | Method | Representative batch | Particle size | Loss on drying | Sulphated ash |
|---|---|---|---|---|---|---|---|
| Grape Seed Extract Powder 95% OPC | Seed | OPC 95% by UV (result 95.68%) | UV | LXPTZ250721 | 98% through 80 mesh | ≤ 5.0%; result 4.12% | ≤ 5.0%; result 3.78% |
| Grape Seed Extract Powder 30% OPC | Seed | OPC 30% by UV (result 31.26%) | UV | LXPT210607 | 98% through 80 mesh | ≤ 5.0%; result 3.82% | ≤ 5.0%; result 3.99% |
| Grape Skin Extract Powder 20% Resveratrol | Skin | Grape-source resveratrol 20% by HPLC (result 20.16%) | HPLC | LXPTP240715 | 98% through 80 mesh | ≤ 5.0%; result 4.67% | ≤ 5.0%; result 3.99% |
| Grape Seed Powder | Seed | Seed powder; no extract ratio or marker assay stated | Identity / physical | LXPTZ250116 | 98% through 80 mesh | ≤ 12.0%; result 10.82% | ≤ 8.0%; result 6.99% |
Grape Seed Extract Powder 95% OPC
Grape Seed Extract Powder 95% OPC is a Fine brown-red powder supplied as follows: OPC 95% by UV (result 95.68%), determined by UV. The representative batch is LXPTZ250721, milled to 98% through 80 mesh. Loss on drying is ≤ 5.0%; result 4.12% and the ash parameter is ≤ 5.0%; result 3.78%.
Botanical identity for this grade is Vitis vinifera L.; the plant part is Seed.
Grape Seed Extract Powder 30% OPC
Grape Seed Extract Powder 30% OPC is a Fine brick-red powder supplied as follows: OPC 30% by UV (result 31.26%), determined by UV. The representative batch is LXPT210607, milled to 98% through 80 mesh. Loss on drying is ≤ 5.0%; result 3.82% and the ash parameter is ≤ 5.0%; result 3.99%.
Botanical identity for this grade is Vitis vinifera L.; the plant part is Seed.
Grape Skin Extract Powder 20% Resveratrol
Grape Skin Extract Powder 20% Resveratrol is a Fine reddish-brown powder supplied as follows: Grape-source resveratrol 20% by HPLC (result 20.16%), determined by HPLC. The representative batch is LXPTP240715, milled to 98% through 80 mesh. Loss on drying is ≤ 5.0%; result 4.67% and the ash parameter is ≤ 5.0%; result 3.99%.
Botanical identity for this grade is Vitis vinifera L.; the plant part is Skin.
Grape Seed Powder
Grape Seed Powder is a Fine brick-red powder supplied as follows: Seed powder; no extract ratio or marker assay stated, determined by Identity / physical. The representative batch is LXPTZ250116, milled to 98% through 80 mesh. Loss on drying is ≤ 12.0%; result 10.82% and the ash parameter is ≤ 8.0%; result 6.99%.
Botanical identity for this grade is Vitis vinifera L.; the plant part is Seed.
Grade comparison: grape seed and skin extract powder
| Your requirement | Grade to specify | Why |
|---|---|---|
| Your claim names OPC or proanthocyanidins | 30% or 95% Seed Extract | Seed-derived, assayed by UV against OPC |
| Your claim names resveratrol | 20% Skin Extract | Skin-derived, assayed by HPLC; note the certificate specifies grape-source resveratrol |
| You need milled seed, not an extract | Grape Seed Powder | No marker or ratio declared; sold on identity and physical specification |
| You need a specific marker at high concentration | Specify part and marker | OPC and resveratrol are not interchangeable — state both the plant part and the marker in the inquiry |
Buyer Decision Guide
Work through these in order — each step narrows the next:
- Start from the claim, not the percentage. Identify the marker your label or customer specification names. A grade declaring a different marker is a different product, whatever its headline number.
- Fix the assay method in writing. UV and HPLC results are not interchangeable for the same material. State the method your specification requires.
- Ask for the batch, not the sheet. A specification describes a grade; the COA describes the batch you will receive. Require the batch number on the packing list.
- Check the physical parameters too. Loss on drying and the ash determination reveal process consistency. A result far outside the representative range is worth questioning even if the marker is on target.
- Confirm mesh size against your process. Particle size affects blending, tabletting and hydration. It can usually be adjusted if stated up front.
Qualification and COA Review
Every grade on this page is produced at the same certified manufacturing site, and each batch is released against its own certificate of analysis. When you review the COA, confirm four things: the batch number matches your order documents; the assay method is the one you specified; the marker result sits inside the declared limit; and the physical parameters are reported rather than left blank.
For first orders, requesting a retention sample alongside the shipping documents makes incoming inspection considerably easier.
Certification coverage for this product line
Botanical extract powders in this range are produced at the certified Zhashui site of Shaanxi Longsheng Biotechnology Co., Ltd., which holds five third-party-issued certificates: FSSC 22000 (certificate CN26/00005265, issued by SGS United Kingdom Ltd, valid 13 Jul 2026 – 12 Jul 2029), ISO 22000:2018 (CN26/00005266, issued by SGS United Kingdom Ltd, valid 13 Jul 2026 – 12 Jul 2029), SGS cGMP (CN26/00005948, valid 12 Aug 2026 – 12 Aug 2027), Star-K Kosher Pareve (account NCZSI67Q, valid through 31 Mar 2027) and Halal (3391260000, issued by Shandong Halal Certification Service, valid 28 Jun 2026 – 25 Jun 2029). The original certificate documents are published on the certificate register for Shaanxi Longsheng Biotechnology.
Frequently Asked Questions
Is grape seed extract the same as grape skin extract?
No. They are different plant parts with different dominant marker families. Seed extract in this range is standardised to OPC (oligomeric proanthocyanidins) by UV. Skin extract is standardised to grape-source resveratrol by HPLC. Different markers, different methods, different materials.
Why does the skin grade specify “grape-source” resveratrol?
Because the certificate wording matters. Resveratrol is also produced from other botanical sources such as Japanese knotweed, and a specification that simply says “resveratrol 20%” does not tell you the origin. Stating grape-source makes the material identifiable and is worth checking on any quotation you receive.
OPC is assayed by UV and resveratrol by HPLC — can I compare the two percentages?
No. They are different markers measured by different methods, and a UV result reports a group absorbance rather than a single resolved compound. Within each marker family the percentages are comparable between grades; across the two families they are not.
The 95% OPC grade shows a result of 95.68% — what does that tell me?
That the representative batch met and slightly exceeded the declared minimum. The specification is the guaranteed floor. For your order, what matters is that the COA for your allocated batch reports a result at or above the declared limit.
Does the seed powder have a declared OPC content?
No. The grape seed powder is a milled botanical rather than a standardised extract, so no marker assay or extraction ratio is stated, and its moisture and ash limits are wider (12.0% and 8.0%). If you need a declared OPC value, choose one of the seed extract grades.
Why are the skin and seed grades similarly priced in appearance but different in performance?
Pricing reflects the marker and the purification route, not the product name. Because the two are standardised to different compounds by different methods, you cannot judge them against each other on the headline percentage. Compare them against the claim you intend to make.
What particle size do the grape grades have?
All four are milled at 98% through 80 mesh. If you need a different particle size for tabletting or blending, specify it when you inquire.
How do I avoid a mismatch when ordering a “grape extract”?
Put four things in writing: the plant part (seed or skin), the marker (OPC or resveratrol), the assay method you require, and the declared percentage. A specification that omits the plant part cannot be verified, because the same product name covers both materials.
Request a Grade Comparison
Send the grade you are considering, your target marker value, the method you need it declared by, and your destination market. We will reply with the matching specification, a representative batch COA and a sample offer.
Practical next step: send your requirement as an inquiry, or write to gshuai@long-bio.com.