Black Soybean Extract 5–25% Anthocyanins

Black soybean extract comes from the dark seed coat of Glycine max black-seeded varieties, the kuromame of Japanese cooking, and not from yellow soybean or from the isoflavone-rich cotyledon. Ethanol extraction concentrates the anthocyanins of the hull, and the liquor is dried to a purple-red, water-soluble powder.

The primary grade is 25% anthocyanins by UV using the pH differential method, with 5% as the lower end of the range. The powder is 80 mesh. The 25% grade serves capsules and drink sticks with a small fill, while the 5% grade suits beverage bases and gummy premixes where color is wanted at a higher gram dose.

SKU: BOT-STX-0108 Category: Standardized Extracts Tags: Anthocyanins, Ethanol Extracted, Gummies & Chews, Polyphenols, Seed & Grain, Soybean, Standardized Extracts

Anthocyanin Standardization & Grades

The color of black soybean is concentrated in the thin seed coat, and the pigments are almost entirely anthocyanins, with cyanidin-3-glucoside as the dominant member and delphinidin-3-glucoside and petunidin-3-glucoside as smaller ones. The page standardizes to the summed class, because the seed coat holds a few related pigments that respond together in a colorimetric assay. A second figure for cyanidin-3-glucoside is recorded in the data and is described here without numbers. The botanical entity is Glycine max (L.) Merr., and the part used is the seed.

Grade	Assay & Method	Where It Fits
5% Anthocyanins	UV (pH differential)	Beverage bases and gummy premixes
25% Anthocyanins	UV (pH differential)	Capsules and drink sticks with small fill

Dose, pigment intensity and fill weight decide the grade. The 25% grade carries five times the pigment load per gram of the 5% grade, so it reaches a target in a very small fill and colors a base intensely at low inclusion. The 5% grade keeps more of the seed coat polysaccharides and phenolic acids and gives a softer, more diluted color. Siblings from the same crop are the ratio-based Black Soybean Extract Powder, the isoflavone-graded Soybean Extract 20–80% Isoflavones and the fermented Fermented Soybean Extract Powder.

The pigment grade and the isoflavone grade of soybean are different products. Isoflavones such as genistin and daidzin are found in the cotyledon of any soybean, yellow or black, whereas anthocyanins occur only in the seed coat of black-seeded types. Buyers who compare quotes should check which marker the percentage describes and which part of the seed it came from.

The pH differential method counts only monomeric anthocyanins, so the figure is a pigment value and not a total polyphenol value. A formulator who needs a defined cyanidin-3-glucoside share should request an HPLC profile alongside the UV figure.

Anthocyanin Analysis & Purity Risks

The pH differential method by UV gives the figure for both grades. Two readings are taken at the pigment maximum, one in strong acid and one near pH 4.5; their difference reflects only the monomeric anthocyanins that shift color with pH. The result is usually expressed as an equivalent of a reference pigment, most often cyanidin-3-glucoside, which makes it a natural fit for a seed coat dominated by that pigment.

UV delivers one summed value and no breakdown by pigment. An HPLC profile resolves cyanidin-3-glucoside from the delphinidin and petunidin glucosides, and it is a different measurement that is not interchangeable with the UV total. The profile is also the better identity test, since a soybean seed coat extract is dominated by a single pigment, unlike most berry extracts.

Polymeric pigments form during heating and storage and are not counted by the method, so a heated or old lot reads lower than its visual color suggests. Seed coat extracts also carry tannin-like procyanidins, which add astringency and color depth but do not change the UV reading.

Purity risks follow from the raw material. Black rice, purple corn and black carrot carry similar pigments and read alike in a UV test, so the figure alone does not prove a soybean origin. A named species, the seed coat as the stated part and a profile dominated by cyanidin-3-glucoside protect identity better than a percentage.

Typical Specifications

Specification Item	Product Information
Latin Name	Glycine max
Plant Part	Seed & Grain
Processing	Ethanol Extraction
Compound Class	Anthocyanins, Flavonoids, Polyphenols
Common Name	Black Soybean, Kuromame
Ingredient Type	Standardized Extract
Marker Compound(s)	Anthocyanins (mainly cyanidin-3-glucoside of black Glycine max seed coat)
Primary Grade	25% Anthocyanins (UV, pH differential)
Available Grades	5% · 25% Anthocyanins (UV, pH differential)
Appearance	Purple Red powder
Solubility / Dispersibility	Water Soluble
Quality Parameters
Moisture (LOD)	≤5.0%
Total Ash	≤5.0%
Particle Size	80 mesh
Heavy Metals	Lead ≤2 ppm · Arsenic ≤1 ppm · Cadmium ≤1 ppm · Mercury ≤0.1 ppm
Microbiology	TPC ≤1,000 cfu/g · Yeast & Mold ≤100 cfu/g · E. coli Negative · Salmonella Negative/25 g
Shelf Life	24 months in unopened original packaging, cool and dry storage

Applications by Grade

25% Grade for Compact Capsules

The 25% grade packs the pigment into a very small capsule fill. The purple-red powder is hygroscopic and stains, so use a dry filling room and dedicated scoops, and check fill weights at the start of each run because the black soybean powder bridges in narrow hoppers.

25% Grade in Drink Sticks

Being water soluble, the high grade goes into solution at once and colors the liquid red in acid and violet near neutral. Citric acid holds the shade, and even a small stick dose colors a full glass.

5% Grade for Soy-Based Beverage Bases

Plant-protein beverage bases sit near neutral pH, where anthocyanins turn violet and fade, so the lower grade works best in acidified or fruit-juice-based drinks. Add the black soybean powder last and cool, and test for haze, because seed coat tannins can bind proteins.

5% Grade for Gummy Premixes

Gummies can take the lower grade after cooking, which spares the pigment from prolonged heat. A low-pH pectin gel keeps the red-violet color, while starch-based gels near neutral pH turn bluish gray, so set the acid level before choosing the dose.

25% Grade in Dry Beverage Colorants

Dry drink powders use the high grade as a natural dark red colorant at very low inclusion. Blend it into a bulking agent beforehand and test uniformity, since a little strongly colored powder reveals uneven mixing quickly.

Technical & Quality Considerations

The black soybean extract is a purple-red powder with a faint beany, slightly sweet odor and a mildly astringent taste. Dissolved in water, the pigment shows a pH-dependent shade, red at low pH, violet in the middle range and bluish toward alkaline. At intermediate pH the color fades because the pigment forms a colorless hemiketal, which returns on acidification.

Anthocyanins fade with heat, light, oxygen and ascorbic acid, while iron and aluminum ions flatten the color. Use stainless steel, add the black soybean extract late in the process and keep heat treatment short. At scale, pass the powder through a screen before dosing and blend it into a portion of the carrier first, as it cakes when humid.

Clean-down matters because the pigment stains. Mixers and hoppers are rinsed promptly, a dedicated scale and scoop are used, and each lot is compared with a retained sample for color and flow. Keep the drum closed, cool and dry, and record the date it was opened, so that older lots are used first and moisture-related caking is limited.

A black soybean extract is checked by color in dilute acid, where a bright red shows intact cyanidin-3-glucoside, and by taste, where a beany note should be faint. Keep a retained sample of every black soybean extract lot, and use an HPLC profile to confirm that one pigment dominates, since that pattern separates a seed coat extract from berry-based anthocyanin sources.

Packaging & Commercial Supply

Essencefield supports product evaluation, formulation trials, commercial orders, and ongoing ingredient supply. Packaging, storage, and shipping arrangements are determined by product characteristics, order quantity, stability requirements, and destination-market needs.

Supply Item	General Information
Sample	Available upon request for formulation, testing, and supplier evaluation
Order Quantities	100 g · 1 kg · 5 kg · 25 kg · 100 kg · 500 kg · Bulk
Sample Lead Time	Typically 5–7 days after sample confirmation
Production Lead Time	Typically 15–30 days after order and specification confirmation
Packaging	Suitable protective inner packaging with bags, cartons, drums, or other appropriate outer packaging
Storage	Store in tightly sealed, suitable protective packaging in a cool, dry environment. Protect from moisture, heat, and direct sunlight. Specific storage conditions follow the approved product specification.
Documentation	COA · Product Specification · TDS · SDS · Applicable declarations (as applicable)

Final order quantities, lead times, packaging, documentation, and shipping arrangements are confirmed according to the selected product and commercial requirements.