Food · Thickeners & gelling agents

Kudzu Starch

葛粉 (Kuzuko)

Also known as: Kuzu Starch, Pueraria Root Starch

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At a glance

CategoryFood
INCI namePueraria Lobata Root Extract (for cosmetic uses, distinct from starch)
Japanese labeling nameプエラリアミリフィカ根エキス (different species) / クズ根エキス (cosmetic)
Common Japanese notations葛粉, クズコ
OriginPlant-derived (Pueraria lobata root starch)
Typical functionsGelling agent, Thickener
Regulatory status in JapanFood ingredient regulated under the Food Sanitation Act. The related root is also a Kampo material (葛根, kakkon).

Kudzu starch — kuzuko — is the traditional starch extracted from Pueraria lobata roots through a labor-intensive crushing, washing, and settling process. It is the defining gelling agent for kuzu-mochi, kuzu-kiri, and kuzu-yu (a thick hot starch drink sometimes prepared in cold-season recovery contexts). Several Japanese regions have historical production, including the area around the town of Yoshino in Nara.

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Classification

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Common OEM product categories

Finished-product categories where Japanese OEM manufacturers commonly formulate with this ingredient.

  • Traditional confectionery (kuzu-mochi, kuzu-kiri)
  • Culinary thickening (kuzu-yu, sauce-making)
  • Traditional Kampo preparations

Ingredient profile

Kuzuko is extracted by crushing Pueraria lobata roots, washing the starch fraction out of the fibrous material with water, allowing the starch to settle, and then drying and milling the final product. The traditional process yields a fine-grained starch with distinctive gelling and texture properties.

Note: Some specific regional kuzuko brands (including those associated with the Yoshino area) may fall under geographical indication or trademark protection. Generic "kudzu starch" or "kuzuko" terminology is used on cosmetic and ingredient labels without regional designations.

OEM applications

In food, kuzuko is the thickener for kuzu-mochi, the base for kuzu-kiri cold noodle-style dessert, and the central ingredient in kuzu-yu. It is also used in sauce-thickening applications.

In Kampo, the related root preparation 葛根 (kakkon) is a traditional medicinal material used in specific formulations, separately regulated from food use.

Regulatory classification in Japan

Food regulation under Food Sanitation Act. Kampo applications under the Pharmaceutical and Medical Device Act.

Regulatory classification in other markets

EUFood use established. Cosmetic use of Pueraria extracts should be verified against CosIng.
USAFood and supplement uses established.
ChinaWidely used in Chinese food and traditional medicine under various names.
KoreaSimilar uses exist in Korean cuisine.

Market reference formulations

Example finished products will be added after verification. Regional brands with GI or trademark protection are handled as descriptive production-region notes.

All brand names and product names referenced anywhere on this site are the property of their respective owners. Example entries are provided for informational purposes only and do not imply endorsement.

Alternative ingredients

Related ingredients commonly evaluated as substitutes.

Quick answers

What is Kudzu Starch?
Kudzu starch — kuzuko — is the traditional starch extracted from Pueraria lobata roots through a labor-intensive crushing, washing, and settling process. It is the defining gelling agent for kuzu-mochi, kuzu-kiri, and kuzu-yu (a thick hot starch drink sometimes prepared in cold-season recovery contexts). Several Japanese regions have historical production, including the area around the town of Yoshino in Nara.
What is the regulatory status of Kudzu Starch in Japan?
Food ingredient regulated under the Food Sanitation Act. The related root is also a Kampo material (葛根, kakkon).
What products typically use Kudzu Starch?
Traditional confectionery (kuzu-mochi, kuzu-kiri) / Culinary thickening (kuzu-yu, sauce-making) / Traditional Kampo preparations
Where does Kudzu Starch come from?
Plant-derived (Pueraria lobata root starch)
What is the INCI / JSCI labeling name for Kudzu Starch?
INCI: Pueraria Lobata Root Extract (for cosmetic uses, distinct from starch) / JSCI: プエラリアミリフィカ根エキス (different species) / クズ根エキス (cosmetic)

FAQ for OEM buyers

Q. What is kudzu starch (kuzuko) and how is it produced?

Kuzuko is the pure starch isolated from the tuberous root of Pueraria lobata (Japanese kudzu). The traditional 'Yoshino-zarashi' method, practised in Yoshino (Nara) since the Edo period, crushes winter-harvested roots, washes the starch fraction repeatedly with cold spring water over 30–90 days to settle and re-suspend the starch, then air-dries the white blocks. The process yields a high-purity starch with characteristic gelling and thermo-reversible properties.

Q. How is kuzuko used in traditional Japanese cooking?

Three classic uses: kuzu-mochi (chilled translucent jelly cubes coated in kinako and kuromitsu), kuzu-kiri (cold dessert noodles served with kuromitsu), and kuzu-yu (a hot, viscous starch drink consumed during winter or convalescence). Kuzuko is also used as a thickener for ankake sauces, where it gives a glossier, more elastic texture than potato or corn starch.

Q. Is kudzu root the same as the Kampo medicine 'kakkon'?

The same plant species (Pueraria lobata) supplies both. The dried root used in Kampo formulas under the name 葛根 (kakkon) — for example in Kakkonto (葛根湯) — is regulated as a crude drug under Japan's Pharmaceutical and Medical Device Act and is processed differently from the food-grade starch. Kuzuko is the isolated starch fraction; kakkon is the whole dried root used in herbal preparations.

Q. Is 'Yoshino kuzu' a protected designation?

There is no Geographical Indication (GI) registration under Japan's Act on Protection of the Names of Specific Agricultural, Forestry and Fishery Products for 'Yoshino kuzu' as of public registry data, but the term is associated by local industry convention with starch processed in the Yoshino area. Some Yoshino producers are protected by individual trademarks. Pure kuzuko on the Japanese market is often labelled '本葛 100%' (100% hon-kuzu), distinguishing it from blends of kuzu starch with sweet potato or other starches.

Use cases

  • Premium wagashi and gluten-free desserts

    Positioning
    Authentic Japanese gluten-free thickener for kuzu-mochi cubes, warabi-mochi blends, and chilled translucent jellies for café and luxury-retail channels.
    Typical usage level
    8–15% by weight of the liquid base, depending on the desired firmness.
    Formulation notes
    Dissolve in cold water before heating; gels at approximately 70–80 °C. Re-melts on heating, allowing thermo-reversible textures.
  • Premium ankake and Japanese restaurant sauce thickener

    Positioning
    Substitute for potato or corn starch in restaurant sauces where a glossier, more elastic mouthfeel and cleaner flavor are desired.
    Typical usage level
    1–3% in finished sauce.
    Formulation notes
    Slurry in cold dashi or water, add late in cooking, simmer briefly to clarify. Sauce remains glossy on chilled storage longer than corn-starch versions.

    Sources

    Industry-knowledge claim — not yet pinned to a single primary source

  • Convalescent / wellness 'kuzu-yu' beverages

    Positioning
    Heritage 'warming starch drink' positioned for winter wellness lines, often combined with ginger or umeboshi.
    Formulation notes
    5–8% kuzuko in hot water with sugar; gives the characteristic translucent, viscous texture.

    Sources

    Industry-knowledge claim — not yet pinned to a single primary source

  • Gluten-free baking and binding ingredient

    Positioning
    Specialty gluten-free flour blends for premium bakeries, where kuzu provides binding and a distinctive snap to crackers and biscuits.
    Typical usage level
    5–20% of the dry-flour blend.

    Sources

    Industry-knowledge claim — not yet pinned to a single primary source

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Official regulatory databases

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References

  1. 農林水産省 (Ministry of Agriculture, Forestry and Fisheries) food classification — kuzuko

Last updated: 2026-04-22. Ingredient entries are reviewed at least annually against current regulatory listings.

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