Curdlan

INS 424CAS 54724-00-4

Listed as a thickener and a stabiliser by Codex and the US.

Listed as thickeners (US, Codex) · stabilisers (US, Codex) · gelling agents (Codex) · firming agents (Codex) · texturisers (US) · formulation aids (US) · processing aids (US)

Curdlan is a fermentation-derived gelling agent unusual in that it forms a firm gel when heated rather than when cooled, and the gel does not melt again. It is used in noodles, processed meats and jellies.

Where it is and isn’t permitted

Status of Curdlan by jurisdiction. Every jurisdiction this site covers is listed, including those where the substance does not appear.
JurisdictionStatusScope and limitsCitation
Australia and New ZealandFood Standards Australia New ZealandNo listed food uses foundThis site has not matched this substance to any food use on this jurisdiction’s list of authorised food additives. A food additive may be used only in foods that list names. Flavourings, enzymes, processing aids and added nutrients are regulated separately and do not appear on it.
CanadaHealth CanadaNo listing matchedHealth Canada’s lists name additives without E or INS numbers, so this site matches them by exact name. A substance listed there under a name this site does not recognise has no row here.
European UnionEuropean Commission / EFSANo listed food uses foundThis site has not matched this substance to any food use on this jurisdiction’s list of authorised food additives. A food additive may be used only in foods that list names. Flavourings, enzymes, processing aids and added nutrients are regulated separately and do not appear on it.
Great BritainFood Standards Agency / Food Standards ScotlandNo listed food uses foundThis site has not matched this substance to any food use on this jurisdiction’s list of authorised food additives. A food additive may be used only in foods that list names. Flavourings, enzymes, processing aids and added nutrients are regulated separately and do not appear on it.
JapanConsumer Affairs AgencyNo listing matchedThis site imports only Japan’s list of designated additives (Appended Table 1 to the Regulations for Enforcement of the Food Sanitation Act), matched by English name. Existing additives, natural flavouring agents and ordinary foods used as additives are permitted outside that list and are not imported, so an empty row does not show that Japan does not permit the substance.
South KoreaMinistry of Food and Drug SafetyPermitted, with conditions
Designated food additive: Standards and Specifications for Food Additives, Part III, 1. …

Designated food additive: Standards and Specifications for Food Additives, Part III, 1. 일반식품첨가물 (general food additives), 커드란 (“Curdlan”, the English the Code prints beside it). Main use (주용도) of 커드란: 증점제, 안정제. Standard for use (사용기준) of 커드란: (1) [to be used under the general standard for use in II. 2. 1), the minimum amount that achieves the technical effect, with no limit set for this additive in particular] “II. 2. 1)의 규정에 따라 사용하여야 한다.” The Korean is the standard as published. There is no official English translation of the current Code (the English version on MFDS’s website is the 2020 edition and has no legal effect); the English in square brackets is this site’s description of what each sentence does, not a translation of the foods or the levels. Compositional specifications (Part IV) are not imported, nor are the general standards in Part II, which apply to every additive.

Standards and Specifications for Food Additives (식품첨가물의 기준 및 규격), MFDS Notification, Part III (Standards for use, by item)retrieved 2026-10-18
United StatesFood and Drug AdministrationPermitted, with conditions21 CFR 172.809retrieved 2026-10-17
Codex AlimentariusCodex Alimentarius Commission / JECFAPermitted, with conditions

1 food category

no numerical limit (good manufacturing practice)

Note 211 For use in noodles only.

CXS 192-1995 Table Three, INS 424and 1 further provisionretrieved 2026-09-07

How much is permitted

A listing usually limits the quantity as well as the food. Only one of the forms that takes is a figure: quantum satis and good manufacturing practice permit the amount the technological effect requires and no more, which is a limit rather than the absence of one. Figures below are the range across every food category this page is listed in, and categories differ between regulators — see how much is permitted.

South Korea—1 no quantity stated
United States—1 no quantity stated
Codex Alimentarius—2 GMP

No regulator sets a figure for Curdlan. That is not an absence of control: where the listing says quantum satis or good manufacturing practice, the quantity is limited to what the effect requires.

What it is made from

Produced by fermenting a sugar feedstock with the bacterium Agrobacterium biovar 1, then recovering the polysaccharide.

  • Vegan
  • Vegetarian

Compare other additives on the dietary indexes.

CAS registry number
54724-00-4

How JECFA defines it

The international specification for identity and purity, prepared by the Joint FAO/WHO Expert Committee on Food Additives and published by FAO. It is a different document from any above, written by a different body and revised on its own cycle; it is advisory, and a country adopts it or does not.

INS 424 Curdlan

Curdlan is a high molecular weight polysaccharide consisting of β -1,3-linked glucose units, produced by pure-culture fermentation from a non-pathogenic and non-toxicogenic strain of Agrobacterium biovar 1 (identified as Alcaligenes faecalis var. myxogenes at the time of discovery) or Agrobacterium radiobacter . Curdlan consists of β -(1,3)-linked glucose residues and has the unusual property of forming an elastic gel upon heating its aqueous suspension.

Synonyms: Beta-1,3-glucan; INS No. 424

Assay, identification and purity criteria

Description and assay

Specification history
Prepared at the 57th JECFA (2001) and published in FNP 52 Add 9 (2001), superseding specifications prepared at the 53rd JECFA (1999) and publishe d in FNP 52 Add 7 (1999). An ADI “not specified” was established at the 57th JECFA (2001).
C.A.S. number
54724-00-4
Chemical formula
(C 6 H 10 O 5 ) n
Assay
Not less than 80% (calculated as anhydrous glucose)
DESCRIPTION
Odourless or almost odourless, white to nearly white powder.
FUNCTIONAL USES
Firming agent, gelling agent, stabilizer, thickener.
METHOD OF ASSAY
Transfer about 100 mg of the sample, accurately weighed, into a 100-ml volumetric flask and dissolve in about 90 ml of 0.1 N sodium hydroxide. Add 0.1 N sodium hydroxide to volume and mix well. Transfer 5 ml of the solution into a 100-ml volumetric flask, add water to volume and mix well. Quantitatively transfer 1 ml of the solution to a small flask or test tube, add 1 ml of a 5% (w/v) solution of reagent grade phenol in water and 5 ml of sulfuric acid TS. Shake vigorously and cool in ice-cold water. Prepare a blank and a reference standard solution in the same manner, using 0.1 ml of water and 100 mg of reagent grade glucose, respectively. Determine the absorbances of the sample solution and the reference standard solution in 1-cm cells at 490 nm with a suitable spectrophotometer, using the blank solution as the blank. Calculate the content (%) of curdlan in the sample using the following formula: Curdlan content (%) = (A/A R ) × (0.9 × W R /W) × 100 where A = the absorbance of the sample solution A R = the absorbance of the reference standard solution 0.9 = the molecular weight of anhydrous glucose divided by the molecular weight of glucose W = the weight of the sample (mg) WR = the weight of the glucose standard used as reference (mg)

Identification

Solubility (Vol. 4)
Insoluble in water and ethanol.
Solubility in alkali
Passes test Suspend 0.2 g of the sample in 5 ml of water, add 1 ml of 3 N sodium hydroxide, and shake. The sample dissolves.
Gel formation
Heat a 2% aqueous suspension of the sample in a boiling water bath for 10 min and cool. A firm gel forms.
Precipitate formation with cupric tartrate
Passes test See description under TESTS
Test: Precipitate formation with cupric tartrate
Add 5 ml of sulfuric acid TS to 10 ml of a 2% aqueous suspension of the sample, heat in a boiling water bath for 30 min and cool. Neutralize the mixture with barium carbonate. Centrifuge the mixture at 900xg for 10 min. Add 1 ml of the supernatant to 5 ml of hot alkaline cupric tartrate TS. A copious red precipitate of cuprous oxide is formed.
Test: Gel strength
Place 200 mg of the sample into the tube of a Potter homogenizer, add 10 ml of water and homogenize at about 3,500 rpm for 5 min. Transfer the suspension into a 16 mm × 150 mm test tube, deaerate in vacuum for 3 min and heat in a boiling water bath for 10 min to form a gel. Cool the tube under running water, let stand for 30 min, then remove the gel from the tube. Cut the gel accurately at distances of 20 mm and 30 mm from the bottom to obtain a piece 10 mm long. Determine gel strength with a Rheo Meter Model CR-200D (Sun Scientific Co., Ltd., Japan; Load cell: 1,000 g) or an equivalent instrument, under the following conditions: Measurement mode: 4 Velocity of moving plate: 250 mm/min Plunger: cylindrical type, 0.5 cm diameter Read the breaking point of the gel (B). Calculate the gel strength using the following formula: Gel strength (g/cm²) = 1,000B/ π r² where r = the radius of the plunger (cm)

Purity criteria

Gel strength
Not less than 600 g/cm² (2% aqueous suspension) See description under TESTS
pH (Vol. 4)
6.0 - 7.5 (1% aqueous suspension)
Loss on drying (Vol. 4)
Not more than 10% (60º for 5 h, in vacuum)
Sulfated ash (Vol. 4)
Not more than 6% Test 1 g of the sample (Method I)
Nitrogen (Vol. 4)
Not more than 0.3% Test 1 g of the sample (Method II)
Lead (Vol. 4)
Not more than 0.5 mg/kg Determine using an atomic absorption technique appropriate to the specified level. The selection of sample size and method of sample preparation may be based on the principles of the method described in Volume 4, “Instrumental Methods.”
Microbiological criteria (Vol. 4)
Total plate count: Not more than 1,000 cfu/g E. coli: Negative in 1 g

FAO JECFA Monograph 1 (2006)

Every name it appears under

4 recorded names. A label may use any of them.

INS number

  • 424

CAS registry number

  • 54724-00-4

As it appears in regulation

  • Curdlan

Other names

  • Curdlan

Hazard reference values

EFSA and JECFA have both assessed Curdlan and their conclusions are not two comparable figures — EFSA records not allocated, JECFA not specified. An acceptable daily intake is a reference value set by a committee, not a threshold above which harm begins. “Not specified”, “not limited” and “not allocated” are conclusions, not missing data, and they are shown in the words each body used rather than reduced to a number. See where the two committees differ.

Values set by assessing bodies. A body that has not set a value is not listed here.
TypeValuePopulationAssessed byOpinion
ADInot allocatedconsumersEFSA FAF2023
ADInot specified—JECFA2001

Evidence and how bodies read it

Studies, and the differing conclusions regulators drew from them, are curated rather than machine-read, and none has been written for this substance yet.

Common questions

Assembled from what is above, in the words the questions are usually asked in. Each answer is the same statement the relevant section makes, with the same citations behind it.

What is INS 424?
INS 424 is Curdlan. Curdlan is a fermentation-derived gelling agent unusual in that it forms a firm gel when heated rather than when cooled, and the gel does not melt again. It is used in noodles, processed meats and jellies.
What is Curdlan used for in food?
It is listed as a thickener and a stabiliser — the role Codex and the US assign it. This page shows every function each regulator records, with the citation for each.
Is Curdlan banned in Europe?
No. Curdlan does not appear on the EU's list of authorised food additives, which is not the same as being banned: the EU permits an additive only where it has authorised it, and usually the reason for an absence is that no one applied. The EU has made no finding against this substance. It does mean it may not be used as a food additive in the EU today.
Where is Curdlan permitted?
Of the seven regulators this site reads, South Korea, the US and the Codex standard permit it. Each permission is for named foods at named levels, not a blanket one; the table on this page gives them with citations.
Is Curdlan vegan?
Yes. Curdlan is not derived from animals, and is suitable for vegetarians. This page says what it is made from and how.

Sources for this page

  • kr retrieved 2026-10-18
  • ecfr retrieved 2026-10-17
  • gsfa retrieved 2026-09-07
  • jecfaspecs retrieved 2026-09-23

Full licence terms and publisher details on Sources. How this page is built and updated: Method.

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