E-numbers  /  Thickeners & emulsifiers  /  E427

Cassia gum

also: Cassia tora gum · INS 427

A plant-derived thickening gum from the cassia seed, used to give ice cream, yogurt and sauces a smooth, gel-like texture.

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An ingredient list from the cakes, biscuits and desserts aisle

Water, Gelling Agents: Gellan Gum, Xanthan Gum, Cassia Gum, Acid: Citric Acid, Colour: Anthocyanins, Acidity Regulator: Potassium Citrates, Flavouring, Sweeteners: Sucralose, Acesulfame K, Rowan Berry Extract

E427Thickener / Emulsifier

Cassia gum

The raw plant material contains anthraquinones, compounds linked to laxative effects and potential DNA damage.

VeganVegetarian

How common it is in UK food

28

of the 43,325 UK supermarket foods we checked declare E427 in their ingredients

That is under 0.1%, counted by its code or its name.

Counted by NutraSafe from UK supermarket ingredient lists, September 2026. How we counted

What cassia gum is, what it does and where you will see it

Why it’s worth knowing. The raw plant material contains anthraquinones, compounds linked to laxative effects and potential DNA damage. Food-grade E427 must be purified to near-undetectable levels, but only when processors meet the specification is the risk controlled.

What is it?

Cassia gum is a polysaccharide (galactomannan) extracted from the endosperm of seeds of Senna obtusifolia (formerly classified as Cassia obtusifolia), a leguminous plant. It consists mainly of a linear chain of mannose units with branching galactose units, giving it gel-forming and water-thickening properties similar to locust bean gum. The raw seed also contains anthraquinones, naturally occurring compounds that must be removed to below 0.5mg per kg before the gum may be used as a food additive under UK and EU rules.

What does it do?

In water, cassia gum chains swell and entangle to form a thick, viscous network. This raises the viscosity of liquid food systems, prevents ice crystals from growing in frozen products, stabilises emulsions (keeping fat and water from separating), and gives dairy and sauce products a smooth, creamy mouthfeel. It behaves similarly to locust bean gum but with a slightly stronger gel at equivalent concentrations.

Where you will see it

Most commonly found in ice cream and ice lollies (where it controls ice crystal size), flavoured yogurts and fermented milk products, processed cheese, meat-based sauces, ready-made soups and packet broths. On a UK ingredient label it appears as Cassia gum or E427.

What the science says

Anthraquinones in the raw plant

The cassia plant naturally produces anthraquinones, a class of compounds that at high doses act as stimulant laxatives and have shown genotoxic (DNA-damaging) effects in laboratory tests. This is why regulators required a purification step before authorising the gum for food use. The specification of less than 0.5mg anthraquinones per kg of finished gum was set as the threshold below which the food additive is considered not to present a safety concern at permitted use levels.

EFSA's Panel on Food Additives concluded that cassia gum meeting the specification of anthraquinones below 0.5mg per kg does not raise a safety concern at the proposed food uses and levels.

2006Regulatory reviewEFSA Panel on Food Additives and Nutrient Sources (ANS), Scientific Opinion on cassia gum

EFSA's feed additive panels reiterated that only semi-refined cassia gum meeting the food-additive specification (anthraquinones below 0.5mg per kg) can be considered acceptable; higher anthraquinone content is not acceptable.

2017Regulatory reviewEFSA FEEDAP Panel, Safety of cassia gum as a feed additive for dogs and cats (Intercolloid dossier)

Genotoxicity of anthraquinones

Several anthraquinones found in cassia, including emodin, have shown positive results in bacterial gene-mutation tests (Ames test) and chromosomal aberration assays in cultured cells. Emodin has also caused kidney tumours in male rats in long-term animal studies. These findings applied to the unrefined plant extract, not to food-grade cassia gum that meets the specification, but they drove the decision to require tight purity controls before EU and UK authorisation.

Emodin, a cassia-derived anthraquinone, tested positive for genotoxicity in in vitro assays and caused renal tubular tumours in male rats in a 2-year National Toxicology Program study.

2001AnimalNational Toxicology Program, Technical Report on Emodin

Multiple hydroxyanthraquinones present in cassia seed extracts showed mutagenic activity in Salmonella typhimurium Ames tests.

2006LabEFSA Panel on Food Additives, Scientific Opinion on cassia gum

Digestive effects at high intake

As a galactomannan dietary fibre, cassia gum is not absorbed and passes through the gut largely intact. At the small amounts present in food from permitted uses, it contributes negligible fibre. Very large doses of galactomannans can loosen stools, but this is a class effect of insoluble fibre at high intake and is not specific to the anthraquinone concern above.

Galactomannans including cassia gum are classified as dietary fibre; at food-additive use levels (up to 2.5g per kg of finished food) the dietary fibre contribution per typical serving is small and laxative effects are not expected.

2006Regulatory reviewEFSA Panel on Food Additives, Scientific Opinion on cassia gum

Where it stands with the regulators

Approved for use in the UK and EU
Legal basis
UK FSA approved-additives list and assimilated EU Regulation 1333/2008 (Annex II). Approved in the EU following implementation by Commission Regulation (EU) 2019/1947 (October 2019), which added cassia gum to Annex II for specific food categories.
Permitted foods
Ice cream and similar frozen confections (max 2.5g per kg); Flavoured yogurts and other fermented milk products (max 1.5g per kg); Processed cheese (max 1.5g per kg); Meat products in sauces and dressings (max 1.5g per kg); Ready-made broths and packet soups (max 1.5g per kg)
Maximum levels
1.5g per kg in most permitted categories; 2.5g per kg in ice cream
Safe-intake limit (ADI)
No numerical ADI established; approval conditional on anthraquinone specification below 0.5mg per kg of additive
History
Cassia gum was not included in the original EU Regulation 1333/2008 annexes at adoption. EFSA issued a scientific opinion in 2006 concluding it was acceptable provided anthraquinone content was controlled. The European Commission added E427 to Annex II via Commission Implementing Regulation (EU) 2019/1947, which came into force in November 2019. Prior to that date it was not authorised as a food additive in the EU. It is approved for pet food use in the EU under separate feed additive rules. The UK adopted the EU position on transition, and E427 appears on the UK FSA approved additives list.

Who should be careful

No specific population group needs to avoid E427 at permitted food levels on the basis of current evidence. People sensitive to legume-derived gums or with diagnosed galactomannan intolerances may react, though cassia gum allergy is not formally recognised as a declarable allergen under UK food law. Anyone who notices digestive discomfort after eating products listing cassia gum or E427 may choose to avoid those products.

The honest read

The concern with cassia gum is not the purified food additive itself but the anthraquinone compounds naturally present in the raw plant. Regulators made the approval conditional on manufacturers purifying the gum to near-undetectable anthraquinone levels. The science supporting that specification is solid: anthraquinones from cassia have genuine genotoxic signals in lab and animal tests. What is less clear is whether routine commercial production consistently meets the specification, and there is no publicly available post-market monitoring data showing what anthraquinone levels consumers are actually exposed to. The additive is not widely used, and exposure from typical diets is likely low. But the science underpinning the specification is real, and the approval rests entirely on that purity condition being met.

Common questions about cassia gum

Is E427 banned in the UK?

No. E427 cassia gum is approved in the UK, listed on the UK FSA approved-additives register. It was not permitted in the EU until November 2019, when the European Commission added it to Annex II of food additive legislation after an EFSA opinion. The UK adopted that position. It is only permitted in a defined set of food categories at set maximum levels, and only when the anthraquinone content of the gum meets the specification of less than 0.5mg per kg.

Why do regulators set a purity condition on E427?

The cassia plant naturally contains anthraquinones, compounds that have shown genotoxic (DNA-damaging) effects in laboratory and animal tests. Food-grade cassia gum must be purified so anthraquinone levels fall below 0.5mg per kg of additive. The EFSA opinion that supported authorisation was conditional on this specification. Unrefined cassia seed extract is not an approved food additive.

What foods contain E427?

Cassia gum is used in ice cream, ice lollies, flavoured yogurts, fermented milk products, processed cheese, meat-based sauces and ready-made soups and broths. It is not a widely used additive and you are less likely to encounter it than common thickeners such as guar gum (E412) or locust bean gum (E410). Check labels for cassia gum or E427.

Is E427 vegan?

Yes. Cassia gum is derived entirely from the seed endosperm of the cassia plant and contains no animal-derived ingredients.

Sources

Last reviewed: 20 June 2026

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