Partial polyglycerol esters of polycondensed fatty acids of castor oil
A castor-oil-derived emulsifier not currently authorised for use in food in the UK or EU.
E498 is not a permitted food additive in the UK or EU. If you see it on a label, the product may not comply with UK or EU food law.
What is it?
E498 is a fatty-acid emulsifier made by partially esterifying polyglycerol with polycondensed (chain-linked) fatty acids derived from castor oil, chiefly ricinoleic acid. It is closely related to E476 (polyglycerol polyricinoleate, or PGPR), which is the fully esterified, EU/UK-authorised counterpart. The partial esterification gives E498 a slightly different chemical profile, with more free hydroxyl groups remaining on the glycerol backbone.
What does it do?
Like E476, E498 acts as an emulsifier by bridging oil and water phases, reducing surface tension at oil-water interfaces. In chocolate and fat-based coatings this lowers viscosity and allows manufacturers to use less cocoa butter. The partial esterification makes it a somewhat less efficient viscosity reducer than PGPR, but it can also function as a thickener in certain fat systems by cross-linking fatty-acid chains.
Where you will see it
E498 is not lawfully permitted in UK or EU food products. Its authorised counterpart E476 (PGPR) is used in chocolate, chocolate-flavoured coatings, and emulsified sauces. No confirmed authorisation of E498 as a distinct compound (partial ester) was found for any third-country jurisdiction searched, including the USA (FDA) and Australia (FSANZ). On a label it would read 'emulsifier (E498)' or 'thickener (E498)'.
What the science says
Relationship to PGPR (E476) and the gap in safety evaluation
E498 is chemically similar to E476 (PGPR) but involves only partial esterification of the polyglycerol backbone. EFSA has conducted two full re-evaluations of E476 (in 2017 and a follow-up in 2022), concluding it raises no safety concern at the levels used in food. E498 has not been separately evaluated by EFSA or the UK FSA, and it does not appear in the EU's authorised additives list (Annex II of Regulation 1333/2008). The absence of authorisation means there is no agreed safety assessment, ADI, or specification for this specific compound in the UK or EU.
EFSA re-evaluated PGPR (E476), the fully esterified relative of E498, and raised its ADI from 7.5 to 25mg/kg body weight per day, concluding the data supported no safety concern at authorised levels.
A 2022 EFSA follow-up on E476 found no new data that would alter the 2017 conclusions, and addressed specification updates and proposed use extensions in edible ices and emulsified sauces.
E498 does not appear in the UK FSA's approved additives and E numbers list, meaning it has no legal basis for use in food placed on the UK market.
Castor oil fatty acids: ricinoleic acid background
The fatty acid backbone of E498, like E476, is dominated by ricinoleic acid from castor oil. Ricinoleic acid is a hydroxy-fatty acid with a long history of use in food and pharmaceutical emulsifiers. Animal studies on PGPR showed low acute oral toxicity and no genotoxicity or carcinogenicity signals at high doses, but those findings apply to the fully esterified E476 and cannot be assumed to transfer directly to the partially esterified E498 without equivalent studies.
Rat metabolism studies showed that ingested PGPR (E476) is largely hydrolysed in the gastrointestinal tract to glycerol, ricinoleic acid, and polyglycerol, with most absorbed as normal fatty-acid metabolites. These findings relate to E476, not E498 specifically.
Where it stands with the regulators
Who should be careful
Anyone buying food in the UK or EU: a product listing E498 as an ingredient is not compliant with UK or EU food additive law. People with castor oil or ricinoleic acid sensitivities should also note the source. Look for 'emulsifier (E498)' or 'thickener (E498)' on the label.
The honest read
E498 sits in an unusual position: it is chemically close to the widely-used and thoroughly evaluated E476 (PGPR), but the partial esterification makes it a distinct compound with no standalone regulatory authorisation in the UK or EU. There is no EFSA opinion, no agreed ADI, and no permitted food categories for E498. That does not mean it has been tested and found harmful, but it does mean it has not been tested and found acceptable either. The safety database that exists for E476 cannot simply be transferred to E498. If a product in the UK carries E498, that is a compliance issue independent of any health question.
Related additives
Common questions
Is E498 banned in the UK?
E498 is not authorised for use in food in the UK. It does not appear on the UK FSA's approved additives list or in the EU Regulation 1333/2008 list retained in UK law. It has not been formally banned following a safety review; it simply has never been approved. Food sold in the UK cannot legally contain E498.
How is E498 different from E476 (PGPR)?
Both are derived from castor oil fatty acids reacted with polyglycerol. E476 (PGPR) is fully esterified and is an authorised EU and UK food additive evaluated by EFSA. E498 is only partially esterified, leaving more free hydroxyl groups, which gives a different chemical structure. E498 has not been evaluated as a food additive and is not permitted in the UK or EU.
What foods contain E498?
No food legally sold in the UK or EU should contain E498, as it is not an authorised additive. No confirmed authorisation of E498 as a distinct compound was found in any third-country jurisdiction searched. Its authorised counterpart E476 is used in chocolate and chocolate-flavoured coatings.
Is E498 vegan?
The base ingredient, castor oil, is plant-derived, so the additive itself does not contain animal products. However, E498 is not an authorised food additive in the UK or EU, so the vegan question is secondary to the legality question for any UK-sold product.
Sources
- UK FSA Approved Additives and E Numbers
- EFSA re-evaluation of polyglycerol polyricinoleate (E 476) as a food additive (2017)
- EFSA follow-up re-evaluation of polyglycerol polyricinoleate (E 476) (2022)
- Fedtke N et al. - The fate of ingested PGPR in the rat, Food and Chemical Toxicology (1998)
- EU Regulation (EC) No 1333/2008 on food additives (Annex II)
- FAO GSFA Online -- Codex General Standard for Food Additives database
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