PGPR
An emulsifier made from castor oil and glycerol, used mainly in chocolate to replace some cocoa butter and improve texture.
Commercial PGPR contains process contaminants: glycidyl esters, which are genotoxic and potentially carcinogenic, and 3-MCPD, linked to kidney damage in animal studies. EFSA flagged both in 2022 and called for tighter specification limits.
What is it?
Polyglycerol polyricinoleate (PGPR) is a synthetic emulsifier produced by reacting polyglycerols with fatty acids derived from castor oil (ricinoleic acid). It is a viscous, yellowish liquid. The manufacturing process can leave behind process contaminants including glycidyl esters and 3-monochloropropane-1,2-diol (3-MCPD) depending on the oils and fats used.
What does it do?
PGPR reduces the viscosity of molten chocolate by coating cocoa and sugar particles and lowering friction between them. This allows manufacturers to use less cocoa butter while still achieving a smooth, pourable texture. It works differently from lecithin (E322), which primarily reduces yield stress; PGPR primarily reduces plastic viscosity, so the two are often used together at lower combined doses.
Where you will see it
Most commonly found in milk chocolate, dark chocolate, compound coatings, chocolate-flavoured confectionery, and chocolate spread. Also permitted in edible ices and emulsified sauces following a 2023 UK FSA use extension. On a UK label it appears as 'emulsifier (E476)', 'emulsifier (PGPR)', or 'polyglycerol polyricinoleate'.
What the science says
Process contaminants: glycidyl esters
Glycidyl esters form during high-temperature refining of plant oils and fats. They can be present in the fats used to make PGPR. Glycidyl esters are hydrolysed in the body to glycidol, which is genotoxic and classified as probably carcinogenic to humans by IARC. EFSA's 2022 follow-up review detected glycidyl esters in commercial PGPR samples and called for a specification limit of 1mg/kg to manage this risk.
Commercial PGPR samples tested in 2022 contained detectable glycidyl esters. EFSA recommended a specification limit of 1mg/kg and noted the current EU specification limits for impurities were insufficient.
Glycidol, the metabolite of glycidyl esters, is genotoxic and classified as Group 2A (probably carcinogenic to humans) by IARC.
Process contaminants: 3-MCPD
3-MCPD (3-monochloropropane-1,2-diol) is another process contaminant found in refined fats and oils. It was detected in commercial PGPR samples reviewed by EFSA in 2022. In animal studies, 3-MCPD causes kidney damage and is classified as possibly carcinogenic to humans by IARC. EFSA recommended a specification limit of 2.5mg/kg for 3-MCPD and related compounds in PGPR.
3-MCPD and related compounds were detected in commercial PGPR samples. EFSA's 2022 opinion recommended a specification limit of 2.5mg/kg in the additive specification.
3-MCPD is classified by IARC as Group 2B (possibly carcinogenic to humans), with primary animal evidence for kidney toxicity.
PGPR itself: genotoxicity and carcinogenicity
The PGPR molecule itself, separate from its contaminants, has been assessed as not genotoxic and not carcinogenic in the existing study set. Short-term, subchronic and chronic animal feeding studies did not reveal tumour formation or genotoxic effects attributable to PGPR directly. Human volunteer studies showed no significant adverse effects. The concern sits with the manufacturing impurities, not the compound itself.
PGPR itself is not of concern with regard to genotoxicity or carcinogenicity based on available animal and human data.
Acceptable daily intake and dietary exposure
The original ADI set in 1978 was 7.5mg/kg body weight per day. The 2017 EFSA re-evaluation raised this to 25mg/kg body weight per day based on a larger data set, including a two-year rat study. The 2022 follow-up confirmed this ADI remained appropriate and that estimated dietary exposure from current permitted uses did not exceed it.
EFSA revised the ADI upward from 7.5 to 25mg/kg body weight per day in 2017, and the 2022 follow-up confirmed this remained adequate even with proposed use extensions.
Arsenic exposure from specification limits
EFSA's 2022 review also found that, at the then-current EU arsenic specification limits for PGPR, the margin of exposure for arsenic was too low, particularly if use was extended to edible ices. The Panel recommended tightening the arsenic specification limit based on actual measured levels in commercial samples, which were well below the permitted maximum.
The 2022 EFSA follow-up concluded that the margin of exposure for arsenic was insufficient at the lower end when using the existing EU specification limit, and recommended lower maximum permitted levels based on occurrence data.
Where it stands with the regulators
Who should be careful
People with a castor oil allergy should be aware that PGPR is derived from castor oil (ricinoleic acid), though the refining process removes most protein. The additive is not one of the 14 declarable allergens under UK food law, so no mandatory allergen declaration applies. Look for 'emulsifier (E476)' or 'polyglycerol polyricinoleate' on the ingredients list.
The honest read
PGPR itself has been assessed as non-genotoxic and non-carcinogenic across several decades of animal and human data. The real concern is narrower: the manufacturing process can leave behind glycidyl esters and 3-MCPD in the finished additive. Glycidyl esters convert in the body to glycidol, which IARC classifies as probably carcinogenic. 3-MCPD is classed as possibly carcinogenic and damages kidneys in animals. EFSA detected both in commercial PGPR samples in 2022 and called for tighter limits in the additive specifications, which is an active regulatory recommendation, not a resolved one. The PGPR in your chocolate bar is a very small fraction of your total diet, so absolute exposure from this one additive is low. But the contaminants sit in a category (genotoxic potential) where regulators generally try to keep exposure as low as reasonably achievable, rather than pointing to a safe threshold. The specification limits flagged in 2022 may or may not yet be legally binding at the time you are reading this.
Related additives
Common questions
Is E476 banned in the UK?
No. PGPR (E476) is approved for use in the UK in chocolate, cocoa products, edible ices and emulsified sauces. The UK FSA completed a safety assessment of an extended use application in September 2023.
Why did EFSA flag concerns about PGPR in 2022 if the ADI was raised in 2017?
The 2022 follow-up was not about PGPR itself but about impurities in commercial samples, specifically glycidyl esters and 3-MCPD. Both are process contaminants from the manufacturing fats. EFSA recommended tighter specification limits for the additive to reduce exposure to these substances, which have genotoxic or carcinogenic potential.
What foods contain E476?
Mainly milk chocolate, dark chocolate, chocolate coatings, compound chocolate, and chocolate spreads. It is widely used by major confectionery manufacturers. Since the 2023 UK FSA use extension, it can also appear in edible ices and emulsified sauces. Check the ingredients list for 'emulsifier (E476)' or 'polyglycerol polyricinoleate'.
Is E476 vegan?
PGPR is derived from castor oil (a plant) and glycerol (which can be plant- or animal-derived). The glycerol used in food-grade PGPR is typically plant-sourced, but this varies by manufacturer. The additive itself contains no animal-derived ingredients, but vegan certification depends on the specific supply chain. Products certified vegan by a third-party scheme will have confirmed this.
Sources
- EFSA ANS Panel: Re-evaluation of polyglycerol polyricinoleate (E 476) as a food additive (2017)
- EFSA ANS Panel: Follow-up of the re-evaluation of polyglycerol polyricinoleate (E 476) as a food additive (2022)
- EFSA Journal 2022 - Follow-up re-evaluation (Wiley)
- UK FSA: Approved additives and E numbers
- UK FSA: Safety Assessment of E476 use extension (September 2023)
- IARC Monographs Volume 77: Glycidol classified Group 2A (probably carcinogenic to humans) (2000)
- IARC Monographs Volume 101: 3-MCPD classified Group 2B (possibly carcinogenic to humans) (2013)
- Su et al., Analytics and applications of polyglycerol polyricinoleate (PGPR), Comprehensive Reviews in Food Science and Food Safety (2023)
Aaron Keen is the founder of NutraSafe. He researches and writes every additive entry himself, from the primary sources. About the research →
This is a guide, not medical advice. If an additive affects you, speak to your GP or a dietitian.
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