Petunidin
A dark-red plant pigment from berries and grapes, used to add colour to food and drinks.
What is it?
Petunidin is an O-methylated anthocyanidin, one of six common plant anthocyanidins found naturally in blackcurrants, blueberries, chokeberries, and dark grapes. It produces dark red to purple colours and is water-soluble. In food use it typically appears in glycoside form (petunidin-3-glucoside). Chemical formula C16H13O7+, molar mass 317.27 g/mol.
What does it do?
Acts as a natural colour by absorbing light across the visible spectrum, with the hue shifting from red in acidic conditions to purple and blue as pH rises. As part of the broader anthocyanins (E163) category, it colours products without the need for synthetic dyes. The pigment is sensitive to heat, light, and oxygen, which limits shelf stability.
Where you will see it
Berry-based jams, fruit juices, blackcurrant drinks, fruit yogurts, confectionery, and some soft drinks where a red or purple colour is needed. On a UK label it appears as 'colour (anthocyanins)' or 'colour (E163)'. Manufacturers rarely distinguish individual anthocyanidins on the label.
What the science says
Antioxidant properties in laboratory tests
Petunidin shows strong antioxidant activity in lab studies, donating hydrogen atoms to neutralise reactive molecules. Computational analysis found a low bond dissociation energy at its C3 position, indicating high antioxidant capacity. These are laboratory measurements and do not directly translate to benefits from food-additive levels in humans.
Computational modelling found petunidin acts primarily via hydrogen atom transfer, with a bond dissociation energy of 78.72 kcal/mol in gas phase, suggesting strong antioxidant capacity at the molecular level.
A comprehensive food colour review noted that while anthocyanins show antioxidant properties in laboratory conditions, there is no established evidence of antioxidant effects in humans from food-level consumption, including protection of DNA or lipids from oxidative damage.
Cancer cell research in laboratory and animal studies
Petunidin has been tested against cancer cell lines in laboratory conditions, showing antiproliferative and cell-death-inducing effects. Animal studies have shown tumour-related responses. The authors of these reviews consistently flag that long-term human clinical trials are absent, so laboratory findings have not been confirmed in people at food-use levels.
In laboratory studies on glioblastoma cells, petunidin induced cell death via SIRT3/p53 and PI3K/AKT/ERK pathways. Breast and lung cancer cell lines showed G2/M cell cycle arrest and stimulated apoptosis.
A systematic review of anthocyanin anticancer research concluded that human clinical trial evidence is 'notably sparse' and long-term trials are a critical research gap, meaning in vitro findings cannot yet be extrapolated to real-world food consumption.
Bioavailability: low absorption in the gut
Petunidin and its glycosides are not efficiently absorbed in the human gut. In a Caco-2 cell model (a standard proxy for human intestinal absorption), petunidin-3-glucoside was among the least-absorbed anthocyanins tested, with negligible transport to the bloodstream side. Most is broken down by gut bacteria or excreted.
In a Caco-2 intestinal cell model, only malvidin-3-glucoside was detected at the bloodstream side; petunidin-3-glucoside showed negligible basolateral transport, indicating very low intestinal absorption.
In rat models, glycosylated petunidin was among the least efficiently absorbed anthocyanins compared with delphinidin glycosides, supporting the pattern of low gut bioavailability for this compound.
EFSA re-evaluation and the absent ADI
In its 2013 re-evaluation of E163 anthocyanins, EFSA's food additives panel concluded the toxicology database was inadequate to set a numerical acceptable daily intake. Long-term chronic toxicity, carcinogenicity, and reproductive studies were described as extremely limited. EFSA noted that exposures from current permitted uses were unlikely to raise safety concerns, while calling for better characterisation and new toxicological data.
EFSA's ANS Panel concluded the toxicological database for anthocyanins (E163) was inadequate to establish a numerical ADI; long-term chronic toxicity, carcinogenicity, and reproductive function studies are extremely limited.
EFSA stated that, despite the data gap, exposures estimated from current approved uses of grape skin extract and blackcurrant extract were unlikely to be of safety concern, and recommended appropriate characterisation and new toxicological data to support future re-evaluation.
Where it stands with the regulators
Who should be careful
No declarable allergen status and no established group with a known adverse reaction to petunidin specifically. Individuals following strict kosher dietary rules should check whether anthocyanins in a specific product are derived from grape skin, which may require rabbinical certification. The label term to look for is 'colour (anthocyanins)' or 'colour (E163)'.
The honest read
Petunidin is one of the most ordinary natural colourings in the food supply. It occurs in everyday berries and grapes at far higher concentrations than food-additive use levels. The science picture is straightforward: no carcinogen classification, no regulatory ban, no allergen designation, and no established group adversely affected. The one honest note in the regulatory record is that EFSA could not set a formal ADI in 2013 because long-term chronic toxicity studies were limited. That is an absence of data, not a signal of harm. The science on potential benefits (antioxidant, anticancer in cell models) is preliminary and should not be read as established human effect at food colouring doses. The overall body of evidence is thin but points in no concerning direction.
Related additives
Common questions
Is E163f banned in the UK?
No. Petunidin is approved in the UK as part of the anthocyanins (E163) colour group under assimilated EU Regulation 1333/2008. The designation E163f appears in scientific literature but is not a separate regulatory sub-code; the FSA regulated-products database and the legislation both list E163 as a single entry covering all anthocyanins. Petunidin is authorised at quantum satis under that parent code across a range of food categories.
Why does EFSA say there is no acceptable daily intake for E163 anthocyanins?
In its 2013 re-evaluation, EFSA concluded that the available toxicology studies were too limited to set a numerical ADI. Long-term chronic toxicity and carcinogenicity studies were described as extremely scarce. EFSA also said that exposure from current approved uses was unlikely to raise safety concerns, but called for better toxicological data before any future re-evaluation.
What foods contain E163f?
Petunidin occurs naturally in blackcurrants, blueberries, chokeberries, and dark grapes. As a food additive it may appear in berry-based jams, fruit drinks, confectionery, and yogurts. On UK labels it is listed as 'colour (anthocyanins)' or 'colour (E163)'; individual anthocyanidins such as petunidin are not named separately.
Is E163f vegan?
Yes. Petunidin is plant-derived from berries and grape sources. It is suitable for vegans and vegetarians. Those observing kosher dietary rules should verify the specific plant source with the manufacturer, as grape-derived versions may require rabbinical certification.
Sources
- UK FSA Approved Additives and E Numbers
- UK FSA Regulated Products Database: E163 Anthocyanins
- EFSA ANS Panel Scientific Opinion on the re-evaluation of anthocyanins (E 163) as a food additive, EFSA Journal 11(4):3145
- Alam et al. - A computational exploration into the structure, antioxidant capacity, toxicity and drug-like activity of the anthocyanidin Petunidin (PMC7181340)
- Anti-Inflammatory and Anticancer Effects of Anthocyanins in In Vitro and In Vivo Studies (PMC11428540)
- Food Colour Additives: A Synoptical Overview (PMC8834239)
- Exploring the Bioavailability of Red Grape Skin Extract Polyphenols: A Caco-2 Cell Model Study (PMC12248599)
- Petunidin: Advances on Resources, Biosynthesis Pathway, Bioavailability, Bioactivity, and Pharmacology, Springer
- Regulation (EC) No 1333/2008 on food additives (assimilated into UK law)
- Anthocyanidins and anthocyanins: colored pigments as food, pharmaceutical ingredients, and potential health benefits (PMC5613902)
- NATCOL: Anthocyanins (INS 163 / E 163)
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