When scientists want to measure how well a food protects cells from oxidative damage, they run a test called FRAP — Ferric Reducing Antioxidant Power. The result is a number. The Australian Government ran it on Kakadu plum and compared it against blueberry, the fruit most people think of when they hear “antioxidant”.
Kakadu plum scored 10.5 times higher. [1]
A second test, ORAC (Oxygen Radical Absorbance Capacity), gave it 5.7 times the score of blueberry. Total polyphenol content — the compounds behind most of the antioxidant activity — came in at 4.7 times blueberry. [1]
These are not marketing numbers. They are the results of two independent laboratory assays, published in a government-commissioned report in 2009.
Kakadu Plum Vitamin C Capsules — whole fruit and seed, 64 cents each →
What “Antioxidant Power” Actually Measures
Every cell in the body runs on oxygen. As a side effect of that process, unstable molecules called free radicals form continuously. They are missing an electron and they take one from wherever they can — including from the structure of your cells, proteins and DNA. That damage, over time, is called oxidative stress.
Antioxidants donate an electron to a free radical without becoming unstable themselves. The free radical is neutralised before it can cause damage. FRAP measures exactly this: how much reducing power a food has — how many free radicals it can neutralise per gram.
The test does not pick one antioxidant and measure it. It measures the combined effect of every antioxidant in the food at the same time. That is why foods with a wide range of antioxidant compounds score higher than foods with a single high-dose one.
Kakadu plum contains not one antioxidant compound but dozens — from five separate chemical families. That is the reason for the number.
The Comparison — Kakadu Plum Against the Foods You Know
The same RIRDC government study that tested Kakadu plum measured blueberry as its comparison fruit — blueberry is the standard benchmark for high-antioxidant foods in Australian and international research. [1]
| Food | FRAP score (relative to blueberry) |
|---|---|
| Kakadu plum | 10.5× |
| Blueberry | 1× (baseline) |
On the ORAC scale, Kakadu plum scored 5.7 times blueberry. For total polyphenols, Kakadu plum measured 158.6mg per gram of dried fruit, against approximately 34mg/g in blueberry. [1]
An important detail: 26.5% of Kakadu plum’s antioxidant power comes from fat-soluble compounds — vitamin E, lutein and chlorophyll — not only from the water-soluble vitamin C. [1] The body stores fat-soluble antioxidants differently, and the two fractions protect different parts of the cell.
Every Antioxidant Class Found in Kakadu Plum
The 10.5× FRAP score comes from five distinct families of antioxidant compounds working together.
Vitamin C — 7,253mg per 100g dried fruit
Vitamin C is both a nutrient and an antioxidant. In its role as an antioxidant, it neutralises free radicals directly and regenerates vitamin E after vitamin E has donated an electron. FSANZ (Food Standards Australia New Zealand) has approved the wording: “Vitamin C contributes to cell protection from free radical damage.” [3]
Kakadu plum contains 7,253mg of vitamin C per 100g of dried fruit — the highest of every fruit, herb and spice tested in the government study. Our independently lab-tested powder measures 12,100mg/100g, which is over 240 times the concentration in a fresh orange. One 500mg capsule delivers 60mg of vitamin C — more than the adult recommended daily intake of 45mg. [1][2]
Vitamin E — 6.1mg per 100g, the highest of any fruit tested
Vitamin E (alpha-tocopherol, 98% of the total) is a fat-soluble antioxidant that protects cell membranes. It works alongside vitamin C: vitamin E neutralises free radicals in fatty environments like cell walls; vitamin C then regenerates vitamin E so it can work again. FSANZ approves: “Vitamin E contributes to the protection of cells from oxidative stress.” [3]
Kakadu plum contains 6.1mg/100g of vitamin E — the highest of every fruit the government study tested, described as “comparable to Hass avocado.” [1]
Tannins — 11 named compounds, one unique to this fruit
Tannins are the largest group of plant antioxidants by weight in Kakadu plum. A 2022 study of wild-harvested Northern Territory fruit named 11 specific tannins: [4]
- Corilagin: 1.6 to 1.8g per 100g dried fruit — the most plentiful compound in the whole fruit
- Ellagic acid: about 0.65 to 0.73g per 100g as the free form; 2.8 to 3.4g total across the different forms
- Punicalagin — also found in pomegranate
- Castalagin, geraniin, elaeocarpusin, chebulagic acid, chebulinic acid, chebulic acid, helioscopin B
- Terminalagin — a tannin named in a 2024 paper. It appears to be unique to Kakadu plum. [5]
Gallic acid — the building block from which ellagic acid and most of the other tannins are formed — is one of the two main polyphenols alongside ellagic acid. [4]
For the full breakdown of all 11 named tannins, the pomegranate connection, and the urolithin story, see our tannins page.
Flavonoids — quercetin, kaempferol, luteolin, resveratrol
The 2009 government report identified quercetin or hesperetin glucoside and kaempferol or luteolin glycoside, totalling approximately 3.9mg per gram of dried fruit. [1][6]
A 2025 Griffith University analysis identified further compounds including quercetin, rutin, luteolin, vitexin, resveratrol and resveratrol glucoside. Resveratrol belongs to the stilbene family. [7]
Lutein and Chlorophyll
Lutein is a carotenoid antioxidant. Kakadu plum contains 1.52mg per 100g — more than Hass avocado (0.6 to 1.05mg). [1]
Total chlorophyll (a and b combined) is 19.49mg per 100g. Chlorophyll accounts for part of the fat-soluble 26.5% fraction of Kakadu plum’s total antioxidant power. [1]
What Survives Digestion
A food’s antioxidant score in a lab test is measured on the extract. The relevant question is what survives digestion and absorption.
A 2022 study modelled Kakadu plum through digestion: approximately 93% of the vitamin C survived. Ellagic acid came through at 33% to 48%. [8]
University of Queensland research in 2024 found that gut microbes break the large tannins into smaller metabolites that showed higher antioxidant activity in the lab than the original compounds. The full antioxidant effect may be larger after digestion than the FRAP score alone suggests.
Why Our Capsules Contain the Whole Fruit — Seed and All
Most Kakadu plum products use only the dried fruit flesh. Ours uses whole fruit powder — fruit and seed kernel together. Processing the seed to the same fine powder as the fruit, with no grit, costs more and takes more work. We do it because the numbers are worth it.
The seed kernel carries dramatically higher concentrations of every mineral the body needs alongside its antioxidants:
- Zinc: 6.0mg per 100g in the seed — 10 times more than the fruit flesh (0.57mg)
- Copper: 2.5mg per 100g in the seed — 8 times more than the fruit flesh (0.30mg)
- Manganese: 9.1mg per 100g in the seed — 2.6 times more than the fruit flesh (3.5mg)
- Iron: 6.1mg per 100g in the seed — 50% more than the fruit flesh (4.0mg)
These minerals are cofactors your body uses in the same antioxidant and cellular protection processes as vitamin C and vitamin E. A product without the seed leaves the most concentrated part of the plant out.
The powder is smooth — the seed kernel is ground and dried to the same fine powder standard as the fruit. No other Kakadu plum supplement we are aware of includes the seed.
Kakadu Plum Vitamin C Capsules — whole fruit powder including seed, 140 capsules →
Read the full nutrient profile on our vitamin C page, the collagen cofactors on our collagen page, and the vitamin E data on our vitamin E page.
Frequently Asked Questions
What food has the highest antioxidant levels?
Among whole foods tested in independent laboratory studies, Kakadu plum — an Australian native fruit — has been measured at 10.5 times the FRAP (Ferric Reducing Antioxidant Power) score of blueberry and 5.7 times the ORAC score. This comes from an Australian Government report (RIRDC, 2009) using two independent assay methods. The high score reflects five distinct antioxidant families in the fruit: vitamin C, vitamin E, tannins (including 11 named compounds), flavonoids, and fat-soluble carotenoids and chlorophyll.
What is FRAP and what does 10.5 times blueberry mean?
FRAP — Ferric Reducing Antioxidant Power — measures the total electron-donating capacity of a food. Antioxidants work by donating an electron to a free radical, neutralising it. FRAP gives a single number for the combined reducing power of everything in the food at once. A score of 10.5 times blueberry means that, per gram, Kakadu plum can neutralise 10.5 times as many free radicals as blueberry — which is itself considered one of the highest-antioxidant everyday fruits.
What antioxidants are in Kakadu plum?
Five separate classes: (1) Vitamin C — 7,253mg per 100g dried, 240 times the concentration of a fresh orange. (2) Vitamin E — 6.1mg per 100g, the highest of any fruit tested. (3) Tannins — 11 named compounds including corilagin (1.6–1.8g/100g), ellagic acid, punicalagin, and terminalagin (unique to this fruit). (4) Flavonoids including quercetin, kaempferol, luteolin and resveratrol. (5) Fat-soluble pigments: lutein (1.52mg/100g, more than avocado) and chlorophyll (19.49mg/100g). 26.5% of the antioxidant power comes from fat-soluble compounds, not only vitamin C.
Why do tannins matter as antioxidants?
Tannins are polyphenols with multiple hydroxyl groups that readily donate electrons to free radicals. Kakadu plum contains at least 11 named tannins — more than most foods. The most plentiful is corilagin (1.6–1.8g per 100g), making it the single most abundant compound in the whole fruit. Terminalagin was only named in 2024 and appears unique to Kakadu plum. University of Queensland research found that gut bacteria break these tannins into metabolites that show even higher antioxidant activity than the original compounds.
Is vitamin C an antioxidant?
Yes. Vitamin C functions as both a nutrient (for collagen synthesis and immune function) and a water-soluble antioxidant. It neutralises free radicals directly and regenerates vitamin E — a fat-soluble antioxidant — after it has donated an electron. FSANZ approves: “Vitamin C contributes to cell protection from free radical damage.” One 500mg capsule of our Kakadu plum powder delivers 60mg of natural vitamin C — more than the adult recommended daily intake of 45mg.
Why does your Kakadu plum powder include the seed?
Because the seed kernel is the most mineral-dense part of the plant, and those minerals are cofactors in the same antioxidant processes as vitamin C and vitamin E. The seed kernel contains: zinc (6.0mg/100g — 10 times the fruit flesh), copper (2.5mg/100g — 8 times), manganese (9.1mg/100g — 2.6 times), and iron (6.1mg/100g — 50% more). It also carries 32% protein, 35% fat (four-fifths unsaturated), 21% fibre, and significant calcium, magnesium and potassium. The powder is smooth — the seed kernel is ground to the same fine powder standard as the fruit, with no grit. No other Kakadu plum supplement we are aware of includes the seed.
For the complete nutritional profile of the seed kernel — including protein, fat, and the four mineral co-factors that work with vitamin C to build collagen — see our Kakadu plum seed page.
References
- Konczak I, Zabaras D, Dunstan M et al. Health Benefits of Australian Native Foods. RIRDC (Australian Government) Pub. No. 09/133, Sept 2009.
- Phytoverse Australia. Certificate of Analysis — Terminalia ferdinandiana Whole Fruit Powder. 12,100mg/100g ascorbic acid (HPLC).
- Food Standards Australia New Zealand, Standard 1.2.7 — Nutrition, Health and Related Claims.
- Phan ADT et al. Hydrolysable tannins of wild-harvested Terminalia ferdinandiana fruit. Frontiers in Nutrition, 2022. PMC9372433.
- Terminalagin, a New Ellagitannin from Kakadu Plum. PubMed 41391874.
- Bobasa EM et al. Nutritional and Functional Properties of Terminalia ferdinandiana Fruits. Foods, 2024. PMC11431513.
- Cock IE, Matthews B, Basson AE. LC-MS Metabolomic Analysis of Terminalia ferdinandiana Extracts. Molecules, 2025. PMC12029459.
- Akter S et al. In vitro Bioaccessibility of Bioactive Compounds in Terminalia ferdinandiana. Frontiers in Nutrition, 2022. PMC8828953.
32% protein · 421mg magnesium · zinc 10× higher than the fruit flesh. University-measured in a peer-reviewed study. Most processors discard it.
Our products are food, not therapeutic goods, and are not intended to diagnose, treat, cure or prevent any disease or condition.