Star fruit
Averrhoa carambola L.
Star fruit (Averrhoa carambola) is a small tropical tree whose fruit has five longitudinal ridges, so a cross-section forms a star; it is eaten fresh, juiced and added to sour soup. Note the fruit is high in oxalic acid, so people with kidney disease should avoid it.
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Star fruit — PlantStar fruit — Whole tree
Star fruit — Fruit & seeds
Star fruit — Flowers
Star fruit — Leaves
Star fruit — Seeds & young plantsStar fruit — PlantStar fruit — Whole treeOverview
A small tree 3–10 m tall with a broad crown and low branching. Leaves are odd-pinnate with ovate leaflets that are touch-sensitive and fold at night or when touched (nyctinasty). Small pink-purple flowers cluster in leaf axils. The berry is 6–13 cm long, bright yellow with five longitudinal ridges (sometimes 4–6), glossy skin, crisp juicy flesh and a sour-to-sweet taste by cultivar.
The fruit is rich in vitamin C and fibre but contains oxalic acid and caramboxin; people with kidney failure or stones should avoid it as it can cause neurotoxicity. Star fruit is also used in sour fish soup, jam and juice; the light wood, leaves and flowers are ornamental.
Life cycle
From seed to productSeed
Flat seeds from ripe fruit germinate in 2–4 weeks.
Sapling
Saplings grow fast with enough sun and begin fruiting after 3–5 years.
Flowering
Pink-purple flowers open in axillary clusters in several flushes a year.
Fruiting
Fruits ripen yellow with 5 ridges in 2–3 months; trees bear nearly year-round in the tropics.
Distribution & origin
Share of recorded occurrences by region- Southeast Asia (native)30%
- Malaysia · Indonesia22%
- Vietnam18%
- India · South Asia16%
- China · Brazil14%
Chemical composition
Relative content in agarwood resin- Oxalic acidCaution with kidney disease26%
- CaramboxinNeurotoxin in kidney disease18%
- Vitamin CHigh in fresh fruit30%
- Fibre · polyphenolsAntioxidant26%
Uses
- Eaten fresh, juiced, smoothies; plate decoration
- In sour fish soup, jam and candied
- Garden ornamental; light wood for small items
Properties
- Leaf
- Pinnate, folds when touched
- Fruit
- 5-ridged, yellow, crisp
- Flower
- Pink-purple, clustered
Habitat & conservation
Native to Southeast Asia (Malesia); likes a hot, humid, sunny tropical climate and deep, humus-rich, well-drained soil; grown in lowlands, by rivers and in gardens.
Conservation
Not globally threatened (IUCN: Least Concern). Widely cultivated in many tropical countries; supply comes mainly from cultivation.
References
- 1Plants of the World Online — Averrhoa carambola — Kew Science, 2024
- 2IUCN Red List — Averrhoa carambola — IUCN, 2019
- 3Star fruit (Averrhoa carambola) and caramboxin neurotoxicity — Nephrology reviews, 2016
- 4Hình ảnh minh hoạ lấy từ Wikimedia Commons, tôn trọng giấy phép ghi kèm — Wikimedia Commons,
- 5Nguồn ảnh: Vis M (CC BY-SA 4.0), Wikimedia Commons — Wikimedia Commons,
- 6Nguồn ảnh: yakovlev.alexey from Moscow, Russia (CC BY-SA 2.0), Wikimedia Commons — Wikimedia Commons,
- 7Nguồn ảnh: Forest and Kim Starr (CC BY 3.0 us), Wikimedia Commons — Wikimedia Commons,
- 8Nguồn ảnh: Traper Bemowski (CC BY 3.0), Wikimedia Commons — Wikimedia Commons,
- 9Nguồn ảnh: Prenn (CC BY-SA 3.0), Wikimedia Commons — Wikimedia Commons,