Longan

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Not to be confused with Loganberry.
Longan
Dimocarpus longan
Longan fruit
Conservation status
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Sapindales
Family: Sapindaceae
Genus: Dimocarpus
Species: D. longan
Binomial name
Dimocarpus longan
Lour.
Synonyms

Euphoria longan Steud.
Euphoria longana Lamk (1792)
Nephelium longana Cambess

Dimocarpus longan, commonly known as the longan, is a tropical tree that produces edible fruit. It is one of the better-known tropical members of the soapberry family, to which the lychee also belongs. It is native to Southern China.

The longan (龍眼 Lóng Yǎn, lit. "Dragon Eye"[1]), is so named because it resembles an eyeball when its fruit is shelled (the black seed shows through the translucent flesh like a pupil/iris). The seed is small, round and hard, and of an enamel-like, lacquered black. The fully ripened, freshly harvested shell is bark-like, thin, and firm, making the fruit easy to shell by squeezing the fruit out as if one is "cracking" a sunflower seed. When the shell has more moisture content and is more tender, the fruit becomes less convenient to shell. The tenderness of the shell varies due to either premature harvest, variety, weather conditions, or transport/storage conditions. In China, it is also called 桂圆 Guì Yuán and in Myanmar, it is called Deer's Eyes.

Tree description

The Dimocarpus longan tree is a medium-sized evergreen that can grow up to 6 to 7 metres (20 to 23 ft) in height. It is somewhat sensitive to frost. Longan trees prefer sandy soil. While the species prefers temperatures that do not typically fall below 4.5 °C (40 °F), it can withstand brief temperature drops to about −2 °C (28 °F).[2] Longans and lychees bear fruit at around the same time of the year.

Video of longan being peeled and eaten.

The longan is listed as Near Threatened on the IUCN Red List.[3]

A relative of the longan fruit is Lansium domesticum, better known as the langsat fruit, found in and around South East Asia.

Culinary uses

The fruit is sweet, juicy and succulent in superior agricultural varieties and, apart from being eaten fresh, is also often used in East Asian soups, snacks, desserts, and sweet-and-sour foods, either fresh or dried, sometimes canned with syrup in supermarkets. The taste is different from lychees; while longan have a drier sweetness, lychees are often messily juicy with a more tropical, sour sweetness.

The seed and the shell are not consumed.

Dried longan, called guìyuán (桂圆) in Chinese, are often used in Chinese cuisine and Chinese sweet dessert soups. In Chinese food therapy and herbal medicine, it is believed to have an effect on relaxation. In contrast with the fresh fruit, which is juicy and white, the flesh of dried longans is dark brown to almost black. In Chinese medicine, the longan, much like the lychee, is thought to give internal "heat" (上火).

Longans, raw
A peeled longan fruit
Nutritional value per 100 g (3.5 oz)
Energy 251 kJ (60 kcal)
Carbohydrates 15.14 g
- Sugars n/a
- Dietary fiber 1.1 g
Fat 0.1 g
Protein 1.31 g
Thiamine (vit. B1) 0.031 mg (3%)
Riboflavin (vit. B2) 0.14 mg (12%)
Niacin (vit. B3) 0.3 mg (2%)
Vitamin C 84 mg (101%)
Calcium 1 mg (0%)
Iron 0.13 mg (1%)
Magnesium 10 mg (3%)
Manganese 0.052 mg (2%)
Phosphorus 21 mg (3%)
Potassium 266 mg (6%)
Sodium 0 mg (0%)
Zinc 0.05 mg (1%)
Link to USDA Database entry
Vitamin B6/Folate values were unavailable
Percentages are roughly approximated
using US recommendations for adults.
Source: USDA Nutrient Database

Cultivation

Potassium chlorate has been found to cause the longan tree to blossom. However, this causes stress on the tree if it is used excessively, and eventually kills it.[4]

See also

Wikimedia Commons has media related to Dimocarpus longan.
  • List of fruits

References

  1. ↑ Tan, Terry (2007). Naturally speaking: Chinese recipes and home remedies. Singapore: Times. p. 112. ISBN 978-981-232-717-8. 
  2. ↑ Boning, Charles R. (2006). Florida's Best Fruiting Plants: Native and Exotic Trees, Shrubs, and Vines. Sarasota, Florida: Pineapple Press, Inc. p. 125. 
  3. ↑ World Conservation Monitoring Centre (1998). Dimocarpus longan. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on 9 May 2006.
  4. ↑ Manochai, P.; Sruamsiri, P.; Wiriya-alongkorn, W.; Naphrom, D.; Hegele, M.; Bangerth, F. (February 12, 2005). "Year around off season flower induction in longan (Dimocarpus longan, Lour.) trees by KClO3 applications: potentials and problems". Scientia Horticulturae (Department of Horticulture, Maejo University, Chiang Mai, Thailand; Department of Horticulture, Chiang Mai University, Chiang Mai, Thailand; Institute of Special Crops and Crop Physiology, University of Hohenheim, 70593 Stuttgart, Germany) 104 (4): 379–390. Retrieved November 28, 2010. 

External links

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