Kumquat

Kumquat
Malayan kumquat foliage and fruit
Scientific classification
Kingdom:Plantae
Clade:Angiosperms
Clade:Eudicots
Clade:Rosids
Order:Sapindales
Family:Rutaceae
Genus:Citrus
Species: C. japonica
Binomial name
Citrus japonica
Synonyms[1]
  • Atalantia hindsii (Champ. ex Benth.) Oliv.
  • Citrus erythrocarpa Hayata
  • Citrus hindsii (Champ. ex Benth.) Govaerts
  • Citrus inermis Roxb.
  • Citrus kinokuni Yu.Tanaka
  • Citrus madurensis Lour.
  • Citrus margarita Lour.
  • Citrus microcarpa Bunge
  • Fortunella bawangica C.C.Huang
  • Fortunella chintou (Swingle) C.C. Huang
  • Fortunella crassifolia Swingle
  • Fortunella hindsii (Champ. ex Benth.) Swingle
  • Fortunella japonica (Thunb.) Swingle
  • Fortunella margarita (Lour.) Swingle
  • Fortunella obovata Tanaka
  • Sclerostylis hindsii Champ. ex Benth.
  • Sclerostylis venosa Champ. ex Benth.
  • × Citrofortunella madurensis (Lour.) D.Rivera & al.
Kumquat
"Kumquat" in Chinese characters
Chinese name
Chinese 金橘
Literal meaning "golden orange"
Vietnamese name
Vietnamese kim quất
Thai name
Thai ส้มจี๊ด
RTGS somchíd
Korean name
Hangul 금귤
Hanja 金橘
Japanese name
Kanji 金柑
Nepali name
Nepali muntala
Kumquats, raw
Fortunella spp.
Nutritional value per 100 g (3.5 oz)
Energy 296 kJ (71 kcal)
15.9 g
Sugars 9.36 g
Dietary fiber 6.5 g
0.86 g
1.88 g
Vitamins Quantity %DV†
Vitamin A equiv.
2%
15 μg
129 μg
Thiamine (B1)
3%
0.037 mg
Riboflavin (B2)
8%
0.09 mg
Niacin (B3)
3%
0.429 mg
Pantothenic acid (B5)
4%
0.208 mg
Vitamin B6
3%
0.036 mg
Folate (B9)
4%
17 μg
Choline
2%
8.4 mg
Vitamin C
53%
43.9 mg
Vitamin E
1%
0.15 mg
Minerals Quantity %DV†
Calcium
6%
62 mg
Iron
7%
0.86 mg
Magnesium
6%
20 mg
Manganese
6%
0.135 mg
Phosphorus
3%
19 mg
Potassium
4%
186 mg
Sodium
1%
10 mg
Zinc
2%
0.17 mg
Link to USDA Database entry
†Percentages are roughly approximated using US recommendations for adults.
Source: USDA Nutrient Database

Kumquats (or cumquats in Australian English, /ˈkʌmkwɒt/;[2] Citrus japonica) are a group of small fruit-bearing trees in the flowering plant family Rutaceae. They were previously classified as forming the now historical genus Fortunella, or placed within Citrus sensu lato.

The edible fruit closely resembles the orange (Citrus sinensis) in color and shape but is much smaller, being approximately the size of a large olive. Kumquat is a fairly cold-hardy citrus.

Etymology

The English name "kumquat" derives from the Cantonese gām-gwāt 金橘, literally meaning "golden orange" or "golden tangerine".

Origin

The kumquat plant is native to south Asia and the Asia-Pacific region. The earliest historical reference to kumquats appears in literature of China from the 12th century. They have long been cultivated in India, Japan, Taiwan, the Philippines, and southeast Asia. They were introduced to Europe in 1846 by Robert Fortune, collector for the London Horticultural Society, and shortly thereafter were brought to North America.

Description

Illustration by Walter Hood Fitch

They are slow-growing evergreen shrubs or short trees that stand 2.5 to 4.5 meters (8 to 15 ft) tall, with dense branches, sometimes bearing small thorns. The leaves are dark glossy green, and the flowers are white, similar to other citrus flowers, and can be borne singly or clustered within the leaf-axils. Depending on size, the kumquat tree can produce hundreds or even thousands of fruits each year.[3]

Varieties

Citrus taxonomy is complicated and controversial. Different systems place different types of kumquat in different species, or unite them in a single genus. Historically they were viewed as within the genus Citrus, but the Swingle system of citrus taxonomy elevated them to their own genus, Fortunella. Recent phylogenetic anlaysis suggests they indeed fall within Citrus.

Round kumquat

When the kumquats are divided into multiple species, the name Fortunella japonica (or Citrus japonica) is retained by the group. The round kumquat, also called Marumi kumquat or Morgani kumquat, is an evergreen tree that produces edible golden-yellow fruit. The round Hawaiian varietal, the "Meiwa kumquat", is typically eaten raw. The fruit is small and usually spherical but can be oval shaped. The peel has a sweet flavor, but the fruit has a distinctly sour center. The fruit can be eaten cooked but is mainly used to make marmalades, jellies, and other spreads. It is grown as an ornamental plant and can be used in bonsai cultivation. The plant symbolizes good luck in China and other Asian countries, where it is often kept as a houseplant and given as a gift during the Lunar New Year. Round kumquats are more commonly cultivated than other species due to their high cold tolerance.

Oval kumquat

When the kumquats are divided into multiple species, the name Fortunella margarita (or Citrus margarita) is used for this group. The oval kumquat is also called the Nagami kumquat.[4] The most unusual feature of the Nagami kumquat is how the fruit is consumed; namely, that it is eaten whole, skin and all. The inside is still quite sour, but the skin has a very sweet flavour, so when eaten together an unusual tart-sweet, refreshing flavour is produced. The fruit ripens mid- to late winter and always crops very heavily, creating a spectacular display against the dark green foliage. The tree tends to be much smaller and dwarf in nature, making it ideal for pots and occasionally bonsai cultivation.

Jiangsu kumquat

When the kumquats are divided into multiple species, the name Fortunella obovata (or Citrus obovata) is used for this group. The Jiangsu kumquat or Fukushu kumquat bears edible fruit that can be eaten raw, as well as made into jelly and marmalade. The fruit can be round or bell shape and is bright orange when fully ripe. The plant can be distinguished from other kumquats by its distinctly round leaves. It is typically grown for its edible fruit and as an ornamental plant, but cannot withstand frost like the round kumquat. These kumquats are often seen near the Yuvraj section of the Nayak Province.

'Centennial Variegated' kumquat

'Centennial Variegated' kumquat tree
'Centennial Variegated' kumquat fruit

The 'Centennial Variegated' kumquat cultivar arose spontaneously from the oval kumquat. It produces a greater proportion of fruit to peel than the oval kumquat, and the fruit are rounder and sometimes necked. Fruit are distinguishable by their variegation in color, exhibiting bright green and yellow stripes. The tree is distinguishable by its lack of thorns.[5]

Cultivation and uses

Kumquats are much hardier than other citrus plants such as oranges. The Nagami kumquat requires a hot summer, ranging from 25 °C to 38 °C (77 °F to 100 °F), but can withstand frost down to about −10 °C (14 °F) without injury.

In cultivation in the UK, Citrus japonica has gained the Royal Horticultural Society’s Award of Garden Merit[6] (confirmed 2017).[7]

Propagation and pollination

Kumquats do not grow well from seeds and so are vegetatively propagated by using rootstock of another citrus fruit,[8] air layering, or cuttings (using a rooting gel/powder).[9] Like most citrus, they are self-pollinating.

Composition

The essential oil of the kumquat peel contains much of the aroma of the fruit, and is composed principally of limonene, which makes up around 93% of the total.[10] Besides limonene and alpha-pinene (0.34%), both of which are considered monoterpenes, the oil is unusually rich (0.38% total) in sesquiterpenes such as α-bergamotene (0.021%), caryophyllene (0.18%), α-humulene (0.07%) and α-muurolene (0.06%), and these contribute to the spicy and woody flavor of the fruit. Carbonyl compounds make up much of the remainder, and these are responsible for much of the distinctive flavor. These compounds include esters such as isopropyl propanoate (1.8%) and terpinyl acetate (1.26%); ketones such as carvone (0.175%); and a range of aldehydes such as citronellal (0.6%) and 2-methylundecanal. Other oxygenated compounds include nerol (0.22%) and trans-linalool oxide (0.15%).[10]

Hybrids

Hybrid forms of the kumquat include the following:

See also

References

  1. ↑ "The Plant List: A Working List of All Plant Species". Retrieved 28 July 2014.
  2. ↑ "Kumquat". Collins Dictionary. n.d. Retrieved 25 September 2014.
  3. ↑ Morton, Julia (1987). "Kumquat". Fruits of warm climates. Miami, FL. pp. 182–185. A mature specimen on rough lemon rootstock at Oneco, Florida, in 1901, bore a crop of 3,000 to 3,500 fruits.
  4. ↑ Fortunella margarita: oval kumquat, Nagami kumquat, coolexotics.com
  5. ↑ Centennial at the Citrus Variety Collection
  6. ↑ "RHS Plantfinder - Citrus japonica". Retrieved 12 January 2018.
  7. ↑ "AGM Plants - Ornamental" (PDF). Royal Horticultural Society. July 2017. p. 16. Retrieved 24 January 2018.
  8. ↑ "Kumquat". purdue.edu.
  9. ↑ VanZile, Jon. "Fortunella—How to Grow Kumquats Indoors". HousePlants.About.com.
  10. 1 2 Koyasako, A.; Bernhard, R.A. (1983). "Volatile Constituents of the Essential Oil of Kumquat". Journal of Food Science. Wiley & Sons. 48 (6): 1807–1812. doi:10.1111/j.1365-2621.1983.tb05090.x.
  11. ↑ "×Citrofortunella microcarpa". Germplasm Resources Information Network (GRIN). Agricultural Research Service (ARS), United States Department of Agriculture (USDA). Retrieved 1 June 2014.

Further reading

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