Figure 2: Kumquat fruit cross-section.
"Kumquats or cumquats are a group of small fruit-bearing trees in the flowering plant family Rutaceae, either forming the genus Fortunella, or placed within Citrus sensu lato. The edible fruit closely resembles that of the orange (Citrus sinensis), but it is much smaller and ovular, being approximately the size and shape of an olive.
They are slow-growing evergreen shrubs or short trees, from 2.5 to 4.5 metres (8 to 15 ft) tall, with sparse branches, sometimes bearing small thorns. The leaves are dark glossy green, and the flowers white, similar to other citrus flowers, borne singly or clustered in the leaf-axils. The kumquat tree produces between 30 to 50 fruit each year. The tree can be hydrophytic, with the fruit often found floating on water near shore during the ripe season.
The plant is native to south Asia and the Asia-Pacific. The earliest historical reference to kumquats appears in literature of China in the 12th century. They have long been cultivated in 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 into North America.
Cultivation and uses
Kumquats are cultivated in China, South Korea, North Korea, Taiwan, Southeast Asia, Japan, the Middle East, Europe (notably Corfu, Greece), southern Pakistan, and the southern United States (notably Florida, Louisiana and California).
They 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 ° to 100 °F), but can withstand frost down to about −10 °C (14.0 °F) without injury. They grow in the tea hills of Hunan, China, where the climate is too cold for other citrus fruits, even the Mikan (also known as the Satsuma) orange. The trees differ also from other citrus species in that they enter into a period of winter dormancy so profound that they will remain in it through several weeks of subsequent warm weather without putting out new shoots or blossoms. Despite their ability to survive low temperatures, kumquat trees grow better and produce larger and sweeter fruits in warmer regions.
Culinary uses include candying and kumquat preserves, marmalade, and jelly. Kumquats can also be sliced and added to salads. In recent years kumquats have gained popularity as a garnish for cocktail beverages, including the martini as a replacement for the more familiar olive. A kumquat liqueur mixes the fruit with vodka or other clear spirit. Kumquat are also being used by chefs to create a niche for their desserts and are common in european countries.
The Cantonese often preserve kumquats in salt or sugar. A batch of the fruit is buried in dry salt inside a glass jar. Over time, all the juice from the fruit is diffused into the salt. The fruit in the jar becomes shrunken, wrinkled, and dark brown in colour, and the salt combines with the juice to become a dark brown brine. A few salted kumquats with a few teaspoons of the brine/juice may be mixed with hot water to make a remedy for sore throats. A jar of such preserved kumquats can last several years and still keep its taste.
In the Philippines and Taiwan, kumquats are a popular addition to green tea and black tea, either hot or iced.
In Vietnam, kumquat bonsai trees (round kumquat plant) are used as a decoration for the Tết (Lunar New Year) holiday. Kumquat fruits are also boiled or dried to make a candied snack called mứt quất."