KANGKONG
pomoea aquatica grows in water or on moist soil. Its stems are 2–3 metres (7–10 ft) or longer, rooting at
the nodes, and they are hollow and can float. The leaves vary from typically sagittate (arrow head-
shaped) to lanceolate, 5–15 cm (2–6 in) long and 2–8 cm (0.8–3 in) broad. The flowers are trumpet-
shaped, 3–5 cm (1–2 in) in diameter, and usually white in colour with a mauve centre. Propagation is
either by planting cuttings of the stem shoots, which will root along nodes, or by planting the seeds from
flowers that produce seed pods.[3][4]
Names
Ipomoea aquatica is widely known as kangkong (also spelled kangkung), its common name in Maritime
Southeast Asia,[2] which possibly originates from Hokkien kháng (孔 'hole') + khong (空 'empty, hollow').
It is also known as water spinach, river spinach, water morning glory, water convolvulus, or by the more
ambiguous names Chinese spinach, Chinese watercress, Chinese convolvulus or swamp cabbage. It is
known as kōngxīncài (空心菜) in Mandarin, ong choy (蕹菜) in Cantonese and in Hawaii, and tung choi
(通菜) in modern Cantonese.[5][6] In Tamil–speaking parts of South India and Sri Lanka, this spinach is
known as vallal (வள்ளல்).
Origin
The origin of Ipomoea aquatica is not quite clear, but it is generally believed to be native to Southeast
Asia and was first cultivated there. This is supported by phylogenetic studies, its ideal climatic conditions,
and the number of native pathogens in the region; as well as its predominant cultivation range, the
prevalence in usage as food and traditional medicine, and the number of distinct native names in
Southeast Asian languages.[2][7]
Several sources have also cited China or India as the location of the plant's domestication.[8][9][10][7]
[11][12][13] However, these claims have no supporting evidence other than the appearance of the
plant's name in historical records. The first clear mention of I. aquatica in Chinese records is in the
Nanfang Caomu Zhuang written by the Chinese botanist Ji Han (AD 263-307). Ji Han specifically identifies
I. aquatica as being "a strange vegetable of the south" with a foreign origin brought over by "western
countries." The claim for an Indian origin is based on the presence of the old name kalamba for the plant
in Sanskrit, presumed to be from around 200 BC, but this is putative.[2]
There are also studies suggesting that the species is native to Africa,[14][15] and it is debated whether it
is part of African indigenous flora or whether it was introduced there by Chinese mariner Zheng He.[16]
Safety
Health risk
Many of the waters where water spinach grows are fed by domestic or other waste. Pigs in southeast
Asia are a natural reservoir for the parasite Fasciolopsis buski. Infections in the Mekong regions resulted
from feeding on water spinach. Infections of F. buski in humans through water spinach can be
anticipated. The infection can be prevented by proper preparation such as frying or boiling.[17]
Contamination with thermotolerant coliforms (ThC) or protozoan bacteria with fecal origin, are very
likely when the water spinach is planted in wastewater fed urban systems.[18] Water spinach has great
potential as a purifier of aquatic habitats. It is an efficient accumulator of cadmium, lead, and mercury.
This characteristic can be dangerous if water spinach is planted for human or animal feed in polluted
aquatic systems. Mercury in water spinach is composed mostly as methylmercury and has the highest
potential of becoming a threat to human health. The edible parts of the plant have a lower heavy metal
concentration. The stems and bottom of the edible portion of the plant are higher in concentration and
should be removed to minimize the heavy metal intake.[19][20]
Uses
Culinary
The vegetable is a common ingredient in East, South and Southeast Asian dishes, such as in stir-fried
water spinach.[21] In Singapore, Indonesia, and Malaysia, the tender shoots along with the leaves are
usually stir-fried with chili pepper, garlic, ginger, dried shrimp paste (belacan/terasi) and other spices. In
Penang and Ipoh, it is cooked with cuttlefish and a sweet and spicy sauce. Also known as eng chhai in the
Hokkien dialect, it can also be boiled with preserved cuttlefish, then rinsed and mixed with spicy rojak
paste to become jiu hu eng chhai. Boiled eng chhai also can be served with fermented krill noodles –
belacan bihun – and prawn mi.[22]
In Burmese cuisine, water spinach is the primary ingredient in a Burmese salad called gazun ywet thoke
(ကန်စွန်းရွက်သု ပ်), made with blanched water spinach, lime juice, fried garlic and garlic oil, roasted rice
flour and dried shrimp.[23]
In Indonesian cuisine it is called kangkung; boiled or blanched together with other vegetables it forms
the ingredient of gado-gado or pecel salads in peanut sauce. Some recipes that use kangkung include
plecing kangkung from Lombok, and mie kangkung (kangkong noodles) from Jakarta.
In Thailand, where it is called phak bung (Thai: ผักบุ ้ง), it is eaten raw, often along with green papaya
salad or nam phrik, in stir-fries and in curries such as kaeng som.[24]
In the Philippines, where it is called kangkóng, the tender shoots are cut into segments and cooked,
together with the leaves, in fish and meat stews, such as sinigang. The vegetable is also commonly eaten
alone. In adobong kangkóng (also called apan-apan), it is sautéed in cooking oil, onions, garlic, vinegar,
and soy sauce.[25] In ensaladang kangkóng (or kinilaw na kangkóng), it is blanched and served in vinegar
or calamansi juice and fresh tomatoes and onions with salt and pepper to taste.[26][27] In binagoongang
kangkóng (or ginisang kangkóng), it is sautéed with garlic and topped with bagoong alamang (shrimp
paste) or bagoong isda (fermented fish) and sliced fresh tomatoes and onions, commonly also with
cubed crispy liempo (pork belly) or pork adobo. It can also be spiced with siling haba or siling labuyo
peppers, soy sauce, black pepper, and sugar. It differs from adobong kangkóng in that it does not use
vinegar.[28][29][30][31] A local appetiser called crispy kangkóng has the leaves coated in a flour-based
batter and fried
