| Adzuki beans | |
|---|---|
 | |
| Also called "red mung beans" | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Fabales |
| Family: | Fabaceae |
| Subfamily: | Faboideae |
| Genus: | Vigna |
| Species: | V. angularis |
| Binomial name | |
| Vigna angularis | |
Vigna angularis, also known as theadzuki bean (Japanese:小豆,Hepburn:azuki),azuki bean,aduki bean,red bean, orred mung bean, is anannualvine widely cultivated throughoutEast Asia for its small (approximately 5 mm or1⁄4 in long)bean. Thecultivars most familiar in East Asia have a uniform red color, but there are white,black, gray, and variouslymottled varieties.
Scientists presumeVigna angularis var.nipponensis is theprogenitor.[2]
The description of the adzuki bean can vary between authors because there are both wild[3] and cultivated forms[4] of the plant. The adzuki bean is anannual,[5][3] rarelybiennial[4] bushy erect or twining herb[5][3] usually between 30 and 90 centimetres (12 and 35 in) high.[3][6] There exist climbing or prostrate forms of the plant.[5] The stem is normally green[6] and sparselypilose.[3]
The adzuki bean has ataproot type of root system that can reach a depth of 40–50 centimetres (16–20 in) from the point of seed germination.[6][7]
The leaves of the adzuki bean aretrifoliate,pinnate and arranged alternately along the stem on a longpetiole.[4][5][6] Leaflets are ovate and about 5–10 centimetres (2.0–3.9 in) long and 5–8 centimetres (2.0–3.1 in) wide.[4][6][7]
Adzuki flowers arepapilionaceous and bright yellow.[5][6][7] Theinflorescence is an axillary falseraceme[6] consisting of six[3] to ten[4] (two to twenty[5]) flowers.[4][3][6]
Adzuki pods are smooth, cylindrical and thin-walled.[6][7] The colour of the pods is green turning white to grey as they mature.[6][7] The size is between 5–13 by 0.5 centimetres (1.97 in–5.12 in × 0.20 in) with 2 to 14 seeds per pod.[5][7]Pod shatter during seed ripening and harvesting might be a difficulty under certain conditions.[6][7]
The seeds are smooth and subcylindric with a length of 5.0–9.1 millimetres (0.20–0.36 in), width of 4.0–6.3 millimetres (0.16–0.25 in), thickness of 4.1–6.0 millimetres (0.16–0.24 in).[6][7] The thousand kernel weight is between 50 and 200 g.[4] There are many different seed colours from maroon to blue-black mottled with straw.[8]
The emergence of the seedlings ishypogeal[6][7] and takes 7–20 days.[5] Compared to other pulses the growth of the plant is slow.[5] Normally the adzuki plant reaches maturity between 80 and 120 days depending on the cultivar and the environmental conditions.[6]Flowering lasts 30–40 days.[5] Commonly the plantself-pollinates butcross-pollination also exists.[5]
The wild ancestor of cultivated adzuki bean is probablyVigna angularis var.nipponensis,[9] which is distributed across East Asia.[10]Speciation betweenVigna angularis var.nipponensis andVigna angularis var.angularis occurred around 50,000 years ago.[11] Wild adzuki likely originated near the Himalayas and spread naturally to central China and Japan.[12] Archaeologists estimate it was domesticated around 3000 BC.[13] However, adzuki beans, as well as soybeans, dating from 3000 BC to 2000 BC are indicated to still be largely within the wild size range. Enlarged seeds occurred during the laterBronze Age orIron Age, periods with plough use.[8]
Domestication of adzuki beans resulted in a trade-off between yield and seed size. Cultivated adzuki beans have fewer but longer pods, fewer but larger seeds, a shorter stature, and also a smaller overall seed yield than wild forms.[10] The exact place of domestication is not known;[9] multiple domestication origins in East Asia have been suggested.[13]
Seed remains of adzuki beans discovered in theCentral Highlands of Japan were dated to c. 6,000–4,000 BP, and represent to date the oldest evidence for its cultivation, supporting an origin in Japan. Evidence suggests that "wild azuki bean have been domesticated and cultivated in Japan for over 10,000 years".[14]
While archaeological studies found early traces of adzuki cultivation in Japan, genetic studies identified highest cultivar genetic variation in central China, suggesting the first domestication in China.[15][16] Cultivated azuki beans have been found inShandong, dated to the 9th millennium BC.[17]
Consistent with archaeological records, a genomic study indicated that all present-day adzuki cultivars descended from the wild adzuki in eastern Japan near the Central Highlands, at about 3000-5000 BP. The cultivars later spread to China and hybridized with local wild adzuki in China, resulting in the high genetic variation of central Chinese cultivars. The study therefore reconciles the discrepancy between archaeological and early genetic studies.[12] Mutations conferring key domestication syndromes (loss of pod shattering and change of seed coat color) also had a single origin in Japan. These mutations originated and continued to increase in frequency since about 10,000 BP, suggesting that domestication syndromes were being selected by the Jōmon people much earlier than clear archaeological traces of large-scale cultivation.[12]
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In Japan, the adzuki bean was one of the first crops subjected to scientificplant breeding.[10] Important breeding traits are yield, pureness of the bean colour, and the maturing time.[4] Separate cultivars with smaller seeds and higher biomass are bred forfodder production and asgreen manure.[4] Locally adapted cultivars are available in China, Japan, Korea, and Taiwan.[5]
More than 300 cultivars/landraces/breeding lines are registered in Japan.[5] Largegermplasm collections of adzuki bean are in China, at the Institute of Crop Germplasm Resources (CAAS),Beijing, with more than 3,700 accessions, and Japan, at the Tokachi Agricultural Experiment Station,Hokkaido, with about 2,500 accessions.[5]
Weed forms of adzuki bean frequently occur in Japan. The wide spread of weed forms is due to adaptation to human-disturbed habitats, escapes of oldcultivars, and natural establishment from derivatives of hybrids between cultivars and wild forms.[9] In contrast to wild forms, the weed forms of adzuki bean are used as a substitute for the cultivated form and consumed as sweet beans, especially if cultivated adzuki beans are attacked by pests. However, in cultivated gardens the weed form is recognized as contamination and lowers the seed quality of adzuki cultivars.[9]
The nameadzuki is a transliteration of the Japaneseアヅキ, as it was spelled according tohistorical kana orthography. The namesazuki andaduki reflect the modern pronunciationアズキ (hiragana:あずき). All are meant to represent the same Modern Japanese pronunciation,azuki.
Japanese also has a Chineseloanword,shōzu (小豆), which means "small bean", its counterpart "large bean" (大豆,daizu) being thesoybean. It is common to write小豆 inkanji but pronounce it asazukilistenⓘ, an example ofjukujikun. In China, the corresponding name (Chinese:小豆;pinyin:xiǎodòu) still is used in botanical or agricultural parlance. In everyday Chinese, the more common terms arehongdou (红豆;紅豆;hóngdòu) andchidou (赤豆;chìdòu), both meaning "red bean", because almost all Chinese cultivars are uniformly red.
In English the beans are often described as "red beans" in the context of Chinese cuisine, such as withred bean paste. In Korean, adzuki beans are calledpat (팥) and it contrasts withkong (콩, "bean"), rather than being considered a type of it.Kong ("beans") without qualifiers usually meanssoybeans. In Vietnamese it is calledđậu đỏ (literally: red bean). In some parts of India, the beans are referred to as "red chori".[18] InMarathi, it is known aslal chavali (लाल चवळी), literally meaning 'redcowpea'. In Iraq its name islūbyā ḥamrāˈ (لوبيا حمراء) meaning "red cowpeas".
The adzuki bean is mainly cultivated in China (670,000 hectares or 1,700,000 acres), Japan (60,000 hectares or 150,000 acres), South Korea (25,000 hectares or 62,000 acres), and Taiwan (15,000 hectares or 37,000 acres) (data published 2006).[5] The bean is also grown commercially in the US, South America, India,[19] New Zealand, Congo, and Angola.[4]
In Japan, the adzuki bean is the second most importantlegume after thesoy bean. In 1998, the annual crop yield was around 100,000 tonnes (98,000 long tons; 110,000 short tons).[4] In 2006, Japan consumed about 140,000 tonnes (140,000 long tons; 150,000 short tons)/year. Japan is the largest importer of adzuki beans.[5] The imports come from China, Korea, Colombia, Taiwan, the US, Thailand, and Canada.[4][5]
Optimal temperature range for adzuki bean growth is between 15 and 30 °C (59 and 86 °F). The crop is not frost-hardy and needs soil temperatures above 6–10 °C (43–50 °F) (30–34 °C (86–93 °F) optimal) forgermination. Hot temperatures stimulate vegetative growth and are therefore less favorable for pea production.[4][5][19] The adzuki bean is usually not irrigated. Annual rainfall ranges from 500 to 1,750 millimetres (20 to 69 in) in areas where the bean is grown. The plant can withstanddrought but severe reduction in yield is expected.[4][5] The cultivation of the adzuki bean is possible on preferably well drained soils with pH 5–7.5.[5][19] Fertilizer application differs widely depending on expected yield but is generally similar to soybean. Due to nodulation withrhizobia,nitrogen fixation of up to 100 kilograms per hectare (89 lb/acre) is possible.[5][19]
The sowing of the peas is in 2–3 centimetres (0.79–1.18 in) depth in rows 30–90 centimetres (12–35 in) apart and 10–45 centimetres (3.9–17.7 in) within the row. Rarely seeds are sown by broadcast. The amount of seeds ranges between 8–70 kilograms per hectare (7.1–62.5 lb/acre). Growth of the crop is slow, thereforeweed control is crucial mainly between germination and flowering. Cultivation systems differ largely among different countries. In China adzuki bean is often grown inintercrops with maize, sorghum and millet while in Japan the bean is grown incrop rotations. Harvest of the peas should not be done as long as moisture content of the seed is higher than 16%.[5]
Fungal and bacterial diseases of the adzuki bean arepowdery mildew, brownstem rot, and bacterialblight. Furthermore, pests such as the adzuki pod worm, Japanese butterbur borer, andcutworm attack the crop. Thebean weevil is an importantstorage pest.[5]
InEast Asian cuisine, adzuki beans are most commonly sweetened before eating. They are often boiled with sugar to produce red bean paste, a widely used ingredient throughout the region. The paste is sometimes flavored with ingredients such as chestnut and serves as a filling or topping in numerous traditional dishes.
In Chinese cuisine, red bean paste appears in foods such astangyuan,zongzi,mooncakes,baozi, andred bean ice. A more liquid preparation, made by boiling adzuki beans with sugar and a pinch of salt, is known ashong dou tang, a sweet soup-like dessert.
In Japanese cuisine, red bean paste is used in confections includinganpan,dorayaki,imagawayaki,manjū,monaka,anmitsu,taiyaki, anddaifuku. It is also used inamanattō and in ice cream, either as whole beans or as a paste. Rice with adzuki beans (赤飯;sekihan) is traditionally prepared in Japan for auspicious occasions.[20]
Across East Asia, red bean paste and adzuki beans are also enjoyed in waffles, pastries, baked buns, spring rolls, and biscuits. In addition, adzuki beans may be eaten sprouted or boiled in a hot, tea-like drink.
| Nutritional value per 100 g | |||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Energy | 536 kJ (128 kcal) | ||||||||||||||||||||||||||||||||||||||||||||||||||
24.8 g | |||||||||||||||||||||||||||||||||||||||||||||||||||
| Dietary fiber | 7.3 g | ||||||||||||||||||||||||||||||||||||||||||||||||||
0.1 g | |||||||||||||||||||||||||||||||||||||||||||||||||||
7.5 g | |||||||||||||||||||||||||||||||||||||||||||||||||||
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| Other constituents | Quantity | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Water | 66 g | ||||||||||||||||||||||||||||||||||||||||||||||||||
| †Percentages estimated usingUS recommendations for adults,[21] except for potassium, which is estimated based on expert recommendation from theNational Academies.[22] | |||||||||||||||||||||||||||||||||||||||||||||||||||
Cooked adzuki beans are 66% water, 25%carbohydrates, including 7%dietary fiber, 8%protein, and contain negligiblefat (table). In a 100-gram reference amount, cooked beans provide 536 kilojoules (128 kilocalories) offood energy, a moderate to high content (10% or more of theDaily Value, DV) of theB vitaminfolate (30% DV), and severaldietary minerals (11% to 27% DV, table).
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Authority control databases: National |
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