The mung bean, also called green gram (Vigna radiata), is a type of plant in the legume family. It is grown mainly in East, Southeast, and South Asia and is used in both savory and sweet dishes.
Names
The English names "mung" and "mungo" come from the Hindi word "mūṅg," which is based on the Sanskrit word "mudga." In the Philippines, it is sometimes called "mongo bean." Other names that are not used as often include "golden gram" and "Jerusalem pea."
Description
The green gram is a plant that grows as a vine each year. It has yellow flowers and pods that are brown and fuzzy. It can grow to be about 15–125 cm (6–49 in) tall.
Mung beans have strong roots. These roots have many thin side roots with small bumps called nodules. The stems are branched and sometimes twist at the ends. Young stems are purple or green, and older stems are grayish-yellow or brown. They can be grouped into three types: upright, partly trailing, and trailing. Wild mung beans usually grow flat on the ground, while those grown by people are more upright.
The leaves are oval or wide-oval in shape. After the seedling emerges, the first leaves (cotyledons) die, and the plant grows three-leaf clusters. Each leaf is 6–12 cm long and 5–10 cm wide. Yellow flowers grow in clusters on the stems and leaf tips, with 10–25 flowers on each stalk. These flowers pollinate themselves. The pods are long and narrow or flat, with 30–50 pods per plant. Each pod is 5–10 cm long and 0.4–0.6 cm wide, containing 12–14 seeds. The seeds can be round or oval and come in colors like green, yellow, brown, or blue. Seed color and whether they have a rough texture help identify different types of mung beans.
Mung beans usually germinate in 4–5 days, but the speed depends on how much water they get during this time. The germination is above-ground, with the stem and first leaves growing out of the soil.
After germination, the seed splits open, and a soft white root grows. Mung bean sprouts are often harvested at this stage. If not harvested, the plant develops roots, then a green stem with two leaves that grow out of the soil. Later, seed pods form on the branches, with each pod containing 10–15 seeds.
It takes up to 60 days for the plant to mature. It can grow up to 76 cm (30 in) tall with many branches and seed pods. Most pods turn darker, while some stay green.
Vigna radiata is sometimes mistaken for Vigna mungo (black gram) because they look similar.
Taxonomy
Mung beans were reclassified from the genus Phaseolus to the genus Vigna in the 1970s. Their earlier scientific names were Phaseolus aureus or P. radiatus.
This plant belongs to the Fabaceae family and is also called green gram.
There are three subgroups: one is cultivated (V. radiata subsp. radiata), and two are wild (V. radiata subsp. sublobata and V. radiata subsp. glabra).
Ecology
Mung bean is a type of legume plant that works with Rhizobia bacteria to take nitrogen from the air and change it into a form plants can use. This process helps the plant grow and also adds nitrogen to the soil, with amounts ranging from 30 to 251 kg per hectare. Mung bean can produce a large amount of plant material, about 7.16 tons per hectare. The ability to fix nitrogen helps the plant meet its own needs and also improves the soil for crops that are planted after it. It can be planted before or after cereal crops in a rotation system. This practice helps improve the soil as a green manure.
Domestication
The mung bean was first grown in India, where its wild ancestor, Vigna radiata subspecies sublobata, still grows naturally.
In ancient texts from the 2nd millennium BCE, the Yajurveda mentions "mudga" (मुद्ग) as an important grain. It asks the god Rudra to help ensure a good harvest of this grain. In Vedic astrology, the mung bean is one of the nine lucky grains (navdhānya) and is connected to the planet Budha (Mercury).
Burned mung beans have been found at many archaeological sites in India. Early discoveries include areas in the eastern part of the Harappan civilization (modern-day Pakistan) and western and northwestern India, where mung beans date back about 4,500 years. In South India, specifically in the state of Karnataka, mung beans have been found from more than 4,000 years ago. Some experts believe this suggests two separate domestications in northern and southern India. However, a recent study suggests that mung beans may have originated from a single genetic source, which helped reduce a trait called "pod shattering," important for domestication. In South India, evidence shows that larger-seeded mung beans appeared between 3,500 and 3,000 years ago. By about 3,500 years ago, mung beans were widely grown across India.
After being cultivated in India, mung beans spread to China and Southeast Asia. Studies of ancient plant remains in southern Thailand, at a site called Khao Sam Kaeo, show that mung beans reached Thailand at least 2,200 years ago.
A genetic study shows that after being domesticated in South Asia, mung beans spread first to Southeast Asia, then to East Asia, and finally to Central Asia. This happened even though South and Central Asia are close geographically. The study explains that the short, dry growing seasons in northern Asia were not suitable for mung beans grown in the south, which were bred to grow over longer periods for better harvests. This shows how climate and other environmental factors greatly influence how crops develop over time.
Cultivation
Mung bean varieties today are mainly developed to resist pests and diseases, especially the bean weevil and mung bean yellow mosaic virus (MYMV). In India, common varieties include Samrat, IPM2-3, SML 668, and Meha. In Australia, varieties like Crystal, Jade-AU, Celera-AU, Satin II, and Regur are used. In China, varieties such as Zhonglv No. 1, Zhonglv No. 2, Jilv No. 2, Jilv No. 7, Weilv No. 4, Jihong 9218, Jihong 8937, Bao 876-16, and Bao 8824-17 are grown. With help from the World Vegetable Center, the traits of mung beans have improved significantly.
'Summer Moong' is a type of mung bean that grows quickly and is planted in northern India. Because it grows fast, it fits well into many farming systems. It is mainly grown in East and Southeast Asia and the Indian subcontinent. It is considered one of the hardiest pulse crops and needs a hot climate to grow.
Mung beans are warm-season plants that cannot survive frost. They grow best in temperate, sub-tropical, and tropical regions. The ideal temperature for mung bean germination and growth is 15–18 °C (59–64 °F). Mung beans can grow in many soil types, but the best soil pH is between 6.2 and 7.2. Mung beans are short-day plants, meaning long days delay flowering and pod formation.
The maximum yield of mung beans is about 2.5 to 3.0 tons per hectare. However, due to environmental stress and poor management, the average harvest is only 0.5 tons per hectare. Mung beans have an indeterminate flowering habit, which means flowers and pods can grow on the same plant, making harvesting difficult. The best time to harvest is when 90% of the pods turn black. Mung beans can be harvested with a machine, but the header must be adjusted to avoid over-threshing.
For transportation, mung bean grains should have a moisture level of 13%. Before storage, the grains must be cleaned and graded. The ideal storage condition keeps the moisture level at exactly 12%.
Most mung bean varieties can produce 1.8–2.5 tons per hectare, but the average harvest is usually 0.5–0.7 tons per hectare. Factors like pests, diseases, and environmental stress reduce yields and harm seed quality. These issues can cause yield losses of up to 10–100%.
Insects attack mung beans at all stages, from planting to storage, and can destroy crops. Some insects damage plants directly, while others spread diseases.
Stem fly (bean fly) is a major pest. It infests crops within a week of germination and can destroy entire fields.
Whitefly, B. tabaci, harms mung beans by feeding on plant sap and spreading mung bean yellow mosaic disease (MYMD). Whitefly can reduce yields by 17–71%.
Thrips attack mung beans during the seedling and flowering stages. Severe infestations can kill seedlings or prevent pod formation.
Spotted pod borer, Maruca vitrata, causes yield losses of 2–84% in tropical and subtropical regions. The larvae damage flowers, stems, and pods, especially during flowering.
Cowpea aphid harms plants by sucking sap, which weakens them and causes yellowing or stunting. Aphids also spread the mung bean common mosaic virus.
Bruchid is a serious pest in stored legumes. It can destroy up to 100% of stored mung beans within 3–6 months if not controlled.
Mung bean yellow mosaic disease (MYMD), caused by viruses spread by whitefly, causes severe yield losses in India, reducing harvests by up to 85%.
Major fungal diseases include Cercospora leaf spot, dry root rot, powdery mildew, and anthracnose. Dry root rot causes 10–44% yield losses in India and Pakistan by damaging plant roots.
Bacterial diseases like halo blight, bacterial leaf spot, and tan spot also harm mung beans.
Environmental stress, such as salinity, high temperatures, drought, and waterlogging, harms mung bean growth. Salinity reduces water and nutrient uptake, while high temperatures can harden seeds. Drought and waterlogging also damage plants.
Using online climate tools helps farmers analyze weather patterns to avoid stress. Planting disease-resistant varieties is an effective way to improve yields. Developing mung bean varieties with short seed dormancy helps prevent pre-harvest sprouting.
Mung beans have been eaten by humans for a long time. The main parts consumed are the seeds and sprouts. Mature seeds are a valuable food source.
Uses
The mung bean is known for being very nutritious. Each mung bean has about 55–65% carbohydrates (equal to 630 g/kg dry weight) and contains a lot of protein, vitamins, and minerals. It has about 20–50% protein in its dry weight, with globulin (60%) and albumin (25%) being the main storage proteins (see table). Mung beans are a good source of protein for food. These proteins break down more easily during sprouting. The carbohydrates in mung beans are easy to digest, which causes less gas in humans compared to other legumes. Both mung bean seeds and sprouts have fewer calories than other cereals, making them a better choice for people who are overweight or have diabetes.
Whole cooked mung beans are usually made by boiling dried beans until they are soft. Mung beans turn light yellow when their skins are removed. Mung bean paste is made by removing the skins, cooking the beans, and grinding them into a dry paste.
Although whole mung beans are sometimes used in Indian cooking, beans without skins are more common. In Karnataka, Maharashtra, Odisha, Gujarat, Kerala, and Tamil Nadu, whole mung beans are often boiled to make a dry dish served with congee. Hulled mung beans can also be used in the same way to make sweet soups.
In Madhya Pradesh and Rajasthan, mung beans are mashed, fermented, and made into fritters called mangode, which are a popular snack like Pakora.
In Goa, sprouted mung beans are cooked in a mild curry made with coconut milk called moonga gaathi.
In some parts of India, mung beans are stripped of their outer coats to make mung dal. In Odisha, West Bengal, and Bangladesh, the stripped and split beans are used to make a soup-like dish called mug dal.
In southern India, including Karnataka, Tamil Nadu, Telangana, Andhra Pradesh, and Maharashtra, steamed whole beans are seasoned with spices and fresh grated coconut. In South India, especially Andhra Pradesh, a batter made from ground whole mung beans (including the skin) is used to make a popular type of dosa called pesarattu or pesara-dosa.
In India and Pakistan, cooked mung dal is often served with boiled white basmati rice in a dish called "dal chawal."
In Sri Lanka, boiled mung beans are usually eaten with grated coconut and lunu-miris, a spicy chili and onion mixture, often as a breakfast food. Mung beans are also added to kiribath, a rice dish called mung-kiribath. During the traditional New Year Celebration in April, mung beans are used to make a fried sweet called mung-kavum.
In southern Chinese cuisine, whole mung beans are used to make a dessert called lǜdòu tángshuǐ, which is served warm or cold. They are also cooked with rice to make congee. Unlike in South Asia, whole mung beans are rarely used in savory dishes.
In Hong Kong, hulled mung beans and mung bean paste are made into ice cream or frozen pops. Mung bean paste is also used as a filling for Chinese mooncakes in East China and Taiwan. During the Dragon Boat Festival, boiled and shelled mung beans are used as filling in zongzi. The beans can also be cooked, blended into a liquid, sweetened, and served as a drink. In South China and Vietnam, mung bean paste is mixed with sugar, fat, and fruits or spices to make pastries like bánh đậu xanh.
In Korea, skinned mung beans are soaked and ground with water to make a thick batter used for bindae-tteok and Hobak-tteok pancakes.
In the Philippines, ginisáng monggó/mónggo (a stew of whole mung beans with prawns or fish) is traditionally served on Fridays during Lent. Variants may also include chicken or pork. Mung beans are also used in the Filipino dessert ginataang munggo, a rice gruel with coconut milk and sugar flavored with pandan leaves or vanilla.
Mung bean paste is used as a filling in pastries like ondé-ondé and bakpia in Indonesia, hopia in the Philippines, and pan de monggo in the Philippines. In Indonesia, mung beans are also made into a dessert called es kacang hijau, a porridge-like snack cooked with sugar, coconut milk, and ginger.
In some parts of the Middle East, mung beans and rice are cooked together in a pilaf-like dish called māš wa-ruzz.
Mung beans are germinated by soaking them in water for four hours of daylight and keeping them in the dark for the rest of the day. They can also be sprouted under artificial light for a week. These sprouts are often called "bean sprouts," though recipes usually refer to mung bean or soybean sprouts.
Mung bean sprouts are stir-fried as a vegetable side dish in Chinese meals, often with garlic, ginger, spring onions, or salted dried fish. Uncooked sprouts are used in Vietnamese spring rolls and as a garnish for phở. They are also used in Malaysian and Peranakan dishes like char kway teow, hokkien mee, mee rebus, and pasembor.
In Korea, slightly cooked mung bean sprouts called sukjunamul are served as a side dish. They are blanched, cooled, and mixed with sesame oil, garlic, salt, and other ingredients.
In the Philippines, mung bean sprouts are called togue and are used in lumpia rolls called lumpiang togue.
In India, mung bean sprouts are cooked with green chili, garlic, and other spices.
In Indonesia, mung bean sprouts are used as fillings in dishes like tahu isi (stuffed tofu) and are added to meals such as rawon and soto.
In Japan, mung bean sprouts are called moyashi.
Mung bean starch, extracted from ground mung beans, is used to make transparent noodles called cellophane noodles or bean thread noodles. These noodles soften when soaked in hot water. A variation called mung bean sheets is also available.
In Korea, a jelly called nokdumuk is made from mung bean starch. A similar jelly colored yellow with gardenia is called hwangpomuk.
In northern China, mung bean jelly is called *liang