They are one of the easier legumes to digest and fetch a higher crop price than Australian wheat, yet mung beans are not mainstream in the western world. But, while the vigna radiata has been nourishing populations across India and Asia for millennia, in recent decades enterprising scientists have started investigating the legume’s potential to improve food security and farmers’ incomes.
Since its inception 50 years ago, the World Vegetable Centre (also known as WorldVeg) in Taiwan has collected more than 8,000 “accessions”, or varieties, of mung bean seeds, genebank manager, Dr Maarten van Zonneveld, says. Much like other species, such as humans and dogs, plants – including mung beans – need genetic diversity to create robust offspring. Diversity also enables selective crossing of different varieties to create new lines with desirable traits.
Like many of the best things in life, growing the mung bean – also known as moong bean, green gram, golden gram, black gram and Jerusalem pea – has its challenges.
Shanice Van Haeften, is a mung bean researcher at the University of Queensland. Once, while teaching a primary school science workshop in the farming region of Queensland’s Western Downs region, a student told her: “Oh yeah, my dad calls them mongrel beans because we tried to plant them and they didn’t grow well.”
Van Haeften, who completed a fellowship at WorldVeg in 2023, says mung bean crops can be “kind of wild and hard to manage”, and sensitive to pests, diseases and the weather (biotic and abiotic stresses, in more scientific terms).
But at the International Mungbean Improvement Network (Imin), led by WorldVeg with partners including the Australian Centre for International Agricultural Research (ACIAR), new varieties are being bred to overcome many of the trials that have plagued farmers.
Growing a better bean
In the case of mung beans, careful screening has revealed varieties with greater resistance to pathogens like powdery mildew, anthracnose and fusarium wilt, and pests such as cowpea aphid, thrips and stem fly. A wild beach variety could help breed lines that can tolerate salinity and improved lines have shortened the bean’s growing time.
“We have got varieties that mature in 50 days,” the regional director of Imin in South and Central Asia, Dr Ramakrishnan Nair, says. This makes mung beans – one of the only summer rotation options among legumes – ideal to plant between other crops such as rice or wheat, enriching the soil with nitrogen and supplementing smallholder farmers’ incomes.
Van Zonneveld says: “So, if you have your short season mung bean, it helps you diversify and if some other crop fails it still gives you some return.”
And although mung beans already have high heat tolerance, Nair says they’ve even been able to improve that. “One of our lines will be released very soon in Tajikistan where the temperatures go up to 45C.”
In Australia, Van Haeften says mung beans are one of the highest value grain crops, attracting about $1,100 a tonne – three times higher than wheat. Currently 90% is exported to India and broader Asia, but she thinks demand will increase domestically. The CSIRO has predicted that Australia’s retail plant protein market will skyrocket from $150m in 2019 to $6bn by 2030. “The plant-based market is meant to just completely explode, and even further by 2050,” says Van Haeften. “So even though mung bean isn’t a major crop now, I think it has the potential to grow exponentially.”
Fewer farts, and rich in fibre
Not only do mung beans contain the myriad nutritional benefits of legumes in general, as a rich source of protein, fibre, antioxidant polyphenols and essential vitamins and minerals, they also have a few special qualities.
Mung beans are easy to digest, for instance – good news if you suffer from bloating after eating beans. That not only makes them a less embarrassing choice for people with sensitive guts, it also makes their protein more available to the body. In Bangladesh, Nair says, people mix mung bean powder with milk powder to make a nutritious, tummy-friendly drink for children.
They are also low in phytates, the compounds in legumes that can reduce absorption of iron, a vital nutrient that is commonly deficient in developed and developing countries. In one of Nair’s projects exploring varieties with enhanced nutritional properties, he says researchers discovered a line that takes up more than double the iron from good soil, which they are crossing with improved lines to help address malnutrition in Kenya, Tanzania and Uganda.
In traditional Chinese medicine, mung beans are believed to have a cooling effect on the body, and have been used for thousands of years to treat fever and heatstroke as well as other conditions including hypertension, gastrointestinal problems and inflammation. This belief is baring out in research. “The seed coat has got some goodies,” says Nair, “like two compounds particularly which help to reduce the body’s heat.”
How to cook mung beans
Many Australians might be familiar with mung bean sprouts, often referred to as “bean sprouts”. But un-sprouted beans are less common in mainstream western cuisine in Australia.
If you’re unsure how to cook with them, Yotam Ottolenghi’s eggplant and mung bean curry, tamarind greens and mung beans with turmeric oil and a colourful herby roti and mung bean curry are excellent launchpads. Elsewhere, there’s his mung bean salad with roasted carrots and feta, a rice and mung bean kubbeh, as well as Meera Sodha’s Gujarati dal with sambharo (a sweet-and-sour relish).
Van Haeften’s favourite mung bean dish is chè ba màu, a Vietnamese tricolour dessert topped with ice, while Nair loves parippu, a coconut-based dal from his home region of Kerala. At weddings or during festivals like Onam, he says this dish is served first, traditionally on banana leaves and rice, along with a teaspoon of ghee, and pappadams squashed ceremoniously on top. “The pappadams should make that crunch,” he says.
Ram Nair’s parippu (coconut and mung bean dal) – recipe
1 cup dried split mung beans
3 cups water
1 tsp turmeric
1 tsp ground cumin
1 tsp salt
1 cup fresh coconut, grated (can be substituted with tinned coconut cream)
1 garlic clove
Chilli powder, to taste
1 tbsp ghee (can be substituted with butter)
A handful of fresh curry leaves
Fresh banana leaf (optional), pappadams and rice, to serve
Rinse the mung beans under cold running water. In a medium pot, add the mung beans, turmeric, cumin, salt and four cups of water. Bring to a boil then reduce to a simmer and cook until the beans are soft (approximately 45 minutes).
While the mung beans are cooking, in a blender or with a mortar and pestle, blend or grind the coconut with the garlic and chilli powder (if you are using coconut cream, do this in a blender). Add the coconut mixture to the cooked mung beans, stir and simmer on low heat for a three to four minutes, stirring occasionally to make sure the mixture doesn’t stick to the bottom of the pan.
In a fry-pan over a medium heat, melt the ghee. Add the curry leaves and gently toast them until aromatic.
To serve, lie a banana leaf (if using) on a platter. Make a bed of rice and spoon the parippu on top, followed by the melted ghee and curry leaves. Just before eating, scatter with broken pappadams.
This story evolved from a visit to the World Vegetable Centre in Taiwan, a trip the reporter made as winner of the Crawford Fund’s Food Security Journalism Award.
