Fellow desis, throw away that split, yellow moong dal in your pantry. Ok, I know that’s rather dramatic. Ok, fine…don’t actually throw it away. Just promise me, in the future, you will use green moong much more (at least 3X more) than the split, yellow version.
The more research I read on green moong (mung beans, biological name: vigna radiata), the more it bothers me that we don’t use this amazing ingredient that is right under our noses more often. Hopefully, by the end of this blog post, you all will be convinced of its benefits as well.
Structure of whole moong
Let’s start by super quickly (I promise) looking at the structure of a bean. Legumes, in general, contains an embryonic plant surrounded by a protective seed coat. Structurally, whole legume consist of the seed coat (hull), embryo and the cotyledons.
Figure below from “On Food and Cooking” by Harold McGee.
Mung bean consists of 12.1% seed coat, 2.3% embryo and 85.6% cotyledons (Singh et al. 1968)
The cotyledons (fleshy insides) provide the bulk of the nourishment, similar to the endosperm in grains. So, just like the manufacturers sell us white rice, they sell us the inside of the dals – yellow moong? That makes sense, right? The answer is NO!!
You see, there is a difference. The outside of the grain (the bran) contains fat, which can cause the grain to go rancid early. For e.g, the shelf life of brown rice is 6 months and the shelf life of white rice is 2 years. If I was a shopkeeper, I would stock up on white rice to avoid any customer complaints on the stock quality. But, get this – the shelf life of green moong is the exact same as the shelf life of yellow moong dal = 2 years. So, what’s going on?
Is it possible that the dehulling process is easy enough that the food manufacturers decided to be nice and dehull the moong bean for us? Again, the answer is no…
According to Conditioning and Dehulling of Pigeon Peas and Mung Beans “Legume grains may be classified as easy-to-dehull and hard-to-dehull. Legume grains such as pigeon pea and mung bean belong to the hard-to-dehull group because of the presence of mucilage and gum forming a strong bond between the hulls and the cotyledons.”
So, manufacturers are literally ripping apart the moong bean to give us the yellow insides. Plus polishing it to death, which is another story. But, back to the seed coat. Why is this a big deal?
The importance of seed coat
Let’s think about this…Why does the seed coat exist? The seed coats are literally like guards at a palace guarding the baby prince inside. It is basically rich with antioxidants, flavonoids, polyphenols, etc.
According to Harold McGee, in reference to the legume seed coat, he states: “The coats of colorful varieties – pinks, reds, black etc are rich in anthocyanin pigments, and related phenolic compounds and therefore in antioxidant power.”
Eat the rainbow, we say proudly and fill our plate with carrots, bell pepper, blueberries and fruits/veggies of all colors.
Meanwhile, we rip apart our black urad, green moong, red masoor and eat only the starchy insides.
Do you get the irony? You know, who understands the usefulness of these seed coats? the pharma, food and cosmetic industry. Don’t get me wrong. They are not ‘conspiring’ or doing this secretly. The data is there for everyone to see.
According to Antioxidant and antimicrobial activity of legume hulls: “Antioxidant activity of aqueous hull extracts of commonly consumed legumes in India namely Vigna radiata (mung bean), Cicer arietinum (Bengal gram) and Cajanus cajan (pigeon pea) was studied by several in vitro assays. This study indicated that legume hulls have good antioxidant potential comparable to the synthetic antioxidant butylated hydroxy toluene and could therefore have application in food, cosmetic and pharmaceutical industry.“
While we are not eating these awesome native whole legumes; the industry is ready to extract them and sell it back to us for a profit!!
All the goodness – especially concentrated in the seed coats
The mung bean is rich in polyphenolics. Both the cotyledons and seed coats of mung beans contain phenolics, but most are concentrated in the seed coats. The polyphenols, polysaccharides, and polypeptides contained in the mung bean all exert antioxidant activity, which can contribute to disease prevention.
Another example: The seed coat of mung bean contains the flavonoids 95.6% of the total vitexin and 96.8% of the total isovitexin. “Both of these compounds are functional food ingredients in mung bean, having a wide range of biological activities including antioxidant, anti-inflammatory, antidiabetic, antiviral, anticancer and antitumor activity, hepatoprotective activity, antibacterial and antifungal activity, and other detoxification activities.“
“Furthermore, the study concluded that vitexin and isovitexin in the mung bean may be the main active components to play a remarkable role in regulating glucose metabolism.“
There are a lot more studies that prove the exact point over and over, but let’s move on.
Fine, but what about all the anti-nutritional factors?
I’m sure you would have heard that moong dal skin is hard to digest. You would have heard that there is phytic acid and tryptin inhibitors and all anti-nutritional factors that take away the minerals from your body. Right? These are common arguments; but I hope the research below will encourage you not to “throw the baby out with the bathwater”.
First of all, like ayurveda states, moong is one of the gentlest of dals. Gentle on the stomach… what does that mean? Not only are the anti-nutritional factors low, they can be further removed by cooking or germinating. And yes, I am talking about whole (sabut) moong dal, not just the split yellow kind.
Scientists have found that cooking mung bean reduces trypsin inhibitor, tannins and hemagglutinin activity contents. Also, germination was more effective in reducing phytic acid, stachyose and raffinose. Germination resulted in a greater retention of all minerals compared to other processes. All processes improved in-vitro protein digestibility and protein efficiency ratio.
In simple terms, if you want more mineral absorption, cooking removes the bad anti-nutri dudes!! If you want less gas, sprout them!!
Does it really though? Let’s look at 2 studies that prove this point:
Anti-nutrition factors: Phytic Acid, Tannin, Trypsin Inhibitor
In the study on mung beans, look at change to the 3 factors: Trypsin Inhibitor, Tannin and Phytic Acid below when cooked.
1) Trypsin inhibitor is completely broken down on cooking. It becomes 0. Great!!
2) Tannin levels are down 60-70% with cooking. That’s impressive, isn’t it? But, some of you can be like Indian parents – asking where is the remaining 30%? To which I tell you – stop drinking coffee, chai, stop eating chocolate and grapes which have significantly higher tannin content and then come and talk to me. By the way, eating dehulled moong is not going to get rid of your tannins either, if you noticed.
3) Phytic Acid: Finally let’s tackle the phytic acid numbers. So soaking and cooking brings it down 32, 37%. While that’s good, is it good enough? For the sake of context, let us look at phytic acid numbers in other food items. Even without soaking, cooked moong dal has 0.86 mg/g of phytic acid.
As you can see, for the same 100g, the levels of phytic acid in whole green moong are super low. At .086 g /100 g; it stands least of all items listed above. (Psst…look at Phytic Acid levels for nuts? Super high, eh?)
Ok, so what about the gas levels in whole moong beans? We know that oligosaccharides, including raffinose, stachyose, ciceritol, and verbascose, are commonly found in legumes and often result in flatulence in humans. How is it different from the anti-nutrition factors above? The oligo saccharides are heat stable, no matter how long you cook them. So, there has to be another way to tackle them, just cooking alone will not help.
I want to make 2 points regarding the wonders of moong bean with regards to oligosaccharide.
First, the oligosaccharide content in moong beans is among the least of beans and legumes. According to a study by the University of Illinois, the amount of oligosaccharides in whole moong is estimated to be: 0.68-2.19g per 100g. How does that compare to chickpeas and yellow peas (vatana)? In a paper published by the Washington State University, the total oligosaccharide content of raw legumes ranged from 70.7 mg/g in yellow peas to 144.9 mg/g in chickpeas. Let us convert everything to 100g, you get:
|Type of Legume||% of Oligosaccharides|
Think about it: Vatana has 3x flatulent capacity & chickpeas has 7x flatulent capacity relative to green moong!!
Second, even the meager 2% oligosaccharides can drop to nearly 0 by Day 3-4 of germination.
In a study, aptly named: “Germination Effects on Flatus-Causing Factors and Antinutrients of Mungbeans and Two Strains of Small-Seeded Soybeans” they found that raffinose and stachyose either completely disappeared or remained in only trace amounts by the third day of germination for mungbeans.
So, germinate it, and be gas free!! Yay!!
Green Moong is wonderful, but does it solve all world’s problems? 🙂
Now that we have established the awesomeness of green moong. Should we banish yellow moong from our kitchens completely? The answer is no. In food, just like in life, there is a need for balance.
In a study looking at weaning foods for babies, they found that: “Among the rice-bean diets, it was noted that rice-mungbean with hull had a lower digestibility as compared to rice-dehulled mungbean diet. The poor digestibility of rice-mungbean with hull diet is the first limiting factor in its utilization by infants. Dehulling of mungbean before cooking is recommended for preparing weaning food for infant feeding.“
So, if you are a baby, a person older than 70 or if you are sick, you should not be straining your digestive system with green moong. Use dehulled yellow bean instead.
But, if you are a diabetic, pre-diabetic or a normal person eating pizza and burger every week; I’m sure your digestive system can handle and your body can immensely benefit from eating whole green moong.
Remember, it has been documented that the polyphenols, polysaccharides, and polypeptides contained in the mung bean all exert antioxidant activity, which can contribute to disease prevention. To date, the mung bean and its extracts have shown excellent health implications, such as hypoglycemic and hypolipidemic effects and antihypertensive, anticancer, anti-melanogenesis, hepatoprotective, and immunomodulatory activities. Don’t miss out on all these benefits!!
I hope I really impressed upon you the need to be eating whole legumes – especially whole green moong. Everyone talks about whole grains, not so much about whole legumes.
Say, 30-50 years ago, it might have made sense to pick split moong over whole green moong given that you had to cook them in a open pot for a long time. But, in the age of instant pot and electric pressure cookers, what’s your excuse?
So, buy them, sprout them, cook them. Post your favorite ways to cook green moong below. I look forward to seeing them.
Follow me on twitter: @Upgrade_My_Food
I am not a nutritionist/nurse/doctor. I am just an engineer who studies numbers and reports them. Please don’t post comments or send me emails asking for medical advice. Consult your doctor before making any major changes to your diet.
Of course, my favorite book below continues to be my starting point for all research:
Another great article, Swetha! I use few of those dehulled legumes – I replaced the traditional moong dal and urad dal in my pantry long ago with the split, but not hulled versions, which still cook fast, plus I also use a lot of the whole ones, as well. And here’s a useful tip I learned years ago – brining the mung beans, as well as other small legumes (works with red chori, French puy, and sabud masoor, too), helps the hull stay attached, when cooked, which is great for salads, or whenever you don’t want them falling to pieces. Just soak an hour in a brine of 1 qt water with 1 tb salt, then rinse, and cook, until tender.
I like many of the legumes sprouted. It’s great to keep finding more good things about them!
Soaking in brine to keep the hulls intact is a great idea!! I will absolutely have to try it. Thank you for sharing.
Wow your blog is such a treasure trove!! I stumbled upon the 3 part series on low GI foods and that just seems to be the tip of an iceberg. Thank you for sharing all the detailed research and analysis in an easy to understand manner. Respect!
Thanks Preetha…That’s so lovely to hear!!
Fascinating article and provides the answers I was searching for. I wanted to know the difference between yellow and green moong dal. Thank you for this great explanation!
Very detailed, amazing
Hi Swetha, do you have any idea why split mung dal is white from inside, while the washed mung dal is yellow? Same is not the case with Urad dal, which is white both in split and washed(dehulled) form.
That is a very good question. In the article, I mentioned that legume grains such as pigeon pea and mung bean belong to the hard-to-dehull group because of the presence of mucilage and gum forming a strong bond between the hulls and the cotyledons. So, they undergo some treatment process to remove the skin like roasting or steaming which causes the color change. See example of a home made split-mung here: https://youtu.be/AX6DOaL0ORk
The color change has happened there too.
Wow what a great article!
I’ve been trying to figure out the difference in vitamins of whole mung bean vs split yellow mung beans.
Do you have any ideas on this? Have you seen any science papers?
I’m particularly interested in folate, but can’t find anything online.
Thanks for your time
Hi M, happy that you found it useful. Re: folate, I am not sure. If I find any data in the future, I will pass it along.
I’m happy to find your blog as I’m looking for benefits of mung beans vs split beans. When boiling mung beans I normally strain the floating skin/peel, does it mean I can leave them in the dish as they nutritious anyway? Thanks
Hi Autumn, I would strain them out since they will affect the taste and texture of the dish especially if you want it to be creamy.
I assume there should be significant amount left with skin still on, which would make it a very healthy dish.
Interesting article on mung beans. I haven’t cooked them yet; however, I do use them for sprouting a lot. I put the beans in a glass jar with some mesh over the mouth of the jar and then I soak and drain the beans twice a day. The longer I leave them to sprout, the longer the white sprouted bean is and I enjoy their crisp, fresh taste in a salad or on a wrap. When sprouting them, as the sprouts “explode” from their hulls, many of the hulls float to the surface during the rinse cycle. Usually, I try to remove as many of the floating hulls as possible so that when they are finished sprouting I have a container of nice white sprouts. Removing the hulls floating on the water or left behind after the drain cycle takes a long time. After reading your article I am wondering if I should I leave them alone. I have wondered before, if I leave them, do they provide more fibre to my meal, and now I wonder should I leave them for additional reasons.I would love to hear what you have to say.
Hi, as the days of sprouting go by, the hull texture gets very tough and unappetizing. So, it may be best to remove them.
If you are using fresh 1 or 2 day sprouts, then I think using the attached hull is a good idea. Any longer, and I think you should remove the floating hull for the sake of good taste.