The Smell of Broccoli
The smell of broccoli can be perceived as either pleasant or unpleasantly strong and usually sends people running. But why?
According to Dr. Paul Schroy, a nutrition professor at The Harvard Medical School, the smell of broccoli is released when cooking cells are ruptured and a compound called glucosinolate is released.
Glucosinolate is naturally found in a wide variety of cruciferous vegetables, such as kale, brussels sprouts, cauliflower, and broccoli. It is responsible for their distinct smell and is released when cut, chewed, or cooked.
“When glucosinolate is released, enzymes are responsible for breaking it down into allyl isothiocyanate and a little bit of hydrogen sulfide, which gives off the distinct smell that we know,” said Schroy.
In addition to decay processes in the vegetable, hydrolysis can also occur when glucosinolates come into contact with water, breaking it down into hydrogen sulfide and ammonia. Heat can also speed up this process, releasing even more sulfur compounds, adding to the smell.
Dr. Catherine Woteki, Chief Scientist for the USDA supplements this information by saying, “It is the volatile sulfur components in broccoli like isothiocyanate which are produced when glucosinolates are hydrolyzed under high acidic conditions that cause the strong odor that some people find unpleasant.”
But why do some people find the smell to be pleasing? Amy Cadwallader, a certified nutritionist, says that when we eat something flavorful for the first time, it may not be immediately accepted, but making it part of your diet over a period of time can actually reduce the pungent smell and replace it with a more pleasing aroma.
Effects of Heat
Heat can play a major role in the strength of the smell broccoli emits. Constance Brown-Riggs, M.S.E.D., RD, CDE, CDN, and author of “The African American Guide to Living Well with Diabetes”, says that overcooked broccoli can cause an even stronger odour. “Cooking broccoli too long leads to the breakdown of its compounds, which causes the release of more volatile sulfur compounds. You should aim to cook it just enough to be tender but to still have a nice, crunchy texture, since that will ensure you get the highest nutritional value with the least amount of smell.”
It is important to note that when it comes to broccoli, the freshness of the vegetable can also impact its smell. Heiting suggests purchasing a “pleasantly green” broccoli and cooking it on the same day for the best results. “If it is too fresh, the sulfur smell will be much more notable. If it is past its prime, it will have a barn-like scent —pungent and earthy.”
Harmful Vapours
It’s well known that cooking any cruciferous vegetable can release an unpleasant smell. But is it harmful? Schroy said, “The smell itself is not toxic; it is the glucosinolate breakdown product that can cause respiratory irritation if exposed to high levels.”
An article published by the National Centre for Biotechnology Information (NCBI) gives more depth to this topic. It states that the chemical components released from cruciferous vegetables on boiling can be irritating to the nose and mucous membranes of the respiratory tract. It suggests using an exhaust fan or having the broccoli in a sealed dish reducing vapours that can be released.
But there are benefits to eating broccoli too. Food nutritionist Kim Hines, RD, CISSN, says, “Broccoli contains fiber, phytonutrients, iron, vitamin C, and minerals that our bodies benefit from.” Additionally, it is high in vitamins A and K, folates, and potassium. Because of its nutrient density it promotes overall health benefits, making it a great addition to one’s weekly grocery list.
Traditional Cooking Methods
Though it is recommended to steam, bake, or roast the green vegetable for the best nutrition profile, traditional methods of cooking it, such as frying or stir-frying, are popular in certain cultures. Unfortunately, these methods cause the most smell.
For instance, according to traditional Chinese medicine, it is best to thinly slice the vegetable prior to cooking in order to reduce the smell.
Another popular way in which to reduce the smell is to add other smelly ingredients such as onions, garlic, or smoked bacon. The smell of the other ingredients can often overpower the broccoli.
Additives and Deodorizing Broccoli
Linda Heiting, an editorial director for the American Cancer Society says, “When cruciferous vegetables are cooked in water, an acidic solution, such as vinegar or lemon juice, can be added to the cooking water to neutralize the smell while still maintaining the nutritional value of the vegetable.”
This method is used to deodorize the vegetable and reduce the smell, but as Schroy noted, it won’t remove the smell completely. He said, “The best way to reduce the smell naturally is to cook it as briefly as possible and add lemon juice, which helps to bring the flavor out and reduce the smell.”
Conclusion
Though many people do not enjoy the smell of broccoli, there are many who do. In either case, it may be valuable to try to mask it due to its numerous health benefits. It is well established that healthy compounds can be released from broccoli when it is cooked, even if it is cooked to reduce the unpleasant smell.
