Scientists from China went from the market straight to the lab to test which way of cooking will cause broccoli to give you the most health benefits, but you might not have the stamina for their answer.
Broccoli has the reputation of being one of the healthiest foods you can eat. It even looks like a food made for a sensible and healthy diet, and it’s a vegetable with significant amounts of vitamins, minerals and dietary fiber. Like the rest of its cruciferous vegetable family such as cauliflower and cabbage, it contains a natural compound called sulforaphane, which is linked to improved heart health and digestion.
Studies have shown that these compounds help regulate blood sugar levels and there are signs that they may even reduce the risk of certain types of cancer. Some people try to get these health benefits from dietary supplements, yet scientific evidence suggests that consuming the actual vegetable has more benefits than one gets by taking supplements. This is why Chinese scientists decided to find the best way to cook and eat broccoli in order to get the most out of its health benefits.
They published their findings in an article in the Journal of Agricultural and Food Chemistry, but if you like light and quick meals that don’t require too much fuss, their findings may deter you.
First, it should be understood that the sulforaphane compound isn’t completely present in broccoli in its natural state. Instead, the vegetable contains some compounds called glucosinolates and also the enzyme myrosinase which evolved in plants to protect them from grass-eating animals. Through myrosinase activity, the glucosinolates are converted to sulforaphane, which is what you want to happen.
Need to do damage to receive benefits
To get the myrosinase activity started, you need to "damage" the broccoli. Cooking it isn’t enough. Studies show that common cooking methods for broccoli, such as boiling it on the stove or in the microwave, actually significantly reduce the levels of glucosinolates in vegetables, even if you cook quickly for only a few minutes. myrosinase is quite sensitive to heat. So the way to get the most sulforaphane is by eating uncooked broccoli florets.
The researchers thought of testing another cooking method, the most common in China: frying in a pan. Few studies until now have examined the levels of sulforaphane in broccoli that had been sautéed in a pan and "no study to date has examined the stability of sulforaphane compounds in the process of frying broccoli in a pan,” they stated.
Researchers bought broccoli at the local market and went to work. They measured the levels of various natural compounds in the broccoli at each stage of the preparation process. In the first stage, they crushed the broccoli into small pieces of 2 mm in an attempt to extract as much myrosinase as possible which, as mentioned, is secreted when the plant is damaged.
They then divided the produce into three groups - one was left raw, another was sautéed for four minutes immediately after being cut, and the third group lay aside for 90 minutes after chopping and only then was also cooked for four minutes. The reason the second group was left to rest for an hour and a half was to see if the extra stay would allow the broccoli to excrete and produce a greater amount of the beneficial compounds before being cooked quickly.
And this is indeed what they found. Broccoli that was sautéed immediately after being chopped contained 2.8 times less sulforaphane than the broccoli that was given "rest time." "Our results suggest that after cutting the broccoli into small pieces, the chopped vegetable should be allowed to rest for about an hour and a half before cooking," the researchers concluded.
Of course, there’s the question of how practical a preparation process is that requires an hour and a half wait between chopping and cooking. The researchers thought of it too, so they said that waiting half an hour is also good, though this period was not tested in the experiment.