Scientists Have Found a New, Healthier Way to Cook Broccoli
Lately, broccoli has gained a reputation as an ultra-healthy vegetable because of its content of sulforaphane (SFN), a particularly beneficial compound.
SFN doesn't just sit there in the broccoli florets, ready to be consumed. This vegetable contains several glucosinolates including glucoraphanin (GRA). It also contains myrosinase, an enzyme that plants evolved to protect themselves from herbivores. Through so-called "myrosinase activity", GRA are converted into SFN, which is exactly what we want. For the myrosinase activity to work, you need to damage the broccoli. But unfortunately, studies have shown that common broccoli cooking methods, such as boiling and microwaving, can seriously reduce the amount of glucosinolates in the vegetable - even for just a few minutes. Myrosinase is also very sensitive to heat. So, by far, the way we get the most SFN from broccoli is by eating it raw. But that doesn't fit our eating habits, so a team of Chinese researchers decided to try to find the best way to cook broccoli. They succeeded and published their findings in the Journal of Agricultural and Food Chemistry.
The team bought a bunch of broccoli from a local market and measured the compounds in the vegetables. First, they crushed the broccoli and cut it into 2mm pieces to get as much myrosinase activity as possible. They then divided the samples into three groups - one group eaten raw, one group chopped and then fried directly for four minutes, and a third group chopped and left for 90 minutes, then stir-fried for another four minutes. The 90-minutes wait time is to see if the broccoli has more time to develop beneficial compounds before being stir-fried.
And that's exactly what the team found - broccoli left to "develop" longer had 2.8 times more SFN ratio than broccoli that was stir-fried immediately. "Our findings suggest that after dicing broccoli, it should be left for about 90 minutes before cooking," the team concluded, adding that they didn't experiment with it more, but estimated that "30 minutes would be fine. "