In recent years, broccoli has emerged as a highly esteemed vegetable, largely attributed to its considerable concentrations of sulforaphane, a compound renowned for its health benefits.
This compound has been linked to improved blood sugar regulation, and its potential anti-cancer properties have fueled interest in broccoli supplements that have gained popularity.
Nevertheless, previous research indicates that consuming the whole vegetable yields greater amounts of sulforaphane compared to supplements. This prompted a team of Chinese researchers to investigate optimal cooking methods for broccoli.
Their findings, published in the Journal of Agricultural and Food Chemistry in 2018, established a definitive preparation method—though it may demand a significant time investment.
The rationale is intricate: sulforaphane is not immediately available in the florets; rather, it exists as glucosinolates. Coupled with the enzyme myrosinase, which serves as a natural defense against herbivores, these glucosinolates convert into sulforaphane during ‘myrosinase activity.’ To activate this process, the broccoli must be physically damaged.
However, conventional cooking methods like boiling and microwaving have been shown to drastically diminish glucosinolate levels—even minor exposure significantly impacts myrosinase’s efficacy, which is notably sensitive to heat.
The researchers then explored the implications of stir-frying, a prevalent cooking technique in China. They noted a dearth of studies on sulforaphane concentrations in stir-fried broccoli, prompting a comprehensive analysis.
After procuring fresh broccoli, they finely chopped it to augment myrosinase activity and divided it into three groups: one raw, one stir-fried immediately after chopping, and one allowed to rest for 90 minutes before stir-frying. Their findings revealed that allowing the chopped broccoli to rest significantly enhanced sulforaphane concentrations, suggesting a waiting period could prove beneficial. They proposed that even a 30-minute interval could yield positive results.
While the prospect of lengthy preparation may be off-putting, the research team is seeking methods to simplify the process—until then, opting for raw broccoli remains a sound choice.
The findings were published in the Journal of Agricultural and Food Chemistry.
An earlier version of this article was published in February 2018.
Vocabulary List:
- Sulforaphane /sʌlˈfɔːrəfeɪn/ (noun): A compound found in broccoli known for its health benefits particularly its anti-cancer properties.
- Glucosinolates /ɡluːˈkoʊsɪnəˌleɪts/ (noun): Natural compounds in cruciferous vegetables that can convert into sulforaphane.
- Myrosinase /maɪˈrɔːsɪneɪs/ (noun): An enzyme that helps convert glucosinolates into sulforaphane.
- Diminish /dɪˈmɪnɪʃ/ (verb): To make or become less.
- Prevalent /ˈprɛvələnt/ (adjective): Widespread in a particular area at a particular time.
- Augment /ɔːɡˈmɛnt/ (verb): To make something greater by adding to it.
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