The most efficient way to get the nutrients from broccoli is to cut it into 2 mm sizes and let it sit for an hour-and-a-half before stir-frying, suggests a study.

Such methods will allow a beneficial compound found in broccoli - sulforaphane - to develop. Sulforaphane is said to have anti-cancer properties and can regulate blood sugar.  

“Broccoli is found to be a good source of glucosinolates, which can be hydrolyzed by endogenous myrosinase to obtain chemopreventive isothiocyanates (ITCs); among them, sulforaphane (SF) is the most important agent,” according to researchers, led by Yuanfeng Wu, from the School of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Zhejiang, in China.

Typically, the compound in the vegetable can be destroyed just right after minutes of cooking. And as a supplement, sulforaphane is poorly absorbed, which makes the long preparation time to be worth it.

In the study, researchers bought several broccoli from a local market, then chopped the vegetables into 2mm sizes to activate the myrosinase which causes the sulforaphane to be eligible for absorption.

Broccoli is also a good source of vitamins K and C, folic acid, potassium and fibre.

The researchers divided the chopped vegetables into three groups, one left raw, one group was stir-friend for four minutes just after chopping and the third group was left to sit for 90 minutes before it was stir-fried for four minutes as we'll.

They found that the group of chopped broccoli which was immediately fried has 2.8 times less sulforaphane compared with the group that had time to develop.

“Our results suggest that after cutting broccoli florets into small pieces, they should be left for about 90 minutes before cooking,” the researchers concluded.

They did note, however, that 30 minutes of waiting could suffice. They did so without testing.

The study was published in the Journal of Agricultural and Food Chemistry. MIMS