Broccoli sprouts are particularly rich in glucoraphanin and 3-day old broccoli sprouts are concentrated sources of glucoraphanin. Fresh broccoli sprouts contain 10 to 100 times more glucoraphanin by weight than mature broccoli plants.
A study from 2015 published in the Royal Society of Chemistry demonstrated the following results of freezing broccoli sprouts.
Royal Society of Chemistry – Effect of freezing methods on sulforaphane formation in broccoli sprouts
- glucoraphanin content was not significantly affected by freezing
- myrosinase activity was enhanced
- sulforaphane yield was increased by 1.54–2.11 fold
Freezing fresh broccoli sprouts increases sulforaphane by an average of 1.825 times its original value.
It is recommended to use the frozen broccoli sprouts in a smoothie, however, it is important to use the broccoli sprouts straight from the freezer and do not allow them to thaw.