Sulforaphane formation and bioaccessibility are more affected by steaming time than meal composition during in vitro digestion of broccoli

Sarvan I, Kramer E, Bouwmeester H, Dekker M, Verkerk R · Food Chemistry

Cooking is the variable that decides the dose. Sulforaphane is not present in broccoli — it is made when the enzyme myrosinase meets glucoraphanin during chewing, and gastric acid then inactivates myrosinase irreversibly, so no further conversion happens downstream. Raw and 1-minute-steamed broccoli yielded up to ten times more sulforaphane after digestion than longer-steamed samples. Adding protein or fat to the meal changed nothing.

Population

Broccoli steamed for 0, 1, 2 or 3 minutes, through a simulated mouth-stomach-intestine digestion

Intervention

Steaming time; added protein or lipid

Comparator

Raw broccoli

Limitations

A simulated digestion model without colonic fermentation, which matters because gut bacteria can convert glucoraphanin when myrosinase is gone.