Fermentation for enhancing the bioconversion of glucoraphanin into sulforaphane and improve the functional attributes of broccoli puree

Broccoli is a rich source of glucoraphanin, which is converted into the bioactive sulforaphane upon cell disruption by the activity of endogenous myrosinase. Conventional broccoli processing involves heating that inactivates myrosinase. We investigated the feasibility of lactic acid bacteria (LAB) fermentation as an alternative process for maintaining myrosinase activity and enhancing the biotransformation of glucoraphanin into sulforaphane. LAB fermentation inhibited the growth of undesirable spoilage and pathogenic microorganisms in broccoli puree and increased the yield of sulforaphane in the puree from 845 to 1617 μmol/kg dry matter (DM). High sulforaphane content was observed in the fermented puree throughout storage especially at 4 °C; the sulforaphane content after ∼three months storage was 1012.9 μmol/kg DM, 62.6% of the level just after fermentation. The results indicate that fermentation enables the production of safe, stable and sulforaphane rich broccoli product that can be used as a dietary supplement or potentially an ingredient in functional foods.