Enhancing the formation of functional glucosinolate degradation products in fermented broccoli stalk by-product with lactic acid bacteria

Broccoli stalk by-product (BsBP) is rich in glucosinolates (GSLs). Its fermentation process is generally characterized by the degradation of GSLs and formation of bioactive isothiocyanates (ITCs), in which lactic acid bacteria (LAB) play an important role. The GSLs-degrading capacity of 61 LAB strains was investigated in vitro. Lacticaseibacillus paracasei YC5, Pediococcus pentosaceus RBHZ36, and Lactiplantibacillus plantarum ND1, with high potential to transform GSLs into ITCs, were screened. The functional GSL degradation products (total content of sulforaphane, indol-3-carbinol, and ascorbigen) increased 22.0-33.5 % compared to natural fermentation after 24 h when BsBP was fermented by the three screened strains in pure culture. LAB fermentation also helped to increase the quantity of indolic GSL degradation products in BsBP brine, suggesting that LAB fermentation promoted BsBP GSLs transformation into bioactive ITCs. The proposed use of the LAB strains characterized in this study provided a fermented BsBP and brine with high profile of functional GSL degradation products.