Lactic acid fermentation of legume seed sprouts as a method of increasing the content of isoflavones and reducing microbial contamination

•The content of isoflavones in four species of legume seeds increased during sprouting.•During lactic acid fermentation of pulses, the content of phytoestrogens increases.•Fermented sprouts of pulses are dominated by aglycones of isoflavones over glycosides. Legume seeds and sprouts are a rich source of phytoestrogens in the form of isoflavonoids. For the first time, lactic acid fermentation of four types of legume sprouts was used to increase the content of isoflavonoids and microbiological safety. After germination, the highest content of isoflavonoids was observed in the clover and chickpea sprouts, which amounted to 1.1 g/100 g dw., whereas the lactic acid fermentation allowed the increase to as much as 5.5 g/100 g dw. The most beneficial properties were shown by fermented chickpea sprouts germinated in blue light. During fermentation the number of lactic acid bacteria increased by 2 Log10 CFU/mL (LU), whereas mold decreased by 1 LU, E. coli and Klebsiella sp. by 2 LU, Salmonella sp. and Shigella sp. did not occur after fermentation, similar to Staphylococcus epidermidis, while S. aureus and S. saprophyticus decreased by 3 LU and in some trials were not detected.