A discovery-based metabolomic approach using UHPLC Q-TOF MS/MS unveils a plethora of prospective antihypertensive compounds in Korean fermented soybeans

Abstract

Treating soybean with proteases and subsequent fermentation increases the release of bioactive compounds that may be strongly attached to the food matrix. In our quest to choose the best material to develop an antihypertensive functional food from soybean, we assessed the ability of raw soybean, Prozyme 2000p-hydrolyzed soybean (PSB) and Enterococcus faecium EBD1-fermented PSB to inhibit angiotensin converting enzyme (ACE). Treating soybean with Prozyme 2000p increased the ACE inhibitory ability from 15 ± 3% to 40 ± 2%. Subsequent fermentation of the hydrolyzed samples further increased the inhibitory ability to 80 ± 5%. A discovery-based metabolomic approach using UHPLC Q-TOF MS/MS of the fermented sample showed that E. faecium fermentation increased the levels of phenolic compounds, gamma aminobutyric acid, antioxidant and antihypertensive peptides. The fermentation also increased the levels of essential amino acids relative to the enzyme treated and raw samples. The high levels of potential antihypertensive compounds in the fermented samples imply that fermenting Prozyme-treated soybean with Enterococcus faecium EBD1 would be a good strategy for developing functional foods with antihypertensive properties.