Evaluating the effect of lactic acid bacterial fermentation on salted soy whey for development of a potential novel soy sauce-like condiment.

There were two main objectives of this study: (1) to understand the effect of salt concentration on the growth of four lactic acid bacteria (LAB) in soy whey and determine the non-volatile and volatile profiles generated after fermentation; (2) to evaluate the potential of using salted soy whey to develop a sauce-like condiment through LAB fermentation. The four LAB included non-halophilic ML Prime, PCC, Enoferm Beta and halophilic DSM20337. At 2% salt, all LAB grew remarkably from day 0 to day 1, except for , while at 6% salt, the growth of , and was suppressed. Conversely, the higher salt concentration enhanced the growth of . in soy whey as the cell count only increased from 6.36 to 6.60 log CFU/mL at 2% salt but it elevated from 6.61 to 7.55 log CFU/mL at 6% salt. Similarly, the higher salt content negatively affected the sugar and amino acids metabolism and organic acids production by non-halophilic LAB. and generated significantly ( < 0.05) more lactic acid (3.83 g/L and 4.17 g/L, respectively) than and (2.02 g/L and 0 g/L, respectively) at 2% salt. In contrast, a higher amount of acetic acid was generated by (0.72 g/L at 2% salt) and (0.51 g/L at 6% salt). LAB could remove the green and beany off-flavours in soy whey by metabolizing C6 and C7 aldehydes. However, to develop a novel soy sauce-like condiment, yeast fermentation and Maillard reaction may be required to generate more characteristic soy sauce-associated aroma compounds.