Abstract:
Lactic acid bacteria (LAB) fermentation is a viable approach for producing plant-
based flavour compounds; however, little is understood about the impact of different LAB strains
and medium compositions on the production of volatile organic compounds (VOCs). This study
investigated the impact of the addition of individual amino acids (AAs) (L-leucine, L-isoleucine,
L-phenylalanine, L-glutamic acid, L-aspartic acid, L-threonine, or L-methionine) to a defined
medium (DM) on the generation of VOCs (after 0, 7, and 14 days) by one of three LAB strains
(Levilactobacillus brevis WLP672 (LB672), Lactiplantibacillus plantarum LP100 (LP100),
and Pediococcus pentosaceus PP100 (PP100)), using proton transfer reaction-time of flight-mass
spectrometry (PTR-ToF-MS). The concentration of m/z 45.031 (t.i. acetaldehyde) was
significantly (p < 0.05) higher after 7 days of fermentation by LP100 in the DM supplemented
with threonine compared to all other media fermented by all three strains. The concentrations
of m/z 49.012 (t.i. methanethiol) and m/z 95.000 (t.i. dimethyl disulfide) were significantly (p <
0.05) higher after 7 days of fermentation by either LP100, PP100, or LB672 in the DM
supplemented with methionine compared to all other media. Information on the role of individual
AAs on VOCs generation by different LAB strains will help to guide flavour development from
the fermentation of plant-based substrates.
