Abstract:
Bacterial fermentation is considered to be a cost-effective means of generating desired
flavour compounds from plant-based substrates. However, the wide range of substrates present in
plants makes it challenging to understand how individual components impact on flavour volatile
organic compound (VOC) production. To simplify this, a defined medium can be used to better
understand VOCs production with regard to individual compounds. In the current study, the
VOCs produced by the lactic acid bacterium, Levilactobacillus brevis WLP672, growing in a
defined medium containing different carbon sources (either glucose (DM), fructose (DMFr) or
citrate (DMCi)) under a range of fermentation conditions (time: 0, 7, and 14 days; and
temperature: 25 and 35 °C) were assessed using proton transfer reaction time-of-flight mass
spectrometry (PTR-ToF-MS). Among the detected mass peaks (m/z), after 7 days of
fermentation, the concentrations of m/z 45.033 (t.i. acetaldehyde), m/z 49.011 (t.i. methanethiol),
and m/z 89.060 (t.i. ethyl acetate) were significantly (p < 0.05) higher in DM at 35 °C than all
other treatments at either temperature. The knowledge obtained will help to produce desirable
LAB fermentation flavour VOCs or VOC mixtures that could be used in developing plant-based
analogues with acceptable sensory properties.T8 (100% IF + VW). T1 and T2 also showed
comparable net benefits to T8 and T9. Therefore, this concluded that the combined application of
vermicompost, inorganic fertilizers, and vermiwash significantly enhances Amaranthus growth
and yield, compared to control and chemical fertilizers alone highlighting the potential of
integrated nutrient management for sustainable agriculture.
