Volatile formation by combined cultures of yeast and homofermentative or heterofermentative lactobacilli in plant-based fermented foods.

Despite increasing interest of consumers in plant-based products, sales of the latter have been subtly decreasing mainly due to organoleptic challenges. Fermentation offers a sustainable option for improving flavour production in plant-based products. Yeast and lactobacilli are common food fermenting microbes, but a proper understanding of the interactions between the two microorganisms during flavour formation is lacking. This study explored the impact of a co-cultures of yeast and lactobacilli on aroma formation during fermentation of wheat and pulse-based food systems. Volatile analysis using HS-SPME GC-MS revealed that homofermentative lactobacilli produced diacetyl in both substrates and under all conditions. In the pulse-based samples, ferulic acid was converted to 4-vinylguaiacol only when Cp. paralimentarius and S. cerevisiae were used together. Additionally, heterofermentative lactobacilli reduced lipid oxidation aldehydes to the corresponding alcohols, and this was found to be a key element for increased ester formation by the yeast across all substrates.