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RESEARCH PRODUCT

Effect of Microbial strains on Hexanal

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The positive effects of plant-based protein consumption have been reported, nonetheless, several disadvantages suchgrassy or beany off-flavors are encountered (1) and are limiting the consumers acceptance towards these proteins.In this project, we investigated the potential of selected microorganisms to metabolize compounds responsible forthe leguminous off-flavor. Hexanal, well-known as a main contributor to the beany descriptor (2), was chosen for thisstudy.A selection of 16 strains representative of different fermentative types has been used to treat a liquid model matrixcontaining hexanal at 2 mg/L. The strains were applied on the medium at the end of their growing phase. Theinoculum was between 10α and 10α UFC/mL depending on the microorganism. The amounts of hexanal and hexanolat the end of the fermentation were determined using HS-SPME-GC-MS.Hexanal was reduced by all the strains but at different levels, and different amounts of hexanol were produced.Results were discussed regarding the different metabolic pathways of the strains with particular attention to thealcohol dehydrogenase, responsible for the conversion of hexanal into hexanol (3,4,5,6,7). Strains presentingconstitutive alcohol dehydrogenase in their catabolism, like obligatory heterofermentative lactic acid bacteria oracetic acid bacteria, were particularly efficient for the reduction of hexanal.1 Rackis, J. J. et al. (1979). JAOCS, 56, 262-271.2 Warner, K. et al. (1978). JAOCS, 55, 252-256.3 Caplice, E. and Fitzgerald, G. F. (1999). Int. J. Food Microbiol., 50(1-2), 131-149.4 Garrigues, C. et al. (1997). J. Bacteriol., 179 :6, 5282-5287.5 Faria-Oliveira, F. et al. (2013). Food Industry, Intech, 23, 519-547.6 Cruz Ramos, H. et al. (2000). J. Bacteriol., 182(11), 3072-3080.7 Lynch, K. M. et al. (2019). Compr. Rev. Food Sci. Food Saf., 18(3), 587-625.