Aunsbjerg, Stina Dissing5; Honoré, Anders Hans6; Marcussen, J.4; Ebrahimi, Parvaneh7; Vogensen, Finn Kvist5; Benfeldt, C.4; Skov, Thomas7; Knøchel, Susanne5
1 Microbiology and Fermentation, Department of Food Science, Faculty of Science, Københavns Universitet2 Chemometrics and Analytical Technology, Department of Food Science, Faculty of Science, Københavns Universitet3 Quality & Technology, Department of Food Science, Faculty of Life Sciences, Københavns Universitet4 DuPont (Biz)5 Microbiology and Fermentation, Department of Food Science, Faculty of Science, Københavns Universitet6 Quality & Technology, Department of Food Science, Faculty of Life Sciences, Københavns Universitet7 Chemometrics and Analytical Technology, Department of Food Science, Faculty of Science, Københavns Universitet
Lactic acid bacteria with antifungal properties can be used to control spoilage of food and feed. Previously, most of the identified metabolites have been isolated from cell-free fermentate of lactic acid bacteria with methods suboptimal for detecting possible contribution from volatiles to the antifungal activity. The role of volatile compounds in the antifungal activity of Lactobacillus paracasei DGCC 2132 in a chemically defined interaction medium (CDIM) and yogurt was therefore investigated with a sampling technique minimizing volatile loss. Diacetyl was identified as the major volatile produced by L. paracasei DGCC 2132 in CDIM. When the strain was added to a yogurt medium diacetyl as well as other volatiles also increased but the metabolome was more complex. Removal of L. paracasei DGCC 2132 cells from CDIM fermentate resulted in loss of both volatiles, including diacetyl, and the antifungal activity towards two strains of Penicillium spp. When adding diacetyl to CDIM or yogurt without L. paracasei DGCC 2132, marked inhibition was observed. Besides diacetyl, the antifungal properties of acetoin were examined, but no antifungal activity was observed. Overall, the results demonstrate the contribution of diacetyl in the antifungal effect of L. paracasei DGCC 2132 and indicate that the importance of volatiles may have been previously underestimated.
International Journal of Food Microbiology, 2015, Vol 194, p. 46-53