title: Contribution of volatiles to the antifungal effect of Lactobacillus paracasei in defined medium and yogurt.
abstract: 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.
authors.affiliation: Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg C, Denmark.
authors.forename: S D
authors.initials: SD
authors.lastname: Aunsbjerg
authors.affiliation: Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg C, Denmark; DuPont Nutrition Biosciences ApS, Edwin Rahrs Vej 38, 8220 Brabrand, Denmark.
authors.forename: A H
authors.initials: AH
authors.lastname: Honoré
authors.affiliation: DuPont Nutrition Biosciences ApS, Edwin Rahrs Vej 38, 8220 Brabrand, Denmark.
authors.forename: J
authors.initials: J
authors.lastname: Marcussen
authors.affiliation: Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg C, Denmark.
authors.forename: P
authors.initials: P
authors.lastname: Ebrahimi
authors.affiliation: Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg C, Denmark.
authors.forename: F K
authors.initials: FK
authors.lastname: Vogensen
authors.affiliation: DuPont Nutrition Biosciences ApS, Edwin Rahrs Vej 38, 8220 Brabrand, Denmark.
authors.forename: C
authors.initials: C
authors.lastname: Benfeldt
authors.affiliation: Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg C, Denmark.
authors.forename: T
authors.initials: T
authors.lastname: Skov
authors.affiliation: Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg C, Denmark. Electronic address: skn@food.ku.dk.
authors.forename: S
authors.initials: S
authors.lastname: Knøchel
mesh_terms: D000093:Acetoin / Q000494:pharmacology; D000935:Antifungal Agents / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D003470:Culture Media; D003931:Diacetyl / Q000378:metabolism / Q000494:pharmacology; D005516:Food Microbiology; D007778:Lactobacillus / Q000737:chemistry* / Q000378:metabolism; D010407:Penicillium / Q000187:drug effects; D015014:Yogurt / Q000382:microbiology*
chemical_list: D000935:Antifungal Agents; D003470:Culture Media; D000093:Acetoin; D003931:Diacetyl
keywords: Antifungal; Diacetyl; GC–MS; Lactobacillus; Molds; Volatiles