title: Evaluation of growth, metabolism and production of potentially bioactive components during fermentation of barley with Lactobacillus reuteri.
abstract: Eighteen bacterial isolates from millet, buckwheat and rye flour were identified as Lactobacillus reuteri. Genomic fingerprinting (rep-PCR) revealed that they represented five strains and phylogenetic analyses using multi locus sequence analysis (MLSA) showed that all clustered with strains of rodent origin. Two strains (SU12-3 and SU18-3) from different phylogenetic clades were used in fermentations of six varieties of barley, both untreated and heat-treated (with inactivated indigenous enzymes) flour. They were compared with two probiotic strains of human origin (DSM 17938 and ATCC PTA 6475), one previously isolated sourdough strain (LTH 5531) and one strain of Lactobacillus plantarum (36E). Analyses of growth (CFU) and metabolism (1H-NMR) revealed differences at species level, with L. plantarum showing a higher capacity to assimilate nutrients without help of the cereal enzymes. Similarities were observed between L. reuteri strains isolated from sourdough, while the greatest differences between L. reuteri strains were observed between strains 6475 and 17938. Multivariate analysis of the metabolic profiles revealed clear clustering according to flour treatment, species of bacteria and barley variety and to some extent also bacterial strain. Possible bioactive compounds such as γ-aminobutyric acid (GABA), 1,3- propanediol (sign of reuterin production) and histamine were identified and quantified.
authors.affiliation: Department of Microbiology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Box 7025, SE 750 07, Uppsala, Sweden. Electronic address: anton.pallin@slu.se.
authors.forename: Anton
authors.initials: A
authors.lastname: Pallin
authors.affiliation: Department of Chemistry and Biotechnology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Box 7015, SE 750 07, Uppsala, Sweden. Electronic address: peter.agback@slu.se.
authors.forename: Peter
authors.initials: P
authors.lastname: Agback
authors.affiliation: Department of Microbiology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Box 7025, SE 750 07, Uppsala, Sweden. Electronic address: hans.jonsson@slu.se.
authors.forename: Hans
authors.initials: H
authors.lastname: Jonsson
authors.affiliation: Department of Microbiology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Box 7025, SE 750 07, Uppsala, Sweden. Electronic address: stefan.roos@slu.se.
authors.forename: Stefan
authors.initials: S
authors.lastname: Roos
mesh_terms: D005285:Fermentation; D005433:Flour / Q000382:microbiology; D005516:Food Microbiology; D006632:Histamine / Q000032:analysis / Q000378:metabolism; D001467:Hordeum / Q000378:metabolism / Q000382:microbiology*; D052200:Limosilactobacillus reuteri / Q000737:chemistry / Q000254:growth & development* / Q000378:metabolism*; D011409:Propylene Glycols / Q000032:analysis / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000032:analysis / Q000378:metabolism
chemical_list: D011409:Propylene Glycols; D005680:gamma-Aminobutyric Acid; C041787:1,3-propanediol; D006632:Histamine
keywords: 1H-NMR; Barley; Bioactive compounds; Fermented cereals; Lactobacillus reuteri