title: Rye bran as fermentation matrix boosts in situ dextran production by Weissella confusa compared to wheat bran.
abstract: The consumption of fiber-rich foods such as cereal bran is highly recommended due to its beneficial health effects. Pre-fermentation of bran with lactic acid bacteria can be used to improve the otherwise impaired flavor and textural qualities of bran-rich products. These positive effects are attributed to enzymatic modification of bran components and the production of functional metabolites like organic acids and exopolysaccharides such as dextrans. The aim of this study was to investigate dextran production in wheat and rye bran by fermentation with two Weissella confusa strains. Bran raw materials were analyzed for their chemical compositions and mineral content. Microbial growth and acidification kinetics were determined from the fermentations. Both strains produced more dextran in rye bran in which the fermentation-induced acidification was slower and the acidification lag phase longer than in wheat bran. Higher dextran production in rye bran is expected to be due to the longer period of optimal pH for dextran synthesis during fermentation. The starch content of wheat bran was higher, which may promote isomaltooligosaccharide formation at the expense of dextran production. W. confusa Cab3 produced slightly higher amounts of dextran than W. confusa VTT E-90392 in all raw materials. Fermentation with W. confusa Cab3 also resulted in lower residual fructose content which has technological relevance. The results indicate that wheat and particularly rye bran are promising matrices for producing technologically significant amounts of dextran, which facilitates the use of nutritionally valuable raw bran in food applications.
authors.affiliation: VTT Technical Research Centre of Finland Ltd., FI-Tietotie 2, FI-02044, Espoo, Finland. ilkka.kajala@vtt.fi.
authors.forename: Ilkka
authors.identifier: http://orcid.org/0000-0002-0940-9342
authors.initials: I
authors.lastname: Kajala
authors.affiliation: Department of Food and Environmental Sciences, University of Helsinki, P.O. Box 66, FI-00014, Helsinki, Finland.
authors.forename: Jari
authors.initials: J
authors.lastname: Mäkelä
authors.affiliation: Department of Food and Environmental Sciences, University of Helsinki, P.O. Box 66, FI-00014, Helsinki, Finland.
authors.forename: Rossana
authors.initials: R
authors.lastname: Coda
authors.affiliation: Department of Biotechnology, Indian Institute of Technology Guwahati, 781 039, Assam, India.
authors.forename: Shraddha
authors.initials: S
authors.lastname: Shukla
authors.affiliation: Department of Food and Environmental Sciences, University of Helsinki, P.O. Box 66, FI-00014, Helsinki, Finland.
authors.forename: Qiao
authors.initials: Q
authors.lastname: Shi
authors.affiliation: Department of Food and Environmental Sciences, University of Helsinki, P.O. Box 66, FI-00014, Helsinki, Finland.
authors.forename: Ndegwa Henry
authors.initials: NH
authors.lastname: Maina
authors.affiliation: VTT Technical Research Centre of Finland Ltd., FI-Tietotie 2, FI-02044, Espoo, Finland.
authors.forename: Riikka
authors.initials: R
authors.lastname: Juvonen
authors.affiliation: Department of Food and Environmental Sciences, University of Helsinki, P.O. Box 66, FI-00014, Helsinki, Finland.
authors.forename: Päivi
authors.initials: P
authors.lastname: Ekholm
authors.affiliation: Department of Biotechnology, Indian Institute of Technology Guwahati, 781 039, Assam, India.
authors.forename: Arun
authors.initials: A
authors.lastname: Goyal
authors.affiliation: Department of Food and Environmental Sciences, University of Helsinki, P.O. Box 66, FI-00014, Helsinki, Finland.
authors.forename: Maija
authors.initials: M
authors.lastname: Tenkanen
authors.affiliation: Department of Food and Environmental Sciences, University of Helsinki, P.O. Box 66, FI-00014, Helsinki, Finland.
authors.forename: Kati
authors.initials: K
authors.lastname: Katina
mesh_terms: D003470:Culture Media / Q000378:metabolism; D003911:Dextrans / Q000096:biosynthesis*; D004043:Dietary Fiber / Q000378:metabolism* / Q000382:microbiology; D005285:Fermentation; D012434:Secale / Q000378:metabolism* / Q000382:microbiology; D014908:Triticum / Q000378:metabolism* / Q000382:microbiology; D058836:Weissella / Q000378:metabolism*
chemical_list: D003470:Culture Media; D003911:Dextrans; D004043:Dietary Fiber
keywords: Bran; Dextran; Exopolysaccharide; Fermentation; Weissella