Year: 2015
Type: dissertation
Abstract: Fermentation of foodstuffs has beneficial effects on shelf life, taste and texture and \npossibly also health of the consumer. Products containing microbes with beneficial \nhealth effects for the host are defined as probiotics. One probiotic bacterium, \nLactobacillus reuteri, has been shown to exert positive effects on a number of diseases \nand disorders, including a possible protective role against increased intestinal \npermeability or ‘leaky gut’. Increased intestinal permeability has been linked to e.g. \ninflammatory bowel disease (IBD), irritable bowel disease (IBS), coeliac disease and \ninfectious diarrhoea. This study examined the effect of different cereal substrates on the \ngrowth, general metabolism and production of potential bioactive compounds by L. \nreuteri, with the aim of establishing a synbiotic formulation effective against increased \nintestinal permeability. Combinations of six barley varieties and six strains of bacteria \nwere evaluated using standard plate counts, chemical analysis (1H-NMR) and a small \nintestinal epithelial cell model (IPEC-J2). The overall growth of L. reuteri in barley \nflour was good and reached higher densities in untreated compared with heat-treated \nflours. Differences in growth were also seen between bacterial strains and barley \nvarieties. The general metabolism was similar for all strains with a few exceptions, e.g. \nlower production of succinate from L. reuteri DSM 17938. Two potentially bioactive \ncompounds, γ-aminobutyric acid (GABA) and 3-hydroxypropionic acid (reuterin), were \ndetected in barley fermented by L. reuteri. GABA was present in unfermented flour at \nsimilar levels as in the fermented counterpart, indicating no or low production by L. \nreuteri. Reuterin production was detected as formation of 1,3-propanediol and was \nstrain-specific, being present in fermentation with DSM 17938 and ATCC PTA 6475. \nExperiments with IPEC-J2 cells revealed an increase in epithelial permeability caused \nby untreated flour, both fermented and unfermented. Treatment with heat-treated flour \nhad a slight increasing effect on permeability, but recovered over time. Pre-treatments \nwith live bacteria or fermented heat-treated flour before challenge with enterotoxigenic \nE. coli revealed significantly lower leakage of a molecular probe (FITC-dextran, 4 \nkDa). However, neither live bacteria nor their metabolites had a protective effect on \nepithelial permeability, measured as transepithelial electrical resistance (TEER).
Author: Anton Pallin
Language: English
Subfield: Food Science
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W393863043